Patent ID: 7944778

Claim:
A motor drive control circuit that operates using a primary power supply and controls driving a motor, comprising: a drive circuit that drives the motor; a power supply circuit that is disposed between the primary power supply and the drive circuit, and uses electrical energy supplied from the primary power supply to supply a drive voltage to the drive circuit, the power supply circuit having a field effect transistor of which the drain or the source is connected directly or indirectly to the primary power supply and the other of the drain and the source is connected to a power supply line of the drive circuit; and a power supply control circuit that controls operation of the power supply circuit; wherein the power supply control circuit monitors the drive voltage, stops the power supply circuit and stops supplying electrical energy from the primary power supply to the drive circuit by controlling signal input to the gate of the field effect transistor to turn the field effect transistor off to stop supply of the drive voltage when the drive voltage is greater than or equal to a prescribed constant voltage, and activates the power supply circuit and supplies electrical energy from the primary power supply to the drive circuit by controlling signal input to the gate of the field effect transistor to turn the field effect transistor on to supply the drive voltage when the drive voltage is less than the prescribed constant voltage.