Successive approximation register (SAR) analog-to-digital converter (ADC) trimming method based on charge compensation and trimming circuit

Abstract

The invention provides a successive approximation register (SAR) analog-to-digital converter (ADC) trimming method based on charge compensation and a trimming circuit. The trimming circuit comprises a register block, an attenuation capacitor and a trimming array, wherein the register block comprises groups of registers, the trimming array includes multiple binary-weight capacitor networks, the trimming array is coupled to a to-be-trimmed main capacitor array through the attenuation capacitor, and the registers control the switching direction of corresponding capacitor switches in the trimming array. According to the trimming method and the trimming circuit, the charge compensation is carried out on the mismatched capacitors, the purpose that the capacitors are matched is achieved, compensation vector quantities can be configured through the registers, and the trimming method and the trimming circuit are suitable for being used in large-scale production and tests and can be carried out on most process platforms.

Description

technical field [0001] The invention belongs to the microelectronic circuit design technology, and relates to a trimming method and a trimming circuit of a SAR structure ADC based on charge compensation. Background technique [0002] SAR structure ADC (Successive Approximation Analog-to-Digital Converter) is a very large type of ADC. For SAR ADCs with a precision of 12 bits or more, basically a capacitor array structure or a resistor-capacitor hybrid array structure is used, but the two structures are very sensitive to capacitance and The matching of the resistors puts high demands on it. At the current level of technology, the capacitance mismatch in conventional technology is about 0.1%, and the theoretically possible ADC accuracy can only reach 10 bits. If you need to design a higher-precision ADC, most of them need to be trimmed. The general trimming method is Laser is used to cut capacitors to achieve matching, but this method has two disadvantages: 1. It is not suitab...

AI Technical Summary

Problems solved by technology

At the current level of technology, the capacitance mismatch in conventional technology is about 0.1%, and the theoretically possible ADC accuracy can only reach 10 bits. If you need to design a higher-precision ADC, most of them need to be trimmed. The general trimming method is Use laser to cut capacitors to achieve matching, but this method has two disadvantages: 1. It is not suitable for mass production; 2. Laser trimming requires special devices, and the process platform is limited

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