Lamp Driving Circuit Open State Detection via Transformer Feedback
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Solution Overview
Problem
Existing lamp driving systems for LCD backlights face challenges in detecting open states and abnormal voltages, leading to potential circuit damage and increased manufacturing costs due to complex circuit requirements.
Innovation Solution
An apparatus and method that utilize a switching module, trans-module, and open lamp detecting module to add low-voltage signals of opposite polarities to detect open states and abnormal voltages, simplifying the circuit and reducing part count, thereby protecting the lamp driving circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional open lamp detecting module is used, then lamp open states can be detected, but the circuit complexity and number of parts increase
Solution Approach 1:
The patent merges the open lamp detection function with the existing transformer feedback circuitry. The detecting module combines signal addition circuits that process feedback signals from the transformer windings, integrating detection functionality into the power conversion circuit rather than adding a separate detection system. This reduces overall device complexity while maintaining reliable open state detection.
Solution Approach 2:
The feedback circuit from the transformer serves multiple functions: it provides voltage feedback for regulation and simultaneously serves as the sensing path for open lamp detection. By making the feedback circuit universal, the patent eliminates the need for dedicated detection components, reducing part count and circuit complexity while achieving reliable detection.
2Measurement precision
If additional detection components are added, then detection accuracy improves, but manufacturing costs increase
Solution Approach 1:
The existing transformer feedback circuit performs self-service by simultaneously providing voltage regulation feedback and open lamp detection capability. The circuit uses its own internal signals (transformer winding feedback) for detection purposes, eliminating the need for external detection components and reducing manufacturing costs while maintaining accurate detection.
Solution Approach 2:
The patent detects open states by monitoring changes in voltage parameters from the transformer feedback circuit. When a lamp opens, the voltage parameter measured at the feedback node changes, allowing detection through simple voltage comparison circuits that are already present in the power conversion system. This approach maintains detection accuracy without adding expensive components.
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 states and abnormal voltages, reducing manufacturing costs and improving the reliability of backlight assemblies and liquid crystal displays by simplifying the open lamp detecting module circuit.
Implementation Method 1
a trans-module for converting the alternating signal into high-voltage signals having different phases to supply the high-voltage signals to the lamps
Implementation Method 2
an open lamp detecting module for adding low-voltage signals having different phases feedback from the trans-module to detect open states of the lamps
Data Source
AI summary
Disclosed are an apparatus and a method for controlling driving of a lamp. The apparatus for controlling driving of a lamp includes a plurality of lamps, a switching module for switching supplied power to output an alternating current (AC) signal, a trans-module for converting the alternating signal into high-voltage signals having different phases to supply the high-voltage signals to the lamps, an open lamp detecting module for adding low-voltage signals having different phases feedback from the trans-module to detect open states of the lamps, and a controller for controlling an operation of the switching module by a signal detected in the open lamp detecting module.