Analog signal sampling circuit and switch capacitance circuit

Abstract

An analog signal sampling circuit is provided. The circuit has high linearity and can process the signal lower than the lowest voltage in the circuit. The analog signal sampling circuit generates a constant voltage by setting a voltage constant module as the voltage between the gate and the source when p-type metal oxide semiconductor field effect transistor (PMOSFET) tube used as the switching tube is turned on. The voltage between the gate and the source is kept constant and not changed with the change of the input signal when the PMOSFET tube is in the turn-on state, so that the turn-on resistance of the PMOSFET tube is also not changed with the change of the input signal, thus providing the PMOSFET tube with constant turn-on resistance, and reducing the distortion of the signal through the PMOSFET tube. The sampling circuit realizes high linearity sampling. A switching circuit is also provided.

Description

technical field

[0001] The invention relates to the field of electronic technology, in particular to an analog signal sampling circuit and a switched capacitor circuit. Background technique

[0002] Switched Capacitor Circuit (Switched Capacitor Circuit) is a circuit basically composed of a switch and a capacitor controlled by a clock signal; it uses the storage and transfer of charges to realize various processing functions for signals. In actual circuits, sometimes the circuits based on switches and capacitors cannot meet the requirements, so switched capacitor circuits are often combined with amplifiers or operational amplifiers, comparators, etc. to realize the generation, transformation and processing of electrical signals.

[0003] In common analog signal sampling circuits, sample and hold circuits usually use MOS switched capacitor circuits to implement various signal processing functions, for example, figure 1 The sampling circuit shown. In the usual CMOS process, ...

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