Amplifiers using gated diodes

Abstract

A circuit comprises a control line and a two terminal semiconductor device having first and second terminals. The first terminal is coupled to a signal line, and the second terminal is coupled to the control line. The two terminal semiconductor device is adapted to have a capacitance when a voltage on the first terminal relative to the second terminal is above a threshold voltage and to have a smaller capacitance when a voltage on the first terminal relative to the second terminal is below the threshold voltage. The control line is coupled to a control signal and the signal line is coupled to a signal and is output of the circuit. A signal is placed on the signal line and voltage on the control line is modified (e.g., raised in the case of n-type devices, or lowered for a p-type devices). When the signal falls below the threshold voltage, the two terminal semiconductor device acts as a very small capacitor and the output of the circuit will be a small value. When the signal is above the threshold voltage, the two terminal semiconductor device acts as a large capacitor and the output of the circuit will be influenced by both the value of the signal and the value of the modified voltage on the control line and therefore the signal will be amplified.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of U.S. patent application Ser. No. 10 / 751,714 filed on Jan. 5, 2004, the complete disclosure of which is expressly incorporated by reference herein in its entirety for all purposes. This application is also related to an application by Luk et al., entitled 3T1D MEMORY CELLS USING GATED DIODES AND METHODS OF USE THEREOF, U.S. patent application Ser. No. 10 / 751,713, filed on Jan. 5, 2004, now U.S. Pat. No. 7,027,326, and assigned to International Business Machines, Inc., the disclosure of which is hereby incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to semiconductors and, more particularly, relates to semiconductor devices and circuits using the same for amplifying signals.BACKGROUND OF THE INVENTION[0003]High speed, small signal sensing amplifiers are commonly needed in memory such as Dynamic Random Access Memory (DRAM) and Static Random Access Memory (SRAM). Small sig...

AI Technical Summary

Benefits of technology

[0012]A second circuit can additionally comprise an isolation device on the signal line intermediate the signal and the gate input. The isolation device allows, for instance, separation of load between the gated diode and the signal line and, as another example, prevention of voltage rise at the gate input of the gated diode from affecting the signal on the signal line. The isolation device may be beneficially designed to isolate the gated diode from the signal on the signal line when the signal is a predetermined voltage. The isolation device can be made from an n-type or a p-type device. Additionally, the second circuit can comprise an output device such as a buffer or latch. Furthermore, two such circuits may be used in a differential circuit having also a differential signal output device, such as a differential buffer or differential latch.

Problems solved by technology

In conventional single ended, small signal sense circuits such as class A amplifiers, there are a number of items that are very difficult to control: biasing of the operating point; stability of the reference voltage; biasing current; sensitivity to threshold voltage; and process and temperature variations.

This is especially true for future technology, due to increasing high leakage current and low supply voltage as transistors are scaled smaller, making such circuits very sensitive to voltage, temperature and process variations.

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