Analog-to-digital converter, touch sensing chip and electronic device

An analog-to-digital converter, comprising a digital-to-analog conversion circuit, a comparator, a successive approximation register logic circuit and a residue sampling and summing circuit,

• the successive approximation register logic circuit coupled to an output terminal of the comparator and a control terminal of the digital-to-analog conversion circuit, the successive approximation register logic circuit configured to produce a corresponding quantized digital signal each time, based on the result of comparison from the comparator,
• the digital-to-analog conversion circuit comprising an output terminal coupled to a first input terminal of the comparator, the digital-to-analog conversion circuit configured to receive a common reference voltage signal and a current analog input signal and produce a corresponding residual voltage based on the analog input signal and the common reference voltage, wherein the digital-to-analog conversion circuit is under the control of each quantized digital signal output from the successive approximation register logic circuit,
• the residue sampling and summing circuit comprising an input terminal coupled to the output terminal of the digital-to-analog conversion circuit and an output terminal coupled to a second input terminal of the comparator, the residue sampling and summing circuit configured to obtain a corresponding residue each time, by sampling the residual voltage output from the digital-to-analog conversion circuit, sum a previous sampled residue and the common reference voltage and provide the sum to the comparator,
• the comparator configured to compare a current output of the residue sampling and summing circuit with a current output of the digital-to-analog conversion circuit and thereby obtain a current result of comparison.