If anybody can help it would be appreciated
I have design where a P channel mosfet is used as a switch
The source is 4.2v and the gate is held up by a resistor (100k) to this line
The gate though when it needs to be turned off is being given 3.3v and its not turning it off.
I cannot easily give it the full 4.2v
The circuit is a control for the on/off of a pic, basically when power is attached the battery charger chip pulls a pin low to indicate charging, this pin pulls the base of the mosfet low and this puts a high onto the switch input of the regulator bring the pic to life.
However this reg switch input is also used as part of a button on off system and I need to identify which signal is powering the reg switch.
So the idea is I have the pic line porta.5 floating and then when I do a test I pull the line high which should turn the mosfet off but as I have found out it's not.
Can you think of a way round the issue?
Thanks
I have design where a P channel mosfet is used as a switch
The source is 4.2v and the gate is held up by a resistor (100k) to this line
The gate though when it needs to be turned off is being given 3.3v and its not turning it off.
I cannot easily give it the full 4.2v
The circuit is a control for the on/off of a pic, basically when power is attached the battery charger chip pulls a pin low to indicate charging, this pin pulls the base of the mosfet low and this puts a high onto the switch input of the regulator bring the pic to life.
However this reg switch input is also used as part of a button on off system and I need to identify which signal is powering the reg switch.
So the idea is I have the pic line porta.5 floating and then when I do a test I pull the line high which should turn the mosfet off but as I have found out it's not.
Can you think of a way round the issue?
Thanks