Timing Controller Grey Voltage Compensation for Display Flicker
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Solution Overview
Problem
Incorrect white balance data driving table values are obtained when switching refreshing frequencies in FreeSync displays, leading to screen flickering due to delayed detection response and LC response, resulting in significant luminance differences.
Innovation Solution
A timing controller with a detecting circuit to obtain refreshing frequencies, a control circuit to calculate variances, and a compensation circuit to adjust grey voltages by reading compensation values from a data table, ensuring accurate grey voltage adjustments by summing basic values and compensation values when variances are non-zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refreshing frequency is dynamically adjusted to match frame rate, then screen tearing is prevented, but incorrect white balance data is obtained due to detection and LC response delay, causing flicker
Solution Approach 1:
The patent stores compensation values in advance for different refreshing frequency variances in a compensation data table. When frequency switching occurs, the pre-stored compensation values are immediately applied to correct the white balance data, eliminating the delay caused by real-time detection and LC response.
Solution Approach 2:
The patent introduces a compensation circuit as an intermediary between the detection circuit and the white balance processing unit. This compensation circuit reads pre-calculated compensation values from the compensation data table and applies them to correct the basic values obtained from the detection circuit, thereby resolving the timing mismatch between detection and actual display requirements.
2Measurement precision
If the detection response time is reduced to obtain accurate white balance data, then flicker is eliminated, but the system complexity increases
Solution Approach 1:
Instead of reducing detection response time through faster hardware, the patent pre-calculates and stores compensation values for various frequency variances in the compensation data table. This shifts the complexity from real-time detection to offline computation, simplifying the detection system while maintaining accuracy.
Solution Approach 2:
The patent prepares compensation values in advance to cushion against the inherent delays in detection response and LC response. By having pre-computed correction values ready, the system compensates for the timing mismatch without requiring faster detection hardware.
3Measurement precision
If the LC response time is extended to ensure accurate grey voltage application, then white balance accuracy improves, but flicker occurs due to frequency switching delays
Solution Approach 1:
The patent pre-calculates compensation values that account for LC response characteristics and frequency variance. These values are stored in the compensation data table and immediately applied when frequency switching occurs, eliminating the need to wait for extended LC response time while maintaining grey voltage accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the compensation circuit reads pre-computed compensation values based on the detected frequency variance and applies them to correct the basic values. This closed-loop approach ensures accurate grey voltage application without requiring extended response time.
Data Source
AI summary
A timing controller includes a detecting circuit, a control circuit, and a compensation circuit. The timing controller reads the compensation values according to the variance between refreshing frequencies and compensate the second basic value in the white balance data driving table based on the first basic value accordingly. This could efficiently improve the grey voltage difference between after and before switching the refreshing frequency. This could efficiently improve the flicker issue.