MC121-Q1 accepts a pulse-width modulated (PWM) or a DC (analog) input on the PWM/DC pin to control the motor speed. The MC121-Q1 provides a configurable duty curve to map the input duty (DIN in Figure 6-2) to a user configured target output duty cycle (DOUT_TARGET in Figure 6-2). The MC121-Q1 also provides a user configurable duty ramp to smoothly increase/decrease the output duty cycle (DOUT in Figure 6-2) to reach DOUT_TARGET. The MC121-Q1 supports both open-loop (duty cycle) and closed-loop (speed) control. In open-loop (duty cycle) control, the applied duty cycle is directly set by DOUT while in closed-loop (speed) control, the applied duty cycle is set by the speed loop. An integrated digital-latch Hall sensor provides rotor position and timing information to the commutation algorithm. The MC121-Q1 supports square and output PWM waveshaping schemes to optimize between efficiency/motor speed and acoustic noise. The MC121-Q1 provides synchronous, asynchronous, and hybrid output PWM modulation modes on the H-bridge. Configurable hall lead/lag angle and time adjustment is available to improve the efficiency across both lower and higher speeds. In addition, MC121-Q1 provides a configurable demagnetization (auto or manual) feature to reduce the motor winding current to zero before a commutation to minimize the DC bus (VM) voltage spike, acoustic noise and improve efficiency.

Figure 6-2 shows the motor control block diagram of MC121-Q1.

Figure 6-2 MC121-Q1 Motor Control Block Diagram