Converter circuit, corresponding device and offset compensation method

A device, comprising:

• a signal source, the signal source configured to produce an analog signal having an offset;
• and
• a converter circuit comprising:
• an analog-to-digital signal conversion path from an input port to an output port, the input port coupled to the signal source to receive the analog signal having the offset, and the output port configured to deliver a digital output signal quantized over M levels, the digital output signal resulting from conversion to digital of the analog signal from the signal source;
• a digital-to-analog feedback path from the output port to the input port, the feedback path comprising a digital-to-analog converter configured to apply to the input port of the analog-to-digital signal conversion path an analog feedback signal produced as a function of an M-bit digital word under control of a two-state signal having alternating first states and second states during which the two-state signal has a first value and a second value, respectively;
• and
• M-bit digital word generation circuitry sensitive to the two-state signal and configured to produce the M-bit digital word, alternately:
• during the first states, as a first M-bit digital word which is a function of the digital output signal quantized over the M levels;
• and
• during the second states, as a second M-bit digital word which is a function a correction value of the offset in the analog signal.

A method, comprising:

• receiving, at an input port of an analog-to-digital signal conversion path, an analog input signal having an offset;
• delivering, at an output port, a digital output signal quantized over M levels, the digital output signal resulting from conversion to digital of the analog input signal;
• feeding back, from the output port to the input port, via a digital-to-analog feedback path comprising a digital-to-analog converter, an analog feedback signal produced as a function of an M-bit digital word;
• and
• producing the M-bit digital word, alternately:
• during first time intervals, as a first M-bit digital word which is a function of the digital output signal quantized over M levels;
• and
• during second time intervals interleaved with the first time intervals, as a second M-bit digital word which is a function a correction value of the offset in the analog input signal.