Building a Custom PWM DC Motor Controller: H-Bridge Design & Thermals
Embedded Systems · Control Systems · CAD By Rainer Rodrigues · April 26, 2026 · 14 min read Building the power stage now? IR2110 Gate Driver IC on Amazon.in → | IRF3205 MOSFET (55V 110A) → If you have ever built a mid-to-high-power robotic system, chances are you started with off-the-shelf motor driver modules. But as soon as you push beyond simple desktop toys into high-torque actuators, those generic modules quickly reveal their limitations. Modules built around legacy chips like the L298N rely on bipolar junction transistors (BJTs) with massive internal collector-emitter voltage drops ($V_{CE(\text{sat})} \approx 1.8\text{V}$ to $2.5\text{V}$). At $2\text{ A}$ of load, the driver wastes nearly $5\text{ W}$ of power as pure heat, requiring bulky heatsinks just to keep from thermal throttling. Cheap drivers also cap switching frequencies below $10\text{ kHz}$, forcing your motor windings to emit an annoying, high-pitched acoustic whine during operation. To achieve ...
