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US 12,126,363 B2Granted
Error cancellation delta-sigma DAC with an inverting amplifier-based filter
AssigneeCisco Technology, Inc.
InventorsBibhu Prasad Das, Romesh Kumar Nandwana, Richard Van Hoesen Booth, Pavan Kumar Hanumolu, Kadaba Lakshmikumar
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Abstract
An apparatus includes a delta-sigma modulator digital-to-analog converter section having a multiple stag cascaded error cancellation architecture, each stage including a delta-sigma modulator followed by a digital-to-analog converter, the delta-sigma modulator digital-to-analog converter section configured to receive a digital input and to generate an analog output. An inverting amplifier-based analog filter is coupled to receive the analog output, the inverting amplifier-based analog filter configured to filter the analog output to produce a filtered analog output.
Claims20
An apparatus comprising:
- a delta-sigma modulator digital-to-analog converter section having a multiple stage cascaded error cancellation architecture, each stage including a delta-sigma modulator followed by a digital-to-analog converter, the delta-sigma modulator digital-to-analog converter section configured to receive a digital input and to generate an analog output;
- 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 wherein 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.
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.
1 more element
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, wherein the analog output is a current signal;
- converting the current signal to a voltage signal with an inverting amplifier-based analog filter;
- and
- filtering the voltage signal with the inverting amplifier-based analog filter to produce a filtered analog output.
6 more elements
Dependencies are inferred from the claim text.