Switched Capacitor LED Matrix Driver Gain Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LED driver circuits face efficiency losses when driving multiple LED strings with different forward voltages from a single regulated source, as they require bulky and expensive inductive buck converters to maintain high efficiency, which also suffer from electromagnetic interference (EMI).
Innovation Solution
The use of switched capacitor (SC) DC-to-DC converters between the regulated source and LED strings, which can adjust their gain levels to match the number of active LEDs in each string, allowing for efficient operation with minimal components and reduced EMI, thereby achieving high efficiency even with varying LED string voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inductive buck converters are used to drive multiple LED strings with different forward voltages, then high efficiency is maintained, but device complexity and electromagnetic interference increase
Solution Approach 1:
The system divides the LED strings into different groups based on their forward voltage characteristics. Each group is driven by a dedicated SC converter with optimized gain settings, allowing efficient operation for each segment while reducing overall system complexity compared to using inductive converters for all strings.
Solution Approach 2:
The patent changes the operating parameters by using SC converters with adjustable gain levels instead of fixed inductive converters. The gain can be dynamically adjusted to match the number of active LEDs in each string, maintaining high efficiency across different voltage conditions without the complexity of inductive designs.
2Loss of energy
If inductive buck converters are used to drive multiple LED strings with different forward voltages, then high efficiency is maintained, but cost increases
Solution Approach 1:
The patent replaces expensive inductive buck converters with cheaper SC converter implementations. The SC converters can be realized using simple switched capacitor circuits that are much less expensive to manufacture, while still achieving the required efficiency through proper gain adjustment.
3Device complexity
If a single voltage regulator is used to power multiple LED strings with different forward voltages, then device complexity is reduced, but efficiency dramatically decreases
Solution Approach 1:
The system segments the LED strings into groups that share similar forward voltage requirements. Each segment is then driven by an SC converter with gain optimized for that specific group, maintaining high efficiency while keeping the overall architecture simpler than using inductive converters for every string.
Solution Approach 2:
The SC converters are designed to be universal components that can efficiently drive multiple LED strings with different voltage requirements by adjusting their gain. This multi-functionality allows a single type of converter to replace multiple specialized inductive converters, reducing overall system complexity.
4Loss of energy
If SC converters with adjustable gain are used to drive LED strings, then efficiency is maintained across different voltages, but device complexity increases
Solution Approach 1:
The SC converters incorporate dynamic gain adjustment capability that automatically adapts to the number of active LEDs in each string. This dynamic operation allows the converters to maintain optimal efficiency across varying voltage conditions without requiring complex control circuitry, as the gain adjustment follows simple rules based on LED string configuration.
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 solution enables efficient driving of multiple LED strings with different voltages from a single source, achieving near 100% efficiency by using compact, cost-effective SC converters that reduce complexity and electromagnetic interference, while maximizing battery life in applications like electric vehicles.
Implementation Method 1
The techniques of this disclosure may utilize a switched capacitor DC-to-DC converter between the regulated source and the LED string
Data Source
AI summary
This disclosure is directed to techniques for efficiently driving multiple light emitting diode (LED) strings from a single regulated source. The techniques of this disclosure may utilize a switched capacitor DC-to-DC converter between the regulated source and the LED string. The switched capacitor (SC) converter may have multiple gain levels to efficiently match the drive voltage from the regulated source to the LED string voltage for each particular LED string. In some examples, the SC converter may have multiple gain levels such that the SC converter may deliver an LED string voltage that is approximately a multiple of the number of LEDs in the LED string. Using capacitor components in an SC converter may have the advantages of small size and low cost.