Power-On Reset Threshold Detection via Quadratic-Exponential Currents
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Solution Overview
Problem
Typical power on reset (POR) circuits are prone to inaccuracy due to component variations and voltage-centric dependencies, and they lack effective monitoring of power supply sources, leading to unreliable POR signals.
Innovation Solution
A method and apparatus that generate a reliable POR signal by comparing a first quadratic current with a second exponential current in relation to the power supply voltage, allowing for voltage threshold monitoring and providing a precise POR signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If typical POR circuits use voltage-centric dependencies and component variations, then the circuit can be simple in structure, but the measurement precision and reliability of the POR signal deteriorate
Solution Approach 1:
The patent changes the fundamental parameter from voltage comparison to current comparison. By generating first and second currents with different mathematical relationships to the power supply voltage (e.g., one current proportional to voltage, another proportional to voltage squared), the circuit achieves more accurate voltage threshold detection through current intersection points, eliminating the need for complex voltage division networks and improving measurement precision while maintaining reasonable circuit complexity
Solution Approach 2:
The patent substitutes the traditional voltage-centric electrical system with a current-centric electrical system. Instead of using voltage dividers, resistors, and voltage comparators, the invention uses current sources and current mirrors to create currents with specific mathematical relationships to the power supply voltage, achieving more precise and reliable POR detection through current intersection rather than voltage comparison
2Reliability
If typical POR circuits lack effective monitoring of power supply sources, then the circuit complexity is reduced, but the reliability of the POR signal deteriorates
Solution Approach 1:
The patent implements self-service monitoring where the POR circuit inherently monitors the power supply voltage through the mathematical relationship between the generated currents and the power supply. The current sources are designed such that their intersection point naturally indicates when the power supply reaches the threshold voltage, providing built-in monitoring capability without requiring separate monitoring circuits, thereby improving reliability while avoiding excessive complexity
Data Source
AI summary
Aspects of the present invention include a method, apparatus and device for generating a power on reset (POR) signal in relation to the crossing point of two currents wherein at least one current is a quadratic function and the other is an exponential function, where each has a mathematical correlation to a function of a predetermined power supply voltage.