Patent ID: 8779708

Claim:
A brushless motor driving circuit for driving a brushless motor including: a battery for supplying a power to the brushless motor driving circuit; a driver circuit; a bridge circuit including a first group and a second group of N-channel field effect translators (FETs); a control unit for rotating the brushless motor by switching the bridge circuit through the driver circuit based on a rotor position detection signal; a floating voltage generator for applying a voltage to the first group of the N-channel FETs of the bridge circuit; and a converter which is powered from the battery, wherein the converter has an output connected to an input of the floating voltage generator for the first group of the N-channel FETs of the bridge circuit and an input of the driver circuit for the second group of the N-channel FETs of the bridge circuit to dedicatedly supply a power to gates of the first group and the second group of the N-channel FETs, the control unit is powered from the battery without using the converter, and the converter is configured to determine a voltage of the output based on a voltage of the battery; and wherein, when the voltage of the battery is equal to or lower than a preset voltage, the control unit stops the operation of the first group and the second group of the N-channel FETs, and the preset voltage is determined based on a relationship between an input voltage and an output voltage of the converter.