| 摘要 |
<p>In a direct coupling type power amplifier circuit comprising an input differential amplifier stage, a drive amplifier stage responsive to the output signal of the input differential amplifier stage dc-wise and ac-wise, and a push-pull output amplifier stage responsive to the output signal of the drive amplifier stage dc-wise and ac-wise, the input differential amplifier stage being supplied at one input electrode thereof with an input signal and at the other input electrode thereof with the output of the push-pull output amplifier stage through a negative feedback circuit network, the power amplifier circuit further comprises a bias circuit network for defining the dc bias current through the input differential amplifier stage and a delay circuit coupled between the bias circuit network and a power source voltage supply point. With this circuit arrangement, the dc bias current through the input differential amplifier stage is cut off to hold the whole power amplifier circuit non-responsive to the input signal during a predetermined time internal after the application of the power source voltage to the power source voltage supply point, the predetermined time interval being substantially determined by a predetermined delay time in the delay circuit and a predetermined constant voltage value of a constant voltage circuit component in the bias circuit network.</p> |
