Overvoltage Protection Unit for ADC in Display Pixel Circuits
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Solution Overview
Problem
Current pixel circuits are prone to damage due to sense line voltages exceeding the maximum operating voltage of Analog-to-Digital Converters (ADCs), leading to malfunctioning display panels.
Innovation Solution
An overvoltage protection unit comprising a comparator and an output switch is introduced, where the comparator compares a predetermined maximum voltage with the actual sampled voltage and controls the output switch to prevent excessive voltage from reaching the ADC, using a first voltage signal to turn the switch on when the sampled voltage is lower and a second signal to turn it off when it is higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sense line voltage is monitored without protection, then the ADC can perform normal voltage conversion, but the ADC may be damaged when overvoltage occurs
Solution Approach 1:
The patent applies preliminary action by implementing an overvoltage protection unit that proactively monitors and blocks excessive voltages before they can reach and damage the ADC. The protection unit compares the sense line voltage with a reference voltage and preemptively prevents overvoltage from entering the ADC, rather than reacting after damage occurs.
Solution Approach 2:
The patent uses an intermediary approach by introducing an overvoltage protection unit as a mediator between the sense line and the ADC. This protection unit acts as a buffer that intercepts and blocks overvoltage signals, allowing normal voltage signals to pass through to the ADC while preventing harmful overvoltage from reaching it.
2Reliability
If an overvoltage protection unit is added, then the ADC is protected from damage, but the circuit complexity increases
Solution Approach 1:
The protection unit is integrated into the existing pixel circuit architecture, performing preliminary voltage monitoring and protection functions. The unit includes a comparison module that continuously monitors the sense line voltage and a control module that adjusts the pixel circuit operation based on the voltage level, preventing overvoltage damage before it occurs.
Solution Approach 2:
The overvoltage protection unit serves multiple functions: it monitors sense line voltage, compares it with reference voltage, controls the pixel circuit operation, and protects the ADC. By consolidating these functions into a single integrated unit, the patent minimizes the increase in circuit complexity while maximizing protection effectiveness.
3Productivity
If the sense line voltage exceeds the maximum operating voltage, then the display panel may show normal images, but the ADC suffers irrevocable damage
Solution Approach 1:
The patent implements preliminary protection by monitoring the sense line voltage before it can exceed the ADC's maximum operating voltage. The overvoltage protection unit detects voltage anomalies early and takes preventive action, such as adjusting the pixel circuit operation or blocking the voltage signal, thereby protecting the ADC while maintaining display functionality.
Solution Approach 2:
The patent converts the potentially harmful overvoltage condition into a beneficial protective mechanism. When overvoltage is detected, the system adjusts its operation to prevent damage, using the voltage anomaly information to trigger protective actions that ultimately safeguard the ADC and ensure long-term display panel reliability.
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 effectively prevents overvoltage breakdown, ensuring the ADC converts analog voltage signals safely and stably, thereby protecting the Analog-to-Digital Converter and maintaining display panel functionality.
Implementation Method 1
a first input terminal of the comparator is supplied with a predetermined maximum voltage, a second input terminal of the comparator is supplied with an actual sampled voltage
Implementation Method 2
an output terminal of the comparator is connected with a control terminal of the output switch and the actual sampled voltage is supplied to an input terminal of the output switch; the output switch selectively outputs the actual sampled voltage in accordance with an output signal of the comparator
Data Source
AI summary
An overvoltage protection unit, an overvoltage protection method, a sampling module, a pixel circuit and a display apparatus are provided. The overvoltage protection unit includes a comparator and an output switch, where a first input terminal of the comparator is supplied with a predetermined maximum voltage, a second input terminal of the comparator is supplied with an actual sampled voltage, an output terminal of the comparator is connected with a control terminal of the output switch and the actual sampled voltage is supplied to an input terminal of the output switch; the output switch selectively outputs the actual sampled voltage in accordance with an output signal of the comparator.