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US 6,369,730 B1Granted
Sigma-delta analog-to-digital converter
AssigneeU.S. Philips Corporation
InventorsPieter G. Blanken, Eric J. Van der Zwan, Eise C. Dijkmans
Life of this patent
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Abstract
Sigma-delta analog-to-digital converter topology with an error signal branch including a subtractor (10), a loop filter (4), and a quantizer (6), and a feedback branch including a digital-to-analog converter (8). The gain error caused by a return-to-zero switch in the feedback branch is cancelled by moving the return-to-zero switch (20) to the signal error branch.
Claims2
A sigma-delta analog-to-digital converter for converting an analog input signal into a digital output signal, comprising in a signal processing loop:
- means (10) for providing a difference signal in response to the analog input signal and an analog feedback signal, said means (10) comprising a first voltage-to-current converter (12) for converting the analog input signal to a first output current and a second voltage-to-current converter (14) for converting the analog feedback signal to a second output current;
- means (4) for filtering the difference signal and for providing a filtered difference signal;
- means (6) for sampling and quantizing the filtered difference signal and having an output (26) for providing the digital output signal;
- a digital-to-analog converter (8) for converting the digital output signal to the analog feedback signal;
- and
- a return-to-zero switch (20) included in the signal processing loop, characterized in that the return-to-zero switch (20) is arranged between an output (22) of the means (10) for providing the difference signal and an input (24) of the means (4) for filtering the difference signal.
3 more elements
Dependencies are inferred from the claim text.