Looking for latch circuit advice

[Jon Yaeger]

I've got an ATX power supply that I'd like to turn on and off using a
momentary contact switch. I won't be using it with a computer that has a
flip-flop type latch circuit - I'll have to breadboard a simple circuit that
will do the trick.

There is a 5V DC signal available as a trickle supply. The power supply also
has a signal lead with 5V which turns on the unit when grounded. It doesn't
latch on.

To summarize, I want a circuit to latch the power supply on (using its own
5V signal & circuit) when the momentary SPST switch is depressed; and off
when it is pressed again.

Does anyone know of a suitable on-line circuit?

TIA,

Jon

 

[Tim Wescott]

Jon Yaeger wrote:

I've got an ATX power supply that I'd like to turn on and off using a
momentary contact switch. I won't be using it with a computer that has a
flip-flop type latch circuit - I'll have to breadboard a simple circuit that
will do the trick.

There is a 5V DC signal available as a trickle supply. The power supply also
has a signal lead with 5V which turns on the unit when grounded. It doesn't
latch on.

To summarize, I want a circuit to latch the power supply on (using its own
5V signal & circuit) when the momentary SPST switch is depressed; and off
when it is pressed again.

Does anyone know of a suitable on-line circuit?

TIA,

Jon

You should be able to do this with a toggle flip-flop and a debounce

circuit. At most this would take a 555 timer and a 7476 -- or save
space and do it with a PIC.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com