| 摘要 |
In a power supply control apparatus for controlling supplying of power from a battery to a load, a power supply switch circuit chip is connected to the load, to turn ON and OFF a connection between the battery and the load. A control circuit chip is powered by the battery to control the power supply switch circuit chip. The control circuit chip is constructed by an internal circuit for controlling the power supply switch circuit chip, a parasitic diode connected in parallel to the internal circuit, and a depletion type MOS transistor connected in series to the internal circuit. Diode characteristics of the parasitic diode and the depletion type MOS transistor are opposite to each other with respect to the battery. That is, in a forward-connected battery state, the parasitic diode and the depletion type MOS transistor are reverse-biased and forward-biased, respectively. In a reverse-connected battery state, the parasitic diode and the depletion type MOS transistor are forward-biased and reverse-biased, respectively.
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