A High Linearity Gate Voltage Bootstrap Switching Circuit

Abstract

A high-linearity gate voltage bootstrap switch circuit, the invention disconnects the connection between the source end of the fourth NMOS transistor and the source end of the first NMOS transistor, and turns the source end of the fourth NMOS transistor to ground, thereby eliminating the need for the first NMOS transistor The correlation between the parasitic capacitance of the four NMOS transistors and the input signal, and the parasitic capacitance of the fourth NMOS transistor is no longer connected to the lower plate of the first capacitor, which reduces the nonlinear capacitance in the circuit and improves the linearity of the overall circuit Simultaneously in order to improve the reliability of the circuit, the present invention also introduces an auxiliary module, so that in the sampling phase, before the clock signal is high and the first PMOS transistor is turned on, the gate voltage of the first PMOS transistor is controlled by the auxiliary module pull down to the ground voltage to turn on the first PMOS transistor, and then disconnect the connection between the auxiliary module and the first PMOS transistor, so that the gate voltage of the first PMOS transistor is no longer pulled down to the ground, but follows the gate voltage from The voltage of the input signal of the switch circuit is raised to ensure that the circuit functions normally and at the same time ensure that the first PMOS transistor will not withstand an excessive high voltage drop.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, and relates to a high-linearity grid voltage bootstrap switch circuit, which can be used in a sample-and-hold circuit, and is especially suitable for a SAR ADC and a CDAC to form a sample-and-hold circuit, which samples and holds an input signal by for subsequent circuit processing. Background technique [0002] With the advancement of integrated circuit technology and the development of the communication industry, signal processing tends to be more and more digital, because digital signals have the advantages of strong anti-interference ability, easy integration, low power consumption, and low cost. But real-world signals usually exist in analog form, such as temperature, sound, etc., which are continuous signals. Analog-to-digital converter (ADC), as an important bridge between analog and digital signals, is an integral part of integrated circuits. [0003] The process of c...

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