| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power supply protection circuit that expedites the draw-out of an AC plug from a plug receptacle in an early stage by notifying the severity of overvoltage, and can effectively prevents the breakage of a power supply circuit and the power supply protection circuit. Ž<P>SOLUTION: The power supply protection circuit includes: a means which has a voltage detection circuit 44 for detecting a voltage value related to an alternate current input into the power supply circuit 2 which feeds power to an amplifying circuit 3, and determines whether a voltage value detected in the power supply protection circuit 4 which is constituted so as to block the alternate current input into the power supply circuit 2 is not higher than a first voltage value according to the detected voltage value; a means which determines whether the voltage value is not higher than a second voltage value which is lower than the first voltage value; a relay circuit 47 which blocks the alternate current input into the power supply circuit 2 when it is determined that the voltage value is higher than the second voltage value; and a display part 46 which emits light at higher brightness, or more quickly blinks light compared with the case that the detected voltage value exceeds the second voltage value and is lower than the first voltage value when the detected voltage value is higher than the first voltage value. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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