Hei,
I am giving my best shot to describe what I am doing right now
.
- I am connecting two inputs together (shorting them) through a high side switch (voltage can be up to 50V, low currents ~mA). I am not powering anything through that line directly. Only the switching circuitry.
- This is done by a single tactile push button with a parallel high side switch.
- The shorting switching action is latched (currently by 3V3 rail and/or can be disabled by uC).
(doesn't need to be in the 'IC solution')
- The tactile button also acts as a UI navigation button - thus this needs to be read by a uC.
- Tactile button should be able to be isolated affecting the main switching and only give UI input to uC.
Rather simplified schematic of already tested circuit:
Details:This circuit wakes up a main power module -
only then I get power. I'm dealing with a black box. So all I need to do, to get power for my device is to short two lines together.
These two lines mostly are somekind of higher impedance inputs and outputs that detect states.
That line can and can not have a voltage and the provided current is expected to be low - these parameters vary between those black boxes (from 5V to 50V).
When dealing with lower voltages, it's only a matter of not using a resistor divider for the parallel HS f.i.So when I short the lines, 3V3 comes up and I latch the circuit.
But depending on the black box,
I can remove the short - I don't lose power.
For some boxes, I must remove the short asap, otherwise the module goes to sleep again - thus no power. So the current circuit has to be very flexible and currently is also.
The button 'isolation mosfet's' idea is NOT to allow short between the line while the uC keeps the main HS switch closed. Because previously mentioned, some boxes go to sleep when doing that.
I wonder if there's some IC solution that does all or partially these things.Why I'm looking for some IC is that, creating this with dual mosfet packages and having all those bits and pieces is getting very cluttered and starts to take up much board space.
I've tried to look for some premade High Side switch ICs, but haven't really found a compact version (SOIC8 is too much).
//
EDIT:
Experimented that tactile 'disable' works better when I put one PMOS in parallel with the low side PMOS (in between M4 and M5).
So this complicates the selection of the component even more, because usually discrete HS drivers don't allow to put anything in between the MOSFETs.
Uhh, thinking I can't get around simplifying this a lot.