Harold Hallikainen wrote:
> In your application, I think I'd just try to come up with a constant
> +24V supply.

Why?  That sounds like extra complexity.

If you only have 12V and need to boost up to 24V to occasionally drive the
LED string, then it would be simpler to control the boost switcher as neede=
d
instead of first making 24V, then controlling that down to drive the LEDs.

Since the OP apparently wants short light pulses somewhat like a strobe,
there may be no need for regulation at all.  If the pulse energy is low
enough, a single boost cycle might do it.  Feed the LED string from the 12V
supply thru a Schottky diode.  Also feed it thru a separate inductor
followed by another Schottky diode.  To do a pulse, you pull the point
between inductor and diode low a fixed time to charge up the inductor from
12V, then turn the switch off.  The energy in the inductor will be dumped
into the LED string.

If you can't reasonably get a inductor to hold enough energy for the pulse,
then you'll have to use multiple pulses.


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