HV dc/dc...

[server]

On Fri, 17 Jul 2020 09:49:16 -0700, jlarkin@highlandsniptechnology.com
wrote:

I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides.

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.

Here is the companion micropower 150-volt regulator.

I\'ll probably include a voltage-set trimpot, for a couple of reasons.

Version 4
SHEET 1 1052 680
WIRE -400 -176 -480 -176
WIRE -352 -176 -400 -176
WIRE -160 -176 -272 -176
WIRE 16 -176 -64 -176
WIRE 160 -176 96 -176
WIRE 256 -176 160 -176
WIRE 352 -176 256 -176
WIRE 352 -112 352 -176
WIRE -480 -80 -480 -176
WIRE -80 -48 -80 -128
WIRE 16 -48 -80 -48
WIRE 160 -48 160 -176
WIRE 160 -48 96 -48
WIRE 160 -16 160 -48
WIRE 352 0 352 -48
WIRE -480 32 -480 0
WIRE -80 48 -80 -48
WIRE 160 96 160 64
WIRE 160 96 -16 96
WIRE 160 160 160 96
WIRE -80 192 -80 144
WIRE -80 304 -80 256
WIRE 160 304 160 240
FLAG 160 304 0
FLAG -480 32 0
FLAG -80 304 0
FLAG 352 0 0
FLAG -400 -176 Vin
FLAG 256 -176 Vreg
SYMBOL nmos -160 -128 R270
WINDOW 0 -9 -48 VRight 2
WINDOW 3 -41 -75 VRight 2
SYMATTR InstName M1
SYMATTR Value LND250
SYMBOL res 144 144 R0
WINDOW 0 -67 39 Left 2
WINDOW 3 -86 73 Left 2
SYMATTR InstName R1
SYMATTR Value 450k
SYMBOL voltage -480 -96 R0
WINDOW 0 60 70 Left 2
WINDOW 3 32 109 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 200 1m 20m 0 1)
SYMBOL res 112 -64 R90
WINDOW 0 74 56 VBottom 2
WINDOW 3 82 57 VTop 2
SYMATTR InstName R3
SYMATTR Value 100K
SYMBOL npn -16 48 M0
WINDOW 0 107 21 Left 2
WINDOW 3 82 53 Left 2
SYMATTR InstName Q1
SYMATTR Value 2N5550
SYMBOL res 144 -32 R0
WINDOW 0 66 35 Left 2
WINDOW 3 63 69 Left 2
SYMATTR InstName R4
SYMATTR Value 5e6
SYMBOL cap 336 -112 R0
WINDOW 0 -53 23 Left 2
WINDOW 3 -56 56 Left 2
SYMATTR InstName C1
SYMATTR Value 50n
SYMBOL zener -64 256 R180
WINDOW 0 69 41 Left 2
WINDOW 3 56 6 Left 2
SYMATTR InstName D1
SYMATTR Value BZX84B12VL
SYMBOL res -368 -160 R270
WINDOW 0 -35 56 VTop 2
WINDOW 3 -41 56 VBottom 2
SYMATTR InstName R2
SYMATTR Value 1
SYMBOL res 0 -160 R270
WINDOW 0 -35 56 VTop 2
WINDOW 3 -41 56 VBottom 2
SYMATTR InstName R5
SYMATTR Value 20K
TEXT -462 216 Left 2 !.tran 250m
TEXT -480 128 Left 2 ;150V Regulator
TEXT -480 176 Left 2 ;JL Jul 19 2020
TEXT -184 136 Left 2 ;FCX458
TEXT -216 288 Left 2 ;MAZ3120
TEXT 232 112 Left 2 !.MODEL LND250 NMOS (LEVEL=3 RS=150.00
NSUB=5.0E13 \\n+DELTA=0.1 KAPPA=1.O TPG=1 CGDO=2.1716E-12
\\n+RD=40.0 VTO=-2.0 VMAX=1.0E8 ETA=0.1 \\n+NFS=6.6E10
TOX=1.0E-7 LD=1.698E-9 UO=862.425\\n+XJ=6.4666E-7 THETA=1.0E-5
CGSO=5.09E-10 L=10.0E-6\\n+W=600E-6) \\n.ENDS



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Klaus Kragelund]

On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:

On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides.

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter

Isn’t it more that Baxandall copyed and minimally improved on the 1954 Royer converter?

About the Baxandall, has anyone ever used it for commercial product, or is it like for example the Cuk converter and other “Novel” PhD topologies that is really only good on paper?

I agree that custom magnetics rules. For a volume above 50k you gain a competitive advantage that designs using ready made components fails to have. In my career I have only used ready made for a converter a couple of times (not counting buck converters)

Cheers

Klaus

 

[Klaus Kragelund]

On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:

On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides.

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter

Isn’t it more that Baxandall copyed and minimally improved on the 1954 Royer converter?

About the Baxandall, has anyone ever used it for commercial product, or is it like for example the Cuk converter and other “Novel” PhD topologies that is really only good on paper?

I agree that custom magnetics rules. For a volume above 50k you gain a competitive advantage that designs using ready made components fails to have. In my career I have only used ready made for a converter a couple of times (not counting buck converters)

Cheers

Klaus

 

[Bill Sloman]

On Monday, July 20, 2020 at 3:57:28 PM UTC+10, Klaus Kragelund wrote:

On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:
On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants..com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides..

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter.

The story I heard was that the Linear Technology reps in the UK were asking after high-voltage inverters and got the circuit diagram for a Baxandall class-D oscillator based device.

> Isn’t it more that Baxandall copied and minimally improved on the 1954 Royer converter?

Probably not. He was working in the UK and the Royer paper was in a US trade publication - it doesn\'t show up in the literature cited in his paper.

The inductor on the centre-tap is major difference from the Royer inverter, and produces very different behavior.

> About the Baxandall, has anyone ever used it for commercial product, or is it like for example the Cuk converter and other “Novel” PhD topologies that is really only good on paper?

The link to the Linear Technology application notes AN45, AN49, AN51, AN55, AN61, AN65 answers that question. Laptops with cold-cathode back lighting used it in droves.

I\'ve put it into two products. The GaAs crystal-puller that was making 95% of the single-crystal GaAs crystals in the west in the late 1980\'s isn\'t a mass market item, but it got retrofitted with my variation after 1987. It seemed to work rather better than the original oscillator (which had used parts that had gone obsolete by then).

> I agree that custom magnetics rules. For a volume above 50k you gain a competitive advantage that designs using ready made components fails to have. In my career I have only used ready made for a converter a couple of times (not counting buck converters)

I mostly worked on stuff that sold at the 10 to 100 per year level - the GaAs crystal puller was on the low end of that. If you need the performance custom magnetics can sometimes be the only way to get it.

--
Bill Sloman, Sydney

 

[Bill Sloman]

On Monday, July 20, 2020 at 3:57:28 PM UTC+10, Klaus Kragelund wrote:

On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:
On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants..com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides..

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter.

The story I heard was that the Linear Technology reps in the UK were asking after high-voltage inverters and got the circuit diagram for a Baxandall class-D oscillator based device.

> Isn’t it more that Baxandall copied and minimally improved on the 1954 Royer converter?

Probably not. He was working in the UK and the Royer paper was in a US trade publication - it doesn\'t show up in the literature cited in his paper.

The inductor on the centre-tap is major difference from the Royer inverter, and produces very different behavior.

> About the Baxandall, has anyone ever used it for commercial product, or is it like for example the Cuk converter and other “Novel” PhD topologies that is really only good on paper?

The link to the Linear Technology application notes AN45, AN49, AN51, AN55, AN61, AN65 answers that question. Laptops with cold-cathode back lighting used it in droves.

I\'ve put it into two products. The GaAs crystal-puller that was making 95% of the single-crystal GaAs crystals in the west in the late 1980\'s isn\'t a mass market item, but it got retrofitted with my variation after 1987. It seemed to work rather better than the original oscillator (which had used parts that had gone obsolete by then).

> I agree that custom magnetics rules. For a volume above 50k you gain a competitive advantage that designs using ready made components fails to have. In my career I have only used ready made for a converter a couple of times (not counting buck converters)

I mostly worked on stuff that sold at the 10 to 100 per year level - the GaAs crystal puller was on the low end of that. If you need the performance custom magnetics can sometimes be the only way to get it.

--
Bill Sloman, Sydney

 

[server]

This is a better regulator. The only hitch might be low-current zener
noise, which I\'ll check.

Tempco is OK but not impressive.


Version 4
SHEET 1 1052 680
WIRE -400 -176 -480 -176
WIRE -352 -176 -400 -176
WIRE -160 -176 -272 -176
WIRE 16 -176 -64 -176
WIRE 160 -176 96 -176
WIRE 256 -176 160 -176
WIRE 352 -176 256 -176
WIRE 352 -112 352 -176
WIRE -480 -80 -480 -176
WIRE -80 -48 -80 -128
WIRE 16 -48 -80 -48
WIRE 160 -48 160 -176
WIRE 160 -48 96 -48
WIRE 160 -16 160 -48
WIRE 352 0 352 -48
WIRE -480 32 -480 0
WIRE 160 96 160 64
WIRE 352 112 352 80
WIRE -80 128 -80 -48
WIRE 160 208 160 160
WIRE 160 208 -32 208
WIRE 160 240 160 208
WIRE -80 272 -80 224
WIRE -80 384 -80 336
WIRE 160 384 160 320
FLAG 160 384 0
FLAG -480 32 0
FLAG -80 384 0
FLAG 352 112 0
FLAG -400 -176 Vin
FLAG 256 -176 Vreg
SYMBOL nmos -160 -128 R270
WINDOW 0 -9 -48 VRight 2
WINDOW 3 -41 -75 VRight 2
SYMATTR InstName M1
SYMATTR Value LND250
SYMBOL res 144 224 R0
WINDOW 0 -67 39 Left 2
WINDOW 3 -86 73 Left 2
SYMATTR InstName R1
SYMATTR Value 475k
SYMBOL voltage -480 -96 R0
WINDOW 0 60 70 Left 2
WINDOW 3 32 109 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 200 1m 20m 0 1)
SYMBOL res 112 -64 R90
WINDOW 0 74 56 VBottom 2
WINDOW 3 82 57 VTop 2
SYMATTR InstName R3
SYMATTR Value 100K
SYMBOL res 144 -32 R0
WINDOW 0 66 35 Left 2
WINDOW 3 63 69 Left 2
SYMATTR InstName R4
SYMATTR Value 5e6
SYMBOL cap 336 -112 R0
WINDOW 0 -53 23 Left 2
WINDOW 3 -56 56 Left 2
SYMATTR InstName C1
SYMATTR Value 50n
SYMBOL zener -64 336 R180
WINDOW 0 69 41 Left 2
WINDOW 3 56 6 Left 2
SYMATTR InstName D1
SYMATTR Value BZX84B15VL
SYMBOL res -368 -160 R270
WINDOW 0 -35 56 VTop 2
WINDOW 3 -41 56 VBottom 2
SYMATTR InstName R2
SYMATTR Value 1
SYMBOL res 0 -160 R270
WINDOW 0 -35 56 VTop 2
WINDOW 3 -41 56 VBottom 2
SYMATTR InstName R5
SYMATTR Value 20K
SYMBOL nmos -32 128 M0
WINDOW 0 85 28 Left 2
WINDOW 3 71 63 Left 2
SYMATTR InstName M2
SYMATTR Value LND250
SYMBOL LED 144 96 R0
WINDOW 0 -64 13 Left 2
WINDOW 3 -144 46 Left 2
SYMATTR InstName D2
SYMATTR Value LUW-W5AP
SYMBOL voltage 352 -16 R0
WINDOW 0 60 70 Left 2
WINDOW 3 32 109 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 -10 200m 0 0 1)
TEXT -464 216 Left 2 !.tran 250m
TEXT -480 128 Left 2 ;150V Regulator
TEXT -480 176 Left 2 ;JL Jul 20 2020
TEXT -216 368 Left 2 ;MAZ3120
TEXT 264 208 Left 2 !.MODEL LND250 NMOS (LEVEL=3 RS=150.00
NSUB=5.0E13 \\n+DELTA=0.1 KAPPA=1.O TPG=1 CGDO=2.1716E-12
\\n+RD=40.0 VTO=-2.0 VMAX=1.0E8 ETA=0.1 \\n+NFS=6.6E10
TOX=1.0E-7 LD=1.698E-9 UO=862.425\\n+XJ=6.4666E-7 THETA=1.0E-5
CGSO=5.09E-10 L=10.0E-6\\n+W=600E-6) \\n.ENDS
TEXT -496 264 Left 2 !.step temp 0 50 25





--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[server]

This is a better regulator. The only hitch might be low-current zener
noise, which I\'ll check.

Tempco is OK but not impressive.


Version 4
SHEET 1 1052 680
WIRE -400 -176 -480 -176
WIRE -352 -176 -400 -176
WIRE -160 -176 -272 -176
WIRE 16 -176 -64 -176
WIRE 160 -176 96 -176
WIRE 256 -176 160 -176
WIRE 352 -176 256 -176
WIRE 352 -112 352 -176
WIRE -480 -80 -480 -176
WIRE -80 -48 -80 -128
WIRE 16 -48 -80 -48
WIRE 160 -48 160 -176
WIRE 160 -48 96 -48
WIRE 160 -16 160 -48
WIRE 352 0 352 -48
WIRE -480 32 -480 0
WIRE 160 96 160 64
WIRE 352 112 352 80
WIRE -80 128 -80 -48
WIRE 160 208 160 160
WIRE 160 208 -32 208
WIRE 160 240 160 208
WIRE -80 272 -80 224
WIRE -80 384 -80 336
WIRE 160 384 160 320
FLAG 160 384 0
FLAG -480 32 0
FLAG -80 384 0
FLAG 352 112 0
FLAG -400 -176 Vin
FLAG 256 -176 Vreg
SYMBOL nmos -160 -128 R270
WINDOW 0 -9 -48 VRight 2
WINDOW 3 -41 -75 VRight 2
SYMATTR InstName M1
SYMATTR Value LND250
SYMBOL res 144 224 R0
WINDOW 0 -67 39 Left 2
WINDOW 3 -86 73 Left 2
SYMATTR InstName R1
SYMATTR Value 475k
SYMBOL voltage -480 -96 R0
WINDOW 0 60 70 Left 2
WINDOW 3 32 109 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 200 1m 20m 0 1)
SYMBOL res 112 -64 R90
WINDOW 0 74 56 VBottom 2
WINDOW 3 82 57 VTop 2
SYMATTR InstName R3
SYMATTR Value 100K
SYMBOL res 144 -32 R0
WINDOW 0 66 35 Left 2
WINDOW 3 63 69 Left 2
SYMATTR InstName R4
SYMATTR Value 5e6
SYMBOL cap 336 -112 R0
WINDOW 0 -53 23 Left 2
WINDOW 3 -56 56 Left 2
SYMATTR InstName C1
SYMATTR Value 50n
SYMBOL zener -64 336 R180
WINDOW 0 69 41 Left 2
WINDOW 3 56 6 Left 2
SYMATTR InstName D1
SYMATTR Value BZX84B15VL
SYMBOL res -368 -160 R270
WINDOW 0 -35 56 VTop 2
WINDOW 3 -41 56 VBottom 2
SYMATTR InstName R2
SYMATTR Value 1
SYMBOL res 0 -160 R270
WINDOW 0 -35 56 VTop 2
WINDOW 3 -41 56 VBottom 2
SYMATTR InstName R5
SYMATTR Value 20K
SYMBOL nmos -32 128 M0
WINDOW 0 85 28 Left 2
WINDOW 3 71 63 Left 2
SYMATTR InstName M2
SYMATTR Value LND250
SYMBOL LED 144 96 R0
WINDOW 0 -64 13 Left 2
WINDOW 3 -144 46 Left 2
SYMATTR InstName D2
SYMATTR Value LUW-W5AP
SYMBOL voltage 352 -16 R0
WINDOW 0 60 70 Left 2
WINDOW 3 32 109 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(0 -10 200m 0 0 1)
TEXT -464 216 Left 2 !.tran 250m
TEXT -480 128 Left 2 ;150V Regulator
TEXT -480 176 Left 2 ;JL Jul 20 2020
TEXT -216 368 Left 2 ;MAZ3120
TEXT 264 208 Left 2 !.MODEL LND250 NMOS (LEVEL=3 RS=150.00
NSUB=5.0E13 \\n+DELTA=0.1 KAPPA=1.O TPG=1 CGDO=2.1716E-12
\\n+RD=40.0 VTO=-2.0 VMAX=1.0E8 ETA=0.1 \\n+NFS=6.6E10
TOX=1.0E-7 LD=1.698E-9 UO=862.425\\n+XJ=6.4666E-7 THETA=1.0E-5
CGSO=5.09E-10 L=10.0E-6\\n+W=600E-6) \\n.ENDS
TEXT -496 264 Left 2 !.step temp 0 50 25





--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Piotr Wyderski]

jlarkin@highlandsniptechnology.com wrote:

Sure I use custom magnetics. I\'ve posted lots of examples here. But
98% of the time, you can use standard parts, available in quantity,
cheap, overnight delivery. Or better yet, use the ones downstairs in
the stockroom.

If we exclude buck/boost inductors, the resulting statistics starts to
deviate from the given 98% value. But these standard inductors do indeed
have awfully good volumetric properties. For example, these:

https://www.bourns.com/docs/Product-Datasheets/SRP1265A.pdf

I wouldn\'t be able to make a 47uH/9.5A in the 13.5x12.5mm form factor.
The smallest would be ~15mm OD toroid. Starting at ~22mm (diameter/edge)
outperforming a standard part becomes quite simple, though.

Custom or home-made is generally needed for transmission-line
transformers, big power transformers, a few things like that. Maybe
flybacks, but if you are clever there are lots of ways to use standard
parts.

Multiple windings, high isolation voltage transformers, resonant
converters with integrated magnetic components all require a custom
part. It is good to have a big box of various ferrite and alloy
powder cores and another with all kinds of magnet wires and copper
tapes. You can have even a pretty complex part prototyped within 15-60
minutes. Once proven to work, you send the specs to your favourite coil
maker.

And this all is about linear magnetics only. I can see no way to start
prototyping a non-linear inductor or transformer without these magic boxes.
> https://www.dropbox.com/s/dgno5o0psfzu9we/L_Assy.jpg?dl=0

I like #2. What\'s the bobbin? #1 could be wound with flat wire, it is
much easier, and the cross-section area is larger for the same
prototyping effort.

Best regards, Piotr

 

[Piotr Wyderski]

jlarkin@highlandsniptechnology.com wrote:

Sure I use custom magnetics. I\'ve posted lots of examples here. But
98% of the time, you can use standard parts, available in quantity,
cheap, overnight delivery. Or better yet, use the ones downstairs in
the stockroom.

If we exclude buck/boost inductors, the resulting statistics starts to
deviate from the given 98% value. But these standard inductors do indeed
have awfully good volumetric properties. For example, these:

https://www.bourns.com/docs/Product-Datasheets/SRP1265A.pdf

I wouldn\'t be able to make a 47uH/9.5A in the 13.5x12.5mm form factor.
The smallest would be ~15mm OD toroid. Starting at ~22mm (diameter/edge)
outperforming a standard part becomes quite simple, though.

Custom or home-made is generally needed for transmission-line
transformers, big power transformers, a few things like that. Maybe
flybacks, but if you are clever there are lots of ways to use standard
parts.

Multiple windings, high isolation voltage transformers, resonant
converters with integrated magnetic components all require a custom
part. It is good to have a big box of various ferrite and alloy
powder cores and another with all kinds of magnet wires and copper
tapes. You can have even a pretty complex part prototyped within 15-60
minutes. Once proven to work, you send the specs to your favourite coil
maker.

And this all is about linear magnetics only. I can see no way to start
prototyping a non-linear inductor or transformer without these magic boxes.
> https://www.dropbox.com/s/dgno5o0psfzu9we/L_Assy.jpg?dl=0

I like #2. What\'s the bobbin? #1 could be wound with flat wire, it is
much easier, and the cross-section area is larger for the same
prototyping effort.

Best regards, Piotr

 

[server]

On Mon, 20 Jul 2020 16:30:30 +0200, Piotr Wyderski
<peter.pan@neverland.mil> wrote:

jlarkin@highlandsniptechnology.com wrote:

Sure I use custom magnetics. I\'ve posted lots of examples here. But
98% of the time, you can use standard parts, available in quantity,
cheap, overnight delivery. Or better yet, use the ones downstairs in
the stockroom.

If we exclude buck/boost inductors, the resulting statistics starts to
deviate from the given 98% value. But these standard inductors do indeed
have awfully good volumetric properties. For example, these:

https://www.bourns.com/docs/Product-Datasheets/SRP1265A.pdf

I wouldn\'t be able to make a 47uH/9.5A in the 13.5x12.5mm form factor.
The smallest would be ~15mm OD toroid. Starting at ~22mm (diameter/edge)
outperforming a standard part becomes quite simple, though.

I\'d breadboard any switcher that uses these tiny inductors. They might
get really hot from AC losses. Sometimes a bunch of PCB copper pour
will keep them from frying.

Given how cheap some stock parts are, and how fast a pick-and-place
slams them down, there\'s no reason to not put some in series or
parallel.

Custom or home-made is generally needed for transmission-line
transformers, big power transformers, a few things like that. Maybe
flybacks, but if you are clever there are lots of ways to use standard
parts.

Multiple windings, high isolation voltage transformers, resonant
converters with integrated magnetic components all require a custom
part. It is good to have a big box of various ferrite and alloy
powder cores and another with all kinds of magnet wires and copper
tapes. You can have even a pretty complex part prototyped within 15-60
minutes. Once proven to work, you send the specs to your favourite coil
maker.

Here\'s some magnetics.

https://www.dropbox.com/s/ifbkhomjurtoiwf/DSC05552.JPG?raw=1

The flyback transformer is a Coilcraft stock part.

And this all is about linear magnetics only. I can see no way to start
prototyping a non-linear inductor or transformer without these magic boxes.
https://www.dropbox.com/s/dgno5o0psfzu9we/L_Assy.jpg?dl=0

I like #2. What\'s the bobbin? #1 could be wound with flat wire, it is
much easier, and the cross-section area is larger for the same
prototyping effort.

Those were experiments for high-frequency sinewave oscillators. I
don\'t recall what the bobbins were; probably samples from a Lodestone
kit. I wound up using a stock part in my oscillators.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[server]

On Mon, 20 Jul 2020 16:30:30 +0200, Piotr Wyderski
<peter.pan@neverland.mil> wrote:

jlarkin@highlandsniptechnology.com wrote:

Sure I use custom magnetics. I\'ve posted lots of examples here. But
98% of the time, you can use standard parts, available in quantity,
cheap, overnight delivery. Or better yet, use the ones downstairs in
the stockroom.

If we exclude buck/boost inductors, the resulting statistics starts to
deviate from the given 98% value. But these standard inductors do indeed
have awfully good volumetric properties. For example, these:

https://www.bourns.com/docs/Product-Datasheets/SRP1265A.pdf

I wouldn\'t be able to make a 47uH/9.5A in the 13.5x12.5mm form factor.
The smallest would be ~15mm OD toroid. Starting at ~22mm (diameter/edge)
outperforming a standard part becomes quite simple, though.

I\'d breadboard any switcher that uses these tiny inductors. They might
get really hot from AC losses. Sometimes a bunch of PCB copper pour
will keep them from frying.

Given how cheap some stock parts are, and how fast a pick-and-place
slams them down, there\'s no reason to not put some in series or
parallel.

Custom or home-made is generally needed for transmission-line
transformers, big power transformers, a few things like that. Maybe
flybacks, but if you are clever there are lots of ways to use standard
parts.

Multiple windings, high isolation voltage transformers, resonant
converters with integrated magnetic components all require a custom
part. It is good to have a big box of various ferrite and alloy
powder cores and another with all kinds of magnet wires and copper
tapes. You can have even a pretty complex part prototyped within 15-60
minutes. Once proven to work, you send the specs to your favourite coil
maker.

Here\'s some magnetics.

https://www.dropbox.com/s/ifbkhomjurtoiwf/DSC05552.JPG?raw=1

The flyback transformer is a Coilcraft stock part.

And this all is about linear magnetics only. I can see no way to start
prototyping a non-linear inductor or transformer without these magic boxes.
https://www.dropbox.com/s/dgno5o0psfzu9we/L_Assy.jpg?dl=0

I like #2. What\'s the bobbin? #1 could be wound with flat wire, it is
much easier, and the cross-section area is larger for the same
prototyping effort.

Those were experiments for high-frequency sinewave oscillators. I
don\'t recall what the bobbins were; probably samples from a Lodestone
kit. I wound up using a stock part in my oscillators.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[server]

On Mon, 20 Jul 2020 16:30:30 +0200, Piotr Wyderski
<peter.pan@neverland.mil> wrote:

jlarkin@highlandsniptechnology.com wrote:

Sure I use custom magnetics. I\'ve posted lots of examples here. But
98% of the time, you can use standard parts, available in quantity,
cheap, overnight delivery. Or better yet, use the ones downstairs in
the stockroom.

If we exclude buck/boost inductors, the resulting statistics starts to
deviate from the given 98% value. But these standard inductors do indeed
have awfully good volumetric properties. For example, these:

https://www.bourns.com/docs/Product-Datasheets/SRP1265A.pdf

I wouldn\'t be able to make a 47uH/9.5A in the 13.5x12.5mm form factor.
The smallest would be ~15mm OD toroid. Starting at ~22mm (diameter/edge)
outperforming a standard part becomes quite simple, though.

I\'d breadboard any switcher that uses these tiny inductors. They might
get really hot from AC losses. Sometimes a bunch of PCB copper pour
will keep them from frying.

Given how cheap some stock parts are, and how fast a pick-and-place
slams them down, there\'s no reason to not put some in series or
parallel.

Custom or home-made is generally needed for transmission-line
transformers, big power transformers, a few things like that. Maybe
flybacks, but if you are clever there are lots of ways to use standard
parts.

Multiple windings, high isolation voltage transformers, resonant
converters with integrated magnetic components all require a custom
part. It is good to have a big box of various ferrite and alloy
powder cores and another with all kinds of magnet wires and copper
tapes. You can have even a pretty complex part prototyped within 15-60
minutes. Once proven to work, you send the specs to your favourite coil
maker.

Here\'s some magnetics.

https://www.dropbox.com/s/ifbkhomjurtoiwf/DSC05552.JPG?raw=1

The flyback transformer is a Coilcraft stock part.

And this all is about linear magnetics only. I can see no way to start
prototyping a non-linear inductor or transformer without these magic boxes.
https://www.dropbox.com/s/dgno5o0psfzu9we/L_Assy.jpg?dl=0

I like #2. What\'s the bobbin? #1 could be wound with flat wire, it is
much easier, and the cross-section area is larger for the same
prototyping effort.

Those were experiments for high-frequency sinewave oscillators. I
don\'t recall what the bobbins were; probably samples from a Lodestone
kit. I wound up using a stock part in my oscillators.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[John Larkin]

On Sun, 19 Jul 2020 11:35:01 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2020-07-19 06:57, Phil Hobbs wrote:
On 2020-07-18 22:42, jlarkin@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <news@analogconsultants.com
wrote:

On 2020-07-18 12:39, jlarkin@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <news@analogconsultants.com
wrote:


[...]

Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?

But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.


Yes, and they have limits in terms of voltage.


The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.


I also love dual-winding coils. Just make sure to vet the isolation
voltage with the manufacturer.

Some have no specs. I\'ve tested some to breakdown. One DRQ127 failed
at 2250.

The ones I\'ve used have been Royers, with open-circuit outputs over a
kilovolt (so they can strike the discharge).


They can generate 1200V or more but I never used them that high. I
either drive them with an externally driven Royer (from logic on my
board) or drive them directly from a gate driver.

Here\'s a 1400 volt opamp supply:

https://www.dropbox.com/s/6b0sg9j3t457zl5/28S840A.pdf?dl=0

 

[John Larkin]

On Sun, 19 Jul 2020 11:35:01 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2020-07-19 06:57, Phil Hobbs wrote:
On 2020-07-18 22:42, jlarkin@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <news@analogconsultants.com
wrote:

On 2020-07-18 12:39, jlarkin@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <news@analogconsultants.com
wrote:


[...]

Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?

But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.


Yes, and they have limits in terms of voltage.


The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.


I also love dual-winding coils. Just make sure to vet the isolation
voltage with the manufacturer.

Some have no specs. I\'ve tested some to breakdown. One DRQ127 failed
at 2250.

The ones I\'ve used have been Royers, with open-circuit outputs over a
kilovolt (so they can strike the discharge).


They can generate 1200V or more but I never used them that high. I
either drive them with an externally driven Royer (from logic on my
board) or drive them directly from a gate driver.

Here\'s a 1400 volt opamp supply:

https://www.dropbox.com/s/6b0sg9j3t457zl5/28S840A.pdf?dl=0

 

[Piotr Wyderski]

jlarkin@highlandsniptechnology.com wrote:

I\'d breadboard any switcher that uses these tiny inductors. They might
get really hot from AC losses. Sometimes a bunch of PCB copper pour
will keep them from frying.

A buck would happily accept any oversized inductor. Need 8uH, slam 47uH.
DCR losses would go up by a factor of 5.9 (for a constant coil volume),
AC and core losses would go down 34 times. Find an optimum somewhere in
between. This option allows for high loss magnetic materials like the
NiFe alloy powders (e.g. Hi-Flux):

https://www.mag-inc.com/Products/Powder-Cores/High-Flux-Cores

With delta_IL~3% the inductor is basically DCR-limited and there are
nice flat wires to fill the available window. Swinging chokes might be
an option too, designing them is fun. These 20uH beauties are for a 50A
buck-boost. DCR is below 2mOhms.

https://i.postimg.cc/L5PZsn7B/chokes.png

Probably would be good up to 100A, but I don\'t need that much current.

Given how cheap some stock parts are, and how fast a pick-and-place
slams them down, there\'s no reason to not put some in series or
parallel.

The inductance of uncoupled inductors connected in parallel would only
be proportional to the length of wire instead of the square of it.
This is good for one-offs or low-power applications, but otherwise you
are wasting too much power on the excessive DCR.

Best regards, Piotr

 

[Piotr Wyderski]

Piotr Wyderski wrote:

> The inductance of uncoupled inductors connected in parallel

series...

 

[Klaus Kragelund]

On Monday, July 20, 2020 at 12:59:38 PM UTC+2, Bill Sloman wrote:

On Monday, July 20, 2020 at 3:57:28 PM UTC+10, Klaus Kragelund wrote:
On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:
On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides.

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter.

The story I heard was that the Linear Technology reps in the UK were asking after high-voltage inverters and got the circuit diagram for a Baxandall class-D oscillator based device.

Isn’t it more that Baxandall copied and minimally improved on the 1954 Royer converter?

Probably not. He was working in the UK and the Royer paper was in a US trade publication - it doesn\'t show up in the literature cited in his paper.

It was a public available patent:

https://patents.google.com/patent/US2783384A/en

So, yes, seems like he ripped it off. Nothing wrong with that, except if Bandaxall didn\'t credit Royer and Bright

The inductor on the centre-tap is major difference from the Royer inverter, and produces very different behavior.

Yes, that was a clever addition

[snip]

Cheers

Klaus

 

[Klaus Kragelund]

On Monday, July 20, 2020 at 12:59:38 PM UTC+2, Bill Sloman wrote:

On Monday, July 20, 2020 at 3:57:28 PM UTC+10, Klaus Kragelund wrote:
On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:
On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides.

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter.

The story I heard was that the Linear Technology reps in the UK were asking after high-voltage inverters and got the circuit diagram for a Baxandall class-D oscillator based device.

Isn’t it more that Baxandall copied and minimally improved on the 1954 Royer converter?

Probably not. He was working in the UK and the Royer paper was in a US trade publication - it doesn\'t show up in the literature cited in his paper.

It was a public available patent:

https://patents.google.com/patent/US2783384A/en

So, yes, seems like he ripped it off. Nothing wrong with that, except if Bandaxall didn\'t credit Royer and Bright

The inductor on the centre-tap is major difference from the Royer inverter, and produces very different behavior.

Yes, that was a clever addition

[snip]

Cheers

Klaus

 

[legg]

On Sun, 19 Jul 2020 22:57:23 -0700 (PDT), Klaus Kragelund
<klauskvik@hotmail.com> wrote:

On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:
On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides.

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter

Isn’t it more that Baxandall copyed and minimally improved on the 1954 Royer converter?

About the Baxandall, has anyone ever used it for commercial product, or is it like for example the Cuk converter and other “Novel” PhD topologies that is really only good on paper?

I agree that custom magnetics rules. For a volume above 50k you gain a competitive advantage that designs using ready made components fails to have. In my career I have only used ready made for a converter a couple of times (not counting buck converters)

Cheers

Klaus

It has had commercial applications at medium power levels,
where multiple outputs or isolators are needed. I\'ve never
heard it seriously referred to as a Baxandall circuit -
it\'s just a current-fed inverter.

RL

 

[legg]

On Sun, 19 Jul 2020 22:57:23 -0700 (PDT), Klaus Kragelund
<klauskvik@hotmail.com> wrote:

On Sunday, July 19, 2020 at 5:33:42 PM UTC+3, Bill Sloman wrote:
On Sunday, July 19, 2020 at 12:42:42 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 19:31:09 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-18 12:39, jla...@highlandsniptechnology.com wrote:
On Sat, 18 Jul 2020 11:27:16 -0700, Joerg <ne...@analogconsultants.com
wrote:

On 2020-07-17 09:49, jla...@highlandsniptechnology.com wrote:


I need eight isolated 150 volt DC supplies, low current, under 1 mA
average. Commercial dc/dc converters are crazy expensive:

https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922?k=&pkeyword=&sv=0&pv183=354808&pv183=354809&pv2211=i1&pv1525=100671&pv1525=114705&pv1525=140848&pv1525=157291&pv1525=182727&sf=1&FV=-8%7C922&quantity=&ColumnSort=0&page=1&pageSize=25

I guess I\'ll have to design it. Coilcraft has some nice little flyback
transformers.

I think I can use one flyback driver circuit and put all eight
primaries in parallel. Maybe regulate a little on the high sides.

The application is eight isolated high-voltage pulse outputs. My first
idea was to use grounded drivers and final pulse transformers, but the
volt-seconds get huge so the pulse transformer would be awful. Better
to float the entire output circuit.


Mostly I used CCFL inverter transformers for that. Cheap, fairly small.
Even complete modules can be had for a few dollars:

https://www.ebay.com/itm/1Pc-CCFL-inverter-board-for-LCD-screen-with-1CCFL-backlight-LCD-JN/392849295194

$3.33 with free shipping from China. We pay for that.


Yup, they\'ll make the next aircraft carrier :-(


Or course, with everything going LED and OLED these days it\'s only a
matter of years until the available selection starts to thin out.

I won\'t use ebay or Amazon stuff in my gear. Some of my customers care
about part traceability and anti-Chinese stuff.

Some of those things, ebay and Amazon, are OK for breadboards and lab
cables and such.

One customer recently elected to buy a bunch of $40 cables from us,
when Amazon has them for $6.


It was just meant as an example. On most projects where I needed a few
hundred volts I used the bare CCFL transformers and they cost just a few
bucks. Even from US sources they are often produced abroad, sometimes in
China.

Are the CCFL supplies flybacks or Royers or something? What sorts of
open-circuit voltages do they make?
It\'s probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

From my web-site.

\"The circuit is probably best known from Jim Williams’ series of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper “Transistors as on-off switches in saturable core circuits” in Electrical Manufacturing.\"

The Baxandall inverter is handy for driving high-turns ratio step-up transformers which tend end up with rather low self-resonant frequencies.
But right, it\'s all LEDs now.

I like ISDN transformers, but they will be gone too.

The little DRQ-type dual inductors are great. The autotransformer
flyback and CW multiplier thing is cool.
The Cockroft-Walton multiplier isn\'t all that cool.

Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn\'t all that difficult.

There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn\'t easy, even if you get downright sloppy about \"close enough\".

You seem to indicate Williams ripped off the Baxandall converter

Isn’t it more that Baxandall copyed and minimally improved on the 1954 Royer converter?

About the Baxandall, has anyone ever used it for commercial product, or is it like for example the Cuk converter and other “Novel” PhD topologies that is really only good on paper?

I agree that custom magnetics rules. For a volume above 50k you gain a competitive advantage that designs using ready made components fails to have. In my career I have only used ready made for a converter a couple of times (not counting buck converters)

Cheers

Klaus

It has had commercial applications at medium power levels,
where multiple outputs or isolators are needed. I\'ve never
heard it seriously referred to as a Baxandall circuit -
it\'s just a current-fed inverter.

RL