| 摘要 |
PURPOSE:To eliminate the bad influence of addition of a DC servo system upon circuit characteristics, by providing a current source, which is connected in parallel with a load, in an output terminal and controlling this current source to make the Dc voltage level of the output terminal constant. CONSTITUTION:A DC detecting circuit 5 which detects the DC level of a circuit output OUT is provided. The current value of a current source which is provided in parallel with a load RL is controlled by the detection output of the circuit 5. When DC currents of respective collector outputs of output transistors TRs Q5 and Q5' are denoted as I1 and I2, respectively, the DC voltage level in the output terminal OUT is indicated with (I1-I2)RL. This output DC voltage is detected by the circuit 5, and a control signal is outputted in accordance with this voltage level. The current value of the current source 6 is controlled by this signal so that this current value is equal to I1-I2, and thus, the DC voltage flowed to the load RL becomes zero, and the DC voltage of the output terminal OUT is controlled to zero also. |
