Patent ID: 8598825

Claim:
A lead angle control circuit configured to control a lead angle of a motor drive signal driving a motor, comprising: a control signal generating section configured to generate a control signal corresponding to a motor current flowing through the motor; an upper limit voltage limit section configured to receive an upper limit voltage and configured to output a lead angle control signal obtained by limiting a maximum value of the control signal to the upper limit voltage; and a lead angle data generating section configured to generate a relationship line between lead angle data representing the lead angle and the lead angle control signal, and configured to generate the lead angle data based on the relationship line and the lead angle control signal, wherein the lead angle data generating section receives a changing point voltage and a lead angle setting voltage, the changing point voltage being less than the upper limit voltage, the relationship line reaching an upper limit point from a lower limit point through a changing point, in the changing point, the lead angle control signal being the changing point voltage, the lead angle data representing the lead angle corresponding to the lead angle setting voltage, and in the upper limit point, the lead angle control signal being the upper limit voltage, and the lead angle data representing a maximum lead angle.