Patent ID: 8384325

Claim:
A driving circuit configured to receive a control pulse signal pulse-width modulated according to a target rotational speed, and to drive a motor according to the control pulse signal, the driving circuit comprising: a start pulse signal generating unit configured to generate a start pulse signal having a predetermined duty ratio; a control unit configured to output, as a driving pulse signal, one signal selected from among the start pulse signal and the control pulse signal; and a driving unit configured to drive the motor by pulse width modulation according to the driving pulse signal, wherein, in the state in which the motor has stopped, the control unit starts to drive the motor when the duty ratio of the control pulse signal is switched from zero to a nonzero value, and wherein, in a start period from the commencement of the driving operation for the motor, the control unit outputs the start pulse signal as the driving pulse signal, and wherein, after the start period elapses, the control unit outputs the control pulse signal as the driving pulse signal, and wherein the start pulse signal generating unit generates a start pulse signal which is set to a first level for a predetermined ON time after one edge selected from among a positive edge and a negative edge of the control pulse signal is detected, and which is set to a second level which is complementary to the first level until the next selected edge is detected after the first level state.