Power Driver Circuit Voltage Slope Control for AMOLED Panels
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Solution Overview
Problem
Existing power driver circuits face challenges in controlling the output voltage slope during reset and emission periods in AMOLED display panels, leading to potential voltage/current spikes that can affect the driving operation.
Innovation Solution
A circuit comprising a drive circuit with a first transistor series-connected to a second transistor at an intermediate node, coupled with a capacitance, an amplifier, and a slope control circuit to manage the voltage slope by adjusting the current sourced to the intermediate node, ensuring controlled voltage changes without spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power driver circuit operates during reset and emission periods in AMOLED display panels, then the driving operation is enabled, but voltage/current spikes occur affecting the driving operation
Solution Approach 1:
The patent applies preliminary action by controlling the voltage slope before the actual voltage transition occurs. The slope control circuit pre-regulates the rate of voltage change during reset and emission periods, preventing voltage/current spikes before they can occur. This is achieved by adjusting the charging/discharging current of the capacitor connected to the gate of the transistor, ensuring smooth voltage transitions that eliminate harmful spikes while maintaining reliable driving operation.
2Reliability
If the voltage slope is controlled by adjusting current to intermediate node, then voltage spikes are prevented, but circuit complexity increases with additional components
Solution Approach 1:
The patent applies universality by designing the slope control circuit to serve multiple functions within a compact structure. The circuit uses a capacitor connected to the gate of the transistor, which simultaneously functions as part of the switching mechanism and as the slope control element. The same current control mechanism that drives the transistor also controls the voltage slope, eliminating the need for separate complex control circuits and reducing overall device complexity while maintaining reliable voltage slope control.
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
The solution effectively controls the voltage slope during reset and emission periods, preventing voltage/current spikes and enhancing the operational efficiency of power driver circuits in AMOLED display panels.
Implementation Method 1
a capacitance coupled between the first intermediate node and a second intermediate node
Implementation Method 2
a current source configured to source a current having a selectable value to said second intermediate node
Data Source
AI summary
A drive circuit includes a first transistor coupled in series with a second transistor at a first intermediate node coupled to a load. An amplifier has an output driving a control terminal of the second transistor. The amplifier includes a first input coupled to a second intermediate node and a second input coupled to a reference voltage. A feedback circuit is coupled between the first intermediate node and the second intermediate node. A slope control circuit is coupled the second intermediate node. The slope control circuit injects a selected value of current into the second intermediate node, that current operating to control the output of the amplifier in setting a slope for change in voltage at the first intermediate node.