Display Driving Circuit Dark Current Reduction
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Solution Overview
Problem
Display devices using semiconductor light-emitting elements, such as LEDs, face high power consumption due to standby currents, known as dark currents, especially at low luminance settings, where the proportion of dark current to total power consumption increases, making it challenging to reduce overall energy usage.
Innovation Solution
A display driving circuit that includes element drivers, a memory for storing lighting period information, an element lighting period controller, and a common line lighting period controller, which adjusts the activation of common lines based on actual lighting periods, reducing unnecessary driving and dark current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the common driver is turned on in accordance with the maximum lighting period, then the light-emitting elements can be driven for the full displayable time, but dark current flows intermittently even in black display state, increasing power consumption
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the actual lighting period for each common line in advance before driving the light-emitting elements. The common line lighting period controller reads the lighting period information from memory and uses it to control the switching timing of the common driver, ensuring the driver is turned on only when needed and turned off during black display periods, thus preventing unnecessary dark current flow.
Solution Approach 2:
The patent implements dynamics by making the common driver's operation dynamic rather than static. Instead of keeping the common driver on for a fixed maximum lighting period, the system dynamically adjusts the driver's on/off timing based on the actual lighting period information stored in memory. This allows the common driver to be turned off during periods when no light-emitting elements need to be driven, reducing power consumption while maintaining the ability to drive elements for the full duration when needed.
2Loss of energy
If the display device operates at low luminance, then energy consumption is reduced, but the proportion of dark current to total power consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the actual lighting period for each common line in advance before driving the light-emitting elements. The common line lighting period controller reads the lighting period information from memory and uses it to control the switching timing of the common driver, ensuring the driver is turned on only when needed and turned off during black display periods, thus preventing unnecessary dark current flow.
Solution Approach 2:
The patent converts the potentially harmful effect of dark current into a benefit by using the lighting period information to intelligently control when the common driver is active. Instead of letting dark current flow continuously or for fixed periods, the system uses the stored lighting period data to turn off the common driver during black display periods, transforming what would be wasted energy into active power savings, especially beneficial at low luminance settings.
Data Source
AI summary
A display driving circuit drives a display unit including a plurality of light-emitting elements connected along respective common lines and arranged in a matrix. The driving circuit includes one or more element drivers for driving the plurality of light-emitting elements of the display unit, a memory that stores lighting period information indicating a lighting period in which each light-emitting element is lit by the one or more element drivers, an element lighting period controller that outputs the lighting period information stored in the memory to each element driver, a switching unit that selects each common line based on the lighting period information stored in the memory, and a common line lighting period controller that is interposed between the memory and the switching unit and controls a lighting period in which each common line is activated according to the lighting period information.