I'm looking to use an Arduino to control a secondary fuel pump in the car. What I'm having bother with is if I've grasped what I need to do to run the motor.
The scenario is this: The pump remains dormant the majority of the time, the standard in-tank pump runs and provides enough pre-supply pressure during normal driving. Once boost pressure reaches 18PSI, the Arduino kicks the pump off at 25% duty cycle. 23PSI has 50% duty cycle and 26PSI will run the pump 100% / ON. As boost drops, the duty cycle drops to the previously mentioned set points. At full load, the pump will draw about 16A. The boost measurement and sketch logic is fine, I've tested it out with a small PC fan and a BD237 that I had lying about - it's the driving of the high current pump I'm not sure.
At first, I thought I'd get away with running an appropriately rated MOSFET and supplying the gate with the 5V from a digital pin on the board. From what I see now, doing so would cause quite a high resistance within the source and drain points and generate a shed load of heat (not ideal!) as higher powered FETs look for something closer to 10-15V at the gate.
Now, my next thought is use a smaller FET that's happy being fully saturated at the gate with the 5V from the digital pin and use that to then feed the gate of the higher powered FET - am I right?
Has anyone done anything similar and could recommend the drivers I'd need? I see many drivers seem 'rated' up to the job, but then read stories of them burning out very quickly when pushed.
Even better - are there any drivers that will do this very thing? I've seen H bridges that are capable of driving multi channels with reverse option (not required) and I've also read that H bridges don't like running 100% and are better suited at 95%?