Asynchronous Piecewise Linear Column Driver for OLED Current Spikes
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Solution Overview
Problem
Current display drivers face inefficiencies in power consumption and dynamic current spikes, particularly in OLED displays, due to static current consumption and lack of control over current spikes during settling, which affects the overall performance and longevity of the display.
Innovation Solution
A high-efficiency piecewise linear column driver with asynchronous control is introduced, utilizing a bank of current sources to limit peak current and control dynamic current spikes, and employing asynchronous signaling to reduce power consumption and optimize charging times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional display drivers are used, then the display can operate, but static current consumption occurs and dynamic current spikes are uncontrolled
Solution Approach 1:
The patent implements dynamic current control by using a bank of current sources that can be selectively activated based on the charging requirements. The driver transitions from static current consumption to dynamic current control where the current magnitude and timing are adaptively adjusted during the settling period, eliminating unnecessary static current while providing controlled dynamic current spikes only when needed for charging.
Solution Approach 2:
The patent changes the current parameter from a fixed static value to a variable dynamic value. By using multiple current sources with different current levels that can be selectively enabled, the driver adjusts the current parameter based on the real-time charging state and settling requirements, thereby optimizing power efficiency while maintaining display performance.
2Productivity
If conventional amplifiers are used, then data signals can be supplied, but dynamic current spikes occur during settling
Solution Approach 1:
The patent segments the current supply function by dividing it into multiple discrete current sources within a bank. Each current source can be independently controlled and activated. This segmentation allows the driver to apply current in controlled increments during the settling period, improving charging efficiency by providing exactly the right amount of current needed without excessive current spikes that waste energy.
3Reliability
If static current is continuously supplied, then the display operates continuously, but power efficiency decreases
Solution Approach 1:
The patent implements periodic action by supplying current only during the necessary settling period after a data signal transition, rather than continuously. The driver monitors the charging state and activates current sources only when settling is needed, then deactivates them when the target voltage is reached. This periodic current supply maintains reliable display operation while dramatically reducing overall power consumption by eliminating continuous static current.
Data Source
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AI summary
A device includes a segmented pull-up current source circuit including a first plurality of transistors, a segmented pull-down current source circuit including a second plurality of transistors, a comparator circuit configured to compare an output voltage level at the output of the device with a target voltage level and generate a comparator output at one of two output terminals of the comparator circuit, wherein the segmented pull-up current source circuit and the segmented pull-down current source circuit are connected to the two output terminals of the comparator circuit via one or more multiplexers, the first plurality of AND gate circuits and a second plurality of AND gate circuits; and a logic circuit connected to at least one output terminal of the comparator circuit and configured to control an operation of the segmented pull-up current source circuit and the segmented pull-down current source circuit based on the comparator output.