Voltage Detector Input Limiting for Comparator Reliability
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Solution Overview
Problem
Conventional voltage detectors experience long-term performance degradation due to the continuous application of high voltage to the inversion input terminal of the comparator, which degrades the transistor characteristics and affects detection and release voltages.
Innovation Solution
Incorporating a voltage limiting circuit using an NMOS transistor with a constant gate voltage to limit the divided voltage, preventing transistor characteristic degradation and maintaining accurate detection and release voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage detector operates in release state with high voltage applied to the inversion input terminal, then the voltage detection function is maintained, but the transistor characteristic degrades over time
Solution Approach 1:
The patent introduces a voltage limiting circuit as an intermediary component between the voltage division circuit and the comparator. This circuit includes a first NMOS transistor and a second NMOS transistor that work together to limit the voltage applied to the inversion input terminal. The voltage limiting circuit acts as a mediator that protects the comparator's inversion input terminal from high voltage stress while maintaining the voltage detection functionality, thereby preventing transistor characteristic degradation and improving long-term reliability
2Reliability
If the divided voltage is limited to preset voltage using NMOS transistor, then the transistor characteristic degradation is prevented, but the device complexity increases
Solution Approach 1:
The patent designs the voltage limiting circuit using NMOS transistors that can serve multiple functions. The first NMOS transistor limits the voltage to prevent degradation, while the second NMOS transistor enables switching between different voltage dividing ratios. By making the voltage limiting circuit multi-functional, the patent reduces overall device complexity while maintaining reliability benefits
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 voltage limiting circuit ensures long-term reliability by preventing transistor degradation and maintaining accurate voltage detection and release operations, even when the input voltage exceeds the release voltage.
Implementation Method 1
a voltage limiting circuit which limits the divided voltage to a preset voltage
Data Source
AI summary
A voltage detector includes a voltage division circuit which outputs a divided voltage based on an input voltage, a comparison circuit which compares the divided voltage and a reference voltage to output a detection signal and a release signal, and a voltage limiting circuit which limits the divided voltage to a preset voltage.