Backlight Control Module Ripple Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LCD panels require a separate back light source due to non-self-illumination, leading to manufacturing challenges and increased costs when trying to control multiple channels with a single converter, resulting in voltage fluctuations and ripple values in constant current supply.
Innovation Solution
A back light device with a first light emitting block of series-connected modules, a power supply module, a power switch, and a control module that adjusts the turn-on and turn-off periods of the power switch to maintain a constant ripple value in the current supply, allowing for efficient control of multiple channels with a single converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple channels are connected to one converter, then device complexity is reduced and manufacturing costs decrease, but voltage fluctuations occur causing ripple value variations in constant current supply
Solution Approach 1:
The patent applies dynamics by making the power switch timing adjustable and adaptive. The control module dynamically adjusts the turn-on and turn-off timing of the power switch based on the operational state of light emitting modules, allowing the system to maintain stable constant current despite variations in channel configuration. This dynamic timing adjustment resolves the contradiction by enabling single-converter operation while preventing voltage fluctuations.
Solution Approach 2:
The patent implements feedback through the control module that monitors the actual current and adjusts the power switch timing accordingly. The control module receives information about the operational state of light emitting modules and adjusts the power switch timing to maintain stable constant current, thereby resolving the contradiction between simplified converter configuration and current stability.
2Reliability
If each channel is controlled separately, then constant current stability is maintained, but device complexity increases requiring separate converters for each channel
Solution Approach 1:
The patent applies universality by designing a single converter that can control multiple light emitting modules through shared power switch timing control. The control module universally manages the power delivery to all channels by adjusting the power switch timing, eliminating the need for separate converters per channel while maintaining constant current stability through coordinated control.
Solution Approach 2:
The patent merges multiple channel control functions into a single converter system. By combining the power delivery functions and using a unified control strategy for the power switch timing, the system achieves multi-channel control with one converter, reducing device complexity while maintaining the reliability of constant current supply through integrated control.
3Ease of operation
If power switch timing is fixed, then device operation is simple, but ripple value fluctuations occur when light emitting modules are turned on or off
Solution Approach 1:
The patent transitions from fixed to dynamic power switch timing control. The control module adjusts the turn-on and turn-off timing of the power switch based on the operational state of light emitting modules, preventing ripple value fluctuations. This dynamic adjustment maintains operational simplicity while significantly improving current stability and reducing electromagnetic interference.
Solution Approach 2:
The control module performs preliminary timing adjustment before voltage fluctuations occur. By anticipating the on/off states of light emitting modules and pre-adjusting the power switch timing accordingly, the system prevents ripple value fluctuations before they can affect system performance, maintaining both operational simplicity and electrical stability.
Data Source
AI summary
A back light device includes a first light emitting block including a plurality of light emitting modules connected in series to each other; a power supply module that applies a driving voltage to the first light emitting block; a first power switch connected to the first light emitting block and controls the driving voltage on or off; and a control module that turns on or off the first power switch such that a constant current is supplied to the first light emitting block and controls an on/off of the plurality of light emitting modules based on a dimming signal. The control module, in response to a ripple value of the constant current being different from a certain ripple value, changes at least one of a turn-on period and a turn-off period of the first power switch to calibrate the ripple value of the constant current to the certain ripple value.