| 摘要 |
<P>PROBLEM TO BE SOLVED: To exactly detect a state of overload and to perform protection according to the state of the overload. <P>SOLUTION: A sound signal from a sound source 4 is amplified by a voltage control amplifier 2, amplified by a digital amplifier part 6 and output. Load current supplied from the digital amplifier part 6 to a load is detected and a load current detector 8 generates a load current detection signal representing its magnitude. Load voltage supplied from the digital amplifier part 6 to the load is detected and a load voltage detector 10 generates a voltage detection signal representing its magnitude. The load current detection signal and the load voltage detection signal are supplied to a subtraction circuit 18 and a difference signal representing difference between the both is generated. A gain of the voltage control amplifier 2 is adjusted according to the difference signal. <P>COPYRIGHT: (C)2009,JPO&INPIT |
