I'm rebuilding my circuit over again with single side prototype board, because I discovered the double-sided prototype board has issues with capacitance and shorting, even though the circuit works, which is adding to the heating. I'm building a TL494 based SEPEX motor controller that is switching huge 11X (eleven paralled) IRFP90N20D MOSFETS, with 10 ohm gate resistors on each MOSFET, and I'm using 6A darlington Sanken TO-220 drivers for them, and also smaller 5A TO-126 audio transistors driving one pair of IRFP90N20D Pin a typical NPN/PNP totem-pole arrangement. The emitter of the Vcc-side transistor (whose collector is tied to Vcc) is connected to the collector of the GND-side transistor (whose emitter is grounded) by a diode. What bipolar transistors would you recommend for robust totem pole outputs at approximately 22khz or higher? Should I use heatsinking? Do I need TO247 sized bipolars to drive these massive MOSFETS? Most TTL circuits, however, use a totem pole output circuit, which replaces the pull-up resistor with a Vcc-side transistor sitting on top of the GND-side output transistor.
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