3-Channel TEC Controller with Independent PID Loops

Challenge: Three independent TEC zones in a lab instrument, each needing bidirectional drive (heat and cool) with tight temperature regulation. Solution: Each channel gets its own synchronous buck converter in H-bridge configuration for bidirectional current. Synchronous topology minimizes heat in the driver board itself. Independent PID loops per channel with precision RTD feedback. TEC thermal response is slow and nonlinear, but the tuning achieves fast setpoint transitions with no overshoot. Results: Holds ±0.05°C at setpoint once settled. The three zones don't interact thermally, which simplified tuning considerably.