ZHCSPQ7A december 2022 – april 2023 MCT8315A
PRODUCTION DATA
The MCT8315A offers four methods of directly controlling the speed of the motor. The speed control method is configured by SPD_CTRL_MODE. The speed command can be controlled in one of the following four ways.
The speed can also be indirectly controlled by varying the supply voltage (VM).
The signal path from SPEED pin input (or I2C based speed input) to output duty cycle (DUTY_OUT) applied to FETs is shown in Figure 7-13.
Figure 7-14 shows the transfer function between DUTY_CMD and SPEED_REF / POWER_REF / TARGET_DUTY.
When speed/power loop is disabled (CLOSED_LOOP_MODE = 00b), DUTY_CMD sets the TARGET_DUTY in % - TARGET_DUTY is 100% when DUTY_CMD is 100% and TARGET_DUTY is equal to MIN_DUTY when DUTY_CMD is set to MIN_DUTY. TARGET_DUTY stays clamped at MIN DUTY for ZERO_DUTY_THR ≤ DUTY_CMD ≤ MIN_DUTY.
When speed loop is enabled (CLOSED_LOOP_MODE = 01b), DUTY_CMD sets the SPEED_REF in Hz. MAX_SPEED sets the SPEED_REF at DUTY_CMD of 100%. MIN_DUTY sets the minimum SPEED_REF (MIN_DUTY x MAX_SPEED). SPEED_REF stays clamped at (MIN_DUTY x MAX_SPEED) for ZERO_DUTY_THR ≤ DUTY_CMD ≤ MIN_DUTY.
When power loop is enabled (CLOSED_LOOP_MODE = 10b), DUTY_CMD sets the POWER_REF in W. MAX_POWER sets the POWER_REF at DUTY_CMD of 100%. MIN_DUTY sets the minimum POWER_REF (MIN_DUTY x MAX_POWER). POWER_REF stays clamped at (MIN_DUTY x POWER_REF) for ZERO_DUTY_THR ≤ DUTY_CMD ≤ MIN_DUTY.
ZERO_DUTY_THR sets the DUTY_CMD below which SPEED_REF / POWER_REF / TARGET_DUTY is set to zero and motor is in stopped state. AVS, CL_ACC configure the transient characteristics of DUTY_OUT; the steady state value of DUTY_OUT is directly configured in % through TARGET_DUTY (when speed/power loop is disabled) or through SPEED_REF/POWER_REF (when speed/power loop is enabled).