Dual bootstrap and voltage compensation technology-based A/D converter sampling switch

Abstract

The invention discloses a dual bootstrap and voltage compensation technology-based A/D converter sampling switch, which comprises a primary switch unit used for a to-be-sampled signal channel to sample to-be-sampled signals, a underlayer voltage bootstrap unit for realizing the underlayer voltage bootstrap of a switching tube PMOS Switch in the primary switch unit, a grid voltage bootstrap unit for realizing the grid voltage bootstrap of the switching tube PMOS Switch in the primary switch unit, a storage unit for parallelly sampling input signals VIN and realizing the temporary storage of a VIN voltage, and a voltage compensation unit for compensating the sampling output voltage of an output end VOUT. The invention provides a sampling switch which is capable of working at low voltage and low power consumption and is insensitive to process errors. Meanwhile, the adopted voltage self-compensation method effectively solves a nonlinear problem caused by clock feedthrough occurring after the grid voltage bootstrap of the switching tube.

Description

technical field [0001] The invention relates to the technical fields of microelectronics and solid electronics, in particular to a low-voltage high-linearity A / D converter sampling switch based on double bootstrap and voltage compensation technologies. Background technique [0002] 1. Bootstrap switch and its accuracy limitations [0003] Analog-to-digital A / D (Analog-to-Digital) converter is an essential interface between analog signal and digital signal in all electronic systems, and its conversion accuracy directly affects the overall performance index of the entire electronic system. [0004] At present, in order to adapt to the rapid development of computer, communication and multimedia technologies, A / D converters have made great progress in technology, structure and performance, and are developing in the direction of low power consumption, high speed and high resolution. The sampling circuit is a crucial unit in the A / D converter, and its performance directly determi...

AI Technical Summary

Problems solved by technology

[0008] Two problems can be found from the formula: first, assuming that the threshold voltage V of the switch TH When constant, R ON is the one with the input signal V IN related non-linear resistance, which will cause non-linear distortion of the output signal. For occasions that require high sampling accuracy, the impact of the distortion introduced by the sampling switch on the system accuracy cannot be ignored; second, only When the gate voltage V Gate with source input V IN When the difference is greater than the threshold voltage of the switch, the switch can be turned on normally, which makes V IN The value must satisfy V IN Gate -V TH , this requirement would greatly limit the range of the input signal

[0021] However, this solution has the following problems: first, M2 cannot completely replicate the working state of M1 tube, because M2 is always working in a saturated state, and M1 tube is going through multiple working states under the action of a large signal, and at the same time according to V IN and V OUT The relationship between the two MOS tubes changes continuously with the signal, and there will be a problem of source-drain terminal interchange, and they will work in a non-saturated region before they are finally turned off, which will inevitably make the V of the two MOS tubes TH cannot be exactly the same; secondly, when considering the short channel effect, V TH vs. source-drain voltage V DS related, while M1 and M2 are V DS are not the same...

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