R2R DAC Reference Current Compensation for Stable Voltage
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Solution Overview
Problem
Conventional R2R digital-to-analog converters experience unstable reference voltage due to fluctuating reference current, leading to reduced resolution and performance in terms of signal-to-noise and distortion (SINAD) and spurious-free dynamic range (SFDR).
Innovation Solution
A compensation circuit is introduced to decode digital code fluctuations and generate a compensation code, which is used to stabilize the reference current, resulting in a constant current value for the reference voltage, thereby maintaining a stable reference voltage across different digital codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference current is used to generate reference voltage in an R2R DAC, then the DAC can convert digital code to analog output signal, but the reference current generates current value fluctuation according to the digital code, causing unstable reference voltage and reduced resolution and performance
Solution Approach 1:
The patent implements a feedback mechanism where the fluctuating reference current is fed back to a compensation circuit that generates a compensating signal. This compensating signal is then applied to counteract the fluctuations, stabilizing the reference voltage. The feedback loop continuously monitors and corrects the reference current variations, resolving the contradiction between maintaining functional operation and ensuring voltage stability.
Solution Approach 2:
The patent introduces a compensation circuit as an intermediary element between the reference current source and the R2R DAC. This intermediary circuit processes the fluctuating reference current and generates a stabilized version by producing compensating signals that offset the fluctuations. The mediator approach allows the system to maintain both the necessary current variation for digital code conversion and the voltage stability required for high resolution.
2Productivity
If the reference current fluctuates according to digital code to enable conversion operation, then the DAC functions properly, but the reference voltage becomes unstable, reducing SINAD and SFDR performance
Solution Approach 1:
The compensation circuit uses feedback from the reference current fluctuations to generate corrective signals. The feedback mechanism detects the current variations caused by digital code changes and produces compensating voltages that stabilize the reference voltage, thereby maintaining both conversion functionality and performance reliability.
Solution Approach 2:
The patent converts the harmful effect of reference current fluctuations into a beneficial signal. By feeding back the fluctuation information and generating compensating signals that mirror the fluctuations in opposite polarity, the system transforms the destabilizing effect into a stabilizing mechanism, maintaining both operational functionality and performance reliability.
Data Source
AI summary
A digital-to-analog conversion device and a compensation circuit are provided. A digital-to-analog conversion device includes an R2R digital-to-analog converter and a compensation circuit. The R2R digital-to-analog converter is configured to receive a digital code with a plurality of bits and receive a reference voltage, and convert the digital code into an analog output signal according to the reference voltage. The compensation circuit is configured to receive the digital code, decode the digital code to generate a compensation code with a plurality of bits, and compensate the current value of the reference current according to the compensation code to generate a compensated reference current. The compensated reference current has a constant current value corresponding to different digital codes to make the reference voltage constant.