A3938 Three-Phase Power MOSFET Controller
The A3938 is a three-phase, brushless DC motor controller designed to drive a wide range of N-channel MOSFETs and support motor supply voltages up to 50 V. It integrates a bootstrapped high-side driver to minimize external component count and includes internal fixed off-time, PWM current-control circuitry to regulate maximum load current.
Key features include synchronous rectification to minimize power dissipation, commutation logic for Hall sensors configured for 120-degree spacing, and various protection features such as bootstrap capacitor charging current monitoring, regulator undervoltage monitoring, motor lead short-to-ground detection, and thermal shutdown. The device is available in 32-pin PLCC, 36-pin QSOP, and 38-pin TSSOP packages.
The A3938 can support motor supply voltages up to 50 V.
The Hall input pins are configured for 120-degree spacing and pulled-up to an internally-generated 5 V reference.
The device detects a motor lead short-to-ground and turns off only the high-side power MOSFETs.