Digital PWM Display Current Compensation Circuit
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Solution Overview
Problem
Current display devices face issues such as slow response time, difficulty in implementing flexibility, short lifespan, and low yield in LCDs, and limitations in flexibility and yield in AMOLEDs, as well as challenges in touch screen driving due to noise interference and reduced luminance in time-division driven systems, which require complex circuitry including analog comparators and DACs.
Innovation Solution
A display device and driving method that compensates for current deviations between semiconductor light-emitting diodes in a digital PWM mode using a current sensing unit and compensation unit, eliminating the need for analog comparators and DACs, and allowing serial digital data input, thereby simplifying the micro-integrated circuit and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If digital PWM mode is used to drive semiconductor light-emitting devices, then power consumption is reduced and circuit complexity is simplified, but current deviation between devices occurs affecting image quality
Solution Approach 1:
The patent implements a feedback mechanism where a sensing unit measures the actual current flowing through each semiconductor light-emitting device, and a compensation unit adjusts the driving signal to correct current deviations. This closed-loop feedback system maintains uniform current distribution while operating in digital PWM mode, thereby preserving image quality without requiring analog circuitry.
2Manufacturing precision
If analog comparators and DACs are included to compensate for current deviation, then image quality is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent replaces complex analog circuitry (comparators and DACs) with a simplified digital implementation. The compensation unit uses digital processing to generate corrected driving signals based on sensed current values, eliminating the need for analog components while maintaining current uniformity. This substitution reduces device complexity and power consumption.
3Measurement precision
If time division driving is used for touch screens, then touch recognition accuracy is improved, but display luminance decreases
Solution Approach 1:
The patent enables continuous light emission during both display driving and touch driving periods by maintaining power supply to the semiconductor light-emitting devices throughout the entire frame cycle. This eliminates the luminance reduction caused by traditional time-division driving, allowing touch recognition and display to occur simultaneously without compromising display brightness.
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
This solution improves image quality by stabilizing current flow, reducing circuit complexity, and enabling flexible and high-luminance displays with reduced power consumption and no need for TFT compensation, applicable to tiling displays.
Implementation Method 1
a plurality of semiconductor light-emitting devices applied to sub-pixels included in a pixel of a display panel
Implementation Method 2
a current sensing unit that senses a value of a current flowing through at least one of the plurality of semiconductor light-emitting devices
Data Source
AI summary
Discussed is a display device including a plurality of semiconductor light-emitting devices applied to sub-pixels included in each pixel of a display panel; and a driving unit for driving the plurality of semiconductor light-emitting devices on the basis of a digital pulse width modulation (PWM) signal, wherein the driving unit further includes: a current sensing unit for sensing the value of a current flowing through at least one of the plurality of semiconductor light-emitting devices; and a current compensation unit for compensating for the current deviation between the plurality of semiconductor light-emitting devices on the basis of the current value sensed by the sensing unit.