Many of the microcontroller projects here on MAKE control small things like LEDs, but what about large motors? Roger writes –
This tutorial offers suggestions about controlling large loads with a microprocessor. This is often an issue with those building robots who need to control devices such as lights, motors, vacuums, and other accessories found on robots. We will only deal here with devices that need to be switched ON and OFF – not devices that need the power reversed. Obviously drive motors and other devices need to be switched ON/OFF and also have the power reversed in order to reverse the direction of the motors. That normally requires an H-bridge which is a much more complicated circuit.
Driving high-power loads with a microprocessor – Link.
2 thoughts on “Driving high-power loads with a microprocessor”
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You can drive low trheshold MOSFETs directly from a 5V PIC output. The RFP30N06LE is good for 30A at up to 60VDC. On resistance is only 0.047 Ohms, so you can switch BIG loads with it. That FET costs about $1 each. I use them to switch 15A current pulses through 5W LEDs in just a couple microseconds.
Microchip has MOSFET drivers if you need really fast turn-on and off. They work by providing a very low impedance drive to quickly charge gate capacitance.
MR