Delta-Sigma ADC Reference Voltage Compensation for THD Stability
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Solution Overview
Problem
Conventional delta-sigma analog-to-digital converters (ADCs) experience reference voltage fluctuations due to non-linear withdrawn charges, which degrade the total harmonic distortion (THD) performance.
Innovation Solution
A delta-sigma ADC with a reference voltage compensator that uses the digital output signal to stabilize the reference voltage, thereby reducing fluctuations and improving THD performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reference voltage generator provides withdrawn charges to the sampling capacitors during the transferring phase, then the ADC can complete the signal conversion process, but the reference voltage fluctuates due to non-linear charge withdrawal
Solution Approach 1:
The patent implements a feedback mechanism where the fluctuating reference voltage is fed back to the reference voltage generator, which then adjusts the withdrawn charges to compensate for the fluctuations. This closed-loop feedback system stabilizes the reference voltage while maintaining the signal conversion capability during the transferring phase.
Solution Approach 2:
The patent dynamically changes the parameter of withdrawn charges based on the detected reference voltage fluctuations. By adjusting the charge amount in response to voltage variations, the system maintains stable reference voltage levels while continuing to complete the ADC conversion process.
2Productivity
If the reference voltage fluctuates due to non-linear withdrawn charges, then the ADC can operate in transferring phase, but the total harmonic distortion (THD) performance degrades
Solution Approach 1:
The feedback mechanism monitors reference voltage fluctuations caused by non-linear charge withdrawal and adjusts the charge amount accordingly. This stabilization of reference voltage directly improves THD performance while maintaining the ability to operate in the transferring phase.
Solution Approach 2:
The system takes preliminary action by adjusting the withdrawn charges before significant voltage fluctuations occur. The feedback mechanism anticipates and counteracts the non-linear charge effects, preventing THD degradation before it impacts the conversion accuracy.
Data Source
AI summary
The present invention provides a delta-sigma ADC, wherein the delta-sigma ADC includes an adder, a loop filter, a quantizer, a DAC and a reference voltage compensator. The adder is configured to subtract a feedback signal from an input signal to generate a first signal. The loop filter is configured to receive the first signal to generate at least one filtered signal. The quantizer is configured to generate a digital output signal according to the at least one filtered signal. The DAC is configured to perform a digital-to-analog conversion operation on the digital output signal to generate the feedback signal. The reference voltage compensator is configured to compensate a reference voltage to generate an adjusted reference voltage according to the digital output signal, wherein the adjusted reference voltage is used by the DAC to perform the digital-to-analog conversion operation on the digital output signal to generate the feedback signal.