| 摘要 |
PROBLEM TO BE SOLVED: To use a battery power supply efficiently depending on the control state of a motor. SOLUTION: When a rotation designation signal is open (H level) for a given time or longer, a capacitor 52 is charged with a voltage VBB2 of a second power supply 50 and the voltage of the capacitor 52 approaches the voltage VBB2 of the second power supply 50. Consequently, a gate voltage being fed to the gate terminal of a MOSFET61 increases toward the voltage VBB2. When the gate voltage exceeds a gate breaking voltage upon elapsing the given time and then exceeds an MOS operating voltage range to enter an MOS operation stop range, the MOSFET61 is closed and voltage supply to a drive voltage supply terminal 48 is interrupted thus interrupting drive voltage supply from the drive voltage supply terminal 48 to a motor control circuit 11. |
