Abstract: An analog-to-digital converter (ADC) is provided. The ADC receives an analog input signal and generates a digital code. The ADC includes a sigma-delta modulator (SDM), a decimation filter and a detection circuit. The SDM includes a loop filter, a quantizer and a digital-to-analog converter (DAC). The loop filter receives the analog input signal. The quantizer is coupled to the loop filter and quantizes an output of the loop filter to generate a digital output signal. The DAC is coupled to the quantizer and the loop filter. The decimation filter is coupled to the SDM and converts the digital output signal into the digital code. The detection circuit is coupled to the SDM and detects a node voltage of the SDM and generate a control signal. The control signal is utilized to control the loop filter, the quantizer, a feedback path of the SDM and/or a feedforward path of the SDM.