Two-Stage Power-On Reset Circuit for Low-Voltage Fault Prevention
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Solution Overview
Problem
Existing power-on reset circuits in semiconductor devices fail to effectively prevent malfunctions when the power supply voltage is below a suitable operational level, leading to abnormal operations.
Innovation Solution
A power-on reset circuit comprising two reset circuits connected in series, where a first reset circuit outputs a reset signal when the voltage is less than a reference voltage, and a second reset circuit outputs a system reset signal to reset an external circuit when the voltage is below a predetermined level, ensuring the circuit operates correctly by comparing voltages divided from the power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single reset circuit is used to detect power supply voltage, then the circuit complexity is low, but the reliability of preventing malfunctions at low voltage is insufficient
Solution Approach 1:
The reset detection function is segmented into two independent reset circuits (first reset circuit and second reset circuit) connected in series. Each circuit has its own comparator and voltage division circuit, allowing them to detect different voltage thresholds independently. This segmentation improves reliability by ensuring that both detection paths must agree before triggering a reset, preventing false malfunctions while maintaining manageable circuit complexity through modular design.
2Measurement precision
If two reset circuits are connected in series to improve voltage detection accuracy, then the reliability increases, but the device complexity increases
Solution Approach 1:
The voltage detection system is divided into two separate detection paths, each with its own comparator and voltage division circuit. The first comparator detects whether the first divided voltage exceeds the first reference voltage, while the second comparator detects whether the second divided voltage exceeds the second reference voltage. This segmentation enables more precise voltage threshold detection by using multiple reference levels, improving measurement precision without creating excessive complexity through systematic modular architecture.
Solution Approach 2:
Both reset circuits share common functional elements including the power supply connection, ground connection, and the reset signal output that controls the external circuit. The voltage division circuits use similar resistor configurations, and both comparators perform the same basic function of comparing divided voltage against reference voltage. This multi-functionality approach allows the system to achieve enhanced detection precision while avoiding proportional increases in complexity by reusing design patterns and functional blocks.
Data Source
AI summary
Power-on reset circuits are disclosed. A first reset circuit includes a first comparator to output a system reset signal, and a second reset circuit outputs a first reset signal to control operations of the first comparator, such that the first reset circuit outputs the system reset signal when a first voltage is less than a first reference voltage.