LED Display Driver with Ping-Pong Line Buffers for Lower SRAM Cost
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Solution Overview
Problem
Conventional LED display drivers using ping-pong frame buffers incur high hardware costs and frame latency due to the need for twice the SRAM capacity and one-frame delay, which is not effectively addressed.
Innovation Solution
Implementing a ping-pong line buffer and a single frame buffer to reduce SRAM hardware costs by half and latency to one scan line, by alternating data storage and display operations in a scrambled progressive scan architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a ping-pong frame buffer is used to reduce LED flickering, then the refresh rate is improved, but the SRAM hardware cost increases by two times and frame latency increases by one frame
Solution Approach 1:
The patent divides the frame buffer into multiple line buffers, where each line buffer stores data for a single scan line. This segmentation allows the system to use smaller memory units (line buffers) instead of a large frame buffer, reducing the total SRAM capacity while maintaining the ability to refresh multiple lines simultaneously to reduce flickering.
Solution Approach 2:
The patent transitions from a two-dimensional frame buffer (storing entire frames) to a one-dimensional line buffer approach (storing individual scan lines). By processing and refreshing lines independently in a sequential manner, the system achieves flicker reduction with significantly reduced memory requirements.
2Productivity
If a ping-pong frame buffer is used to reduce LED flickering, then the refresh rate is improved, but the frame latency increases by one frame
Solution Approach 1:
The patent prepares scan line data in advance by storing it in line buffers before it is needed for display. This preliminary action allows the system to have data ready for immediate display, reducing the latency between data generation and display output while maintaining continuous refresh operation.
Solution Approach 2:
The patent maintains continuous data flow and refresh operation by having multiple line buffers that can be filled and displayed in an overlapping manner. While one line buffer is being displayed, another is being filled with new data, ensuring continuous operation without idle periods that would increase latency.
3Productivity
If a ping-pong frame buffer is used to reduce LED flickering, then the refresh rate is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple simple line buffers into a unified buffer structure that can be managed with a single control logic. Instead of implementing separate ping-pong frame buffers, the system merges the functionality into a single buffer structure that sequentially processes scan lines, reducing the overall system complexity.
Solution Approach 2:
The line buffer system automatically manages its own data flow and timing through a simple control mechanism that sequentially fills and displays buffers. This self-service approach eliminates the need for complex control logic and multiple buffer management systems, reducing device complexity while maintaining effective flicker reduction.
Data Source
AI summary
A method and an apparatus for operating an LED display are provided. The method includes: storing Nth scan line data in a line buffer; storing the Nth scan line data in a frame buffer; displaying the Nth scan line data stored in the line buffer; during the displaying of the Nth scan line data stored in the line buffer, storing (N+1)th scan line data in the line buffer; storing the (N+1)th scan line data in the frame buffer; displaying the (N+1)th scan line data stored in the line buffer; repeating the above steps until (N+M)th scan line data stored in the line buffer is displayed; and displaying scan line data stored in the frame buffer from the Nth scan line data to the (N+M)th scan line data.