Self-calibration full-capacitance successive approximation digital-to-analog conversion circuit

Abstract

The invention provides a self-calibration full-capacitance successive approximation digital-to-analog conversion circuit, and the circuit comprises a digital-to-analog converter, the first end of thedigital-to-analog converter being electrically connected with a Vin end, and the second end of the digital-to-analog converter being electrically connected with a Vref end; a comparator circuit, the first end of the comparator circuit being electrically connected with the output end of the digital-to-analog converter; an automatic calibration module, the output end of the automatic calibration module being electrically connected with the second end of the comparator circuit; and a digital control logic module, the first end of the digital control logic module being electrically connected withthe output end of the automatic calibration module, and the second end of the digital control logic module being electrically connected with an EN_CAL signal end. A charge proportion scaling digital-to-analog converter combination is adopted, the digital-to-analog converter is composed of an M-bit sub-digital-to-analog converter of an MSB and a K-bit sub-digital-to-analog converter of an LSB, a sampling holding circuit is not needed, and input voltage is sampled through a capacitor of the digital-to-analog converter.

Description

technical field [0001] The invention relates to the technical field of successive approximation digital-to-analog conversion circuits, in particular to a self-calibrating full-capacitance successive approximation digital-to-analog conversion circuit. Background technique [0002] The successive approximation digital-to-analog conversion circuit (SAR ADC) is mainly composed of a digital-to-analog converter, a comparator, an output register, and digital control logic, and its core is a digital-to-analog converter and a comparator. As the number of bits of the ADC continues to increase, the area required for a single current, voltage, and charge proportional digital-to-analog converter is increasing, and the ratio of the MSB component value to the LSB component value is also increasing. The requirements are getting higher and higher, so the combination of digital-to-analog converters is usually used to solve the above contradictions. [0003] The usual structure of digital-to-...

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Problems solved by technology

[0004] The present invention provides a self-calibrating full-capacitance successive approximation digital-to-analog conversion circuit, the purpose of which is to solve the problem of high requirements for component matching as the number of bits of the ADC continues to increase

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