Patent ID: 7501781

Claim:
A PWM motor drive circuit, comprising: a drive IC member electrically connected with a motor coil, the drive IC member being capable of controlling a speed of a motor by means of a PWM signal; a PWM converter circuit electrically connected with the drive IC member for inputting the PWM signal; and a potential limiter having a first terminal electrically connected with a point between a first pin of the drive IC member and the PWM converter circuit, a second terminal connected with a power source, and a capacitor unit serially connected between the first and second terminals; wherein when the motor starts, said potential limiter builds a predetermined initial voltage on the first pin of the drive IC member by charging the capacitor unit of the potential limiter with the power source in a buffer period, said potential limiter controls the drive IC member to gradually speed up the speed of the motor from zero to a predetermined speed in the buffer period without delay of time.