Over-Current Prevention in OLED DC-DC Converters
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Solution Overview
Problem
Organic light emitting display devices are prone to damage due to over-currents caused by short circuits between data-lines, voltage-lines, and electrodes, leading to degradation or burning of the display panel.
Innovation Solution
Incorporating an over-current prevention unit that detects currents flowing through inductors in DC-DC converters and blocks driving voltage supplies when the current exceeds a reference value, using a detector, comparison unit, and block unit to prevent over-currents from reaching the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If data-lines, voltage-lines, and electrodes are formed in the display panel to enable operation, then the display device can function properly, but short circuits may occur causing over-current that damages the organic light emitting diode
Solution Approach 1:
The over-current prevention unit performs preliminary detection of current through the inductor before the current reaches the organic light emitting diode. By detecting current in advance and comparing it with a reference value, the system can block excessive current before it causes damage, thus preventing the harmful effect before it occurs.
Solution Approach 2:
The over-current prevention unit acts as an intermediary between the power supply and the display panel. It includes a detector that monitors current, a comparison unit that evaluates the current against reference values, and a block unit that intervenes to block current when necessary. This intermediary structure allows normal operation while providing protection against over-current.
2Reliability
If an over-current prevention unit is added to detect and block excessive current, then the organic light emitting diode is protected from damage, but the device complexity increases
Solution Approach 1:
The over-current prevention unit is integrated with the existing DC-DC converter circuit by sharing the inductor that is already part of the power supply. The detector is coupled to the output terminal of the inductor, and the block unit can control the switch in the DC-DC converter. This merging approach allows over-current protection functionality to be added without requiring completely separate protection circuits, thereby reducing overall complexity.
Solution Approach 2:
The inductor in the DC-DC converter serves multiple functions: it is part of the voltage conversion circuitry and simultaneously serves as the sensing point for over-current detection. The switch in the DC-DC converter also serves dual purposes as part of the voltage regulation mechanism and as a controllable element for blocking current during over-current conditions. This multi-functionality reduces the need for additional dedicated components.
Data Source
AI summary
An organic light emitting display device includes a display panel including an organic light emitting diode, a power supply including a DC-DC converter that generates a driving voltage for the organic light emitting diode and that provides the driving voltage to the display panel, the DC-DC converter including an inductor and a switch, and an over-current prevention unit that blocks supply of the driving voltage when a value of a current flowing through the inductor is greater than a reference value.