LED driver

Guest
This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.


Version 4
SHEET 1 880 680
WIRE -144 64 -208 64
WIRE -16 64 -64 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 336 64 240 64
WIRE 400 64 336 64
WIRE 480 64 400 64
WIRE 336 112 336 64
WIRE 480 112 480 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 480 240 480 176
WIRE -16 256 -16 208
WIRE 64 256 -16 256
WIRE 176 256 64 256
WIRE -208 304 -208 256
WIRE 576 304 480 304
WIRE 672 304 576 304
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 480 336 480 304
WIRE 672 336 672 304
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
WIRE 480 464 480 400
WIRE 672 464 672 416
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 480 240 0
FLAG 480 464 0
FLAG 672 464 0
FLAG 576 304 Led_Test
FLAG 400 64 A
FLAG 64 256 B
FLAG 288 320 E
SYMBOL LED 464 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200ľ
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1ľ
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
SYMBOL LED 464 336 R0
WINDOW 0 36 77 Left 2
WINDOW 3 27 103 Left 2
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMBOL current 672 416 R180
WINDOW 0 -69 55 Left 2
WINDOW 3 -75 19 Left 2
SYMATTR InstName I1
SYMATTR Value 1m
SYMBOL res -160 80 R270
WINDOW 0 -39 60 VTop 2
WINDOW 3 -47 55 VBottom 2
SYMATTR InstName R3
SYMATTR Value 1ľ
TEXT 664 184 Left 2 !.tran 100m
TEXT 608 88 Left 2 ;Single-Cell LED driver
TEXT 616 128 Left 2 ;J Larkin Jan 29 2020


--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
 
jlarkin@highlandsniptechnology.com wrote:

This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.
Click to expand...

Wierd oscillator. You have ignored the fact LTspice sets inductor ESR to
1e-3 ohms when you neglect to define it. This raises the unloaded Q to
83,000.

What is strange is the oscillator runs along at zero amplitude, then
suddenly jumps to maximum amplitude in a few cycles. That is normally
impossible with a Q that high.

Another wierdness is if you do not define the time to start saving data and
maximum time step, the oscillator waits for 78 msec before it starts
oscillating.

However, if you set the stop time to 5msec and the maximum time step to
10us, the oscillator starts at 960 us.

I don't think I have ever seen another oscillator like this.

Watch the wrap.

Version 4
SHEET 1 1056 712
WIRE -16 64 -208 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 272 64 240 64
WIRE 336 64 272 64
WIRE 448 64 336 64
WIRE 336 112 336 64
WIRE 448 112 448 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 448 240 448 176
WIRE -16 256 -16 208
WIRE 48 256 -16 256
WIRE 176 256 48 256
WIRE -208 304 -208 256
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 448 240 0
FLAG 272 64 Q1C
FLAG 288 320 Q1E
FLAG 48 256 Q1B
SYMBOL LED 432 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200u
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1u
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
TEXT -168 -64 Left 2 ;'Single-Cell LED driver
TEXT 56 -8 Left 2 ;J Larkin Jan 29 2020
TEXT -136 520 Left 2 ;CT = (33*300) / (33 + 300) = 29.e-9\n \nFc = 1 / (2 *
pi * sqrt(200e-6 * 29e-9)) = 66,085\n \nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 = 83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
TEXT -168 0 Left 2 ;.tran 0 5m 0 10u
TEXT -168 32 Left 2 ;.tran 0 100m
TEXT -168 -32 Left 2 !.tran 0 5m 0 10u
 
On 1/30/20 1:41 AM, Steve Wilson wrote:
jlarkin@highlandsniptechnology.com wrote:

This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.

Wierd oscillator. You have ignored the fact LTspice sets inductor ESR to
1e-3 ohms when you neglect to define it. This raises the unloaded Q to
83,000.

What is strange is the oscillator runs along at zero amplitude, then
suddenly jumps to maximum amplitude in a few cycles. That is normally
impossible with a Q that high.

Another wierdness is if you do not define the time to start saving data and
maximum time step, the oscillator waits for 78 msec before it starts
oscillating.

However, if you set the stop time to 5msec and the maximum time step to
10us, the oscillator starts at 960 us.

I don't think I have ever seen another oscillator like this.
Click to expand...

It's a Colpitts
 
Steve Wilson wrote:
Version 4
SHEET 1 1056 712
WIRE -16 64 -208 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 272 64 240 64
WIRE 336 64 272 64
WIRE 448 64 336 64
WIRE 336 112 336 64
WIRE 448 112 448 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 448 240 448 176
WIRE -16 256 -16 208
WIRE 48 256 -16 256
WIRE 176 256 48 256
WIRE -208 304 -208 256
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 448 240 0
FLAG 272 64 Q1C
FLAG 288 320 Q1E
FLAG 48 256 Q1B
SYMBOL LED 432 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200u
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1u
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
TEXT -168 -64 Left 2 ;'Single-Cell LED driver
TEXT 56 -8 Left 2 ;J Larkin Jan 29 2020
TEXT -136 520 Left 2 ;CT = (33*300) / (33 + 300) = 29.e-9\n \nFc = 1 / (2 *
pi * sqrt(200e-6 * 29e-9)) = 66,085\n \nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 = 83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
TEXT -168 0 Left 2 ;.tran 0 5m 0 10u
TEXT -168 32 Left 2 ;.tran 0 100m
TEXT -168 -32 Left 2 !.tran 0 5m 0 10u
Click to expand...
"unknown schematic syntax" : pi * sqrt(200e-6 * 29e-9)) = 66,085\n
\nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 = 83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
 
jlarkin@highlandsniptechnology.com wrote in
news:9mi43ftihmro28pi1ik6o9ecb6urmtr6ml@4ax.com:

This is a single-cell, single inductor, single transistor LED
driver. The values are all my first wild guesses, none tuned or
tweaked, so it could be improved.

Efficiency is 70% with 1.6 mW into the LED.
Click to expand...

Make me a LED amp driver with precision current adjustment in 50
steps via two buttons. But make it for the high wattage units. So
vary from between your 1.6 mW and say 2 W into the load (LED). Or
even bigger for balanced LED arrays.

Hey!

I know... Make a lab grade bench device that has current readout
to say 3.5 digits for testing LEDs with a small log that can be
plotted to show failure events in order to characterize a given batch
of LEDs. For say matching and culling and proofing of a vendor's
claims of performance.
 
On 1/30/2020 2:35 AM, Robert Baer wrote:
Steve Wilson wrote:
Version 4
SHEET 1 1056 712
WIRE -16 64 -208 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 272 64 240 64
WIRE 336 64 272 64
WIRE 448 64 336 64
WIRE 336 112 336 64
WIRE 448 112 448 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 448 240 448 176
WIRE -16 256 -16 208
WIRE 48 256 -16 256
WIRE 176 256 48 256
WIRE -208 304 -208 256
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 448 240 0
FLAG 272 64 Q1C
FLAG 288 320 Q1E
FLAG 48 256 Q1B
SYMBOL LED 432 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200u
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1u
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
TEXT -168 -64 Left 2 ;'Single-Cell LED driver
TEXT 56 -8 Left 2 ;J Larkin  Jan 29  2020
TEXT -136 520 Left 2 ;CT = (33*300) / (33 + 300) = 29.e-9\n \nFc = 1 /
(2 *
pi * sqrt(200e-6 * 29e-9)) = 66,085\n \nXL = 2 * pi * 200e-6 * 66,085
= 83
\n \nQ = 83 / 1e-3 =   83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
TEXT -168 0 Left 2 ;.tran 0 5m 0 10u
TEXT -168 32 Left 2 ;.tran 0 100m
TEXT -168 -32 Left 2 !.tran 0 5m 0 10u
  "unknown schematic syntax" : pi * sqrt(200e-6 * 29e-9)) = 66,085\n
\nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 =   83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
Click to expand...

He *did* say watch the wrap (which you cut). I got the same message then
unwrapped the lines and it runs fine.
 
DecadentLinuxUserNumeroUno@decadence.org wrote...
Make me a LED amp driver with precision current ...
Click to expand...

Make me an LED driver that can pulse a 3-volt theatre
LED to 350A at 20V (7kW). Make me an LED driver that
can pulse a 30V 3.3A 100W COB LED array to 33A (2kW).


--
Thanks,
- Win
 
Robert Baer wrote:
Steve Wilson wrote:
[Snip...]
Click to expand...

TEXT -168 -64 Left 2 ;'Single-Cell LED driver
TEXT 56 -8 Left 2 ;J Larkin Jan 29 2020
TEXT -136 520 Left 2 ;CT = (33*300) / (33 + 300) = 29.e-9\n \nFc = 1 /
(2 *
pi * sqrt(200e-6 * 29e-9)) = 66,085\n \nXL = 2 * pi * 200e-6 * 66,085
= 83
\n \nQ = 83 / 1e-3 = 83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
TEXT -168 0 Left 2 ;.tran 0 5m 0 10u
TEXT -168 32 Left 2 ;.tran 0 100m
TEXT -168 -32 Left 2 !.tran 0 5m 0 10u
"unknown schematic syntax" : pi * sqrt(200e-6 * 29e-9)) = 66,085\n
\nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 = 83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
Click to expand...

Well, mind the wrap!

Regarding the startup of the thing, it's basically a common
base LC oscillator, so you could add 680nF across R1. If you
also replace V1 by a pulsed source, it will start instantly,
without relying on uncertain numerical noise.

The associated reduction of ripple current in the power supply
is a bonus.

Jeroen Belleman
 
John S wrote:
On 1/30/2020 6:56 AM, Jeroen Belleman wrote:
Robert Baer wrote:
Steve Wilson wrote:
[Snip...]

TEXT -168 -64 Left 2 ;'Single-Cell LED driver
TEXT 56 -8 Left 2 ;J Larkin Jan 29 2020
TEXT -136 520 Left 2 ;CT = (33*300) / (33 + 300) = 29.e-9\n \nFc = 1
/ (2 *
pi * sqrt(200e-6 * 29e-9)) = 66,085\n \nXL = 2 * pi * 200e-6 *
66,085 = 83
\n \nQ = 83 / 1e-3 = 83,000\n \nXC2 = 1 / (2 * pi * 66,085 *
300e-9) =
8.02
TEXT -168 0 Left 2 ;.tran 0 5m 0 10u
TEXT -168 32 Left 2 ;.tran 0 100m
TEXT -168 -32 Left 2 !.tran 0 5m 0 10u
"unknown schematic syntax" : pi * sqrt(200e-6 * 29e-9)) = 66,085\n
\nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 = 83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02

Well, mind the wrap!

Regarding the startup of the thing, it's basically a common
base LC oscillator, so you could add 680nF across R1. If you
also replace V1 by a pulsed source, it will start instantly,
without relying on uncertain numerical noise.

The associated reduction of ripple current in the power supply
is a bonus.

Jeroen Belleman

Really? How do you define ripple current? I'm seeing a sine waveform of
+20mA peak and -16mA peak. The average is 1.36mA and RMS is 13mA. It
seems to be a lot of ripple current to me.
Click to expand...

Indeed, you are correct. I missed the vertical plot scale change
caused by my modifications. Sorry about that.

Jeroen Belleman
 
On 1/30/2020 6:56 AM, Jeroen Belleman wrote:
Robert Baer wrote:
Steve Wilson wrote:
[Snip...]

TEXT -168 -64 Left 2 ;'Single-Cell LED driver
TEXT 56 -8 Left 2 ;J Larkin  Jan 29  2020
TEXT -136 520 Left 2 ;CT = (33*300) / (33 + 300) = 29.e-9\n \nFc = 1
/ (2 *
pi * sqrt(200e-6 * 29e-9)) = 66,085\n \nXL = 2 * pi * 200e-6 * 66,085
= 83
\n \nQ = 83 / 1e-3 =   83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02
TEXT -168 0 Left 2 ;.tran 0 5m 0 10u
TEXT -168 32 Left 2 ;.tran 0 100m
TEXT -168 -32 Left 2 !.tran 0 5m 0 10u
  "unknown schematic syntax" : pi * sqrt(200e-6 * 29e-9)) = 66,085\n
\nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 =   83,000\n \nXC2 = 1 / (2 * pi * 66,085 * 300e-9) =
8.02

Well, mind the wrap!

Regarding the startup of the thing, it's basically a common
base LC oscillator, so you could add 680nF across R1. If you
also replace V1 by a pulsed source, it will start instantly,
without relying on uncertain numerical noise.

The associated reduction of ripple current in the power supply
is a bonus.

Jeroen Belleman
Click to expand...

Really? How do you define ripple current? I'm seeing a sine waveform of
+20mA peak and -16mA peak. The average is 1.36mA and RMS is 13mA. It
seems to be a lot of ripple current to me.
 
On Thu, 30 Jan 2020 06:41:22 -0000 (UTC), Steve Wilson <no@spam.com>
wrote:

jlarkin@highlandsniptechnology.com wrote:

This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.

Wierd oscillator. You have ignored the fact LTspice sets inductor ESR to
1e-3 ohms when you neglect to define it. This raises the unloaded Q to
83,000.
Click to expand...

Then it's a good thing it's loaded.

What is strange is the oscillator runs along at zero amplitude, then
suddenly jumps to maximum amplitude in a few cycles. That is normally
impossible with a Q that high.
Click to expand...

Not strange, obvious. I knew it would do that.


Another wierdness is if you do not define the time to start saving data and
maximum time step, the oscillator waits for 78 msec before it starts
oscillating.
Click to expand...

Ditto.

However, if you set the stop time to 5msec and the maximum time step to
10us, the oscillator starts at 960 us.

I don't think I have ever seen another oscillator like this.
Click to expand...

But it's just a Colpitts.



--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
 
On Wednesday, January 29, 2020 at 10:25:47 PM UTC-5, jla...@highlandsniptechnology.com wrote:
This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.


Version 4
SHEET 1 880 680
WIRE -144 64 -208 64
WIRE -16 64 -64 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 336 64 240 64
WIRE 400 64 336 64
WIRE 480 64 400 64
WIRE 336 112 336 64
WIRE 480 112 480 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 480 240 480 176
WIRE -16 256 -16 208
WIRE 64 256 -16 256
WIRE 176 256 64 256
WIRE -208 304 -208 256
WIRE 576 304 480 304
WIRE 672 304 576 304
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 480 336 480 304
WIRE 672 336 672 304
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
WIRE 480 464 480 400
WIRE 672 464 672 416
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 480 240 0
FLAG 480 464 0
FLAG 672 464 0
FLAG 576 304 Led_Test
FLAG 400 64 A
FLAG 64 256 B
FLAG 288 320 E
SYMBOL LED 464 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200Âľ
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1Âľ
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
SYMBOL LED 464 336 R0
WINDOW 0 36 77 Left 2
WINDOW 3 27 103 Left 2
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMBOL current 672 416 R180
WINDOW 0 -69 55 Left 2
WINDOW 3 -75 19 Left 2
SYMATTR InstName I1
SYMATTR Value 1m
SYMBOL res -160 80 R270
WINDOW 0 -39 60 VTop 2
WINDOW 3 -47 55 VBottom 2
SYMATTR InstName R3
SYMATTR Value 1Âľ
TEXT 664 184 Left 2 !.tran 100m
TEXT 608 88 Left 2 ;Single-Cell LED driver
TEXT 616 128 Left 2 ;J Larkin Jan 29 2020


--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
Click to expand...

Definitely scraping the bottom of the topics barrel with this one.
 
On 30/01/2020 3:25 am, jlarkin@highlandsniptechnology.com wrote:
This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.


Version 4
SHEET 1 880 680
WIRE -144 64 -208 64
WIRE -16 64 -64 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 336 64 240 64
WIRE 400 64 336 64
WIRE 480 64 400 64
WIRE 336 112 336 64
WIRE 480 112 480 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 480 240 480 176
WIRE -16 256 -16 208
WIRE 64 256 -16 256
WIRE 176 256 64 256
WIRE -208 304 -208 256
WIRE 576 304 480 304
WIRE 672 304 576 304
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 480 336 480 304
WIRE 672 336 672 304
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
WIRE 480 464 480 400
WIRE 672 464 672 416
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 480 240 0
FLAG 480 464 0
FLAG 672 464 0
FLAG 576 304 Led_Test
FLAG 400 64 A
FLAG 64 256 B
FLAG 288 320 E
SYMBOL LED 464 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200Âľ
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1Âľ
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
SYMBOL LED 464 336 R0
WINDOW 0 36 77 Left 2
WINDOW 3 27 103 Left 2
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMBOL current 672 416 R180
WINDOW 0 -69 55 Left 2
WINDOW 3 -75 19 Left 2
SYMATTR InstName I1
SYMATTR Value 1m
SYMBOL res -160 80 R270
WINDOW 0 -39 60 VTop 2
WINDOW 3 -47 55 VBottom 2
SYMATTR InstName R3
SYMATTR Value 1Âľ
TEXT 664 184 Left 2 !.tran 100m
TEXT 608 88 Left 2 ;Single-Cell LED driver
TEXT 616 128 Left 2 ;J Larkin Jan 29 2020
Click to expand...

Boring... Make it flash with just one transistor.

A relaxation/squegging Hartley, the second inductor can be an adjacent
moulded inductor - no need for fancy transformers or dual inductors.
This circuit predates the ca 1976 LM3909.

Simulation runs better with a noise starter V2.

Version 4
SHEET 1 880 680
WIRE -64 -288 -208 -288
WIRE 240 -288 -64 -288
WIRE -64 -256 -64 -288
WIRE -64 -160 -64 -176
WIRE 240 -96 240 -288
WIRE -64 -48 -64 -80
WIRE 176 -48 -64 -48
WIRE -64 -32 -64 -48
WIRE -64 48 -64 32
WIRE 16 48 -64 48
WIRE 16 80 16 48
WIRE -208 176 -208 -288
WIRE -64 192 -64 48
WIRE 16 192 16 160
WIRE 240 192 240 0
WIRE 240 192 16 192
WIRE 16 240 16 192
WIRE 240 240 240 192
WIRE -208 352 -208 256
WIRE -64 352 -64 256
WIRE -64 352 -208 352
WIRE 16 352 16 320
WIRE 16 352 -64 352
WIRE 240 352 240 304
WIRE 240 352 16 352
WIRE 240 368 240 352
FLAG 240 368 0
SYMBOL LED 256 304 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind2 0 64 R0
SYMATTR InstName L1
SYMATTR Value 200Âľ
SYMATTR Type ind
SYMATTR SpiceLine Rser=1
SYMBOL npn 176 -96 R0
WINDOW 0 75 17 Left 2
WINDOW 3 47 49 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap -80 192 R0
WINDOW 0 30 6 Left 2
WINDOW 3 28 59 Left 2
SYMATTR InstName C1
SYMATTR Value 10n
SYMBOL cap -80 -32 R0
WINDOW 0 30 7 Left 2
WINDOW 3 30 63 Left 2
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL res -80 -272 R0
WINDOW 0 47 45 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 1Meg
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 50 79 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL ind2 0 224 R0
SYMATTR InstName L2
SYMATTR Value 200Âľ
SYMATTR Type ind
SYMATTR SpiceLine Rser=1
SYMBOL voltage -64 -176 R0
WINDOW 3 -261 31 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
WINDOW 0 -81 -4 Left 2
SYMATTR Value SINE(0 100n 100k)
SYMATTR InstName V2
TEXT 344 280 Left 2 !.tran 500m
TEXT 328 -224 Left 2 ;Single-Cell LED flasher
TEXT 336 -184 Left 2 ;EPW Jan 2020
TEXT -40 392 Left 2 !K1 L1 L2 0.5

piglet
 
bloggs.fredbloggs.fred@gmail.com wrote:
On Wednesday, January 29, 2020 at 10:25:47 PM UTC-5, jla...@highlandsniptechnology.com wrote:
This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.
[...]
--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"

Definitely scraping the bottom of the topics barrel with this one.
Click to expand...

Cheap shot that contributes nothing. Your opinions
don't matter.

Jeroen Belleman
 
On 30 Jan 2020 04:54:23 -0800, Winfield Hill <winfieldhill@yahoo.com>
wrote:

DecadentLinuxUserNumeroUno@decadence.org wrote...

Make me a LED amp driver with precision current ...

Make me an LED driver that can pulse a 3-volt theatre
LED to 350A at 20V (7kW). Make me an LED driver that
can pulse a 30V 3.3A 100W COB LED array to 33A (2kW).
Click to expand...

http://www.highlandtechnology.com/DSS/D100DS.shtml

https://www.dropbox.com/s/rzxmgz6wsgc0l1l/D140_Top.JPG?raw=1

https://www.dropbox.com/s/qyqsjfhuxn9ldnk/D140_200A_Pulse.JPG?raw=1

We don't sell many of this kind of driver, because so many people do
it, it's a price war to the bottom.

The D140 was developed to drive a bar-laser pumped YAG laser for a
battery-powered military rangefinder, but we got outbid for
production.



--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
 
On Thu, 30 Jan 2020 06:55:10 -0800 (PST),
bloggs.fredbloggs.fred@gmail.com wrote:

On Wednesday, January 29, 2020 at 10:25:47 PM UTC-5, jla...@highlandsniptechnology.com wrote:
This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.


Version 4
SHEET 1 880 680
WIRE -144 64 -208 64
WIRE -16 64 -64 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 336 64 240 64
WIRE 400 64 336 64
WIRE 480 64 400 64
WIRE 336 112 336 64
WIRE 480 112 480 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 480 240 480 176
WIRE -16 256 -16 208
WIRE 64 256 -16 256
WIRE 176 256 64 256
WIRE -208 304 -208 256
WIRE 576 304 480 304
WIRE 672 304 576 304
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 480 336 480 304
WIRE 672 336 672 304
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
WIRE 480 464 480 400
WIRE 672 464 672 416
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 480 240 0
FLAG 480 464 0
FLAG 672 464 0
FLAG 576 304 Led_Test
FLAG 400 64 A
FLAG 64 256 B
FLAG 288 320 E
SYMBOL LED 464 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200ľ
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1ľ
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
SYMBOL LED 464 336 R0
WINDOW 0 36 77 Left 2
WINDOW 3 27 103 Left 2
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMBOL current 672 416 R180
WINDOW 0 -69 55 Left 2
WINDOW 3 -75 19 Left 2
SYMATTR InstName I1
SYMATTR Value 1m
SYMBOL res -160 80 R270
WINDOW 0 -39 60 VTop 2
WINDOW 3 -47 55 VBottom 2
SYMATTR InstName R3
SYMATTR Value 1ľ
TEXT 664 184 Left 2 !.tran 100m
TEXT 608 88 Left 2 ;Single-Cell LED driver
TEXT 616 128 Left 2 ;J Larkin Jan 29 2020


--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"

Definitely scraping the bottom of the topics barrel with this one.
Click to expand...

I appoint you a member in full standing of the Crabby Old Gits Who
Never Design Stuff And Probably Never Did Very Well Society.

I was peeling shrimp, minding my own business, when this popped up in
my head, values and all. The Shrimp and Grits and Abita beer were
excellent.

We could discuss Shrimp and Grits but that might be OT.



--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
 
On 1/30/2020 8:37 AM, Jeroen Belleman wrote:
John S wrote:
On 1/30/2020 6:56 AM, Jeroen Belleman wrote:
Robert Baer wrote:
Steve Wilson wrote:
[Snip...]

TEXT -168 -64 Left 2 ;'Single-Cell LED driver
TEXT 56 -8 Left 2 ;J Larkin  Jan 29  2020
TEXT -136 520 Left 2 ;CT = (33*300) / (33 + 300) = 29.e-9\n \nFc =
1 / (2 *
pi * sqrt(200e-6 * 29e-9)) = 66,085\n \nXL = 2 * pi * 200e-6 *
66,085 = 83
\n \nQ = 83 / 1e-3 =   83,000\n \nXC2 = 1 / (2 * pi * 66,085 *
300e-9) =
8.02
TEXT -168 0 Left 2 ;.tran 0 5m 0 10u
TEXT -168 32 Left 2 ;.tran 0 100m
TEXT -168 -32 Left 2 !.tran 0 5m 0 10u
  "unknown schematic syntax" : pi * sqrt(200e-6 * 29e-9)) = 66,085\n
\nXL = 2 * pi * 200e-6 * 66,085 = 83
\n \nQ = 83 / 1e-3 =   83,000\n \nXC2 = 1 / (2 * pi * 66,085 *
300e-9) =
8.02

Well, mind the wrap!

Regarding the startup of the thing, it's basically a common
base LC oscillator, so you could add 680nF across R1. If you
also replace V1 by a pulsed source, it will start instantly,
without relying on uncertain numerical noise.

The associated reduction of ripple current in the power supply
is a bonus.

Jeroen Belleman

Really? How do you define ripple current? I'm seeing a sine waveform
of +20mA peak and -16mA peak. The average is 1.36mA and RMS is 13mA.
It seems to be a lot of ripple current to me.

Indeed, you are correct. I missed the vertical plot scale change
caused by my modifications. Sorry about that.

Jeroen Belleman
Click to expand...

I've done it many times. No apologies needed.
 
On Thu, 30 Jan 2020 15:30:24 +0000, piglet <erichpwagner@hotmail.com>
wrote:

On 30/01/2020 3:25 am, jlarkin@highlandsniptechnology.com wrote:
This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.


Version 4
SHEET 1 880 680
WIRE -144 64 -208 64
WIRE -16 64 -64 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 336 64 240 64
WIRE 400 64 336 64
WIRE 480 64 400 64
WIRE 336 112 336 64
WIRE 480 112 480 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 480 240 480 176
WIRE -16 256 -16 208
WIRE 64 256 -16 256
WIRE 176 256 64 256
WIRE -208 304 -208 256
WIRE 576 304 480 304
WIRE 672 304 576 304
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 480 336 480 304
WIRE 672 336 672 304
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
WIRE 480 464 480 400
WIRE 672 464 672 416
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 480 240 0
FLAG 480 464 0
FLAG 672 464 0
FLAG 576 304 Led_Test
FLAG 400 64 A
FLAG 64 256 B
FLAG 288 320 E
SYMBOL LED 464 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200ľ
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1ľ
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
SYMBOL LED 464 336 R0
WINDOW 0 36 77 Left 2
WINDOW 3 27 103 Left 2
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMBOL current 672 416 R180
WINDOW 0 -69 55 Left 2
WINDOW 3 -75 19 Left 2
SYMATTR InstName I1
SYMATTR Value 1m
SYMBOL res -160 80 R270
WINDOW 0 -39 60 VTop 2
WINDOW 3 -47 55 VBottom 2
SYMATTR InstName R3
SYMATTR Value 1ľ
TEXT 664 184 Left 2 !.tran 100m
TEXT 608 88 Left 2 ;Single-Cell LED driver
TEXT 616 128 Left 2 ;J Larkin Jan 29 2020




Boring... Make it flash with just one transistor.

A relaxation/squegging Hartley, the second inductor can be an adjacent
moulded inductor - no need for fancy transformers or dual inductors.
This circuit predates the ca 1976 LM3909.

Simulation runs better with a noise starter V2.

Version 4
SHEET 1 880 680
WIRE -64 -288 -208 -288
WIRE 240 -288 -64 -288
WIRE -64 -256 -64 -288
WIRE -64 -160 -64 -176
WIRE 240 -96 240 -288
WIRE -64 -48 -64 -80
WIRE 176 -48 -64 -48
WIRE -64 -32 -64 -48
WIRE -64 48 -64 32
WIRE 16 48 -64 48
WIRE 16 80 16 48
WIRE -208 176 -208 -288
WIRE -64 192 -64 48
WIRE 16 192 16 160
WIRE 240 192 240 0
WIRE 240 192 16 192
WIRE 16 240 16 192
WIRE 240 240 240 192
WIRE -208 352 -208 256
WIRE -64 352 -64 256
WIRE -64 352 -208 352
WIRE 16 352 16 320
WIRE 16 352 -64 352
WIRE 240 352 240 304
WIRE 240 352 16 352
WIRE 240 368 240 352
FLAG 240 368 0
SYMBOL LED 256 304 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind2 0 64 R0
SYMATTR InstName L1
SYMATTR Value 200ľ
SYMATTR Type ind
SYMATTR SpiceLine Rser=1
SYMBOL npn 176 -96 R0
WINDOW 0 75 17 Left 2
WINDOW 3 47 49 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap -80 192 R0
WINDOW 0 30 6 Left 2
WINDOW 3 28 59 Left 2
SYMATTR InstName C1
SYMATTR Value 10n
SYMBOL cap -80 -32 R0
WINDOW 0 30 7 Left 2
WINDOW 3 30 63 Left 2
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL res -80 -272 R0
WINDOW 0 47 45 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 1Meg
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 50 79 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL ind2 0 224 R0
SYMATTR InstName L2
SYMATTR Value 200ľ
SYMATTR Type ind
SYMATTR SpiceLine Rser=1
SYMBOL voltage -64 -176 R0
WINDOW 3 -261 31 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
WINDOW 0 -81 -4 Left 2
SYMATTR Value SINE(0 100n 100k)
SYMATTR InstName V2
TEXT 344 280 Left 2 !.tran 500m
TEXT 328 -224 Left 2 ;Single-Cell LED flasher
TEXT 336 -184 Left 2 ;EPW Jan 2020
TEXT -40 392 Left 2 !K1 L1 L2 0.5

piglet
Click to expand...

The LED current spike seems to average about 25 mA and lasts about 5
microseconds, which won't be very visible. It's more of a blocking
oscillator than a squegger. Efficiency looks like about 30%.





--

John Larkin Highland Technology, Inc

The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
 
On 30/01/2020 16:43, jlarkin@highlandsniptechnology.com wrote:
On Thu, 30 Jan 2020 15:30:24 +0000, piglet <erichpwagner@hotmail.com
wrote:

On 30/01/2020 3:25 am, jlarkin@highlandsniptechnology.com wrote:
This is a single-cell, single inductor, single transistor LED driver.
The values are all my first wild guesses, none tuned or tweaked, so it
could be improved.

Efficiency is 70% with 1.6 mW into the LED.


Version 4
SHEET 1 880 680
WIRE -144 64 -208 64
WIRE -16 64 -64 64
WIRE 80 64 -16 64
WIRE 240 64 160 64
WIRE 336 64 240 64
WIRE 400 64 336 64
WIRE 480 64 400 64
WIRE 336 112 336 64
WIRE 480 112 480 64
WIRE -16 128 -16 64
WIRE -208 176 -208 64
WIRE 240 208 240 64
WIRE 480 240 480 176
WIRE -16 256 -16 208
WIRE 64 256 -16 256
WIRE 176 256 64 256
WIRE -208 304 -208 256
WIRE 576 304 480 304
WIRE 672 304 576 304
WIRE 240 320 240 304
WIRE 288 320 240 320
WIRE 336 320 336 176
WIRE 336 320 288 320
WIRE -16 336 -16 256
WIRE 336 336 336 320
WIRE 480 336 480 304
WIRE 672 336 672 304
WIRE 240 352 240 320
WIRE -16 464 -16 400
WIRE 240 464 240 432
WIRE 336 464 336 400
WIRE 480 464 480 400
WIRE 672 464 672 416
FLAG -16 464 0
FLAG 336 464 0
FLAG -208 304 0
FLAG 240 464 0
FLAG 480 240 0
FLAG 480 464 0
FLAG 672 464 0
FLAG 576 304 Led_Test
FLAG 400 64 A
FLAG 64 256 B
FLAG 288 320 E
SYMBOL LED 464 112 R0
WINDOW 0 39 77 Left 2
WINDOW 3 32 106 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind 64 80 R270
WINDOW 0 -32 56 VTop 2
WINDOW 3 -38 55 VBottom 2
SYMATTR InstName L1
SYMATTR Value 200ľ
SYMBOL npn 176 208 R0
WINDOW 0 -54 25 Left 2
WINDOW 3 -90 73 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap 320 112 R0
WINDOW 0 52 26 Left 2
WINDOW 3 48 60 Left 2
SYMATTR InstName C1
SYMATTR Value 33n
SYMBOL cap 320 336 R0
WINDOW 0 49 23 Left 2
WINDOW 3 42 59 Left 2
SYMATTR InstName C2
SYMATTR Value 300n
SYMBOL cap -32 336 R0
WINDOW 0 52 9 Left 2
WINDOW 3 53 44 Left 2
SYMATTR InstName C3
SYMATTR Value 1ľ
SYMBOL res -32 112 R0
WINDOW 0 53 44 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 52 79 Left 2
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL res 224 336 R0
WINDOW 0 -51 43 Left 2
WINDOW 3 -48 74 Left 2
SYMATTR InstName R2
SYMATTR Value 50
SYMBOL LED 464 336 R0
WINDOW 0 36 77 Left 2
WINDOW 3 27 103 Left 2
SYMATTR InstName D2
SYMATTR Value NSCW100
SYMBOL current 672 416 R180
WINDOW 0 -69 55 Left 2
WINDOW 3 -75 19 Left 2
SYMATTR InstName I1
SYMATTR Value 1m
SYMBOL res -160 80 R270
WINDOW 0 -39 60 VTop 2
WINDOW 3 -47 55 VBottom 2
SYMATTR InstName R3
SYMATTR Value 1ľ
TEXT 664 184 Left 2 !.tran 100m
TEXT 608 88 Left 2 ;Single-Cell LED driver
TEXT 616 128 Left 2 ;J Larkin Jan 29 2020




Boring... Make it flash with just one transistor.

A relaxation/squegging Hartley, the second inductor can be an adjacent
moulded inductor - no need for fancy transformers or dual inductors.
This circuit predates the ca 1976 LM3909.

Simulation runs better with a noise starter V2.

Version 4
SHEET 1 880 680
WIRE -64 -288 -208 -288
WIRE 240 -288 -64 -288
WIRE -64 -256 -64 -288
WIRE -64 -160 -64 -176
WIRE 240 -96 240 -288
WIRE -64 -48 -64 -80
WIRE 176 -48 -64 -48
WIRE -64 -32 -64 -48
WIRE -64 48 -64 32
WIRE 16 48 -64 48
WIRE 16 80 16 48
WIRE -208 176 -208 -288
WIRE -64 192 -64 48
WIRE 16 192 16 160
WIRE 240 192 240 0
WIRE 240 192 16 192
WIRE 16 240 16 192
WIRE 240 240 240 192
WIRE -208 352 -208 256
WIRE -64 352 -64 256
WIRE -64 352 -208 352
WIRE 16 352 16 320
WIRE 16 352 -64 352
WIRE 240 352 240 304
WIRE 240 352 16 352
WIRE 240 368 240 352
FLAG 240 368 0
SYMBOL LED 256 304 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMATTR Value NSCW100
SYMBOL ind2 0 64 R0
SYMATTR InstName L1
SYMATTR Value 200ľ
SYMATTR Type ind
SYMATTR SpiceLine Rser=1
SYMBOL npn 176 -96 R0
WINDOW 0 75 17 Left 2
WINDOW 3 47 49 Left 2
SYMATTR InstName Q1
SYMATTR Value BC547C
SYMBOL cap -80 192 R0
WINDOW 0 30 6 Left 2
WINDOW 3 28 59 Left 2
SYMATTR InstName C1
SYMATTR Value 10n
SYMBOL cap -80 -32 R0
WINDOW 0 30 7 Left 2
WINDOW 3 30 63 Left 2
SYMATTR InstName C2
SYMATTR Value 100n
SYMBOL res -80 -272 R0
WINDOW 0 47 45 Left 2
WINDOW 3 44 79 Left 2
SYMATTR InstName R1
SYMATTR Value 1Meg
SYMBOL voltage -208 160 R0
WINDOW 0 54 44 Left 2
WINDOW 3 50 79 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 1.5
SYMBOL ind2 0 224 R0
SYMATTR InstName L2
SYMATTR Value 200ľ
SYMATTR Type ind
SYMATTR SpiceLine Rser=1
SYMBOL voltage -64 -176 R0
WINDOW 3 -261 31 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
WINDOW 0 -81 -4 Left 2
SYMATTR Value SINE(0 100n 100k)
SYMATTR InstName V2
TEXT 344 280 Left 2 !.tran 500m
TEXT 328 -224 Left 2 ;Single-Cell LED flasher
TEXT 336 -184 Left 2 ;EPW Jan 2020
TEXT -40 392 Left 2 !K1 L1 L2 0.5

piglet

The LED current spike seems to average about 25 mA and lasts about 5
microseconds, which won't be very visible. It's more of a blocking
oscillator than a squegger. Efficiency looks like about 30%.
Click to expand...

Yes, Blocking oscillator - thanks that was the description I was looking
for.

I may have the component values all wrong, the ones I remember seeing
made quite fat light blips of at least tens milliseconds long. There was
no explicit C across the tank just stray winding capacity. Crazy
sensitive to cell voltage - optimized for 1.35V button cell probably Hg
in those days and went crazy above 1.5V. I may have got the LED polarity
wrong too - it kinda works either way.

I admired the way to get functionality at extrenme low cost.

piglet
 
jlarkin@highlandsniptechnology.com wrote...
On 30 Jan 2020, Winfield Hill wrote:

DecadentLinuxUserNumeroUno@decadence.org wrote...

Make me a LED amp driver with precision current ...

Make me an LED driver that can pulse a 3-volt theatre
LED to 350A at 20V (7kW). Make me an LED driver that
can pulse a 30V 3.3A 100W COB LED array to 33A (2kW).

http://www.highlandtechnology.com/DSS/D100DS.shtml
https://www.dropbox.com/s/rzxmgz6wsgc0l1l/D140_Top.JPG?raw=1
https://www.dropbox.com/s/qyqsjfhuxn9ldnk/D140_200A_Pulse.JPG?raw=1

We don't sell many of this kind of driver, because so
many people do it, it's a price war to the bottom.
Click to expand...

<Sigh> Is there nothing new under the sun? Well, OK,
maximum current so far is 600A vs 250A, and rise-fall
time is ~1us, faster than 10us. Plus 100W capability.
But this must be an easy-to-copy design. OK, it's in
AoE x-Chapters, and new design details are on DropBox.


--
Thanks,
- Win
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top