PURPOSE: To realize a process of a capacitor within an IC, by securing a small capacity by using a Miller integral network for the feedback capacitor.

CONSTITUTION: A differential amplifier consisting of the transistors (TR)Q5 and Q6 is used for a Miller integral network, and the emitter of TRQ4 is connected to the base of TRQ5 which is opposite to the base of TRQ6 that performs a Miller integration. At the same time, the base input terminal of TRQ4 is connected to the emitter terminal of TRQ2 of the feedback input terminal. The signal leaks into the base of TRQ5 at a low frequency less than the cut-off frequency of the LPF consisting of the base input capacity and the input resistance R at the base side of TRQ4. In the same way, the signal is supplied to the base of TRQ6 at a frequency lower than the cut-off frequency of the LPF type feedback circuit consisting of the resistances Rf and Ri plus the equivalent capacity Ci. This signal has the same phase as the signal of the base terminal of TRQ5, and thus the differential amplifier comprising TRs Q5 and Q6 has no saturation. In such constitution, the value of the capacity Ci can be reduced greatly.