| 摘要 |
<P>PROBLEM TO BE SOLVED: To enlarge the range of power supply voltage where on/off operation of a drive transistor connected with the drive coil of a motor is performed stably. <P>SOLUTION: The motor drive circuit for controlling a motor by performing on/off control of a field effect type drive transistor connected with the drive coil in a motor and controlling the coil current flowing through the drive coil comprises a circuit for generating a drive signal having a first level dependent on the power supply voltage and performing on/off control of the drive transistor, a charge pump circuit for generating a step-up voltage of second level higher than the first level based on the power supply voltage, a circuit for generating a constant voltage by regulating the step-up voltage from the second level to a third level which is higher than the first level but lower than the second level, and an inverter circuit for transforming the drive signal from the first level to the third level and generating a gate voltage being applied to the gate electrode of the drive transistor. <P>COPYRIGHT: (C)2009,JPO&INPIT |
