Re: Another design

On 5/10/2024 5:06 PM, John Larkin wrote:

On Fri, 10 May 2024 11:35:35 -0700, John Larkin
<jjSNIPlarkin@highNONOlandtechnology.com> wrote:
 

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.

 That's overkill. A pfet and one NPN might work.
 

Speaking of overkill, wrt our previous discussion you might be interested in this mixed-signal array that has 8(!) LDOs on board:
<https://www.renesas.com/us/en/products/power-management/multi-channel-power-management-ics-pmics/slg51000-high-psrr-low-noise-multi-output-ldo-ic-advanced-camera-and-sensor-systems#overview>