Circuits for and methods of implementing a charge/discharge switch in an integrated circuit

Abstract

A circuit for implementing a charge / discharge switch in an integrated circuit is described. The circuit comprises a supply bias path (203) coupled to a first node (204), wherein the supply bias path provides a charging bias current to the first node; a charge transistor (206) connected between the first node and a first terminal (212) of a capacitor (202); a charge switch (250) coupled between thefirst node and a ground potential (GND), wherein the charge switch enables charging of the capacitor by way of the first node; a discharge transistor (231 ) connected between the first terminal of the capacitor and a second node; a discharge switch (270) coupled between the second node (236) and a reference voltage, wherein the discharge switch enables discharging of the capacitor by way of the second node; and a ground bias path (232) coupled between the second node and ground, wherein the ground bias path provides a discharging bias current to the second node. A method of implementing a charge / discharge switch in an integrated circuit is also described.

Description

technical field [0001] The present invention relates generally to integrated circuit devices, and more particularly to circuits and methods for implementing charge / discharge switches in integrated circuit devices. Background technique [0002] Capacitors are important components in many electronic devices, including integrated circuit devices. Many applications of capacitors require charging and discharging the capacitor. Charging and discharging, however, can cause problems in the circuit. Conventional circuits that enable charging and discharging of capacitors rely on sink / source devices, such as bias transistors, to control the amount of current flowing to or from the capacitor. The switches are digitally controlled by charge and discharge signals that determine the current. [0003] Traditional circuits have used charge and discharge paths to charge and discharge capacitors, paths that include bias devices to control the magnitude of the current, cascode devices to pr...

AI Technical Summary

Problems solved by technology

While making these switching devices smaller can reduce the glitch size, this reduction in size comes at the expense of bias and cascode device headroom due to the increased resistance of the switches , thus they require more voltage drop in the system

With the continuous reduction of transistor size and the further reduction of voltage supply level, cascode devices become more and more difficult to implement with the reduction of voltage margin

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