LED Short Detection Circuit for Low-Voltage SoC Integration
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Solution Overview
Problem
Traditional LED short detection methods require high-voltage processes, making it difficult to integrate LED short detection circuits into low-voltage integrated circuits like system on chip (SoC), and they often necessitate a large number of pins for the backlight controller, increasing production costs.
Innovation Solution
An apparatus and method that utilize a first node, a second node, a voltage generator, a current source, and a comparator to detect LED short circuits by generating a comparison result based on the voltage across the LED string, allowing for detection without the need for high-voltage integration and reducing the number of pins required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional high-voltage process is used for LED short detection, then detection accuracy is improved, but integration into low-voltage integrated circuits becomes difficult and device complexity increases
Solution Approach 1:
The patent introduces an intermediary circuit that converts the high-voltage detection signal into a low-voltage signal suitable for integrated circuit processing. The converter circuit acts as a mediator between the high-voltage LED string and the low-voltage detection circuitry, enabling accurate detection without requiring high-voltage process integration.
Solution Approach 2:
The patent changes the voltage parameter of the detection signal from high-voltage to low-voltage through the converter circuit. By transforming the signal parameter, the system achieves LED short detection accuracy while maintaining compatibility with low-voltage integrated circuit processes.
2Reliability
If more pins of backlight controller are used for LED short detection, then detection capability is improved, but production cost increases
Solution Approach 1:
The patent designs the backlight controller with multi-functional pins that can serve both LED drive functions and detection functions. The same pins used for controlling LED strings are also utilized for detecting LED shorts through the converter circuit, eliminating the need for additional dedicated detection pins and reducing production costs.
Solution Approach 2:
The patent merges the LED drive function and detection function into a unified circuit architecture. By combining these functions and sharing common pins and circuit resources, the system achieves reliable LED short detection without increasing the pin count or production cost.
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
Enables efficient detection of LED short circuits within low-voltage integrated circuits, reducing production costs by minimizing the number of pins needed for the backlight controller while maintaining effective LED short detection capabilities.
Implementation Method 1
The voltage generator generates an output voltage to the first external circuit via the second node
Implementation Method 2
The current source, coupled to the first external circuit via the first node, provides a current to the first external circuit via the first node to generate a first node voltage
Implementation Method 3
The first comparator, coupled to the first node, generates a first comparison result according to the first node voltage and a reference voltage
Data Source
AI summary
An apparatus and method for detecting a status of at least one of a plurality of light emitting diodes (LEDs), is disclosed in embodiments of the invention. The apparatus includes a first node, a second node, a voltage generator, a current source and a first comparator. The voltage generator generates an output voltage to the first external circuit via the second node. The current source provides a current to the first external circuit via the first node to generate a first node voltage. The first comparator generates a first comparison result according to the first node voltage and a reference voltage, wherein the first comparison result indicates whether the status of at least one of the LEDs is short or not.