Circuit and method for controlling charge injection in radio frequency switches

摘要

A circuit and method for controlling charge injection in a circuit are disclosed. In one embodiment, the circuit and method are employed in a semiconductor-on-insulator (SOI) Radio Frequency (RF) switch. In one embodiment, an SOI RF switch comprises a plurality of switching transistors coupled in series, referred to as “stacked” transistors, and implemented as a monolithic integrated circuit on an SOI substrate. Charge injection control elements are coupled to receive injected charge from resistively-isolated nodes located between the switching transistors, and to convey the injected charge to at least one node that is not resistively-isolated. In one embodiment, the charge injection control elements comprise resistors. In another embodiment, the charge injection control elements comprise transistors. A method for controlling charge injection in a switch circuit is disclosed whereby injected charge is generated at resistively-isolated nodes between series coupled switching transistors, and the injected charge is conveyed to at least one node of the switch circuit that is not resistively-isolated.

主权项

1. A switch circuit, comprising:
(a) a plurality of switching transistors, each having a gate configured to be coupled to a gate control signal and a gate-controlled channel, coupled in series through their respective gate-controlled channels to selectively convey a signal from an input of the series coupled switching transistors to an output of the series coupled switching transistors, the series of switching transistors including:
(1) a plurality of resistively-isolated nodes, each resistively-isolated node located between a different pair of the switching transistors in series; and(2) at least one non-resistively-isolated node located adjacent to one of the plurality of the switching transistors in series; and (b) a plurality of charge injection control transistors, each control transistor having a gate configured to be coupled to a charge injection control signal and a gate-controlled channel operatively coupled between a different one of the plurality of resistively-isolated nodes and the at least one non-resistively-isolated node to selectively communicate injected charge from the different one of the plurality of resistively-isolated nodes to the at least one non-resistively-isolated node; wherein each control transistor selectively switches between an OFF-state and an ON-state in response to application of the charge injection control signal, and selectively controls communication of injection charge only while in the ON-state.