Mosfet Momentary Latching Switch Circuit Not Working

Thread Starter


Joined Oct 23, 2018

I prototyped a circuit on a breadboard referencing the sparkfun soft power switch board to turn on/off power using a momentary switch and it works perfect. However, once I remade the circuit on a custom board it does not work. I'm kind of stumped at this point and any troubleshooting guidance is much appreciated!

Issues I'm Having:
1) The power is on immediately once its connected to power (should be off).
2) Holding the power button does not turn it off. But if I set the "Fast Off" Pin to Low it does turn off (but of course I'm unable to turn it back on at that point because power has been cut off from the MCU).

Schematic (battery isn't shown on schematic but it is present - standard Rechargeable 3.7v Lithium Ion battery):



Joined Jan 23, 2018
The collection of circuit pieces does not tell me anything at all, thus I am unable to evaluate the circuit.
IF it worked on a breadboard but not on a custom PCB then there must be a difference. My suggestion is to re-assemble the breadboard circuit and make an actual copy by tracing out that circuit and then compare that with the posted collection.
My guess is that one of the connections is missing