Driver to drive?

[miso]

On 8/14/2013 8:32 AM, RobertMacy wrote:

On Wed, 14 Aug 2013 08:03:33 -0700, panfilero <panfilero@gmail.com> wrote:

Thanks for the advice, it sounds really good, one concern I have is
that it's tied too much to their design software they sell, I'd hate
to spend 4 days learning how to use a software package to design
magnetics or power supplies, I really do like the hands on aspect of it


Check out LTspice. It's free, educational, and has lots of support people.

LTSpice is brilliant marketing and engineering. The spice works well,
the schematic capture is on par with most pro software, and it seems to
be just a tad bit easier to use LT parts than the competition. But LT
makes good stuff, so that by itself isn't a drawback.

 

[Joerg]

miso wrote:

On 8/14/2013 8:53 AM, John Larkin wrote:
On Tue, 13 Aug 2013 20:38:57 -0700, miso <miso@sushi.com> wrote:


If you are using off the shelf controllers, I'm not so sure this
workshop is really needed. If you are rolling your own switchers, well
you shouldn't be.


Why not? Who wants to just copy eval boards?

And with digital power coming along, designing your own switcher may
be the new
thing.


Uh, because eval boards are designed to provide good working circuits.
Yes, a novel idea.

If you can make a product by simply copying more or less from an eval
board you might as well outsource the whole "design". It's cheaper that
way. The rubber really meets the road when the client or your marketing
folks tell you that they want it in a tube the size of this here
ballpoint pen.

You do realize a chip all by its lonesome is way more reliable than
something that uses firmware to run.

Unless the company making the chip can't deliver quantities in time.
Then the firmware solution, the discrete solution, or pretty much any
other solution is a better solution. Because it avoids the single-source
problem.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Phil Hobbs]

On 08/14/2013 01:40 PM, miso wrote:

On 8/14/2013 8:32 AM, RobertMacy wrote:
On Wed, 14 Aug 2013 08:03:33 -0700, panfilero <panfilero@gmail.com
wrote:

Thanks for the advice, it sounds really good, one concern I have is
that it's tied too much to their design software they sell, I'd hate
to spend 4 days learning how to use a software package to design
magnetics or power supplies, I really do like the hands on aspect of it


Check out LTspice. It's free, educational, and has lots of support
people.

LTSpice is brilliant marketing and engineering. The spice works well,
the schematic capture is on par with most pro software, and it seems to
be just a tad bit easier to use LT parts than the competition. But LT
makes good stuff, so that by itself isn't a drawback.

The competition seems to be in the process of shooting themselves in the
foot by making new models progressively less LTspice compatible. TI
especially.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[John Larkin]

On Wed, 14 Aug 2013 10:34:53 -0700, miso <miso@sushi.com> wrote:

On 8/14/2013 8:53 AM, John Larkin wrote:
On Tue, 13 Aug 2013 20:38:57 -0700, miso <miso@sushi.com> wrote:


If you are using off the shelf controllers, I'm not so sure this
workshop is really needed. If you are rolling your own switchers, well
you shouldn't be.


Why not? Who wants to just copy eval boards?

And with digital power coming along, designing your own switcher may be the new
thing.


Uh, because eval boards are designed to provide good working circuits.

Yeah, 50, maybe even 60 percent of the time. And they are loaded with
expensive side parts, coincidentally all from the same manufacturer.

The nasty thing about a lot of eval boards is that they have jumpers
and optional values for *everything*, so the eval board schematic is
useless as a working example.

>Yes, a novel idea.

Copying circuits from appnotes and handbooks and mags isn't new! Some
engineers literally do nothing else.

You do realize a chip all by its lonesome is way more reliable than
something that uses firmware to run.

Depends. If a uP adds protections that an analog chip doesn't, then
it's safer.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[John Larkin]

On Wed, 14 Aug 2013 10:40:34 -0700, miso <miso@sushi.com> wrote:

On 8/14/2013 8:32 AM, RobertMacy wrote:
On Wed, 14 Aug 2013 08:03:33 -0700, panfilero <panfilero@gmail.com> wrote:

Thanks for the advice, it sounds really good, one concern I have is
that it's tied too much to their design software they sell, I'd hate
to spend 4 days learning how to use a software package to design
magnetics or power supplies, I really do like the hands on aspect of it


Check out LTspice. It's free, educational, and has lots of support people.

LTSpice is brilliant marketing and engineering. The spice works well,
the schematic capture is on par with most pro software, and it seems to
be just a tad bit easier to use LT parts than the competition. But LT
makes good stuff, so that by itself isn't a drawback.

I often sim with an LT part that's close to what I need, and use
something more "affordable" for the real thing.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[John Larkin]

On Wed, 14 Aug 2013 10:19:02 -0700, Joerg <invalid@invalid.invalid>
wrote:

miso wrote:

If you are using off the shelf controllers, I'm not so sure this
workshop is really needed. ...


Off-the-shelf controllers teach you nothing about the magnetics,
intracacies of capacitors, things like that. Heck, they don't even tell
you how an LC post-filter somewhere down the line can cause the whole
chebang to go berserk. If someone isn't very familiar with all that
(usually via blood, sweat and tears) such a workshop can be very worthwhile.

Be sure to ask about sub-cycle oscillations!

... If you are rolling your own switchers, well you shouldn't be.


Almost anyone who has ever designed under super-tight budget for
consumer gear will know otherwise. One of my early cases was when a new
client had a working design but Maxim could not furnish production
quantities of their MAX770. No surprise there. Since there wasn't any
competing part with similar performance and price I ripped it all out,
designed my own discrete solution, with current mode control and all,
and that is still in production.

LM339s and 74HC14's will be around for a while.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[Tim Wescott]

On Wed, 14 Aug 2013 09:43:54 -0700, Jim Thompson wrote:

On Wed, 14 Aug 2013 11:34:20 -0500, Tim Wescott
tim@seemywebsite.really> wrote:

On Tue, 13 Aug 2013 22:08:50 -0700, eric wrote:

I have been all over the place and cannot seem to find an actual
explanation for one or many possible solutions on the race state of a
SR Latch on initialization/power up

I have a small circuit on a bread board using an SR Latch, the circuit
functions correctly once power is on and the SR latch has been
manually used to set the desired initial state.

But, the race condition when the circuit is powered is very
indeterminate and it bounces back and forth to which state wins. But I
cannot seem to find an explanation as to how to set the initial state
properly and then have it function as normal.

I have tried a few methods on my own but none seem reliable enough. Am
I missing something as it seems like it should be quite simple, but I
have not seen a solution I can apply on my board. Either I'm blind and
its right in front of my face or somehow I have been unable to Google
it. Found a LOT of sites explaining the race condition, but no
solutions on how to "set" it.

Flip flops come up in indeterminate states unless you do something
explicit to reset them, or as Jan suggested, to make one input come up
slower than the other.

Because a symmetrical flip-flop that happens to be half way between a 0
state and a 1 state is inherently indeterminate as to which direction
its going to go, you're pretty much doomed to this problem unless you do
something about it.

Use a good POR (power-on-reset) circuit that also copes with brown-outs.

...Jim Thompson

Yup.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

On Wednesday, August 14, 2013 2:39:42 PM UTC-7, John Fields wrote:

On Wed, 14 Aug 2013 13:53:33 -0700 (PDT), eric@bauld.com wrote:





There is no reset pin I am aware of, the SR Latch is constructed from two NOR gates on a quad input NOR gate IC.

If the latch was fully embedded into a IC instead of constructed from two NOR gates.. not sure I understand how the reset works in that case. Do you know of a chip that has that functionality? Just so I can see it and try to figure out how that relates to what was previously brought up.



-E



---

So far, no mention has been made as to how the latch's other input is

connected into the circuit.



Can you post a schematic of your circuit, please?



--

JF

Here is a pic of the circuit as it stands, I added the capacitor in and it has stopped the green LED from starting in a indeterminate state(Sometimes on sometimes off). That is only if the Trip Input is open of course.
And the 100 uF cap on the power has been removed.

http://img33.imageshack.us/img33/8556/jxky.png

- E

 

[Jim Thompson]

On Wed, 14 Aug 2013 13:51:41 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 08/14/2013 01:40 PM, miso wrote:
On 8/14/2013 8:32 AM, RobertMacy wrote:
On Wed, 14 Aug 2013 08:03:33 -0700, panfilero <panfilero@gmail.com
wrote:

Thanks for the advice, it sounds really good, one concern I have is
that it's tied too much to their design software they sell, I'd hate
to spend 4 days learning how to use a software package to design
magnetics or power supplies, I really do like the hands on aspect of it


Check out LTspice. It's free, educational, and has lots of support
people.

LTSpice is brilliant marketing and engineering. The spice works well,
the schematic capture is on par with most pro software, and it seems to
be just a tad bit easier to use LT parts than the competition. But LT
makes good stuff, so that by itself isn't a drawback.


The competition seems to be in the process of shooting themselves in the
foot by making new models progressively less LTspice compatible. TI
especially.

Cheers

Phil Hobbs

All the major players, LT included, are going toward "Spice" models
that only work on their own simulators.

Have you not noted that _most_ LT SMPS models are encoded, and run on
LTspice only.

Likewise TI is evolving toward TINA-only models.

And Analog Devices >:-} Ultimately only simulation via the "cloud".

The fun part is that _many_ of these encrypted models are crap... note
that Analog Devices has NOT corrected the error(s) in the AD8218
model, though they stated correction "within the week" nearly three
weeks ago.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jim Thompson]

On Wed, 14 Aug 2013 13:12:03 -0500, Tim Wescott
<tim@seemywebsite.really> wrote:

On Wed, 14 Aug 2013 09:43:54 -0700, Jim Thompson wrote:

On Wed, 14 Aug 2013 11:34:20 -0500, Tim Wescott
tim@seemywebsite.really> wrote:

On Tue, 13 Aug 2013 22:08:50 -0700, eric wrote:

I have been all over the place and cannot seem to find an actual
explanation for one or many possible solutions on the race state of a
SR Latch on initialization/power up

I have a small circuit on a bread board using an SR Latch, the circuit
functions correctly once power is on and the SR latch has been
manually used to set the desired initial state.

But, the race condition when the circuit is powered is very
indeterminate and it bounces back and forth to which state wins. But I
cannot seem to find an explanation as to how to set the initial state
properly and then have it function as normal.

I have tried a few methods on my own but none seem reliable enough. Am
I missing something as it seems like it should be quite simple, but I
have not seen a solution I can apply on my board. Either I'm blind and
its right in front of my face or somehow I have been unable to Google
it. Found a LOT of sites explaining the race condition, but no
solutions on how to "set" it.

Flip flops come up in indeterminate states unless you do something
explicit to reset them, or as Jan suggested, to make one input come up
slower than the other.

Because a symmetrical flip-flop that happens to be half way between a 0
state and a 1 state is inherently indeterminate as to which direction
its going to go, you're pretty much doomed to this problem unless you do
something about it.

Use a good POR (power-on-reset) circuit that also copes with brown-outs.

...Jim Thompson

Yup.

Virtually every chip I've designed in recent years has a complex POR.
A recent chip monitors three separate supplies for value and
sequencing before allowing the logic to fire up.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jeff Liebermann]

On Wed, 14 Aug 2013 11:03:43 -0700, John Larkin
<jlarkin@highlandtechnology.com> wrote:

Copying circuits from appnotes and handbooks and mags isn't new! Some
engineers literally do nothing else.

Also copying competors products. In the distant past, I designed
marine radios. Motorola owned about 75% of the market. Absolutely
none of my great (and not so great) ideas were even considered unless
Motorola did it first. I had to wait several years with one such
great idea, until Motorola finally produced a product that used it.
Conservative management? Yep, but when you're small, you can't afford
too many mistakes, so copying the competition seemed like a safe bet.

It also works backwards. The company decided to use 16.9MHz as an IF
frequency because 10.7 was too low, and 21.4 would cause the then
fashionable ULN2136 and ULN2111 IF chips to oscillate. The problem
was that we also had to shift the 2nd IF from 455 to 446.25 KHz to
avoid dead channels and mixer spurs. Someone in management thought
that might look like a band-aid, so we didn't really emphasis the 2nd
IF change in the documentation.

Within weeks of release, two competitors had 16.9 MHz IF radios, no
doubt inspired by the crystal filter vendor leaking what we were doing
in trade for a sale. The problem was that they missed the 2nd IF
frequency change, and had some rather interesting problems. Somehow,
I wasn't very sympathetic when they had one of their dealers call us
for tech support about the problem.

Moral: If you're going to copy a circuit from the web, an app note,
or from a competitor, it really helps to understand the circuit
completely.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Fred Abse]

On Tue, 13 Aug 2013 21:10:37 +0100, TTman wrote:

500W Halagen bulb.


just remember it is pretty much a dead short until it heats up

-Lasse

Give me your mailing address and I will send you two 10R 250W resistors.
Small heat sink may be needed.
Cheers, Harry


Thanks, but it's for a company... they can pay...

Check out the Vishay-Sfernice LPS300 range. 300W per unit up to 85C/
Rth case-heatsink 0.112C per watt.

A couple of 10 ohm ones, in series, bolted to a really big heatsink,
should do 500W, 100V, fine.

Farnell should have them in the UK.

Read the datasheet, and do what it says...

--
"Design is the reverse of analysis"
(R.D. Middlebrook)

 

[Tim Wescott]

On Wed, 14 Aug 2013 11:49:42 -0700, eric wrote:

On Wednesday, August 14, 2013 11:33:24 AM UTC-7, Jim Thompson wrote:
On Wed, 14 Aug 2013 13:12:03 -0500, Tim Wescott

tim@seemywebsite.really> wrote:



On Wed, 14 Aug 2013 09:43:54 -0700, Jim Thompson wrote:



On Wed, 14 Aug 2013 11:34:20 -0500, Tim Wescott

tim@seemywebsite.really> wrote:



On Tue, 13 Aug 2013 22:08:50 -0700, eric wrote:



I have been all over the place and cannot seem to find an actual

explanation for one or many possible solutions on the race state
of a

SR Latch on initialization/power up



I have a small circuit on a bread board using an SR Latch, the
circuit

functions correctly once power is on and the SR latch has been

manually used to set the desired initial state.



But, the race condition when the circuit is powered is very

indeterminate and it bounces back and forth to which state wins.
But I

cannot seem to find an explanation as to how to set the initial
state

properly and then have it function as normal.



I have tried a few methods on my own but none seem reliable
enough. Am

I missing something as it seems like it should be quite simple,
but I

have not seen a solution I can apply on my board. Either I'm blind
and

its right in front of my face or somehow I have been unable to
Google

it. Found a LOT of sites explaining the race condition, but no

solutions on how to "set" it.



Flip flops come up in indeterminate states unless you do something

explicit to reset them, or as Jan suggested, to make one input come
up

slower than the other.



Because a symmetrical flip-flop that happens to be half way between
a 0

state and a 1 state is inherently indeterminate as to which
direction

its going to go, you're pretty much doomed to this problem unless
you do

something about it.



Use a good POR (power-on-reset) circuit that also copes with
brown-outs.



...Jim Thompson



Yup.



Virtually every chip I've designed in recent years has a complex POR.

A recent chip monitors three separate supplies for value and

sequencing before allowing the logic to fire up.



...Jim Thompson

--

| James E.Thompson | mens |

| Analog Innovations | et |

| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |

| San Tan Valley, AZ 85142 Skype: Contacts Only | |

| Voice480)460-2350 Fax: Available upon request | Brass Rat |

| E-mail Icon at http://www.analog-innovations.com | 1962 |



I love to cook with wine. Sometimes I even put it in the food.

Im using
http://www.digikey.ca/product-search/en?
x=-1421&y=-72&lang=en&site=ca&KeyWords=HCF4001B
For a chip and using two of the NOR gates to build a Latch
http://upload.wikimedia.org/wikipedia/commons/a/a8/SR-NOR-latch.png

I have 13.5v powering the chip.
But I still don't follow how I can get this latch to power up in a
specific state. Every time I restart it is seemingly random which side
of the latch starts active.

Yes. That is typical, and is to be expected unless you do something
special to make it not happen.

Im not a EE, just a software guy trying that has really wanted to learn
how to build electronics and is getting stuck.

Getting unstuck will teach you a lot, though!

You've been given answers, but maybe not ones that are "unwound" enough
to see them.

Since you're using NOR gates, I assume that your rest state has both
inputs to the SR latch high. What you need to do is to make sure that on
power-on, the correct input on each latch is held low long enough for the
latch to assume your desired state.

One way to do that is what Jan recommended: you make sure that on power-
up, one input always rises significantly slower than the other -- that
input will force its corresponding output to be high when things have
settled out.

Another way to do this is with an explicit reset circuit. You have a
circuit that detects when the power supply is below some threshold, and
as long as it is low, you hold selected inputs on your latches low. This
is easier to understand at a glance of the schematic, and more reliable,
but it takes more components.

I hope this makes sense -- if it doesn't, ask.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Joerg]

miso wrote:

On 8/14/2013 10:19 AM, Joerg wrote:
miso wrote:

If you are using off the shelf controllers, I'm not so sure this
workshop is really needed. ...


Off-the-shelf controllers teach you nothing about the magnetics,
intracacies of capacitors, things like that. Heck, they don't even tell
you how an LC post-filter somewhere down the line can cause the whole
chebang to go berserk. If someone isn't very familiar with all that
(usually via blood, sweat and tears) such a workshop can be very
worthwhile.


... If you are rolling your own switchers, well you shouldn't be.


Almost anyone who has ever designed under super-tight budget for
consumer gear will know otherwise. One of my early cases was when a new
client had a working design but Maxim could not furnish production
quantities of their MAX770. No surprise there. Since there wasn't any
competing part with similar performance and price I ripped it all out,
designed my own discrete solution, with current mode control and all,
and that is still in production.


Funny how these cellphone manufacturers manage to source controller
chips. Well I guess some people know how to run a business.

Some vendors don't know that, as has been evidenced numerous times. If a
manufacturer cannot keep distributors properly stocked then it is not a
good manufacturer. It is that simple.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

John Larkin wrote:

On Wed, 14 Aug 2013 10:19:02 -0700, Joerg <invalid@invalid.invalid
wrote:

miso wrote:
If you are using off the shelf controllers, I'm not so sure this
workshop is really needed. ...

Off-the-shelf controllers teach you nothing about the magnetics,
intracacies of capacitors, things like that. Heck, they don't even tell
you how an LC post-filter somewhere down the line can cause the whole
chebang to go berserk. If someone isn't very familiar with all that
(usually via blood, sweat and tears) such a workshop can be very worthwhile.

Be sure to ask about sub-cycle oscillations!

Yup. And somtimes one just has to live with those, like it can be with
idling combustion engines.

... If you are rolling your own switchers, well you shouldn't be.

Almost anyone who has ever designed under super-tight budget for
consumer gear will know otherwise. One of my early cases was when a new
client had a working design but Maxim could not furnish production
quantities of their MAX770. No surprise there. Since there wasn't any
competing part with similar performance and price I ripped it all out,
designed my own discrete solution, with current mode control and all,
and that is still in production.

LM339s and 74HC14's will be around for a while.

Exactamente. Although I only used one CD40106. More gusto to drive the
FET gate, via a pnp/npn follower. I got about the same efficiency at
much lower cost and most of all we got rid of this unreliable
single-source situation.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

Jim Thompson wrote:

On Wed, 14 Aug 2013 13:51:41 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 08/14/2013 01:40 PM, miso wrote:
On 8/14/2013 8:32 AM, RobertMacy wrote:
On Wed, 14 Aug 2013 08:03:33 -0700, panfilero <panfilero@gmail.com
wrote:

Thanks for the advice, it sounds really good, one concern I have is
that it's tied too much to their design software they sell, I'd hate
to spend 4 days learning how to use a software package to design
magnetics or power supplies, I really do like the hands on aspect of it

Check out LTspice. It's free, educational, and has lots of support
people.
LTSpice is brilliant marketing and engineering. The spice works well,
the schematic capture is on par with most pro software, and it seems to
be just a tad bit easier to use LT parts than the competition. But LT
makes good stuff, so that by itself isn't a drawback.

The competition seems to be in the process of shooting themselves in the
foot by making new models progressively less LTspice compatible. TI
especially.

Cheers

Phil Hobbs

All the major players, LT included, are going toward "Spice" models
that only work on their own simulators.

And the winner is ... LTC. As expected.

Have you not noted that _most_ LT SMPS models are encoded, and run on
LTspice only.

Likewise TI is evolving toward TINA-only models.

Mistake. Big mistake. Just like WebBench is to me.

And Analog Devices >:-} Ultimately only simulation via the "cloud".

DOA.

The fun part is that _many_ of these encrypted models are crap... note
that Analog Devices has NOT corrected the error(s) in the AD8218
model, though they stated correction "within the week" nearly three
weeks ago.

Well, yeah, but they are very fast and can quickly show you if an
unorthodox idea works. Only once (in many years) did I have a
discrepancy between a model and real life that almost became a
showstopper. It was a chip designer error on the LT6700 series, to which
LTC immediately fessed up and issued corrective action.

One of my recent jobs, a set of four switchers operating in a very slow
external non-linear loop, would have taken many hours per run if I had
used real IC models instead of proprietary behavioral.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Wed, 14 Aug 2013 12:36:39 -0700, Joerg <invalid@invalid.invalid>
wrote:

miso wrote:
On 8/14/2013 10:19 AM, Joerg wrote:
miso wrote:

If you are using off the shelf controllers, I'm not so sure this
workshop is really needed. ...


Off-the-shelf controllers teach you nothing about the magnetics,
intracacies of capacitors, things like that. Heck, they don't even tell
you how an LC post-filter somewhere down the line can cause the whole
chebang to go berserk. If someone isn't very familiar with all that
(usually via blood, sweat and tears) such a workshop can be very
worthwhile.


... If you are rolling your own switchers, well you shouldn't be.


Almost anyone who has ever designed under super-tight budget for
consumer gear will know otherwise. One of my early cases was when a new
client had a working design but Maxim could not furnish production
quantities of their MAX770. No surprise there. Since there wasn't any
competing part with similar performance and price I ripped it all out,
designed my own discrete solution, with current mode control and all,
and that is still in production.


Funny how these cellphone manufacturers manage to source controller
chips. Well I guess some people know how to run a business.


Some vendors don't know that, as has been evidenced numerous times. If a
manufacturer cannot keep distributors properly stocked then it is not a
good manufacturer. It is that simple.

When you want to buy 20,000,000 of something, you tend to get real
support. When you want to buy 200, less.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[Joerg]

John Larkin wrote:

On Wed, 14 Aug 2013 12:36:39 -0700, Joerg <invalid@invalid.invalid
wrote:

miso wrote:
On 8/14/2013 10:19 AM, Joerg wrote:
miso wrote:
If you are using off the shelf controllers, I'm not so sure this
workshop is really needed. ...

Off-the-shelf controllers teach you nothing about the magnetics,
intracacies of capacitors, things like that. Heck, they don't even tell
you how an LC post-filter somewhere down the line can cause the whole
chebang to go berserk. If someone isn't very familiar with all that
(usually via blood, sweat and tears) such a workshop can be very
worthwhile.


... If you are rolling your own switchers, well you shouldn't be.

Almost anyone who has ever designed under super-tight budget for
consumer gear will know otherwise. One of my early cases was when a new
client had a working design but Maxim could not furnish production
quantities of their MAX770. No surprise there. Since there wasn't any
competing part with similar performance and price I ripped it all out,
designed my own discrete solution, with current mode control and all,
and that is still in production.

Funny how these cellphone manufacturers manage to source controller
chips. Well I guess some people know how to run a business.

Some vendors don't know that, as has been evidenced numerous times. If a
manufacturer cannot keep distributors properly stocked then it is not a
good manufacturer. It is that simple.

When you want to buy 20,000,000 of something, you tend to get real
support. When you want to buy 200, less.

That's ok but if they think that way then the company should be honest
about it and clearly say so. What I find dishonest is to wet someone's
appetite with ads, demo parts and whatnot, have them design it in, and
then not delivering product in due course.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Joerg]

panfilero wrote:

Thanks for the advice, it sounds really good, one concern I have is
that it's tied too much to their design software they sell, I'd hate
to spend 4 days learning how to use a software package to design
magnetics or power supplies, I really do like the hands on aspect of
it

Why not just ask Ray about that?

--
Regards, Joerg

http://www.analogconsultants.com/

 

[amdx]

On 8/

- E

And after typing up the reply I tried using a 1.8 uF ceramic capacitor on the path between Q and the other input on the S NOR and ground.

And it starts up in the state I want/expect every time. I will have to tweak and see what value capacitor works best, as I think 1.8 uF is a little large but I don't have a background as to why that is just its physical size seems excessive.(Or I have a large capacitor, rated for 630v)

But still curious as to how the other methods would affect this circuitry.

Seems like it was such a simple solution (if correct) but something I was simply unaware of.

- E

Study figure 2.

http://tinyurl.com/mad4akp

What happens when you have this waveform on one input?

This is simple and will work for most power up conditions,
BUT not all.