| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power supply control circuit in which an overvoltage protective circuit normally operates without being influenced by a reversely connected circuit of a power supply with respect to a counter electromotive voltage generated in an output terminal in turning off. <P>SOLUTION: The power supply control circuit includes: an output transistor 109 connected between a first power supply line 101 and an output terminal 106; a load 112 connected between the output terminal and a second power supply line 102; an overvoltage protective circuit including a switch transistor 110 connected between a control terminal of the output transistor 109 and the first power supply line 101 and brought into a conduction state for the counter electromotive voltage from the load; and power supply reverse-connection protective circuits (114, 115, 121, 122) for forming an electric path for the control terminal of the output transistor when the power supply is connected reversely to power supply line, and bringing the electric path into a state of being disconnected from the counter electromotive voltage from the load when the power supply is correctly connected. <P>COPYRIGHT: (C)2009,JPO&INPIT |
