Tree Structured Power Distribution for DAC Linearity
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Solution Overview
Problem
Current steering digital-to-analog converters (DACs) face challenges in maintaining linearity due to IR drops in power and bias voltage distribution across current sources, leading to differences in current cells, which degrade DAC performance and increase integral non-linearity (INL).
Innovation Solution
A multi-tiered tree structure power distribution system is implemented, with top-tier power distribution trunks supplying power to bottom-tier connections, and a unifier to eliminate second-order effects of IR drops, ensuring equal power and bias distribution across current sources, thereby enhancing DAC linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a multi-tiered tree structure power distribution system is implemented, then power and bias distribution uniformity is improved, but device complexity increases
Solution Approach 1:
The power distribution system is divided into multiple tiers with top-tier trunks branching into bottom-tier connections, creating a hierarchical structure that reduces IR drops by distributing power through intermediate nodes rather than direct long connections
Solution Approach 2:
The unifier circuit is introduced as an intermediary component between the power distribution network and current sources, actively compensating for second-order IR drops and ensuring uniform power delivery across all current sources
2Manufacturing precision
If segmentation is increased to reduce DNL, then linearity is improved, but area and complexity increase
Solution Approach 1:
The invention changes the power distribution parameters by implementing a multi-tiered tree structure with optimized trunk and connection dimensions, altering how power is delivered to current sources to reduce IR drops without increasing segmentation
3Device complexity
If low segmentation is used to simplify design, then device complexity is reduced, but linearity deteriorates due to larger DNL
Solution Approach 1:
The unifier acts as a mediator that compensates for the linearity issues arising from low segmentation by actively balancing the power delivery to each current source, eliminating second-order IR drop effects that would otherwise degrade DNL
4Area of stationary object
If conventional power distribution is used, then area is minimized, but noise increases due to IR drops
Solution Approach 1:
The power distribution network is segmented into top-tier trunks and bottom-tier connections, creating multiple intermediate distribution points that reduce the magnitude of IR drops and associated noise in each segment
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
This approach achieves better power and bias distribution with reduced noise and silicon area, resulting in improved resolution and reduced device stress, effectively mitigating the IR drop issues and enhancing the dynamic performance of analog circuits.
Implementation Method 1
maintaining linearity due to IR drops in power and bias voltage distribution across current sources
Implementation Method 2
a unifier to eliminate second-order effects of IR drops, ensuring equal power and bias distribution across current sources
Implementation Method 3
Bias voltages are generated by diode-connected devices and shared by all current source cells
Data Source
AI summary
Systems and methods are disclosed for performing data conversion by matching current sources using a thin oxide device; and minimizing voltage stress on the thin oxide device during operation or power down.