I want a "power button" that is actually two buttons; one on, one off. This needs to switch on the order of 15 V and up to 10 A, for a LiFePO4 battery powered device. I don't want to use a hardwired switch where this is mechanical, because I later also want soft (MCU-based) control of the same on/off functions. I don't want to use a relay because 60 mA for a typical coil current is a lot (the typical load is perhaps 500 mA, but peak load on the device is 10 A.)
This is the best I could come up with. De-bouncing the buttons is not needed. When first connected, I think it enters "off" state because the gate is weakly pulled to ground through the load (output) -- and even if it isn't, the main power P-channel FET isn't going to have any gate charge.
I'm asking for two things here:
- If you want to spend a few minutes helping out a poor n00b on circuit design, please critique this design and suggest whatever you think needs improving in this circuit. (Three FETs? really?)
- If you think my diagram is hard to read (I got that last time :-) then please at least critique exactly what you think is poor about the diagram, so that I can better communicate in the future.
Thanks in advance for any help!