Display Driver IC Temperature Compensation for Always-On Display Accuracy
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Solution Overview
Problem
Electronic devices with an always-on-display (AOD) function face increased time errors in the clock signal when the processor does not supply a reference clock to the display driver integrated circuit (DDI), leading to inaccuracies in time display due to environmental factors like temperature changes.
Innovation Solution
Incorporating a sensor, such as a temperature sensor, to measure variables and correct time errors between the clock signal-generated time information and a reference time, allowing the processor to deliver corrected time information to the DDI for accurate display, even without a reference clock from the processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the processor does not supply a reference clock to the DDI in AOD mode to save power, then power consumption is reduced, but time error accumulation increases
Solution Approach 1:
A temperature sensor is introduced as an intermediary to measure temperature changes that affect the oscillator. The DDI uses this temperature information to compensate for frequency drift without requiring a reference clock from the processor, thus maintaining time accuracy while saving power.
Solution Approach 2:
The system implements feedback by continuously monitoring temperature changes through the temperature sensor and using this information to dynamically adjust the clock signal frequency in the DDI. This closed-loop compensation maintains time accuracy despite the absence of processor-supplied reference clock.
2Device complexity
If the DDI operates without reference clock correction in AOD mode, then device complexity is reduced, but time error increases due to environmental factors
Solution Approach 1:
The DDI performs self-correction of time errors by using the temperature sensor to detect environmental changes and automatically adjusting its own clock signal. This self-service mechanism eliminates the need for complex external reference clock infrastructure while maintaining time accuracy.
Solution Approach 2:
The system changes the operating parameters of the clock signal based on temperature measurements. The DDI adjusts the frequency of the clock signal dynamically according to temperature variations, thereby compensating for time errors without increasing system complexity.
3Measurement precision
If temperature information is used to correct time errors, then time accuracy is improved, but device complexity increases due to additional sensor and processing requirements
Solution Approach 1:
The temperature sensor is merged with the existing DDI structure, and the temperature compensation function is integrated into the DDI's clock management circuitry. This consolidation minimizes additional complexity by combining multiple functions into existing components rather than adding separate dedicated systems.
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
This approach minimizes time errors in AOD mode, reduces power consumption by minimizing the frequency of error corrections, and reduces the maximum error range of the clock signal, thereby ensuring accurate and efficient time display on the electronic device.
Implementation Method 1
a temperature sensor, and at least one processor identifying temperature information measured by using the temperature sensor
Implementation Method 2
The frequency of the clock signal may vary depending on environmental factors such as a change in temperature of the oscillator
Data Source
AI summary
Disclosed is an electronic device including a display panel, an oscillator generating a clock signal, a display driving integrated circuit (DDI) generating first time information, using the clock signal, a sensor, and at least one processor identifying a variable measured by using the sensor or second time information corresponding to a reference time. The at least one processor is configured to measure a variable, using the sensor, to correct an error time between the first time information and second time information corresponding to a reference time, based on the variable, and to deliver the corrected error time or the second time information to the DDI such that the DDI corrects the first time information based on the corrected error time to display a screen of the display panel. Besides, various embodiments as understood from the specification are also possible.