LED String Driver Short-Circuit Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED string driving systems require complex structures and high costs, and are unable to timely protect LED strings from short circuits and other abnormal conditions.
Innovation Solution
A method and system that uses a transistor with a control terminal connected to a driving system, where detected voltages are compared with multiple reference voltages to adjust power supply and detect short circuits, requiring only one or two pins for connection, reducing the number of external pins needed and saving costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional LED short-circuit protector circuit is used, then LED strings can be protected from short circuits, but the circuit structure becomes complex and costs increase
Solution Approach 1:
The patent extracts the protection function from a complex dedicated protector circuit and integrates it into the existing LED driver IC. By using the existing transistor switching elements and control logic within the driver IC, the protection function is achieved without adding separate external protection circuits, thereby reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The LED driver IC is designed to perform multiple functions: normal LED string driving control and short-circuit protection detection. The same transistor and control circuitry used for LED dimming and switching are also utilized for detecting short-circuit conditions, eliminating the need for separate protection components and reducing device complexity.
2Reliability
If a conventional LED short-circuit protector circuit is used, then LED strings can be protected from short circuits, but costs increase
Solution Approach 1:
The protection function is merged with the LED driver IC functionality. By integrating the short-circuit detection and protection logic into the existing driver chip, the patent eliminates the need for separate protection ICs or additional external components, thereby reducing component count, simplifying assembly, and lowering manufacturing costs while maintaining protection reliability.
Solution Approach 2:
The LED driver IC performs self-diagnosis for short-circuit conditions using its own internal transistors and control logic. The system monitors its own operational state and automatically detects faults without requiring external protection circuits, reducing overall system cost while maintaining protection capability.
3Reliability
If a conventional LED short-circuit protector circuit is used, then LED strings can be protected from short circuits, but the protection cannot occur timely
Solution Approach 1:
The patent implements real-time feedback monitoring of the LED string status through the transistor control terminals. The driver IC continuously monitors voltage levels and current flow, and when a short-circuit condition is detected, the system immediately responds by adjusting transistor switching or shutting down affected strings, providing timely protection without delay.
Solution Approach 2:
The system performs preliminary detection of abnormal conditions by monitoring voltage levels at transistor control terminals before complete failure occurs. By detecting early signs of short-circuit conditions through voltage threshold comparisons, the system can take preventive action before damage propagates, ensuring timely protection.
Data Source
AI summary
A method of driving an LED string is provided and includes steps of: (a) determining whether or not a detected voltage of a control terminal of a transistor is lower than a first reference voltage by a first comparator, if not, raising a voltage of the LED string by a power supply device and performing step (a), if yes, performing step (b); (b) determining whether or not the detected voltage is lower than a second reference voltage by a second comparator, if not, determining that a short circuit occurs, if yes, performing step (c); (c) increasing an output current of the LED string by an input current source; and (d) determining whether or not a current of the LED string reaches a maximum current that is adjustable by a light controller, if yes, determining that a short circuit occurs, if not, returning to step (c).