Current Limiting Circuit for Display Power Control
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Solution Overview
Problem
Display devices face excessive power consumption when luminance represented by a video signal abruptly increases, such as switching from all-black to all-white display, exceeding the control target power value.
Innovation Solution
A current limiting circuit that calculates and applies a gain to the video signal based on the power consumption and its rate of change, selecting between a first gain and a second gain to limit current consumption, ensuring the power consumption does not exceed the control target value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If power consumption is reduced by calculating and limiting current based on video signal power consumption, then power consumption can be controlled within target values under normal conditions, but when luminance abruptly increases the power consumption may exceed the control target power value by a large margin
Solution Approach 1:
The patent applies preliminary action by calculating the rate of change of power consumption in advance and using this information to predict future power consumption trends. The second gain calculation circuit computes the rate of change (dP/dt) beforehand, allowing the system to anticipate abrupt luminance increases and adjust the gain accordingly, preventing power consumption from exceeding the target value even during sudden display changes.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual power consumption and comparing it with the control target power value. The gain selection circuit uses this feedback information along with the rate of change to dynamically adjust the gain applied to the video signal, ensuring that power consumption remains controlled even when luminance conditions change abruptly.
2Device complexity
If a single gain calculation method is used to limit power consumption, then the circuit structure can be simplified, but it cannot effectively handle both normal conditions and abrupt luminance changes
Solution Approach 1:
The patent applies dynamics by introducing time-varying parameters into the gain calculation process. Instead of using a static gain value, the system dynamically adjusts the gain based on the rate of change of power consumption. The second gain calculation circuit computes a time-dependent gain that adapts to changing display conditions, allowing the circuit to respond effectively to both normal and abrupt luminance changes without requiring overly complex multiple-circuit architectures.
Data Source
AI summary
A current limiting circuit is a circuit that receives a video signal for a display panel including pixels, and limits current consumption of the pixels. The current limiting circuit includes: a first gain calculation circuit that calculates a first gain for multiplying with the video signal, based on first power consumption that is power consumption of the pixels corresponding to the video signal; a second gain calculation circuit that calculates a second gain for multiplying with the video signal, based on the first power consumption and a rate of change of the first power consumption; a gain selection circuit that selects one of the first gain and the second gain as a gain by which the video signal is to be multiplied; and a gain multiplication circuit that multiplies the video signal by the gain.