Charge redistribution successive approximation-type analog-to-digital converter and control method thereof

Abstract

The invention relates to a charge redistribution successive approximation-type analog-to-digital converter and a control method thereof. The charge redistribution successive approximation-type analog-to-digital converter comprises a comparator, a buffer, a control circuit, multiple first capacitors and at least one second capacitor, wherein the comparator is used for generating a comparison result; the buffer is used for storing a digital output code and deciding the bit value of the digital output code according to the comparison result; the control circuit is used for generating a control signal according to the digital output code; the first capacitor is provided with a first endpoint and a second endpoint, and the first endpoint is coupled with the first input end of the comparator; and the second capacitor is provided with a third endpoint and a fourth endpoint, and the third endpoint is coupled with the first input end of the comparator. Before the voltage of the second endpoint of each first capacitor and the voltage of the fourth endpoint of the second capacitor are switched, the second endpoint is coupled with the first voltage and the fourth endpoint is coupled with the second voltage, and the first voltage is not equal to the second voltage.

Description

technical field [0001] The present invention relates to a continuous approximation ADC, especially a charge redistribution off continuous approximation ADC and its control method. Background technique [0002] figure 1 It is a functional block diagram of a known charge redistribution (charge redistribution) continuous approximation (successive approximation) analog to digital converter (analog to digital converter, ADC). In a certain operation cycle (including the capacitor switching phase and the voltage comparison phase) of the charge redistribution continuous approximation ADC, the continuous approximation register (successive approximation register, SAR) 120 determines the digital output code Dn according to the comparison result of the comparator 105 The control circuit 130 generates the control signal Csw according to the digital output code Dn (that is, indirectly according to the comparison result). Afterwards, the digital to analog converter (DAC) 110 changes the ...

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Problems solved by technology

[0004] In view of the deficiencies in the prior art, an object of the present invention is to provide a charge redistribution continuous approximation ADC and its control method, to solve the problem that the accuracy of the continuous approximation ADC is reduced when it is applied to a single-ended signal

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