I need to power the gate of this n-channel MOSFET (provide +V), and I fear that my processor outputs won't give enough + current. The processor spec only says "weak pull up", and the MOSFET data sheet doesn't show the gate current required to maintain the on-state, so I am going on the assumption that my processor outputs won't provide enough source to activate the MOSFET.
However, the processor outputs will sink up to 5mA, so somehow I need to turn this 5mA sink into a source to power the MOSFET gate. Normally I could just use a pull-up resistor to power the gate and use the processor output (sink) to keep it low, but power usage is critical. My whole control circuit must run 2 years on a pair of AAA batteries, about 1200mAh capacity, and a 10k pull-up resistor alone will eat the batteries in only 151 days so I need a different solution. Does anyone have any ideas?
However, the processor outputs will sink up to 5mA, so somehow I need to turn this 5mA sink into a source to power the MOSFET gate. Normally I could just use a pull-up resistor to power the gate and use the processor output (sink) to keep it low, but power usage is critical. My whole control circuit must run 2 years on a pair of AAA batteries, about 1200mAh capacity, and a 10k pull-up resistor alone will eat the batteries in only 151 days so I need a different solution. Does anyone have any ideas?