How can I make a simple 24V 0.5A LED strip on/off toggle curcuit, that can work in this setup ?
I have to make a small pcb for the resistors and capacitor anyway, so I could just add this curcuit there.
It should start off when the system is powered on.

 

Is 24 Vdc the only power source for the circuit?

The circuit is called a toggle flipflop. You can build one with discrete components, or use an IC with an outboard driver transistor. Here is an example from another thread.

NOTE: This schematic is under review.

ak

 

Is 24 Vdc the only power source for the circuit?

The circuit is called a toggle flipflop. You can build one with discrete components, or use an IC with an outboard driver transistor. Here is an example from another thread.

ak

View attachment 344311

The amp run on 24V, but also has 3.3V or 5V output. I would prefer a small IC for less components. Which could that be ?

 

Is that switch for the LEDs committed to a ground connection or are both pins free?
If both pins are free this classic 555 circuit can work.

 

I would prefer a small IC for less components.

Not sure if there is a single IC that can switch 0.5A @ 24V.

 

Not counting the switch(es) or load, 14 pins versus 21 pins.

ak

 

Not counting the switch(es) or load, 14 pins versus 21 pins.
ak

I only see 17 pins on my circuit if that is what you are referring to.

 

Note that for many toggle circuits, neither side of the switch is connected directly to either Vcc or GND. If this is an issue, the solution is a toggle flipflop IC with a negative-edge clock input.

ak

 

1 - IC = 8
3 - R = 6
2 - C = 4 (don't forget the 555 decoupling cap)
1 - Q = 3

I'll grant you the two unused 555 pins, so 19. If you go by the book and add a noise filter cap to pin 5, you're up to 22.

ak

 

Technically there are only 6 solder connections on the 555.
Take another look at your circuit. I see a P channel mosfet for Q? which is upside down.

 

Yeah, I noticed that. The schematic looks like one of mine, but it has issues. I'll have to fix it.

ak

 

Here's the LTspice sim of a one-IC FF toggle circuit that operates with a grounded push-button switch:
One possible negative is that it triggers when the PB is released, not pressed.

The left FF in the package is configured as a non-inverting buffer with hysteresis to provide switch-bounce suppression, and generate a fast rise-time trigger to toggle the right FF.

 

A circuit with the least parts would likely be a small PIC microcontroller driving a MOSFET switch.

 

8 pins and 76 cents, hard to beat ***once you climb over the learning curve.*** (More like the learning mountain)

UPDATE: 6 pins and 58 cents (SMT).

ak

 

Thanks. So this is the simplest circuit.
What happens if I leave out the cap ?

 

So this is the simplest circuit.
What happens if I leave out the cap ?

It won't work.
Why would you think it's not needed?
There are seldom superfluous parts in a design.

 

The reason I ask is because I have to connect the common line of the 4 button board directly to GND

 

Then that circuit won't work unless you're able to the cut the ground connection to free up that switch.

 

Then that circuit won't work unless you're able to the cut the ground connection to free up that switch.

Ok. Since I can't do that, I guess I need another solution.

 

Ok. Since I can't do that, I guess I need another solution.

The circuit in Post #12 works with a grounded switch.

Otherwise a microprocessor based circuit could also work with that.