LED Driver Brightness Control via Dynamic Current Mirror Rates
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Solution Overview
Problem
Conventional LED drivers face challenges in maintaining LED current within a preset variation range across a wide operating current range, leading to increased test time and cost, and incorrect adjustment of variation amounts.
Innovation Solution
An LED driver with brightness control that adjusts the first rate of a first current mirror, the second rate of a second current mirror, and the reference current based on image brightness information, ensuring a product of these rates is a fixed value, thereby reducing LED current loss and eliminating the need for pre-adjustment of variations across different operating ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the LED driver operates within a wide operating current range, then the brightness control range is improved, but the LED current variation exceeds the preset variation range
Solution Approach 1:
The patent applies dynamics by making the current mirror rates adjustable rather than fixed. The first current mirror rate and second current mirror rate are dynamically changed based on the operating current range, allowing the system to adapt to different brightness levels while maintaining precise LED current control within the preset variation range throughout the entire operating current range.
2Device complexity
If the LED driver uses fixed current mirror rates, then the device complexity is reduced, but the LED current cannot be maintained within preset variation range
Solution Approach 1:
The patent transforms the static current mirror rates into dynamic adjustable parameters. The controller modifies the first current mirror rate and second current mirror rate according to the detected operating current range, enabling precise LED current control without significantly increasing device complexity through systematic rate adjustment methods.
3Manufacturing precision
If the operator adjusts the variation in sections, then the LED current variation can be maintained in preset range, but the test time and cost increase
Solution Approach 1:
The patent implements self-service by enabling the LED driver to automatically adjust its current mirror rates based on the operating current range without requiring manual operator intervention. The controller autonomously detects the current range and selects appropriate rate combinations, eliminating the need for time-consuming manual testing and adjustment across different sections.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the first current mirror rate and second current mirror rate according to predefined operating current ranges. This parameter-based approach allows the system to maintain precise LED current control while avoiding extensive manual testing, as the rate adjustments are determined by the operating conditions rather than requiring empirical section-by-section calibration.
4Manufacturing precision
If the operator adjusts the variation in sections, then the LED current variation can be maintained in preset range, but the adjustment amount may be incorrect
Solution Approach 1:
The patent implements self-service by enabling the LED driver to automatically adjust its current mirror rates based on the operating current range without requiring manual operator intervention. The controller autonomously detects the current range and selects appropriate rate combinations, eliminating the need for time-consuming manual testing and adjustment across different sections.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the first current mirror rate and second current mirror rate according to predefined operating current ranges. This parameter-based approach allows the system to maintain precise LED current control while avoiding extensive manual testing, as the rate adjustments are determined by the operating conditions rather than requiring empirical section-by-section calibration.
Data Source
AI summary
The present disclosure provides an LED driver with brightness control and a driving method thereof, which adjust a first rate of a first current mirror, a second rate of a second current mirror, and a reference current of a current source according to the brightness to be presented (related to image brightness information) to adaptively adjust an LED current flowing through an LED string, thereby reducing the loss of the LED current during operation over an operating current range. Besides, the LED driver with brightness control and the driving method thereof do not require that an operator adjusts the variation of the LED current in different operating current ranges in advance, thereby reducing the test time and cost and avoiding the operator from deciding a wrong adjustment amount.