Filtering applicable to digital to analog converter systems
AssigneeQUALCOMM Incorporated
InventorsEdward A. Keehr, Sean Wang, Seyfollah Bazarjani
Life of this patent
Estimating the term…
Abstract
A digital to analog converter augmented with Direct Charge Transfer (DCT) techniques. A digital to analog converter augmented with DCT and CDS techniques. A digital to analog converter augmented with Postfilter Droop Compensation.
Claims36
An electronic system comprising:
- a digital to analog converter (DAC) having a DAC output;
- and
- an analog postfilter having a postfilter input coupled to the DAC output, said analog postfilter including a first direct charge transfer (DCT) coupled filter having a first DCT coupled filter input and a first DCT coupled filter output and a second DCT coupled filter having a second DCT coupled filter input operably connected with the first DCT coupled filter output.
A method for use with an electronic system, said method comprising:
- coupling a digital to analog converter (DAC) output with an analog post filter having a first direct charge transfer (DCT) coupled filter and a second DCT coupled filter.
A method for use with an electronic system, said method comprising:
- filtering a digital to analog converter (DAC) output signal with an analog post filter having a first direct charge transfer (DCT) coupled filter and a second DCT coupled filter.
An electronic system comprising:
- a digital to analog converter (DAC) having a DAC output;
- and
- an analog postfilter having a postfilter input coupled to the DAC output, said analog postfilter including at least
- a dual common mode switching network coupled between the DAC output and a first DCT coupled filter input, and
- a second DCT coupled filter having a second DCT coupled filter input coupled to a first DCT coupled filter output.
A method for use with an electronic system, said method comprising:
- coupling a DAC output with a first direct charge transfer (DCT) coupled filter input wherein said coupling a DAC output with a first direct charge transfer (DCT) coupled filter input includes:
- coupling a DAC sampling capacitor to a DAC common mode reference with a first switch,
- coupling the first DCT coupled filter input to an analog common mode reference with a second switch, and
- the first switch and the second switch controllable such that the DAC sampling capacitor is couplable to the first DCT coupled filter input shortly after at least one of decoupling the DAC sampling capacitor from the DAC common mode reference and decoupling the first DCT coupled filter input from the analog common mode reference;
- and
- coupling a first DCT coupled filter output with a second DCT coupled filter input.
A method for use with an electronic system, said method comprising:
- compensating for a difference between a digital common mode reference voltage and an analog common mode reference voltage by coupling a Digital to Analog Converter (DAC) to the digital common mode reference voltage and coupling an analog portion to the analog common mode reference voltage at a first time and coupling at least a portion of the DAC with the analog portion at a second time;
- filtering a DAC output signal with a first direct charge transfer (DCT) coupled filter;
- and
- filtering an output of the DCT coupled filter with a second direct charge transfer (DCT) coupled filter.
An electronic system comprising:
- a digital to analog converter (DAC) having a DAC output;
- and
- an analog postfilter having a postfilter input coupled to the DAC output, said analog postfilter including at least a dual common mode switching network coupled between the DAC output and a first DCT coupled filter input.
The electronic system of 35 further comprising:
- a second DCT coupled filter having a second DCT coupled filter input coupled to a first DCT coupled filter output.
Dependencies are inferred from the claim text.