Re: Another design

On Thu, 9 May 2024 23:11:03 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:

"Edward Rawde" <invalid@invalid.invalid> wrote in message
news:v1ho21$4ps$1@nnrp.usenet.blueworldhosting.com...

Now with 9V to 15V input range, direct gate drive and 500mA LED current.
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Startup behaviour is not ideal but maybe that can be fixed if it needs
fixing.
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What's the cheapest op amp I can use for U2 instead of OP07?
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Is there a cheaper comparator instead of LT1719 which will work?
Also the fet is bigger than it needs to ne.
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Is there a better device for D4? Particularly if R4 can be reduced.
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Will it work at all? Except in simulation.
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I think I've answered my own question for the current controller but I don't
think it's feasible to attempt a discrete comparator on cost grounds.

I think the LED constant-current switcher can be done with a pfet and
two NPN transistors.