Power Supply Circuit Buffer for LED Driver Stability
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Solution Overview
Problem
Existing power supply circuits in LED driver applications face instability due to transient fluctuations introduced by switching actions in the current mirror circuit, which can destabilize the output currents and affect the accuracy of grayscale levels in display screens.
Innovation Solution
A power supply circuit design that includes a reference circuit generating a reference current, a current mirror circuit with a gate driver, an input branch, and multiple output branches isolated by a buffer, allowing for dynamic adjustment of current ratios based on grayscale levels or display specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switching actions are used to adjust output currents between frames or lines, then adaptability is improved, but transient fluctuations are introduced that destabilize the current mirror circuit
Solution Approach 1:
A buffer circuit is introduced as an intermediary component between the gate driver and the current mirror circuit. This buffer isolates the switching actions from directly affecting the current mirror, absorbing transient fluctuations and preventing them from destabilizing the reference current. The buffer acts as a mediator that allows current adjustment while protecting the stability of the current mirror circuit.
2Device complexity
If multiple output branches share a common input branch, then device complexity is reduced, but switching actions in one branch affect other branches through the common input
Solution Approach 1:
The buffer circuit serves as an intermediary that decouples the multiple output branches from each other through their shared connection to the current mirror. By placing the buffer between the gate driver and the current mirror inputs, it prevents switching actions in one output branch from propagating transient fluctuations to other branches through the common input structure, ensuring independent operation while maintaining circuit simplicity.
Data Source
AI summary
The present disclosure relates to a power supply circuit, a chip, and a display screen. The power supply circuit includes a reference circuit and a current mirror circuit. The current mirror circuit mirrors a reference current provided by the reference circuit into a plurality of output currents. The current mirror circuit includes an input branch and a plurality of output branches, both of which receive the same gate driving signal to generate the plurality of output currents. A buffer is used to isolate the plurality of output branches from the input branch and improve the stability of the power supply circuit even when the current ratios of the plurality of output branches are dynamically changed.