Analog transcap device

摘要

A novel semiconductor variable capacitor is presented. The semiconductor structure is simple and is based on a semiconductor variable MOS capacitor structure suitable for integrated circuits, which has at least three terminals, one of which is used to modulate the equivalent capacitor area of the MOS structure by increasing or decreasing its DC voltage with respect to another terminal of the device, in order to change the capacitance over a wide ranges of values. Furthermore, the present invention decouples the AC signal and the DC control voltage avoiding distortion and increasing the performance of the device, such as its control characteristic. The present invention is simple and only slightly dependent on the variations due to the fabrication process. It exhibits a high value of capacitance density and, if opportunely implemented, shows a quasi linear dependence of the capacitance value with respect to the voltage of its control terminal.

主权项

1. A semiconductor variable capacitor comprising:
a first equivalent capacitance plate; a second equivalent capacitance plate; at least one control region;
wherein the capacitance value between said first and second capacitance plates of said semiconductor variable capacitor is varied by varying a control voltage;wherein said control region forms a rectifying junction with said first capacitance plate, andwherein the variation of said control voltage causes a variation of the voltage drop across said rectifying junction.