45A H-Bridge Driver Design - 22/10/2026 03:17 EDT

I’m putting together a brushed-DC motion system powered from a 12 V lead-acid battery and I need a robust H-bridge driver designed completely from the ground up. The stage must deliver 45 A continuously and tolerate 80 A for a one-second surge, all while running from a 12–14 V rail. Logic-side compatibility is 3.3 V, and I will PWM it at 5 kHz to start, with the option to move to 20 kHz later. Duty cycles will sit between 50 % and 95 %. Direction control is simply forward and reverse; when the PWM stops I want the motor to coast, not brake.

What I need from you:

• A full schematic and component selection (MOSFETs, gate drivers, current sensing, protection circuitry, etc.) that comfortably meets the thermal and electrical limits above.
• PCB layout files ready for manufacture, preferably in KiCad or Altium, with clear copper weight and thermal-relief guidance for the 45 A paths.
• A concise BOM with part numbers available from major vendors.
• Basic firmware examples or timing diagrams showing how a 3.3 V MCU should drive the bridge safely, including dead-time recommendations.
• Short validation notes or a test plan so I can reproduce your bench results when I build the first boards.

I already have bench supplies, scopes, and a dyno for load testing, so as long as your design files are complete and clearly annotated, I can take it from prototype to verification. If you’ve tackled high-current H-bridges before and can document your work cleanly, let’s get started.