Backlight Driving Module LED Fault Isolation Circuit
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Solution Overview
Problem
The existing display apparatuses with backlight modules face damage to the driving circuit when an LED in the string is broken, as the current systems lack effective protection mechanisms to isolate faulty LEDs and prevent voltage imbalances from affecting the entire backlight driving module.
Innovation Solution
The proposed solution involves a backlight driving module with a feedback system that includes switching units and detecting units to compare voltages between adjacent LEDs, generating control signals to either establish or cut off electrical connections, thereby isolating damaged LEDs and preventing damage to the driving circuit while ensuring the remaining LEDs continue to emit light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backlight driving chip outputs specified voltage to each string of LEDs, then the illumination units can emit light normally, but the driving circuit will be damaged when one LED in the string is broken
Solution Approach 1:
The patent implements a feedback mechanism where detecting units continuously monitor the voltage across each illumination unit. When an LED fails open-circuit, the voltage across that illumination unit becomes abnormally high. The detecting unit detects this voltage change and feeds back a signal to the backlight driving chip, which then adjusts the driving voltage to prevent damage to other components. This feedback loop enables the system to adapt to LED failures and maintain reliable operation.
Solution Approach 2:
The patent employs preliminary protective actions by equipping each illumination unit with detecting units that continuously monitor voltage conditions before damage can occur. When an LED fails, the detecting unit immediately detects the abnormal voltage and triggers the switching unit to isolate the faulty illumination unit before the voltage imbalance can propagate and damage the driving circuit or other LEDs. This preliminary detection and isolation prevent catastrophic failures.
2Productivity
If the system continues to operate with a broken LED, then productivity is maintained, but the driving circuit may be damaged
Solution Approach 1:
The patent divides the backlight module into multiple independent illumination units, each with its own detecting unit and switching unit. When an LED fails in one string, only the affected illumination unit is isolated by its switching unit, while other illumination units continue to receive normal driving voltage and operate normally. This segmentation allows the system to maintain productivity by keeping functional segments operational while protecting the overall system reliability by isolating the faulty segment.
3Illumination intensity
If voltage compensation is implemented for failed LEDs, then illumination uniformity is improved, but device complexity increases
Solution Approach 1:
The patent merges the detecting function and switching control function into an integrated control mechanism within the backlight driving chip. The detecting units monitor voltage across illumination units, and the backlight driving chip processes this information to control the switching units, combining multiple functions into a unified system. This integration reduces device complexity compared to having separate independent control circuits for each illumination unit, while still achieving the goal of maintaining illumination uniformity by compensating for failed LEDs through selective voltage adjustment.
Data Source
AI summary
A display apparatus includes a display panel, a display driving module, a backlight module, and a backlight driving module. The backlight module includes a plurality of illumination units. The backlight driving module includes a driving circuit, a plurality of switch units, and a plurality of detecting units. Each of the switch units connects to exactly one of the illumination units, and each of the detecting units connects to exactly one of the illumination units and two of the illumination units simultaneously. When the illumination unit connected to the switch unit corresponding to the detecting unit is damaged, the detecting unit controls the connected switch unit to be turned off for cutting off an electrical connection between the driving circuit and the illumination unit corresponding to the connected switch unit, and the remaining illumination units continue to emit light.