| 摘要 |
PURPOSE: To automatically suppress the discharging of a battery when power is supplied to the battery by suppressing the consumption of current to be supplied from the battery to portable equipment when a charging voltage is not detected any more. CONSTITUTION: When the power supply of AC 100V to a charging stand mounted with the portable equipment is stopped, a voltage Vb backed up by a battery 36 is supplied through a resistor R2 and a diode D1 to a charging voltage detecting circuit 33A but at the same time, since charging terminals 22 and 31 are coupled, the current flows to a resistor (R1) 23 of the charging stand too. Therefore, the voltage to be supplied to transistors T1 and T2 becomes low as the voltage Vb divided by R1 and R2 and is turned off. Accordingly, a FAIL output is turned to H. Thus, when the FAIL output is made H (abnormal) by power source disconnection or the like during charging, the supply of the power source to respective circuits excepting for a CPU, which required power source supply for control, is stopped, the current consumption is reduced as much as possible and the charging of the battery during power failure is suppressed at a minimum. |
