Error cancellation delta-sigma dac with an inverting amplifier-based filter

An apparatus comprising:

• a delta-sigma modulator digital-to-analog converter section having a multiple stage cascaded error cancellation architecture including a first stage and a second stage, wherein the first stage comprises a first delta-sigma modulator configured to receive a digital input and a first digital-to-analog converter having an input coupled to an output of the first delta-sigma modulator, and the second stage comprises a second delta-sigma modulator and a second digital-to-analog converter having an input coupled to an output of the second delta-sigma modulator, an input to the second delta-sigma modulator being based on a scaled difference between the output of the first delta-sigma modulator and the digital input, an analog output of the delta-sigma modulator digital-to-analog converter section being based on a combination of a scaled output of the second digital-to-analog converter and an output of the first digital-to-analog converter;
• and
• an inverting amplifier-based analog filter coupled to receive the analog output, the inverting amplifier-based analog filter configured to filter the analog output to produce a filtered analog output,
• wherein the analog output is a current signal, and the inverting amplifier-based analog filter is configured to both convert the current signal to a voltage and to perform filtering to produce the filtered analog output.

A method comprising:

• at a delta-sigma modulator digital-to-analog converter section having a multiple stage cascaded error cancellation architecture including a first stage and a second stage, receiving a digital input at a first delta-sigma modulator of the first stage;
• subtracting an output of the first delta-sigma modulator from the digital input to produce a difference;
• scaling the difference to produce a scaled difference that is provided as input to a second delta-sigma modulator of the second stage;
• converting, with a first digital-to-analog converter of the first stage, the output of the first delta-sigma modulator to produce a first analog signal;
• converting, with a second digital-to-analog converter of the second stage, an output of the second delta-sigma modulator to produce a second analog signal;
• generating an analog output of the delta-sigma modulator digital-to-analog converter section being based on a combination of the first analog signal and a scaled version of the second analog signal of the second digital-to-analog converter;
• and
• filtering the analog output with an inverting amplifier-based analog filter to produce a filtered analog output.