Charge-sharing digital to analog converter and successive approximation analog to digital converter

Abstract

In one embodiment, an analog to digital converter includes a comparator having a first input, a second input and an output, the first input being coupled to an analog signal, a successive approximation register having a serial input coupled to the output of the comparator, and being configured to generate a plurality of control signals and an N-bit digital value corresponding to the analog signal, and a digital to analog converter having an input coupled to the plurality of control signals, the digital to analog converter further comprising a first, a second, and a third capacitor and a plurality of switches controlled by the plurality of control signals and being configured to couple the first capacitor to the second capacitor and the third capacitor to the second capacitor mutually exclusively to share charge on the first capacitor and charge on the third capacitor with charge on the second capacitor and to generate an analog signal on the second capacitor, the second capacitor being coupled to the second input of the comparator.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to electronics and more particularly to analog and digital signal converters.BACKGROUND OF THE INVENTION[0002]Electronic components have been developed that convert analog to digital signals and vice versa. These converters are used in applications that receive inputs from analog sensors and / or in cases where digital signals are used to interface with analog components. An analog to digital converter (hereinafter referred to “ADC”), converts an analog voltage to a digital number. A digital to analog converter (hereinafter referred to “DAC”), converts a digital number to an analog equivalent signal.[0003]In certain applications the speed of the signal conversions is controlling. In some of these cases, the converter must be able to keep up with rapidly changing data. In other applications the ability to resolve between two close analog voltages is controlling. The number of bits that make up the digital number as wel...

AI Technical Summary

Benefits of technology

The patent describes an analog to digital converter that includes a comparator, a successive approximation register, and a digital to analog converter. The comparator compares multiple analog signals and generates control signals based on the comparison. The successive approximation register uses the control signals to generate a digital value for each analog signal. The digital to analog converter uses the control signals to couple multiple capacitors and switches to generate the analog signals. The technical effect of this invention is to provide a more efficient and accurate analog to digital converter that can handle multiple analog signals simultaneously.

Problems solved by technology

For example, the number of capacitors used in an ADC / DAC may result in a large footprint for the ADC / DAC. FIG. 1 shows an example of the front end of an N-bit DAC found in the prior art.

However, serial D / A converters, such as the one shown in FIG. 2 are excessively slow for certain applications, and suffer from non-ideal behavior due to charge injection from the switches.

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