Temperature Detection Circuit Leakage Current Compensation
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Solution Overview
Problem
In temperature detection circuits for electro-optical devices, the leakage current of transistors in electrostatic protection circuits increases at high temperatures, causing fluctuations in the output from temperature detection elements, which hinders accurate temperature monitoring in display regions.
Innovation Solution
A temperature detection circuit is designed with a compensation circuit that includes a second transistor with a constant potential source/drain region, which compensates for the leakage current of the first transistor, maintaining the temperature detection element's output accuracy even at elevated temperatures by adjusting the current balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrostatic protection circuit is electrically coupled in parallel with the temperature detection element, then the temperature detection element is protected from electrostatic damage, but the leakage current of the transistor in the electrostatic protection circuit increases at high temperatures, causing the current to deviate from the predetermined constant current and the output to fluctuate from the expected value
Solution Approach 1:
A compensation transistor is introduced as an intermediary element between the electrostatic protection circuit and the temperature detection element. This compensation transistor generates a compensating current that counteracts the leakage current effect, allowing the temperature detection element to maintain accurate output while remaining protected by the electrostatic protection circuit.
Solution Approach 2:
The invention changes the electrical parameters of the circuit by introducing a compensation transistor whose characteristics are designed to offset the temperature-dependent leakage current. By adjusting the compensation transistor's parameters (such as its size ratio relative to other transistors), the circuit maintains a constant effective current through the temperature detection element across different temperatures.
2Ease of manufacture
If the temperature detection element is connected in parallel with the electrostatic protection circuit, then the device structure is simplified and manufacturing is easier, but the leakage current causes the detection output to deviate from expected values at elevated temperatures
Solution Approach 1:
The invention merges the temperature detection function with the electrostatic protection circuit by integrating a compensation transistor within the same circuit structure. This allows the circuit to simultaneously provide electrostatic protection, compensate for leakage current, and maintain accurate temperature detection without requiring separate independent circuits.
Solution Approach 2:
The compensation transistor serves as a mediator that reconciles the conflict between simplified circuit integration and measurement precision. It enables the parallel connection structure to maintain accuracy by actively compensating for the harmful leakage current effect.
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 configuration ensures that the temperature characteristics of the temperature detection element remain linear, allowing for accurate temperature monitoring and reducing measurement errors, even at high temperatures, thus improving the reliability of temperature control in electro-optical devices.
Implementation Method 1
the temperature detection element is a diode, and a temperature dependency of a forward voltage of the diode when driven with a constant current is utilized to detect the temperature
Data Source
AI summary
In a temperature detection circuit of an electro-optical device, an electrostatic protection circuit includes a first wiring line, a first transistor provided with a first source/drain region electrically connected to the first wiring line, and a second wiring line electrically connected to a second source/drain region of the first transistor. A temperature detection element includes diodes electrically connected in series between the first wiring line and the second wiring line. A compensation circuit includes a second transistor, a constant potential Vc is applied to the first source/drain region of the second transistor, and a gate electrode and the second source/drain region of the second transistor are electrically connected to the first wiring line.