Slope conversion circuit applied to two-step type integral analog-to-digital converter

Abstract

The invention belongs to the technical field of semiconductors and integrated circuits, and in particular relates to a slope conversion circuit applied to a two-step type integral analog-to-digital converter. The slope conversion circuit comprises an operational amplifier, a pair of sampling capacitors, a pair of parasitic balance capacitors and six switches. During high-level analog-to-digital conversion in the first step, an input slope signal is directly output, and is sampled and held by the operational amplifier and the first sampling capacitor; during low-level analog-to-digital conversion in the second step, the input slope signal is input to the positive input end of the operational amplifier, the operational amplifier transfers the voltage change of the positive input end to a floating pole plate of the second sampling capacitor in a mode that the gain is 1, and the voltage is superposed to the holding voltage in the first step and serves as the output of the slope conversion circuit. According to the slope conversion circuit, gain errors caused by parasitic capacitors in a process of transferring the voltage change of the two-step type integral analog-to-digital converter can be effectively eliminated, and the accuracy and the speed are improved.

Description

technical field [0001] The invention belongs to the technical field of semiconductors and integrated circuits, and in particular relates to a slope conversion circuit applied to a two-step integral analog-to-digital converter in an integrated circuit. Background technique [0002] Due to its simple structure, low power consumption, and high precision, the integral analog-to-digital converter has very obvious advantages in the low-speed field, especially in the application of multi-channel parallel analog-to-digital converters, the integral analog-to-digital converter is even more Widely used for its excellent channel-to-channel consistency. But the conversion time of the traditional B-bit integrating ADC is 2 B clock cycle, this shortcoming limits the improvement of its accuracy. Therefore, the integral analog-to-digital converter changes from the traditional one-step structure to the two-step structure, and the relationship between conversion time and accuracy is changed ...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problems existing in the prior art of the above-mentioned two-step single-slope single-slope integral analog-to-digital converter, the present invention provides a slope conversion circuit to solve the problem of the first In the process of switching from the first step to the second step and the voltage change caused by the second step operation to the output of the slope conversion circuit, the problem of gain error due to parasitic capacitance

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