I wish to drive a small brushed motor with PWM directly from the pins of a microcontroller. The object is to keep it lightweight for my foam airplane project.
I'm thinking a SOIC-8 PIC, glued to the battery pack, with one input pin from the radio and the rest of the GPIO pins shorted together to drive the motor.
(I'll take the 20ms frame throttle signal from the radio, capture it and output PWM, also I can add low-battery throttling.)
Thing is the motor easily sucks 200-300mA, which exceeds all kinds of max ratings for the PIC, like the 12F629.
eg 25mA per GPIO pin abs max, I'd have max 5 pins free = 125mA max current output
which also just happens to be the abs max total current for all GPIO pins
and in any case you can only pull 250mA abs max into the VDD pin.
Three reasons it won't work.
Is there a microcontroller in that form factor, from any company, that would have stronger output pins, and higher current limits through its power pin?
And no, a brushless motor is not the answer, since they don't typically make brushless motors that small, and the extra weight of the 6 FETs+PCB would be substantial. (There's a reason all the small toy RCs use brushed motors still)