LED Channel Open-Circuit Detection Using Terminal Voltage Monitoring
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Solution Overview
Problem
In LED devices with multiple channels, open-circuited channels are difficult to detect without increasing power consumption and causing heating issues, as existing methods involve providing maximum voltage to all channels to identify open-circuited ones.
Innovation Solution
A driving apparatus and method that includes a power converter, current controllers, a detection controller, and a state detector to identify open-circuited channels by determining a detection time based on terminal voltages, using a state detection current that is smaller than the operation current, and comparing voltages with reference voltages to minimize power consumption and heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If maximum voltage is provided to LED channels to detect open-circuited channels, then detection capability is improved, but power consumption increases and heating problems occur
Solution Approach 1:
The patent applies preliminary action by detecting open-circuited LED channels before the LEDs are fully turned on, during the voltage rise phase. The detection controller monitors terminal voltages while the power converter is still ramping up the output voltage, allowing detection to occur before full operating voltage is reached. This prevents the need to maintain maximum voltage for detection purposes, thereby reducing power consumption and heat generation while still achieving accurate open-circuit detection.
2Measurement precision
If maximum voltage is provided to LED channels to detect open-circuited channels, then detection capability is improved, but heating problem increases
Solution Approach 1:
The patent applies preliminary action by detecting open-circuited LED channels before the LEDs are fully turned on, during the voltage rise phase. The detection controller monitors terminal voltages while the power converter is still ramping up the output voltage, allowing detection to occur before full operating voltage is reached. This prevents the need to maintain maximum voltage for detection purposes, thereby reducing power consumption and heat generation while still achieving accurate open-circuit detection.
3Use of energy by moving object
If state detection current is used instead of operation current, then power consumption is reduced, but detection time determination complexity increases
Solution Approach 1:
The patent applies feedback by using the detection controller to monitor terminal voltages of LED channels and compare them against reference voltages. The controller receives feedback signals from voltage dividers that sample the terminal voltages, and based on this feedback, the controller determines when the detection time has been reached (when terminal voltage exceeds a threshold). This feedback mechanism enables automatic detection time determination without requiring complex external timing circuits, balancing reduced power consumption with manageable control complexity.
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
Effectively detects open-circuited channels before reaching operating voltage, reducing power consumption and heat generation while maintaining efficient LED operation.
Implementation Method 1
a power converter for converting an input voltage into an output voltage to output the output voltage to an output terminal
Implementation Method 2
a state detector for detecting the open-circuited states of the plurality of LED channels based on voltages of the second terminals of the plurality of LED channels at the detection time
Data Source
AI summary
An apparatus for driving an LED device having a plurality of LED channels is disclosed. Each LED channel has a plurality of LEDs connected in series. A power converter converts an input voltage into an output voltage and outputs the output voltage to an output terminal that is connected to first terminals of the plurality of LED channels. A plurality of current controllers are connected to second terminals of the plurality of LED channels, respectively. Each current controller controls a current of a corresponding LED channel. A detection controller determines a detection time based on voltages of the second terminals of the plurality of LED channels. A state detector detects the open-circuited states of the plurality of LED channels based on voltages of the second terminals of the plurality of LED channels at the detection time.