Adaptive DAC Switch-Driver Calibration for Low Distortion
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Solution Overview
Problem
Current digital-to-analog converters (DACs) face challenges in maintaining low distortion across operation corners without increasing area or power consumption, particularly due to non-idealities at the common source node in current-steering DACs.
Innovation Solution
Incorporating calibration circuitry that senses the voltage of the common source node and adjusts the power supply voltage for the switch driver to ensure optimal operation, thereby reducing disturbance and improving dynamic performance across process, voltage, and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If calibration circuitry is added to sense voltage and adjust power supply for switch driver, then distortion is reduced and SNDR is improved, but device complexity increases
Solution Approach 1:
The calibration circuitry senses the voltage at the common source node and uses this feedback information to adjust the power supply voltage for the switch driver, creating a closed-loop system that reduces distortion by compensating for voltage variations
Solution Approach 2:
The calibration circuitry acts as an intermediary component that mediates between the power supply and the switch driver, adjusting the power supply voltage based on sensed conditions to optimize switch driver performance and reduce distortion
2Manufacturing precision
If calibration circuitry is added to sense voltage and adjust power supply for switch driver, then signal-to-noise-and-distortion ratio is improved, but area increases
Solution Approach 1:
The calibration circuitry is integrated within the DAC structure, merging the calibration function with the existing DAC components rather than adding completely separate calibration equipment, thereby reducing the overall area impact
3Manufacturing precision
If power supply voltage is adjusted dynamically for switch driver, then distortion is reduced across operation corners, but power consumption increases
Solution Approach 1:
The power supply voltage for the switch driver is adjusted dynamically based on the sensed voltage at the common source node, allowing the system to adapt to different operation corners and reduce distortion while managing power consumption through conditional adjustment rather than continuous maximum power delivery
Data Source
AI summary
Methods and apparatus for controlling a power supply voltage for a switch driver in a digital-to-analog converter (DAC). An example DAC generally includes a plurality of DAC cells, each DAC cell comprising a current source, a first switch coupled in series with the current source at a first node, and a switch driver having an output coupled to a control input of the first switch; and calibration circuitry having a first input coupled to a first DAC cell in the plurality of DAC cells and having an output coupled to at least one of the plurality of DAC cells, the calibration circuitry being configured to sense a voltage of the first node in the first DAC cell and to control the power supply voltage for the switch driver in the at least one of the plurality of DAC cells, based on the sensed voltage of the first node.