I am making a circuit to discharge an 18V Li-ion battery, with multiple cells, in order to condition it. Each 18V cell has a capacity of 100Wh when fully charged. I would like to control the condition of each cell individually with PWM (to control the current flow), in order to regulate the discharge based on battery and heat sink temperature. A common power resistor is diode or'ed between the 4 switches (Only 1 switch is on at a time).
My question is this, what type of FET or switch circuit (U1) could I control with a 3.3V MCU PWM and also ensure the lowest amount of leakage from the battery when not in discharge mode? Protection against over current, 0 leakage, and lowest footprint are a bonus. It needs to be able to handle currents of up to 1A.