Sigma-Delta Modulator Resonator Tuning for PVT Error Correction
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Solution Overview
Problem
Sigma-delta modulators (SDMs) are susceptible to resolution degradation and errors due to manufacturing process, voltage, and temperature (PVT) variations, necessitating a correction method and circuit to maintain efficiency and accuracy.
Innovation Solution
A correction method and circuit for SDMs that input a test signal, obtain signal characteristic values, and adjust the resonator of the loop filter to optimize the noise transfer function, thereby improving the signal-to-noise ratio (SNR) and reducing error vector magnitude (EVM) and noise intensity, especially in the frequency band of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the SDM is used as an ADC, then analog-to-digital conversion is achieved, but resolution degradation and errors occur due to PVT variations
Solution Approach 1:
The patent adjusts the resonator parameters (such as resonant frequency and quality factor) based on measured signal characteristic values to compensate for PVT variations. By dynamically changing the resonator parameters, the system maintains optimal performance across different operating conditions, thereby resolving the contradiction between measurement precision and reliability under PVT variations.
2Measurement precision
If the resonator is adjusted to correct PVT effects, then SNR and noise characteristics improve, but additional correction circuitry is required
Solution Approach 1:
The patent implements a feedback mechanism where the output signal of the SDM is fed back to measure signal characteristic values, which are then used to adjust the resonator parameters. This closed-loop feedback system automatically compensates for PVT effects and optimizes SNR without requiring complex external correction circuitry, thus resolving the contradiction between measurement precision and device complexity.
3Reliability
If correction is performed during chip operation, then real-time performance optimization is achieved, but correction time is required
Solution Approach 1:
The patent performs correction by adjusting the resonator parameters during chip operation based on real-time measurement of signal characteristic values. This preliminary action approach allows the system to proactively compensate for PVT variations before they significantly degrade performance, maintaining operational stability while minimizing correction time through continuous monitoring and adjustment.
Data Source
AI summary
A correction method and a correction circuit for a sigma-delta modulator (SDM) are disclosed. The SDM includes a loop filter, a quantizer, and a digital-to-analog converter (DAC), and the loop filter includes a resonator. The correction circuit includes a memory and a control circuit. The memory stores multiple program instructions. The control circuit executes the program instructions to correct the SDM. The correction procedure of the SDM includes the following steps: inputting a test signal to the SDM; obtaining a signal characteristic value of an output signal of the SDM; and adjusting the resonator according to the signal characteristic value.