Gate voltage bootstrap switching circuit applied to ultra-low power consumption analog-to-digital converter

Abstract

The invention discloses a gate voltage bootstrap switching circuit applied to an ultra-low power consumption analog-to-digital converter, which adopts a single-phase clock SP, and sets the gate voltage of a sampling MOS tube MS as Vin+2VDD through a first-stage bootstrap circuit and an auxiliary-stage bootstrap circuit during sampling, so that the gate-source voltage difference of the sampling MOS tube MS is constant as 2VDD in the sampling stage; the conduction resistance of the sampling tube is further reduced, so that the linearity is improved, and the precision of the sampling switch circuit is also improved; and based on the proposed two-stage bootstrap circuit, a sixth NMOS transistor M6 and a seventh NMOS transistor M7 are connected in series to serve as a substrate switch of a sampling MOS transistor MS, and when the bootstrap circuit is in a sampling mode, the grid potential of the sampling MOS transistor MS is kept consistent with the substrate potential, the substrate bias effect of the sampling MOS transistor MS is reduced, and harmonic distortion is reduced.

Description

technical field [0001] The invention relates to the technical field of integrated circuit design, in particular to a gate voltage bootstrap switch circuit applied to an ultra-low power consumption analog-to-digital converter. Background technique [0002] The sampling switch is the front-end circuit of the ultra-low power analog-to-digital converter, which has the function of sampling and holding. The accuracy and linearity it can achieve will affect the system performance of the entire analog-to-digital converter, so the design of the sampling switch circuit is particularly important . The sampling switch in the sampling and holding circuit is divided into three types: a single NMOS tube or PMOS tube, a CMOS transmission gate and a grid voltage bootstrap switching circuit. These three switches have their own advantages. Although the Bootstrap Switch Circuit has a complex structure, it has the advantages of the smallest on-resistance, large input range, and high linearity, ...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the problem that the linearity of the existing grid voltage bootstrap switch circuit is not high, and provides a grid voltage bootstrap switch circuit applied to an ultra-low power consumption analog-to-digital converter

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