Capacitive nonlinear calibration circuit of bit-by-bit approximation analog-digital converter and method

Abstract

The invention belongs to the technical field of analog-digital converters, and particularly relates to a capacitive nonlinear calibration circuit of a bit-by-bit approximation analog-digital converter and a method. The circuit structurally comprises a digital-analog converter, a clock control circuit, a calibration logic control circuit, an error measurement and storage circuit, a summator logic circuit, a comparator circuit and a bit-by-bit approximation analog-digital converter logic circuit. The method comprises the steps that the calibration logic control circuit is switched on, the analog-digital converter starts to carry out error measurement, and the error measurement and storage circuit calculates and stores the error factors of capacitors on all bits respectively; after the error factors are all stored, the calibration logic control circuit is switched off, and the analog-digital converter adds output codes and the error factors through the summator to obtain the final calibration output code. The capacitive nonlinear calibration circuit and the method are suitable for the high-precision low-power-consumption bit-by-bit approximation analog-digital converter, and mainly have the advantage that under the condition of not adding extra analog circuits, nonlinear errors caused by stray capacitors and capacitor array mistaching in a calibration capacitor array and hardware and power consumption cost are low.

Description

technical field [0001] The invention belongs to the technical field of analog-to-digital converters, and in particular relates to a capacitance nonlinear calibration circuit and method of a bridge-connected capacitance array type bit-by-bit approximation analog-to-digital converter, which can compensate the capacitance nonlinearity problem caused by process deviation. Background technique [0002] With the development of integrated circuits and the continuous self-fulfillment of Moore's Law, modern analog and analog-digital hybrid circuits require smaller power consumption and higher precision. Under this opportunity, important changes have taken place in the application fields of traditional analog-to-digital converters. Under the requirements of medium speed and medium precision, bit-by-bit approximation analog-to-digital converters are being widely used by people due to their extremely low power consumption and small area. Attention, its application in medical equipment, ...

AI Technical Summary

Problems solved by technology

There is similarity between this method and the present invention, but it requires additional analog circuits, and the power consumption requirement is relatively large

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