Patent ID: 8351172
Filing Date: 2013-01-08
Classification: H02J,H03K

Abstract:
1. A power supply control apparatus comprising: an output transistor coupled between a first power supply line and an output terminal, the output terminal being configured to be coupled with a load; a discharge transistor coupled between a gate of the output transistor and the output terminal, and rendered conductive when the output transistor is brought into a non-conduction state; a negative voltage control unit coupled between the first power supply line and the gate of the output transistor, and bringing the output transistor into a conduction state when a counter electromotive voltage applied to the output terminal from the load exceeds a predetermined value; a diode having a cathode coupled with the first power supply line, and an anode; a third resistor provided between the anode of the diode and a second power supply line; a compensation transistor coupled between the second power supply line and the output terminal, and rendered conductive based on a voltage difference between the output terminal and a connection node between the compensation transistor and a second resistor when the counter electromotive voltage from the load is applied to the output terminal; a protection transistor coupled between the gate of the output transistor and the second power supply line, and bringing the output transistor into a conduction state when a polarity of a power supply coupled between the first power supply line and the second power supply line is reversed; and a back gate control circuit comprising a first resistor coupled between the connection node between the diode and the third resistor and both back gates of the compensation transistor and the protection transistor.