Vision Sensor Chip Open-Loop Amplifier Reduces Transistor Count
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Solution Overview
Problem
Conventional motion sensors in portable electronic devices face challenges in reducing size and power consumption without compromising sensitivity, as they often require numerous transistors and capacitors, which can hinder performance.
Innovation Solution
Integration of an open-loop amplifier within the vision sensor chip, which includes a photoelectric conversion element, current-voltage converter, AC coupling capacitor, event detection block, and reset signal generator, allows for reduced transistor and capacitor count while maintaining sensitivity through efficient motion detection using amplified output voltage and control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the number and size of transistors and capacitors are reduced to decrease sensor size, then the size and power consumption are reduced, but the sensitivity of the motion sensor is degraded
Solution Approach 1:
The patent combines multiple functions (photoelectric conversion, current-voltage conversion, amplification, and event detection) into an integrated vision sensor pixel structure. The open-loop amplifier is directly integrated with the photoelectric conversion element and AC coupling capacitor, eliminating the need for separate discrete components and reducing overall sensor size while maintaining sensitivity through optimized signal processing within the integrated architecture.
Solution Approach 2:
The patent changes the operational parameters of the amplifier by using an open-loop configuration with direct coupling to the AC capacitor. This parameter change allows the system to achieve high gain without requiring additional feedback components, thereby reducing the number of transistors and capacitors needed while preserving signal sensitivity for motion detection.
2Use of energy by moving object
If the number and size of transistors and capacitors are reduced to decrease power consumption, then the power efficiency is improved, but the sensitivity of the motion sensor is degraded
Solution Approach 1:
The integrated structure merges the amplifier and AC coupling capacitor into a unified circuit block, reducing the total number of active components that consume power. The shared transistor structures and combined signal paths minimize redundant power consumption while maintaining the sensitivity required for accurate motion detection through coordinated operation of the integrated elements.
Solution Approach 2:
By changing the amplifier configuration to open-loop with direct AC coupling, the patent reduces the power required for signal amplification. This parameter change eliminates the need for complex feedback circuitry and associated power consumption, while the direct coupling path preserves signal integrity and sensitivity for motion detection events.
3Device complexity
If conventional motion sensor design is used, then the structure is simple, but the size and transistor count cannot be sufficiently reduced
Solution Approach 1:
The patent applies functional merging by integrating the open-loop amplifier, AC coupling capacitor, and event detection circuitry into a single vision sensor pixel unit. This consolidation reduces the overall sensor size and transistor count while maintaining structural coherence through a unified circuit architecture that processes signals through integrated paths rather than separate discrete stages.
Solution Approach 2:
The patent implements a nested structure where the open-loop amplifier is embedded within the vision sensor pixel, which itself is part of a larger sensor array. The AC coupling capacitor is nested within the amplifier circuit, and the event detection block is nested within the overall pixel structure. This nesting approach minimizes the total component count and interconnect requirements, reducing sensor size while maintaining functional simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in significantly smaller and more power-efficient motion sensors with improved sensitivity, enabling effective detection of motion while minimizing size and power consumption.
Implementation Method 1
a photoelectric conversion element that generates current based on an incident light
Data Source
AI summary
A vision sensor chip includes a photoelectric conversion element that generates a current based on an incident light, a current-voltage (I-V) converter that converts the current into a voltage, an AC coupling capacitor directly connected to the I-V converter, an open-loop amplifier that includes a reset switch and amplifies a voltage provided by the I-V converter via the AC coupling capacitor. An event detection block detects motion according to a change in the amplified output voltage and generates first and second detection signals. A reset signal generator generates a reset signal controlling operation of the reset switch in response to first and second control signals respectively related to the first and second detection signals.