Methods and circuits for suppressing quantization noise in digital-to-analog converters

A circuit comprising:

• a most significant bit (MSB) path comprising:
• a first delta-sigma modulator having first and second outputs;
• and
• a first digital-to-analog converter coupled to the first output of the first delta-sigma modulator;
• an amplifier coupled to the second output of the first delta-sigma modulator;
• and
• a least significant bit (LSB) path comprising:
• a second delta-sigma modulator comprising a loop filter and a quantizer, the quantizer having an input coupled to the loop filter and to the amplifier;
• and
• a second digital-to-analog converter coupled to an output of the quantizer.

A method for controlling a digital-to-analog converter (DAC) having a plurality of switches, the method comprising:

• processing an input digital signal with a delta-sigma modulator;
• and
• generating, based on the processed input digital signal, a control signal comprising N control bits, each one of the N control bits being configured to control a respective switch of the plurality of switches of the DAC, wherein:
• the generating comprises toggling, in each of a plurality of clock cycles, a same number of control bits of the N control bits from a first value to a second value, the number being less than N, and
• the toggling comprises setting a threshold value.