Electronically Tunable Third-Order Switched-Capacitor Filter with Feedforward Signal to Minimize Overshoot
The study proposes an Electronically Tunable Third-Order Switched-Capacitor Filter with Feedforward Signal to minimize Overshoot Configuration. This circuit is designed for center frequency f0=15 KHz. The proposed circuit discusses a new configuration to realize third-order with three filter functions low-pass, band-pass, and high- pass simultaneously in single circuit. The circuit uses OP-AMP and MOSFET with Capacitor as Switched-Capacitor. The response of circuit is studied for different circuit merit factor Q and center frequency f0=15 KHz. The filter circuit can be used for both narrow as well as for wide bandwidth, Also, this circuit works for electronically tunable bandwidth. The gain roll-off for this circuit is close to the ideal value of 18 dB / octave (40dB/ decade) as for third order filters. This filter configuration shows better response for Q ≥ 0.4. Also, stabilization of gain for High- pass filter function can be achieved at 0dB for Q≥0.4. In the proposed circuit configuration, the peak gain for overshoot is minimizing from 44dB to 5dB due to the feedforward input signal. The Low-pass filter function works practically only for higher merit factor Q. The circuit shows better response for Q ≥ 0.4 and f0 =15 kHz.
