Circuit for compensating nonlinear capacitance to reduce harmonic distortion to greatest extent

Abstract

Provided is a circuit for compensating nonlinear capacitance to reduce harmonic distortion to the greatest extent. The circuit can improve stray capacitance between transistors and is independent of the adopted process technology. In a preferential instance, a pair of diodes with inversely proportional actions is provided for a parasitic diode in an integrated circuit during operation, so stray capacitance of the transistors in the circuit is linearized. If the diodes do not exist in the circuit, different input signals can give rise to changes of the stray capacitance, and therefore harmonic distortion of the circuit is caused. Another embodiment of the invention further provides a complementary transistor. The complementary transistor forms another stray capacitance which is basically opposite to the stray capacitance in the transistors. In addition, according to proportions of different elements, the two methods can be combined, for instance, the diodes can be added while the complementary transistor is used.

Description

Technical field: [0001] This invention relates to the parasitic capacitance of transistors, particularly in track and hold (T / H) circuits or other circuits in combination with T / H circuits. More specifically, the present invention relates to circuits and methods for minimizing non-linear capacitance in T / H and other circuits. Background technique: [0002] T / H circuits are used to maintain a constant amplitude output based on the input, such as in an analog-to-digital converter (ADC). Therefore, the T / H circuit may have high system accuracy requirements, including the accuracy of any data created by the ADC. The T / H circuit generally operates in two different modes, namely "tracking mode" and "holding mode". In tracking mode, the T / H circuit generally acts as an input voltage follower. In hold mode, the T / H circuit holds this input signal as an output signal when time hold mode is activated. T / H circuits typically switch between modes with simple flip-flops. When the T / ...

AI Technical Summary

Problems solved by technology

One disadvantage of this simple MOS transistor T / H circuit is that the parasitic capacitance of the transistor varies non-linearly with the voltage across the transistor junction

However, not only does this approach require more space and cost more, but there are also limitations to the circuits to which it can be applied

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