Digital-to-analog converter glitch reduction techniques
AssigneeAnalog Devices International Unlimited Company
InventorDennis A. Dempsey
Life of this patent
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Abstract
A digital technique to reduce or minimize switching in a DAC by using a partial DAC data ignore switching mode. In the partial DAC data ignore switching mode, a control circuit compares first and second data, such a first and second digital words, and operates corresponding switches only when the first data differ from the second data. The techniques are applicable to many types of DACs, including voltage output DACs, current output DACs, variable resistance DACs, digital rheostats, digital potentiometers, digiPOTs.
Claims20
A digital-to-analog converter (DAC) system to convert a digital input signal to an output level of an analog output signal, the DAC system comprising:
- a plurality of analog switches;
- a digital DAC register;
- a DAC circuit coupled to the digital DAC register and configured to generate the analog output signal;
- and
- a control circuit coupled to the plurality of analog switches and the digital DAC register, wherein the control circuit includes a partial DAC data ignore switching mode, and wherein the control circuit is configured to perform operations including:
- receiving first data from the digital DAC register, wherein the first data represents a first digital input signal;
- and
- receiving second data coupled to an input of the digital DAC register, wherein the second data represents a second digital input signal received after the first digital input signal;
- wherein, in the partial DAC data ignore switching mode, the control circuit is configured to perform operations including:
- comparing the first data and the second data;
- and
- operating corresponding ones of the plurality of analog switches only when DAC decoded states of the first data differ from DAC decoded states of the second data.
A method of operating a digital-to-analog converter (DAC) system to convert a digital input signal to an output level of an analog voltage output signal, the method comprising:
- receiving first data from a digital DAC register, wherein the first data represents a first digital input signal;
- and
- receiving second data coupled to an input of the digital DAC register, wherein the second data represents a second digital input signal received after the first digital input signal;
- in a partial DAC data ignore switching mode:
- comparing the first data and the second data;
- and
- operating individual ones of a plurality of analog switches only when DAC decoded states of the first data differs from DAC decoded states of the second data.
A digital-to-analog converter (DAC) system to convert a digital input signal to an output level of an analog output signal, the DAC system comprising:
- a plurality of analog switches;
- a digital DAC register;
- a DAC circuit coupled to the digital DAC register and configured to generate the analog output signal;
- and
- a control circuit coupled to the plurality of analog switches and the digital DAC register, wherein the control circuit includes a partial DAC data ignore switching mode and a normal switching mode, and wherein the control circuit is configured to perform operations including:
- receiving first data from the digital DAC register, wherein the first data represents a first digital input signal;
- and
- receiving second data coupled to an input of the digital DAC register, wherein the second data represents a second digital input signal received after the first digital input signal;
- wherein, in the partial DAC data ignore switching mode, the control circuit is configured to perform operations including:
- comparing the first data and the second data;
- and
- operating individual ones of the plurality of analog switches only when DAC decoded states of the first data differ from DAC decoded states of the second data;
- and
- wherein, in the normal switching mode, the control circuit is configured to perform operations including:
- overriding the partial DAC data ignore switching mode;
- and
- operating individual ones of the plurality of analog switches even when the first data does not differ from the second data.
Dependencies are inferred from the claim text.