| 摘要 |
PURPOSE:To reduce the current consumption of a time piece motor without making the chip area of an integrated circuit too large, by always holding voltage applied to the motor in the vicinity of the min. driving voltage of the motor. CONSTITUTION:Voltage applied to the coil of a motor 10 is detected through a voltage difference circuit 12 and the ON-resistance of MOSFET for amplification of a drive circuit 18 is made variable by the positive and negative of the value obtained by subtracting the min. driving voltage of the motor 10 from the detected voltage to control the voltage applied to the motor 10. By this method, the voltage applied to the motor 10 is always kept constant at the min. driving voltage of the motor 10 and current consumption can be reduced. In addition, it is unnecessary to use a regulator and the formation of an integrated circuit is performed only by dividing the gate in a conventional drive circuit and the increase of a chip area can be reduced. |
