Distributed Output Network for LDO Voltage Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image sensor voltage regulator circuits face issues with voltage variation across pixel arrays due to IR drop and heat dissipation problems, which affect performance and lifespan, and increasing metal track width is not a viable solution as it requires significant circuit space and may compromise stability.
Innovation Solution
A low drop-out voltage regulator circuit with a distributed output network that spatially distributes transistors across two metal tracks, reducing IR drop and improving heat dissipation without additional circuitry, by maintaining consistent output voltage across each output node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the width of the metal output track is increased to reduce IR drop, then voltage uniformity across pixel columns is improved, but circuit space requirement increases significantly
Solution Approach 1:
The patent divides the single metal output track into multiple parallel metal tracks (first metal track, second metal track, etc.). Each track carries a portion of the total current to different pixel column groups, thereby reducing the current density and IR drop in each individual track without requiring a single excessively wide track. This segmentation approach achieves voltage uniformity while conserving circuit space.
Solution Approach 2:
The patent transitions from a single-dimensional (single track) current distribution to a multi-dimensional (multiple parallel tracks) distribution. By utilizing additional metal layers or parallel routing paths, the current is distributed across multiple spatial dimensions, reducing the IR drop effect along any single path while maintaining compact overall layout.
2Reliability
If the width of the metal output track is increased to reduce IR drop, then voltage uniformity across pixel columns is improved, but regulator stability deteriorates due to increased load capacitance
Solution Approach 1:
By segmenting the output into multiple tracks, each track presents a smaller effective capacitance to the regulator output node compared to a single wide track. This reduces the total load capacitance seen by the regulator, thereby maintaining stability while still achieving improved voltage uniformity through the distributed track structure.
3Area of stationary object
If conventional dense unit transistor layout is used in voltage regulator, then circuit space is minimized, but heat dissipation deteriorates during high current consumption
Solution Approach 1:
The patent distributes the transistor units across multiple parallel current paths instead of concentrating them in a single dense block. This spatial distribution of current-carrying elements improves heat dissipation by spreading thermal load across different regions of the circuit, while still maintaining compact overall footprint through systematic arrangement of the distributed units.
Data Source
AI summary
Disclosed is a low drop-out voltage regulator circuit with a distributed output network coupled to a pixel array for use in image sensor circuitry. The regulator circuit comprises voltage regulating circuitry and a distributed output network, wherein the distributed output network comprises drive transistors disposed along and connected between a supply track and an output track. The spatial distribution of the drive transistors improves heat dissipation within the regulator circuit, and a combination of low current flow and regulated output voltage reduces IR drop across the output track. The improved heat dissipation increases device lifespan and performance, whereas the reduction in IR drop across the output track provides better pixel response, readout uniformity, and image quality.