Troubleshooting P-Channel MOSFET Switching in Electrical Power Systems

[urb]

Hi all,

I'm using 7 P-channel mosfets to switch different loads using 1 microcontroller on an electrical power and distribution system. My circuit is as follows for each of the 7 Mosfets.

Gate: through a resistor to ground on microcontroller and through a High value (600 kilaohms)
Drain: to load
Source: I/O line from microcontroller and input power

So all the gates are interconnected to the ground on the cpu

The problem I'm having is that when I turn one mosfet on all the mosfets turn on and I can't figure out why. I am unable to use N-Channel mosfets. Any help on this matter would be very very appreciated

 

[lostinxlation]

Are you sending 0s or 1s from microcontroller to source of PMOSs when all of them gets turned on ?

if the gate is connected to gnd, sending 0 to PMOS's source will turn it off, but sending 1 keeps it turned on all the time. I suspect that your microcontrollers are sending 1s to all the PMOSs.

 

[skeptic2]

I don't understand what you have from your description. Can you post a schematic?