OLED Threshold Voltage Sensing Circuit Scaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional threshold voltage sensing circuits for OLED display devices do not effectively scale down sensed threshold voltages to a range that ensures stable operation within the analog-to-digital converter, leading to potential discharge due to leakage current and inaccurate storage of threshold voltage values.
Innovation Solution
A threshold voltage sensing circuit that employs a sampling capacitor and a charge-share capacitor to scale down sensed threshold voltages through charge sharing, with a comparator ensuring the variation range is within a predetermined reference value, preventing discharge and ensuring accurate storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the threshold voltage is directly transmitted to the analog-to-digital converter without scaling, then the measurement precision is maintained, but the low-voltage driving elements in the ADC may be damaged due to excessive voltage
Solution Approach 1:
The patent introduces a sampling capacitor and charge-share capacitor as intermediary components between the OLED threshold voltage sensing circuit and the analog-to-digital converter. The sampling capacitor temporarily stores the sensed threshold voltage, and the charge-share capacitor shares the charge to scale down the voltage level. This intermediary voltage scaling mechanism protects the low-voltage driving elements in the ADC from excessive threshold voltages while maintaining measurement precision through controlled charge sharing.
Solution Approach 2:
The patent changes the voltage parameter by scaling down the threshold voltage through charge sharing between capacitors. By controlling the capacitance values of the sampling capacitor and charge-share capacitor, the voltage level is transformed from the original threshold voltage range to a scaled-down range suitable for the ADC's low-voltage driving elements, thereby protecting the circuit while preserving the essential measurement information.
2Reliability
If the threshold voltage is scaled down through charge sharing, then the low-voltage driving elements are protected, but the device complexity increases due to additional capacitors and control circuits
Solution Approach 1:
The sampling capacitor and charge-share capacitor serve multiple functions: they scale down the voltage for protection, store the threshold voltage for measurement, and enable controlled charge sharing. The control circuit integrates multiple functions including voltage level detection, timing control for charge sharing, and coordination with the analog-to-digital converter. This multi-functionality reduces the need for separate dedicated components for each function.
Solution Approach 2:
The charge-share capacitor is nested within the existing sampling capacitor structure, where the charge-share capacitor is connected in parallel with the sampling capacitor during the charge sharing phase. This nested configuration allows the voltage scaling function to be integrated into the existing capacitor architecture rather than requiring completely separate components, thereby limiting the increase in device complexity.
3Measurement precision
If the threshold voltage is sampled and held in the sampling capacitor, then the voltage is available for processing, but the voltage may exceed the operating range of the analog-to-digital converter
Solution Approach 1:
The patent performs preliminary voltage scaling down the threshold voltage before it is transmitted to the analog-to-digital converter. The sampling capacitor first stores the threshold voltage, then the charge-share capacitor immediately shares the charge to scale down the voltage level. This preliminary action ensures that the voltage entering the ADC is already within the safe operating range, preventing subsequent discharge or damage.
Solution Approach 2:
The charge-share capacitor acts as a cushioning element that absorbs excess voltage energy before it reaches the ADC. By sharing the charge between the sampling capacitor and charge-share capacitor, the voltage is softened and scaled down to a level that cushions against the potential harm of voltage exceeding the ADC's operating range.
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
The solution effectively scales down threshold voltages to a stable range, preventing discharge and ensuring accurate storage and transmission to the analog-to-digital converter, maintaining constant OLED brightness and protecting low-voltage driving elements.
Implementation Method 1
a sampling capacitor configured to sample a threshold voltage of the OLED
Implementation Method 2
a charge-share capacitor configured to charge-share the voltage sampled in the sampling capacitor
Data Source
AI summary
The present invention relates to a technique for outputting threshold voltages by properly changing the threshold voltages such that the threshold voltages can protect low-voltage driving elements within an analog to digital converter when the threshold voltages of an OLED display panel are sensed and outputted to the analog to digital converter. The present invention comprises: a sampling capacitor which samples threshold voltages sensed and inputted from an organic light-emitting diode on a display panel; a charge-sharing capacitor which charges and shares the threshold voltages sampled from the sampling capacitor, or solely charges the threshold voltages to bypass the threshold voltages; and a sample-and-hold unit which has a plurality of switches for performing switching operations for the sampling operation of the sampling capacitor and the charging and the sharing of the charge-sharing capacitor, and scales the threshold voltages to threshold voltage areas having a certain value or less.