Power Supply Controller for LED Arrays Using Time-Multiplexed Current Sharing
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Solution Overview
Problem
Existing power supply controllers for multiple lighting components in battery-powered devices face issues such as large semiconductor die area, high pin count, limited usage cases, and efficiency limitations due to separate current sources and boost converters for each LED array, leading to uneven luminosity and high power consumption.
Innovation Solution
A power supply controller with a common current source and adaptive boost converter that uses time-sharing and pulse-width modulation to ensure identical current to each LED array, allowing for simultaneous use of multiple lighting components while reducing voltage drop and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate current sources and boost converters are used for each LED array, then independent luminosity control is achieved, but semiconductor die area increases
Solution Approach 1:
The patent merges multiple separate current sources and boost converters into a single shared current source and a single boost converter that serves all LED arrays. This consolidation is achieved through a multiplexer that dynamically connects the shared current source to different LED arrays, enabling independent luminosity control without requiring separate power supply circuits for each array, thus significantly reducing semiconductor die area.
Solution Approach 2:
The shared current source and boost converter are designed to serve multiple LED arrays universally. The multiplexer enables these components to be dynamically allocated to different LED arrays based on operational requirements, allowing the same hardware resources to provide independent luminosity control for multiple displays simultaneously.
2Adaptability or versatility
If separate current sources are used for each LED array, then independent luminosity control is achieved, but pin count increases
Solution Approach 1:
The patent consolidates multiple current source outputs into a single shared current source that is time-multiplexed across different LED arrays. This merging approach reduces the number of required output pins from the current source by factor equal to the number of LED arrays, while the multiplexer adds minimal pin overhead compared to having separate current sources for each array.
3Adaptability or versatility
If multiple lighting components are activated simultaneously, then lighting coverage is improved, but uniformity of lighting decreases
Solution Approach 1:
The patent implements periodic time-multiplexed switching where the shared current source is sequentially connected to different LED arrays in rapid succession. Each LED array receives current during its designated time slot, creating the perception of simultaneous operation while actually using periodic sequential activation. This approach ensures uniform current delivery to each array during its active period, maintaining lighting uniformity while enabling multiple displays to be illuminated.
Solution Approach 2:
The system dynamically allocates the shared current source to different LED arrays based on real-time operational requirements. The multiplexer dynamically switches connections to provide current to the appropriate LED array, enabling flexible simultaneous illumination of multiple displays while maintaining precise control over current distribution to ensure uniform lighting quality.
4Loss of energy
If separate boost converters are used for different lighting arrays, then voltage drop control is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple separate boost converters into a single shared boost converter that serves all LED arrays through time-multiplexed operation. The converter is dynamically controlled to provide appropriate voltage boosting to the currently active LED array, reducing voltage drop efficiently without requiring multiple converter circuits. This consolidation significantly reduces device complexity and component count while maintaining effective voltage control.
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 achieves improved uniformity and efficiency in lighting, reduces semiconductor die area, and allows for simultaneous operation of multiple lighting components with minimal luminosity mismatch and high power supply efficiency, addressing the limitations of existing systems.
Implementation Method 1
with a DC-DC converter, for example
Implementation Method 2
the backlight may comprise a plurality of light emitting diodes (LEDs)
Data Source
AI summary
A power supply controller for a plurality of lighting components in a battery-powered apparatus. The power supply controller comprises a current source common to the lighting components, and a sequencer for coupling the current source sequentially to each of the lighting components with a repetition rate substantially faster than the flicker perception rate. Each of the lighting components comprises a respective array of lighting elements connected in series to receive the same current as the other lighting elements of the same lighting component.