LED Driving Device Current Range Segmentation
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Solution Overview
Problem
Existing driving circuits for LEDs face challenges in maintaining high accuracy of output current, especially at low current values, due to error sources that become significant when the working current range is wide, leading to display defects in applications like LCDs, and current solutions either increase device size or require complex trimming and higher costs.
Innovation Solution
The driving device partitions the output current into multiple partial current ranges, using conversion units and control mechanisms to selectively enable branches and adjust reference voltages, maintaining high accuracy without significant size increases or complex trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the working current range is made wide to allow versatile usage, then adaptability is improved, but manufacturing precision deteriorates due to increased relative weight of error sources at low current values
Solution Approach 1:
The patent divides the wide working current range into multiple partial current ranges, with each range handled by a dedicated conversion unit. This segmentation allows each unit to be optimized for its specific range, maintaining high precision even at low current values while preserving overall adaptability across the full range.
2Manufacturing precision
If error sources are limited by increasing the size of the driving device, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
Instead of increasing overall device size to reduce error impact, the patent segments the current range and uses multiple conversion units with overlapping partial voltage ranges. This approach maintains precision without requiring a single large device, as each unit is sized appropriately for its specific current range.
3Manufacturing precision
If operational amplifier with low offset voltage is used to improve accuracy, then manufacturing precision is improved, but device complexity increases due to heavy trimming and higher circuit complexity
Solution Approach 1:
The patent avoids the need for heavy trimming by segmenting the current range into multiple partial ranges handled by different conversion units. Each unit operates within its optimized range, eliminating the requirement for complex trimming procedures while maintaining high accuracy.
Solution Approach 2:
The control means dynamically selects which conversion unit to activate based on the required current value and swings the reference voltage within appropriate partial voltage ranges. This dynamic adaptation allows the system to maintain high precision across the full current range without requiring static high-precision components with complex trimming.
4Manufacturing precision
If multiple conversion units with partitioned current ranges are used, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
Multiple conversion units share common control means and reference voltage generation, allowing them to function as a unified multi-range system. This multi-functionality approach reduces overall complexity compared to having completely separate circuits for each current range, as the conversion units can be selectively activated based on the required current level.
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 approach achieves high accuracy of the output current across a wide range without increasing the device size or requiring heavy trimming, thus reducing costs and ensuring uniform LED control, which is crucial for display applications.
Implementation Method 1
an operational amplifier with an inverting input terminal for the first partial working range and another inverting input terminal for the second partial working range
Data Source
AI summary
An embodiment of a driving device is proposed for supplying at least one regulated global output current to a load. The driving device includes programming means for programming a value of the global output current within a global current range. Reference means are provided for supplying a reference voltage, which has a value corresponding to the value of the global output current. Conversion means are then used for converting the reference voltage into the global output current. The conversion means may further include a plurality of conversion units for corresponding partial current ranges, which partition the global current range.