| 摘要 |
PROBLEM TO BE SOLVED: To prevent clipping corresponding to the impedance change of a load. SOLUTION: A power supply voltage supplied to the output stage of a power amplification part is detected by a power supply voltage detection part, an output current output from the output stage of the power amplification part is detected by a current detection part, a voltage value corresponding to an output current detected by a conversion table part 50 is output, and a clip detection level based on the voltage value and the power supply voltage is determined by a subtraction part 51 and a second attack release part 52. In the meantime, the level of audio signals input to a full wave rectification part 54, a first attack release part 55 and a level adjusting part 56 is detected. When the level of the audio signals is higher than a clip detection reference level as the result of division in a division part 57, control signals are generated from a control signal generation part 58 and a level control part performs the level attenuation control of the audio signals so as to prevent the clip. COPYRIGHT: (C)2009,JPO&INPIT |
