Brushless DC electric (BLDC) motor driver circuit and start-up control method thereof

A brushless DC electric (BLDC) motor driver circuit, which is configured to operably drive a BLDC motor;

• the BLDC motor driver circuit comprising:
• a driving power stage circuit, which is configured to operably provide a start-up test signal in a start-up mode to excite the BLDC motor, so as to drive a rotor of the BLDC motor to rotate for a test;
• a current unidirectional circuit having a reverse end coupled to the BLDC motor, wherein the current unidirectional circuit is configured to operably detect a back electromotive force (BEMF) generated during a period wherein the BLDC motor rotates for the test in the start-up mode, so as to generate at least one detection signal at a forward end of the current unidirectional circuit, and wherein when a voltage at the reverse end is higher than a voltage at the forward end, the current unidirectional circuit is configured to operably limit the voltage at the forward end not to be higher than a clamp voltage;
• a biasing circuit coupled to the forward end of the current unidirectional circuit, wherein the biasing circuit is configured to operably bias the current unidirectional circuit in a forward operation state and is configured to operably provide the clamp voltage;
• and
• a sensor circuit coupled to the forward end, wherein the sensor circuit is configured to operably generate at least one sensing signal according to the detection signal, wherein the sensing signal is indicative of a test rotation state of the BLDC motor.