LED Constant-Current Trimming Using Stored Memory Calibration
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Solution Overview
Problem
Existing constant current driving devices face challenges in supplying precise constant current to LEDs and non-volatile memory devices due to non-uniform device characteristics and current fluctuations, leading to reduced trimming accuracy.
Innovation Solution
A constant current driving device with a reference current source, memory for storing fine current trimming data, and a current control circuit that adjusts the output current based on this data to match a target current, ensuring high-precision constant current supply despite device characteristics and operational fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional constant current driving devices are used, then device simplicity is maintained, but current precision deteriorates due to non-uniform device characteristics and current fluctuations
Solution Approach 1:
The patent segments the current control into multiple independent components: a reference current source generating base current, a memory device storing trimming data, and a current control circuit applying corrections. This segmentation allows each component to be optimized independently, achieving high current precision without requiring complete redesign of the entire driving device.
Solution Approach 2:
The patent introduces memory device as an intermediary component that stores fine current trimming data. This intermediary enables precise current adjustment by mediating between the reference current source and the LED, allowing correction of current deviations without direct complex control mechanisms.
2Measurement precision
If fine current trimming data is stored in memory, then current precision is improved, but device complexity increases due to additional memory and control circuits
Solution Approach 1:
The current control circuit automatically reads trimming data from memory and applies corrections without external intervention. The system serves itself by autonomously adjusting the output current based on stored trimming information, reducing the need for complex external control mechanisms while maintaining high precision.
Solution Approach 2:
The trimming data is pre-stored in the memory device during manufacturing or initialization. This preliminary action allows the system to automatically compensate for device variations without requiring real-time complex calculations or adjustments, simplifying the operational complexity while maintaining precision.
3Manufacturing precision
If output current is trimmed based on stored data, then current accuracy is improved, but manufacturing complexity increases due to trimming processes
Solution Approach 1:
The patent replaces complex mechanical or manual trimming processes with an electronic system that reads pre-stored trimming data from memory. This substitution eliminates the need for physical adjustments or complex manufacturing procedures, improving current accuracy while maintaining ease of manufacture through standardized electronic processes.
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 enables the delivery of high-precision constant current to LEDs and non-volatile memory devices, maintaining accuracy even during real-time operations and power interruptions, thereby improving brightness control and data retention.
Implementation Method 1
a reference current source configured to supply a reference current
Implementation Method 2
a memory configured to store fine current trimming data determined by a difference between a target current and an output current before trimming
Implementation Method 3
a current control circuit controlled through a circuit control signal and configured to generate an output current corresponding to the reference current and to supply an output current trimmed based on the fine current trimming data
Data Source
AI summary
The present disclosure provides a technology for precisely controlling an LED driving current using fine current trimming data stored in a memory when driving an LED.