LED Drive Circuit with Stable Voltage Reference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED drive solutions are inefficient and costly for powering arrays of hundreds or thousands of low-power micro-LEDs, as they require numerous circuits and are not optimized for medium to high total LED power applications, leading to reliability and cost issues.
Innovation Solution
A drive circuit and system topology that uses controlled current sources with a stable voltage reference to efficiently power series-connected light emitting elements, capable of sourcing milliamps of current without voltage droop, and can be scaled to accommodate up to 10,000 elements, incorporating excess voltage take-up elements to minimize component count and space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional LED driver circuits are used to power arrays of hundreds or thousands of micro-LEDs, then each LED can be driven at moderate to high current levels, but the system requires hundreds of separate driver circuits which increases device complexity and cost prohibitively
Solution Approach 1:
The patent merges multiple LED strings into parallel configurations that can be driven by a single driver circuit. Instead of requiring separate drivers for each LED or small groups, the invention combines hundreds of micro-LEDs into parallel strings that share common current paths, allowing one driver to control the entire array efficiently
Solution Approach 2:
The driver circuit is designed with universal applicability to drive large arrays of micro-LEDs across various configurations. The circuit topology supports parallel connection of multiple LED strings and can be scaled to accommodate different numbers of LEDs and power requirements, making it a multi-functional solution rather than requiring specialized circuits for each application
2Power
If high current driver circuits are used to drive micro-LEDs in parallel to achieve high total power output, then power output increases, but reliability decreases due to the large number of parallel connections and inductors required
Solution Approach 1:
The patent segments the LED array into multiple series strings that are then connected in parallel. Each string contains multiple micro-LEDs connected in series, which reduces the current requirement per string while maintaining high total power output. This segmentation approach minimizes the number of parallel connections needed compared to driving individual LEDs in parallel
Solution Approach 2:
The invention extracts and eliminates the need for individual inductors for each parallel LED connection that would be required in conventional high-current driver approaches. By using a unified driver topology with shared current paths, the design removes numerous discrete inductive components that would compromise reliability and increase complexity
3Use of energy by moving object
If low current is used to drive each micro-LED to achieve low power consumption, then individual LED current requirements are met, but the system cannot achieve medium to high total LED power output
Solution Approach 1:
The patent employs multiple copies of the same low-current LED string configuration connected in parallel. Each string operates at low current to maintain efficiency and meet micro-LED requirements, but by replicating and parallel-connecting many such strings, the system achieves high total power output through cumulative effect rather than requiring high current through single paths
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 provides inexpensive and accurate current control for LED arrays, achieving high efficiency and reliability, with system efficiency approaching 97% for medium to high total LED power applications, and can be applied to other semiconductor devices like laser diodes.
Implementation Method 1
The circuit has a stable voltage reference that is capable of sourcing milliamps of current to multiple current sources without voltage droop
Implementation Method 2
Illumination based on semiconductor light sources, such as light-emitting diodes (LEDs)
Data Source
AI summary
Strings of light-emitting elements are driven by providing a fixed voltage reference to a plurality of parallel-connected current sources, each of the current sources being connected in series with a string, supplying current from each current source to the string to which it is connected, whereby the fixed voltage reference is independent of the current supplied to each string, and taking up excess voltage not required by any one of the strings of light-emitting elements.