Source Driver High Speed Charging Discharging
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Solution Overview
Problem
Existing source drivers for display panels face challenges in achieving high-speed operation without increasing power consumption, which is crucial for improving frame rates in displays like virtual reality devices, as higher bias currents lead to increased power consumption and are not suitable for mobile environments.
Innovation Solution
The source driver employs a dual-driving mechanism, where a first driving unit, either with pull-up and pull-down switches or a pumping capacitor, initially drives the output node to a predetermined voltage, and then an amplifier takes over to provide the grayscale signal, allowing for faster voltage changes without the need for increased bias currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If bias current is increased to improve slew rate, then output speed is improved, but power consumption increases
Solution Approach 1:
The output node is preliminarily driven to a target voltage level by the first driving unit (first switch and second switch) before the amplifier takes over. This preliminary action prepares the output node in advance, reducing the burden on the amplifier and enabling faster overall response without requiring excessive bias current from the amplifier.
Solution Approach 2:
The driving function is segmented into two distinct units: the first driving unit (comprising first switch and second switch) that performs initial rapid voltage transition, and the amplifier that performs subsequent precise grayscale signal driving. This segmentation allows each unit to operate in its optimal performance range without compromising overall speed or power efficiency.
2Productivity
If bias current is increased to improve response speed, then frame rate is improved, but power consumption increases making it unsuitable for mobile environments
Solution Approach 1:
The first driving unit performs preliminary voltage transition before the amplifier operates, preparing the output node in advance. This reduces the time the amplifier needs to operate at high current, thereby improving frame rate while keeping power consumption within acceptable limits for mobile devices.
Solution Approach 2:
The circuit dynamically switches between two driving modes: the first driving unit operates during initial voltage transitions requiring high speed, while the amplifier operates during grayscale signal modulation requiring precision. This dynamic operation allows the system to achieve high frame rates without continuously consuming high power.
Data Source
AI summary
Provided are a source driver for receiving a digital signal and providing a grayscale signal corresponding to the digital signal and a display device for displaying content. The source driver includes an amplifier configured to provide a grayscale signal, a second driving switch configured to provide the grayscale signal provided by the amplifier to an output node or block the grayscale signal, and a first driving unit including a first switch whose one end is connected to a first voltage and whose other end is connected to the output node and a second switch whose one end is connected to a second voltage and whose other end is connected to the output node, and configured to first drive the output node. The output node is first driven by the first driving unit and then second driven by the amplifier with the grayscale signal.