LED Driving Apparatus Open-Circuit Fault Detection
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Solution Overview
Problem
Existing LED devices stop operation unnecessarily when an open-circuit condition occurs, as the protection circuit fails to differentiate between short-circuit and open-circuit faults, leading to premature shutdown of the power converter.
Innovation Solution
A driving apparatus and method for an LED device that includes a power converter, current controllers, a voltage sensor, and a fault controller. The fault controller compares the sensed voltage with a reference voltage after a predetermined period, using a timer and logic operations to determine if the power converter should be stopped, thereby distinguishing between short-circuit and open-circuit conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection circuit stops operation when the end terminal voltage becomes 0V, then the power converter is protected from short-circuit damage, but the LED device stops operation unnecessarily when an open-circuit fault occurs
Solution Approach 1:
The protection function is segmented into two independent detection mechanisms: one for short-circuit faults (voltage sensing) and one for open-circuit faults (current sensing). This allows each fault type to be handled independently, preventing the misidentification problem where open-circuit faults were incorrectly treated as short-circuit faults.
Solution Approach 2:
A fault type determination unit is introduced as an intermediary that analyzes both voltage and current sensor signals to identify the actual fault type before triggering the protection response. This intermediary layer prevents direct and incorrect mapping of 0V detection to power converter shutdown, enabling accurate fault-based decision making.
2Device complexity
If the protection circuit uses only voltage sensing at the end terminal, then the circuit complexity is reduced, but the fault detection precision cannot differentiate between short-circuit and open-circuit conditions
Solution Approach 1:
The protection circuit is designed with multi-functionality by incorporating both voltage sensing (for short-circuit detection) and current sensing (for open-circuit detection) capabilities within a single integrated protection module. This allows the circuit to handle multiple fault types without requiring separate independent protection systems.
Solution Approach 2:
The fault type determination unit serves as an intermediary that processes signals from both voltage and current sensors, analyzing their combined information to accurately identify fault types. This intermediary layer enables precise fault differentiation while maintaining a relatively simple overall circuit structure.
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 allows the LED device to continue normal operation during open-circuit faults while stopping the power converter only when a short-circuit occurs, preventing unnecessary shutdowns and ensuring reliable operation.
Implementation Method 1
The voltage sensor may include a plurality of resistors connected in series between the output terminal and a ground terminal, and may sense a fraction of the output voltage by voltage division of the resistors as the sensed voltage
Implementation Method 2
The power converter has an output terminal connected to a first terminal of each LED channel, and converts an input voltage into an output voltage to output the output voltage to the output terminal
Data Source
AI summary
A driving apparatus of an LED device is provided. The LED device includes a plurality of LED channels, and each LED channel includes a plurality of LEDs connected in series. A power converter has an output terminal connected to a first terminal of each LED channel, and converts an input voltage into an output voltage to output the output voltage to the output terminal. A plurality of current controllers correspond to the plurality of LED channels, respectively. Each current controller is connected to a second terminal of a corresponding LED channel, and controls a current of the corresponding LED channel. The voltage sensor outputs a sensed voltage corresponding to the output voltage of the output terminal. The fault controller determines whether to stop operation of the power converter by comparing the sensed voltage with a reference voltage.