LED driver

Terrible approach. If a hang is possible, it'll get there somehow. The job is to prove that it can't. Proving a negative is *very* difficult. It's far easier to design it out.

There is *always* a path to a hang state. It may only happen once in a million tries and be a fault (ESD, or whatever) but it *will* get there with any production volumes and volume.

At 50 KHz pulse rate, 1 million tries takes 20 seconds.

I was thinking more along the lines of power cycles with various turn-on times, ESD hits, or whatever. Hoping that the stars don't line up wrong is not a good plan.

I have an idea that i am working on. It needs that magic CC fet stack though to get enough power at low voltages for a useful blink rate.

?-/

assuming

namely

me, right

name - and

Just another evasion. Post the circuit with your noise pulse addition to show that in can indeed happen.

?-)

We've discussed that before. Given the CC stack, we don't need to blink... a good LED would be plenty bright at 200 uA. But the stack is big and expensive and dissipates a lot of power, and has its own hazards.

I'm not going to enter that hairball into LT Spice. If you can't see the latch state, you can't.

Well you seem to have forgotten a few points. For a resistor to produce enough usable power from 100 V it wastes way too much at 5 kV. I have noticed your blinkers run only over a 5:1 voltage range, but the requirement is for 50:1 (100:1 as originally stated 5 kV to 48 V) and get to marginal to unacceptable slow blink rates.

Your own sims that you posted.

?-)

In article , joseph snipped-for-privacy@sbcglobal.net says...

Current regulation isn't all that bad, LED blink rate between scales holds well with this one I have. Yes there is some heat losses, little over 1 watt. I think that can be lived with. Version 4 SHEET 1 880 680 WIRE 192 -48 160 -48 WIRE 304 -48 256 -48 WIRE 80 -16 -80 -16 WIRE 160 -16 160 -48 WIRE 160 -16 80 -16 WIRE 304 -16 304 -48 WIRE 368 -16 304 -16 WIRE 160 16 160 -16 WIRE 192 16 160 16 WIRE 304 16 304 -16 WIRE 304 16 256 16 WIRE 368 16 368 -16 WIRE -320 32 -320 0 WIRE -224 80 -272 80 WIRE -80 80 -80 -16 WIRE -80 80 -224 80 WIRE 80 80 80 -16 WIRE 176 80 80 80 WIRE -272 112 -272 80 WIRE -432 128 -496 128 WIRE -336 128 -352 128 WIRE -320 128 -336 128 WIRE 80 128 80 80 WIRE 368 128 368 96 WIRE -496 144 -496 128 WIRE -336 144 -336 128 WIRE -304 144 -336 144 WIRE -224 144 -224 80 WIRE -80 144 -80 80 WIRE 176 176 176 160 WIRE 176 176 144 176 WIRE 80 224 64 224 WIRE 176 224 176 176 WIRE 176 224 144 224 WIRE 368 240 368 208 WIRE -496 256 -496 224 WIRE -80 272 -80 208 WIRE 0 272 -80 272 WIRE 64 272 64 224 WIRE 64 272 0 272 WIRE 80 272 64 272 WIRE 0 288 0 272 WIRE 64 304 64 272 WIRE 96 304 64 304 WIRE 368 336 368 304 WIRE 0 384 0 368 WIRE 144 384 144 320 FLAG -496 256 0 FLAG 0 384 0 FLAG 144 384 0 FLAG 368 336 0 FLAG -320 0 0 SYMBOL pnp 144 224 R180 WINDOW 0 103 133 Left 2 WINDOW 3 56 76 Left 2 SYMATTR InstName Q1 SYMATTR Value 2N3906 SYMBOL voltage -496 128 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 3 -7 178 Left 2 SYMATTR Value 48 SYMATTR InstName V1 SYMBOL res -336 112 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 22Meg SYMBOL res -16 272 R0 WINDOW 0 60 50 Left 2 SYMATTR InstName R2 SYMATTR Value 22MEG SYMBOL zener -64 208 R180 WINDOW 0 24 64 Left 2 WINDOW 3 32 4 Left 2 SYMATTR InstName D1 SYMATTR Value BZX84C15L SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 352 240 R0 SYMATTR InstName C1 SYMATTR Value 100n SYMBOL ind 352 112 R0 SYMATTR InstName L1 SYMATTR Value 100m SYMATTR SpiceLine Ipk=0.15 Rser=6 Rpar=225324 Cpar=5.2462p SYMBOL LED 256 0 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D2 SYMATTR Value AOT-2015 SYMATTR Description Diode SYMATTR Type diode SYMBOL diode 192 -32 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D4 SYMATTR Value 1N914 SYMBOL res 352 0 R0 SYMATTR InstName R3 SYMATTR Value 330 SYMBOL res -208 128 R90 WINDOW 0 59 96 VBottom 2 WINDOW 3 -29 -33 VTop 2 SYMATTR InstName R4 SYMATTR Value 2.2MEG SYMBOL res 160 64 R0 SYMATTR InstName R5 SYMATTR Value 1Meg SYMBOL pmos -272 32 M0 WINDOW 3 96 23 Left 2 SYMATTR InstName M1 SYMATTR Value IRF9Z24S_L SYMBOL nmos 96 224 R0 SYMATTR InstName M2 SYMATTR Value FDR4420A TEXT -240 -64 Left 2 !.tran 10 startup

Jamie

My Schmitt_Blinker_2 works from 38 volts to 2000 with a 3 meg series resistor, the upper limit set by a reasonable power dissipation limit in the resistor.

At 50 volts, the blink rate is just about 1 Hz. That will work for me.

So what have I forgotten?

stack

produce

get

resistor,

resistor.

That range is not shown in any of the files you have posted.

Show it by posting it with proper voltage ranges.

?-)

Drop dead.

Spoken like a true professional :)

Jamie

Short, to the point, and a good answer. What's not to like? ;-)

stack

is

produce

have

get

resistor,

resistor.

At last your true colors flying full.

?-)

Maybe undeserved, but you *were* hectoring.

Instead of demanding answers to your questions, you could consider trying, analyzing, reporting, and contributing to the conversation.

Jus' sayin'...

With best regards, James Arthur