Display Driving Device Sub-Frame PWM Brightness Control
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Solution Overview
Problem
Existing display panel driving technologies face challenges in managing peak current and PWM duty resolution, particularly requiring high-frequency oscillation circuits that are difficult to realize, and struggle to maintain average brightness perception over an image frame period.
Innovation Solution
A driving device with a data driving circuit and timing control circuit that divides the image frame period into sub-frame periods, allowing each bit in the target pixel data to correspond to specific sub-frame periods, determining whether to light up the pixel circuit based on the current bit during its corresponding sub-frame period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the pixel circuit is lit up during only part of the scan line period to maintain average brightness perception, then the peak current of the PWM signal stream increases, but the power consumption and current management becomes more difficult
Solution Approach 1:
The scan line period is divided into multiple sub-scans, and each sub-scan is further divided into multiple PWM periods. This segmentation allows the pixel circuit to be updated multiple times with lower peak currents during the same period, rather than requiring a single high peak current pulse, thus resolving the contradiction between maintaining brightness perception and managing peak current.
Solution Approach 2:
By performing multiple PWM updates within a single scan line period through sub-scans and multiple PWM periods, the useful action of updating pixel data is made continuous rather than instantaneous. This distributes the current demand over time while maintaining the visual effect, reducing peak current requirements while preserving brightness perception.
2Measurement precision
If the PWM duty resolution is increased to improve brightness control precision, then the minimum clock period decreases requiring higher oscillation circuit frequency, but the device complexity and difficulty of realization increases
Solution Approach 1:
The PWM duty cycle control is segmented into multiple update opportunities within a scan line period. Instead of requiring ultra-precise single-shot PWM control, the system achieves fine brightness control through multiple coarser-resolution updates, effectively distributing the precision requirement across time while reducing the instantaneous frequency demands on the oscillation circuit.
Data Source
AI summary
A driving device, an operation method thereof, and a display apparatus are disclosed. The driving device is configured to drive a display panel. The driving device divides an image frame period into a plurality of sub-frame periods. A target pixel circuit in the display panel corresponds to target pixel data comprising at least one bit. Each bit in the target pixel data corresponds to at least one corresponding sub-frame period among the sub-frame periods. Different bits in the target pixel data correspond to different sub-frame periods among the sub-frame periods. According to a current bit in the target pixel data, the driving device determines whether to light up the target pixel circuit during the at least one corresponding sub-frame period corresponding to the current bit.