Pixel Current Detection Circuit for AMOLED Display Panels
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Solution Overview
Problem
In Active-Matrix Organic Light Emitting Diode (AMOLED) display panels, existing pixel current detection circuits face inaccuracies due to the limited detection range of Analog-to-Digital Converters (ADCs), failing to accurately detect pixel currents that are either too large or too small.
Innovation Solution
A pixel current detection circuit that converts the input pixel current into multiple detection voltages using a pixel current conversion circuit and a current detection circuit, employing differential operational amplifiers and storage capacitors to determine the pixel current accurately, thereby overcoming the limitations of ADC detection ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single ADC is used to detect pixel current, then the device complexity is reduced, but the measurement precision deteriorates when pixel current is too large or too small
Solution Approach 1:
The pixel current detection range is segmented into multiple intervals by dividing the detection circuit into three parallel detection paths, each handling a specific current range. The pixel current conversion circuit generates three different pixel currents (first, second, third) that are detected by separate detection circuits, allowing accurate measurement across the full range without requiring a single complex high-precision ADC.
2Adaptability or versatility
If the ADC input voltage range is fixed, then the device complexity is reduced, but the adaptability deteriorates when pixel current varies widely
Solution Approach 1:
The pixel current conversion circuit changes the current parameter by generating three different pixel currents (first, second, third) with different magnitudes from the same input pixel current. This allows the system to adapt to widely varying pixel current values while keeping the ADC input voltage range fixed, as each converted current corresponds to a specific detection range.
3Reliability
If external compensation is implemented, then the reliability is improved, but the device complexity increases due to additional detection requirements
Solution Approach 1:
The pixel current detection circuit is designed to serve multiple functions: it detects pixel current for display purposes and simultaneously provides accurate current data for external compensation of the driving transistor. By implementing multi-range detection that covers both normal and extreme current values, the circuit enables reliable compensation without requiring separate detection circuits.
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
Enables accurate detection of pixel currents across a wider range, improving external compensation and enhancing the stability of AMOLED display panels by accurately converting and sampling pixel currents.
Implementation Method 1
an integration circuit composed of a differential operational amplifier is required
Implementation Method 2
the pixel current is accumulated for a specified amount of time by an integrator connected to an external compensation line
Data Source
AI summary
The present disclosure provides a pixel current detection circuit, a pixel current detection method, and a display device. The pixel current detection circuit includes: a pixel current conversion circuit which obtains a first pixel current, a second pixel current and a third pixel current according to an input pixel current to be detected, wherein a ratio of the first pixel current to the second pixel current and a ratio of the second pixel current to the third pixel current are predetermined values; and a current detection circuit which is connected to the pixel current conversion circuit, converts the first pixel current into a first detection voltage, the second pixel current into a second detection voltage, and the third pixel current into a third detection voltage, and determines the pixel current according to the first detection voltage, the second detection voltage and the third detection voltage.