Differential capacitor array applied to charge mode SAR ADC and switching method thereof

Abstract

The invention provides a differential capacitor array applied to a charge-type SAR ADC and a switching method thereof. The differential capacitor array comprises a P-terminal capacitor array, an N-terminal capacitor array, a first switch array, a second switch array and a reference voltage terminal. The first switch array is electrically connected to a reference voltage terminal and a lower plateof a P-terminal capacitor array, respectively. The second switch array is electrically connected to the reference voltage terminal and the lower plate of the N-terminal capacitor array, respectively.The upper plates of the P-terminal capacitor array and the N-terminal capacitor array are connected with the positive input VIP and the inverting input VIN through switching, respectively. Three reference voltages VREF, VCMH and VCML are used to switch the capacitor array switches, and a novel high-efficiency switching timing is combined, which is based on multi-reference voltage technology and unilateral switching technology, can greatly reduce the power consumption and area of the differential capacitor array, and meanwhile significantly reduce the settling time of the highest bit in the SARADC conversion process, and has the characteristics of high speed and low power consumption.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits and relates to a successive approximation analog-to-digital converter, in particular to a differential capacitance array applied to a charge-type SAR ADC and a switching method thereof. Background technique [0002] The successive approximation analog-to-digital converter (SAR ADC) is an analog-to-digital converter that works according to a binary search algorithm, mainly including a sample-and-hold circuit, a comparator, a digital-to-analog converter (DAC) and a successive approximation logic control. Compared with analog-to-digital converters (ADCs) of other structures, SAR ADC is an analog-to-digital converter with medium precision, medium conversion rate and low power consumption. Because SAR ADC has the advantages of simple structure, small area, low power consumption, etc., it is widely used in portable, medical and other equipment. [0003] In the circuit of SAR ADC, the functi...

AI Technical Summary

Problems solved by technology

In the SAR ADC using the traditional switching method, the power consumption of the DAC module accounts for 2 / 3 of the overall power consumption

Images