| 摘要 |
A motor drive device (2) comprising an H-bridge circuit (21) having four switching elements (QH, QH2, DL1, DL2) connected in an H bridge form to a motor coil L, a control circuit (22) for on-off controlling each switching element, and a PWM signal generating circuit (23) for generating a PWM signal having a duty according to a ration between a power supply voltage Vcc and a control voltage Vref, wherein the control circuit (22) is so constituted as to select a switching element to be turned on according to an operation mode control signal FIN, RIN and control its on-duty according to the PWM signal. This constitution can variably control easily and over a wide range a drive voltage applied to one end of the motor coil L according to an externally input control voltage Vref. |
