Latching cicuit chip for push buttons

Hi Gianluca,

It's fairly simple to create turn a push-button (momentary switch) into a toggling switch. There's a video on the topic here: 

Convert a Momentary Switch to a Toggle Switch

There are a number of ways to build a 'smart button' like what you're describing, but we don't have a dedicated logic device that does every part of it. You'd be designing a circuit with multiple components to create it.

The simplest method (in my opinion) would be to add an RC delay to the circuit shown in the video above, which would require holding the button for a certain amount of time before the button would cause the latch to switch. Making that delay different for on vs off is a bit more complex, requiring some feedback circuitry or added logic.

The easiest way to do it with a single device is with a low cost microcontroller - you just program it with your desired settings and it's job would be to watch the button and handle button pushes correctly.

Either way, to handle 500mA at the output, you'd need some kind of driver since logic or MCUs don't typically handle that much current.

Hey Gianluca,

You may be able to do this with a D-flip flop with the configuration in the video Emrys linked to convert you momentary push button to and a toggle switch then adding a 2:1 multiplexer and the flip flop output to trigger whether the push button will need to ramp up to register high for the instances of holding the button to switch off or just pressing to switch on. 
I've shown a circuit below to help understand this better. Picking the correct R and C values may be a bit tricky with such a large (3-4 second) ramp time required with the push button hold. 




Another option you could look into would perhaps be some configuration with the TPS3420 push buttons with the configurable delays. There are two button inputs on those IC's but there may be a method to get the functionality you want with this.

Thanks,
Rami Mooti