Asynchronous Piecewise Linear Column Driver for OLED Current Spikes
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Solution Overview
Problem
Current display drivers for OLED displays face inefficiencies in power consumption and dynamic current spikes, leading to energy wastage and reduced performance due to static current consumption and uncontrolled current spikes during settling.
Innovation Solution
A high-efficiency piecewise linear column driver with asynchronous control is introduced, utilizing segmented pull-up and pull-down current source circuits, a comparator circuit, and a logic circuit to dynamically adjust current sources, eliminating static current consumption and controlling dynamic current spikes by using a bank of current sources and asynchronous signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional display drivers are used, then the display can operate, but static current consumption occurs leading to power inefficiency
Solution Approach 1:
The patent implements dynamic current control by replacing static bias circuits with dynamic switching mechanisms. The driver alternates between charging and discharging phases, where current sources are activated only when needed to transition the output voltage, eliminating continuous static current consumption while maintaining operational functionality.
Solution Approach 2:
The driver operates in periodic charging and discharging cycles. During each frame period, the output voltage is adjusted through controlled charging phases followed by discharging phases, creating a periodic action pattern that eliminates the need for continuous static current while achieving the required voltage levels for display operation.
2Stability of the object's composition
If conventional current drivers are used, then the output can settle, but uncontrolled current spikes occur during settling
Solution Approach 1:
The current control is segmented into multiple discrete levels using a bank of current sources with different magnitudes. Instead of allowing uncontrolled current flow during settling, the driver segments the charging and discharging processes into controlled steps, selecting appropriate current source combinations to achieve the target voltage without generating harmful current spikes.
Solution Approach 2:
The driver incorporates feedback mechanisms that monitor the output voltage during settling and dynamically adjust the current source activation. This feedback control ensures that charging current is applied only until the target voltage is approached, preventing overshoot and uncontrolled current spikes while maintaining stable output settling.
3Use of energy by moving object
If segmented current sources are used, then power efficiency improves, but device complexity increases
Solution Approach 1:
The patent merges multiple current sources into a unified bank that shares common control logic and switching mechanisms. By combining the charging and discharging current sources into a single integrated structure with shared control circuits, the design achieves the power efficiency benefits of segmented current control while minimizing the increase in overall device complexity.
Solution Approach 2:
The current source bank is designed with multi-functionality, where the same set of current sources can be selectively activated for both charging and discharging operations. This universal design approach allows a single bank of current sources to perform multiple functions, reducing the need for separate dedicated circuits and thereby limiting the increase in device complexity.
Data Source
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.