| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect an anomaly in a DC offset voltage value of an output signal of a signal amplification device which may damage a speaker, and quickly stop a signal output operation.SOLUTION: A threshold excess detection section 140A detects that each of voltage values of one and the other of differential signals output from an amplification section 110 is outside a predetermined allowable range related to a DC offset voltage. A reference value crossing detection section 150A also detects that each of the voltage values of one and the other of the differential signals has changed across a reference value. If there is no change across the reference value over a predetermined determination time or longer after either of the voltage values of one and the other of the differential signals has been detected being outside the allowable range, a supply control section 160A opens switch elements in switch sections 120, 120to prevent the differential signals from being supplied to a speaker 220.</p> |
