| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor drive device, capable of variably controlling drive voltages easily and widely that are applied to one end of motor coils, in response to control voltage that is input externally. <P>SOLUTION: A motor drive device 2 comprises an H-bridge circuit 21, having four switching elements (QH1, QH2, DL1, DL2) connected in H-bridge type to a motor coil L, a control circuit 22 for performing on/off control of each switching element, and a PWM signal generating circuit 23 for generating a PWM signal of a duty that is commensurate with a ratio of power supply voltage V<SB>cc</SB>versus control voltage V<SB>ref</SB>.The control circuit 22 is configured to select a switching element that should be turned on, in response to the operating mode control signals FIN, RIN, as well as to control the on-duty, in response to the PWM signal. <P>COPYRIGHT: (C)2007,JPO&INPIT |
