Switched capacitor

(electronics) An integrated circuit element, consisting of a capacitor with two metal oxide semiconductor (MOS) switches, whose function is approximately equivalent to that of a resistor.

A module consisting of a capacitor with two metal oxide semiconductor (MOS) switches connected as shown in illus. a. These elements in the module are easily realized as an integrated circuit on a silicon chip by using MOS technology. The switched capacitor module is approximately equivalent to a resistor, as shown in illus. b. The fact that resistors are relatively difficult to implement gives the switched capacitor a great advantage in integrated-circuit applications requiring resistors. Some of the advantages are that the cost is significantly reduced, the chip area needed is reduced, and precision is increased. Although the switched capacitor can be used for any analog circuit realization such as analog-to-digital or digital-to-analog converters, the most notable application has been to voice-frequency filtering. See also Analog-to-digital converter; Digital-to-analog converter; Electric filter; Integrated circuits.

Switched capacitor, (a) Basic circuit, (b) Equivalent resistive circuit.