The DRV10974 device is a three-phase sensorless motor driver with integrated power MOSFETs, which provide drive-current capability up to 1 A continuous (rms). The device is specifically designed for low-noise, low external-component count, 12-V motor-drive applications. The 180° commutation requires no configuration beyond setting the peak current, the lead angle, and the acceleration profile, each of which is configured by an external resistor.

The 180° sensorless-control scheme provides sinusoidal output voltages to the motor phases as shown in #T4509467-20.

Figure 7-1 180° Sensorless-Control Scheme

Interfacing to the DRV10974 device is simple and intuitive. The DRV10974 device receives a PWM input that it uses to control the speed of the motor. The duty cycle of the PWM input is used to determine the magnitude of the voltage applied to the motor. The resulting motor speed can be monitored on the FG pin. The FR pin is used to control the direction of rotation for the motor. The acceleration ramp rate is controlled by the RMP pin. The current limit is controlled by a resistor on the CS pin. The lead angle is controlled by a resistor on the ADV pin. When the motor is not spinning, a low-power mode turns off unused circuits to conserve power.

The DRV10974 device features extensive protection and fault-detect mechanisms to ensure reliable operation. The device provides overcurrent protection without the requirement for an external current-sense resistor. Rotor-lock detect uses several methods to reliably determine when the rotor stops spinning unexpectedly. The device provides additional protection for undervoltage lockout (UVLO), for thermal shutdown, and for phase short circuit (phase to phase, phase to ground, phase to supply).