Abstract

The present invention discloses a biquadratic switched-capacitor filter, which merely utilizes one operational amplifier to implement a biquadratic transfer function. The biquadratic switched-capacitor filter further comprises ten switched-capacitor circuits, two feedback capacitors, and two individual switching devices. The switching devices in this switched-capacitor filter can be controlled by six different clock signals. The first and second clock signals are two-phase, complementary but non-overlapping pulse trains with a reference period. The third clock signal is a pulse train with double the reference period and coincident with the first clock signal. The fourth, the fifth, and the sixth clock signals are pulse trains that result from delaying the third, the fourth, and the fifth clock signals by half the reference period. The obtained switched-capacitor filter can be used to simplify some applications, such as sigma-delta modulators.