Wheel drive is the densest subsystem in an AMR: it draws on more component categories than any other function. The reason is the closed loop. Driving a wheel means switching power, sensing the result, conditioning the signal, and acting on it in real time, with protection standing by throughout.
some architectures use discrete switches with separate drivers, others integrate the driver with the switch or the controller.
some architectures use discrete switches with separate drivers, others integrate the driver with the switch or the controller.
Main functions
The following table shows the main semiconductor components and their roles in driving a wheel.
| Component | Category | Role in wheel drive |
|---|---|---|
| Power discretes (MOSFET, IGBT, GaN) | Power management | Switch the motor current |
| Gate drivers | Power management | Translate control signals into switch drive |
| Switch-driver integrated modules | Power management | Combine switch and driver in one package for simpler design and thermal management |
| Controller-driver integrated ICs | Power management | Combine control logic and driver, with external switches |
| MCU | Processing | Run the real-time control loop (commutation, torque, speed) |
| Motion sensing (encoder, IMU) | Sensing | Feed speed and position back to the control loop |
| Current sense amplifiers | Signal conditioning | Prepare the current signal for closed-loop control |
| Comparators | Signal conditioning | Detect zero-crossings for sensorless commutation, trip on fault thresholds |
| Op amps | Signal conditioning | Buffer and scale signals ahead of the controller's inputs |
| TVS and ESD devices | Clamping | Keep the circuit alive through electrical transients |
| DC-DC converters | Power management | Supply the gate drive and logic rails |
| EEPROM | Memory | Hold calibration data the control loop reads at startup |