| 摘要 |
PURPOSE:To set optionally a clipping level with simple constitution by providing a constant current supply circuit regulating the lower limit of the clipping level and a control transistor (TR) regulating the upper limit of the clipping level. CONSTITUTION:When an input signal is applied to a base of a TRQ1, an output of a differential circuit 11 drives a TRQ5 via a current mirror circuit 12 and an output signal corresponding to the input signal is generated at an output terminal 15. When a voltage level of the output signal is lower, a minimum value of a current flowing to resistors R1, R2 is regulated by a constant current source I2 and the lower limit of the output signal is clipped by a voltage level V2 being I2(R1+R2). On the other hand, when the voltage level of the output signal is high and the TRQ5 approaches nearly the saturating state, the TRQ6 is conductive, an output current of the current mirror circuit 12 is bypassed to ground and the upper limit of te output signal is clipped by a voltage level V1 being (I3-I2)(R1+R2). |
