| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a speaker protection circuit capable of detecting overpower, obviating the need of an external power source, supplying a sound current to a speaker in a normal state, and preventing the occurrence of a sound break. Ž<P>SOLUTION: The speaker detection circuit is composed by including: two voice coils 5, 6 connected in series to each other for input of a sound signal between both ends thereof; an overpower detection circuit 3 for rectifying and smoothing the sound signal and detecting overpower; and a switch circuit 4 including a battery 41, driven by the battery 41, and executing a switch operation using a photo-relay 42 based on an output signal from the overpower detection circuit 3; wherein the switch circuit 4 is connected between one end of the one-side voice coil 5 and a connection point 7 of the two voice coils 5, 6. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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