Low power delta sigma converter
AssigneeGeneral Electric Company
InventorsDavid Byrd Ribner, Juha Mikko Hakkarainen, David Henry Kenneth Hoe
Life of this patent
Estimating the term…
Abstract
A delta sigma modulator that has a low power dissipation without sacrificing modulator resolution includes, in one embodiment, a current mode digital to analog converter (DAC) in shunt with a conventional op amp in the first stage of the delta sigma modulator. By adding the current mode DAC in shunt with the first (or only) stage op amp of the delta sigma modulator, the slewing current needed during transients is provided by the combination of the op amp and DAC output signals. Since the DAC provides the slewing current required for the output signal change, the op amp need not apply the slewing current and therefore need only operate at low quiescent power.
Claims15
A delta sigma analog-to-digital converter comprising:
- an oversampled interpolative modulator for receiving an input analog signal to be converted and generating an output digital signal;
- a digital filter coupled to receive the output digital signal of said oversampled interpolative modulator for generating a filtered digital output signal;
- and
- a decimator coupled to receive the filtered digital output signal of said digital filter for reducing the sampling rate of said filtered digital output signal, said oversampled interpolative modulator comprising:
- at least a first integrator coupled to receive samples of the input analog signal and for generating an integrated analog output signal V.sub.O ;
- an analog-to-digital converter coupled to receive the output signal of said first integrator;
- a digital-to-analog converter coupled to receive the output signal of said analog-to-digital converter, an output of said digital-to-analog converter being coupled to the input of said first integrator;
- a step-size estimator coupled to the output of said analog-to-digital converter for estimating a voltage .DELTA.V.sub.0 ;
- and
- a current mode digital-to-analog converter controlled by the output of said step-size estimator and coupled between the output of said first integrator and the input of said analog-to-digital converter.
An oversampled interpolative modulator for receiving an input analog signal and generating an output digital signal, said modulator comprising:
- at least a first integrator coupled to receive samples of the input analog signal and for generating an integrated analog output signal V.sub.O ;
- an analog-to-digital converter coupled to receive the output signal of said first integrator;
- a digital-to-analog converter coupled to receive the output signal of said analog-to-digital converter, an output of said digital-to analog converter being coupled to the input of said first integrator;
- a step-size estimator coupled to the output of said analog-to-digital converter for estimating a voltage .DELTA.V.sub.0 required to be added to output signal V.sub.O ;
- and
- a current mode digital-to-analog converter controlled by said step-size estimator and coupled between the output of said first integrator and the input of said analog-to-digital converter.
Dependencies are inferred from the claim text.