Current digital-to-analog converter with high-impedance output

A circuit comprising:

• a delta-sigma modulator configured to receive a digital input signal;
• circuitry configured to generate a differential output signal at an output comprising a first output terminal and a second output terminal, the circuitry comprising:
• a switched-tapped output impedance having a plurality of impedance elements and a plurality of taps comprising a respective tap at each end of each of the plurality of impedance elements, wherein each tap is coupled to a first power supply voltage via a respective tap switch;
• and
• wherein:
• each of the first output terminal and the second output terminal is coupled to a second power supply voltage via a respective current source;
• and
• the tap switches are responsive to the delta-sigma modulator.

A method comprising:

• receiving a digital input signal at a delta-sigma modulator;
• performing a digital-to-analog converter (DAC) decode operation responsive to the delta-sigma modulator;
• and
• generating, by a plurality of DAC elements and responsive to the DAC decode operation, a differential output current signal based on the digital input signal to:
• a load coupled to a pair of output terminals of a differential output current digital-to-analog converter (IDAC) circuit;
• and
• an output impedance coupled between the pair of output terminals such that the output impedance is in parallel with the load.

A method comprising:

• receiving a digital input signal at a delta-sigma modulator;
• generating a differential output signal at an output comprising a first output terminal and a second output terminal using circuitry comprising:
• a switched-tapped output impedance having a plurality of impedance elements and a plurality of taps comprising a respective tap at each end of each of the plurality of impedance elements, wherein each tap is coupled to a first power supply voltage via a respective tap switch;
• and
• wherein:
• each of the first output terminal and the second output terminal is coupled to a second power supply voltage via a respective current source;
• and
• the tap switches are responsive to the delta-sigma modulator.