Reset-Biased Amplifier Circuit for Reliable Event Image Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Event-based image sensor devices suffer from reliability issues due to leakage currents and device noise in amplifiers, leading to unintended false events and reduced accuracy.
Innovation Solution
An amplifier design incorporating a first and second capacitor, an amplifying element, a current bias source, and reset switches, along with a reset bias generator circuit, which prevents leakage currents and device noise by resetting the floating node and output node to a reset voltage, thereby improving signal reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional amplifier design is used in event-based image sensor, then device complexity is reduced, but reliability deteriorates due to leakage currents and device noise causing false events
Solution Approach 1:
The amplifier is divided into multiple functional blocks including a first amplifying circuit with floating node, a reset circuit with reset switch, and a reset bias generator circuit. Each block performs a specific function to collectively eliminate leakage currents and device noise while maintaining manageable complexity through modular design
Solution Approach 2:
A reset bias generator circuit is introduced as an intermediary component that provides controlled reset bias to the reset switch. This intermediary element enables precise control of the reset operation to eliminate leakage currents without requiring complex redesign of the entire amplifier structure
2Reliability
If reset circuit is added to eliminate leakage current, then reliability improves, but device complexity increases due to additional components
Solution Approach 1:
The reset circuit performs preliminary action by resetting the floating node and output node to a predetermined reset voltage before the amplifier processes new input signals. This preliminary reset operation eliminates leakage currents and device noise that would otherwise accumulate and cause false events
Solution Approach 2:
The amplifier circuit serves itself by including an integrated reset bias generator that automatically provides the necessary reset bias to the reset switch. The reset bias generator uses readily available power supply voltage and ground voltage to generate the reset bias, eliminating the need for external complex biasing circuits
Data Source
AI summary
An amplifier includes a first capacitor connected between an input node and a floating node, a second capacitor connected between the floating node and an output node, an amplifying element connected between a power supply voltage and the output node and operating in response to a voltage level of the floating node, a current bias source connected between the output node and a ground voltage, a first reset switch connected between the floating node and an intermediate node and operating in response to a reset bias, a second reset switch connected between the intermediate node and the output node and operating in response to the reset bias, and a reset bias generator circuit that outputs the reset bias in response to a reset signal. The reset bias is one of a reset voltage of the intermediate node, the power supply voltage, and the ground voltage.