Reference circuit and reference voltage device applied to Sigma-Delta ADC

Abstract

The invention belongs to the technical field of analog integrated circuits, and discloses a reference circuit and a reference voltage device applied to a Sigma-Delta ADC (Analog to Digital Converter), comprising a positive temperature coefficient voltage circuit, a negative temperature coefficient voltage circuit and a base current offset circuit, the positive temperature coefficient voltage circuit and the base current offset circuit are both connected with the negative temperature coefficient voltage circuit, the positive temperature coefficient voltage circuit is used for generating positive temperature coefficient voltage and sending the positive temperature coefficient voltage to the negative temperature coefficient voltage circuit, and the negative temperature coefficient voltage circuit is used for generating negative temperature coefficient voltage. The positive temperature coefficient voltage and the negative temperature coefficient voltage are superposed according to a preset weight to obtain a reference voltage, and the reference voltage is output through a collector electrode of a transistor used for generating the negative temperature coefficient voltage inside; the base current counteracting circuit is used for counteracting base current of a transistor in the negative temperature coefficient voltage circuit. Compared with a traditional structure, the low-dropout regulator has the advantages that the low-dropout regulator has high driving capacity without an LDO (low dropout regulator) or a buffer, can be directly used for reference voltage and operational amplifier common-mode voltage of Sigma-Delta, does not need an operational amplifier and is simple in structure.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, and relates to a reference circuit and a reference voltage device applied to a Sigma-Delta ADC. Background technique [0002] Reference voltage source is an irreplaceable basic module in integrated circuit design. It can provide reference voltage for various analog integrated circuits, digital integrated circuits and digital-analog hybrid integrated circuits. It is widely used in analog-to-digital converters, digital-to-analog converters , oscillator, voltage regulator and battery management system and other chips, and the output of the reference voltage is hardly affected by changes in temperature, process and power supply voltage. [0003] At present, the conventional reference voltage source is mainly composed of a negative temperature coefficient voltage generation module and a positive temperature coefficient voltage generation module. The positive temperature coefficient ...

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Problems solved by technology

[0004] However, the above-mentioned reference voltage sources generally have very weak driving ability, and an external buffer needs to be connected to obtain greater driving ability, which can be input to other modules of the circuit, which undoubtedly increases the power consumption and complexity of the chip.

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