Dynamic Resistance Delta-Sigma Modulator for Low-Noise Fast Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Delta-Sigma modulators used in analog-to-digital converters for digital pixel image sensors face challenges in achieving high-speed integration and high signal handling due to issues like detector bias spikes, power consumption, and modulator clock jitter, which limit dynamic range and signal-to-noise ratio.
Innovation Solution
The proposed electronic circuit incorporates a dynamic resistance element with variable resistance, a charge transfer switch, and a recharge circuit, allowing for efficient charge transfer between capacitors on a common supply voltage, reducing power supply spiking and increasing integration speed while maintaining low noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional Delta-Sigma modulators are used for high-speed integration, then integration speed increases, but detector bias spikes and power consumption increase
Solution Approach 1:
The patent introduces a dynamic resistance element as an intermediary component between the integrating capacitor and the detector. This element acts as a mediator that controls charge transfer, enabling fast integration when needed while preventing bias spikes by dynamically adjusting its resistance based on voltage conditions across the detector.
Solution Approach 2:
The patent employs a dynamic resistance element whose resistance value changes over time based on voltage conditions. This dynamic behavior allows the circuit to adapt its charge transfer characteristics during operation, providing low resistance for fast integration and high resistance for preventing bias spikes, thus resolving the contradiction between speed and harmful effects.
2Measurement precision
If conventional Delta-Sigma modulators operate at high clock frequencies, then ADC resolution improves, but power consumption increases
Solution Approach 1:
The patent implements periodic charge transfer through the dynamic resistance element, controlled by clock signals. This periodic action enables the circuit to achieve high ADC resolution through multiple sampling cycles while consuming less power than continuous operation, as the dynamic resistance element efficiently manages charge transfer only when needed during each period.
Solution Approach 2:
The patent changes the resistance parameter of the dynamic resistance element based on operating conditions. By adjusting resistance values dynamically, the circuit can optimize power consumption at different clock frequencies while maintaining the necessary charge transfer for high ADC resolution, thus resolving the contradiction between precision and energy use.
3Reliability
If conventional Delta-Sigma modulators are used, then dynamic range can be achieved, but circuit layout area increases
Solution Approach 1:
The patent extracts the dynamic resistance element as a separate, dedicated component from the conventional modulator architecture. This extraction allows for optimized placement and sizing of the resistance element, reducing overall circuit area while maintaining dynamic range performance by focusing the area investment on the most critical function.
Solution Approach 2:
The dynamic resistance element provides a compact solution for achieving wide dynamic range by replacing larger, static circuit components with a dynamically controllable element. This dynamic approach allows the same component to serve multiple functions across different operating ranges, reducing the total area required compared to conventional static designs.
Data Source
AI summary
The present disclosure provides a delta-sigma modulator circuit for use in a pixelated image sensor or a readout integrated circuit. In one aspect, the modulator circuit includes a dynamic resistance element configured to have a variable resistance that changes in accordance with a voltage difference across the dynamic resistance element.