| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress with a simple constitution the noises which are in applying a power supply and to improve the quality of an amplified output signal. SOLUTION: A second bias generation circuit 8 supplies a second bias current IB2 only to a second amplifier 2 of a current output type immediately after a power supply is applied. Meanwhile, a first bias current IB1 that is generated by a first bias generation circuit 7 to a first amplifier 1 is set at zero. Thus, the amplifier 1 is cut off, and a slow rising output signal of the amplifier 2 is applied to a loudspeaker 5. Then the current IB1 increases as the current IB2 gradually decreases. The current IB2 is finally set at zero, and the current IB1 is set at a fixed level. As a result, the amplifier 1 beings to operate in place of the amplifier 2.</p> |
