Power-On Reset Circuit With Dual Voltage Comparison
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Solution Overview
Problem
Conventional power-on reset circuits in semiconductor devices fail to reliably detect decreases in power-supply voltage due to differences between primary and secondary voltages, leading to potential malfunctions and instability in system operations.
Innovation Solution
A power-on reset circuit is designed with both primary and secondary voltage comparison circuits, using transformers and comparators to generate a reset signal based on reference voltages, ensuring reliable detection of voltage decreases and preventing malfunctions by monitoring both voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an external capacity is attached to stabilize the secondary voltage, then the secondary voltage stability is improved, but the ability to detect primary voltage decrease is worsened because the secondary voltage remains stable even when primary voltage decreases
Solution Approach 1:
The voltage detection function is segmented into two independent comparison circuits: one for detecting primary voltage and another for detecting secondary voltage. Each circuit operates independently with its own comparator and reference voltage, allowing the system to monitor both voltages separately and issue reset signals based on either condition, thus resolving the conflict between stabilizing secondary voltage and detecting primary voltage decreases
2Device complexity
If only a single comparison circuit is used to monitor power supply voltage, then the device complexity is reduced, but the measurement precision of voltage decrease detection is worsened due to the voltage difference between primary and secondary sides
Solution Approach 1:
The single comparison circuit is segmented into two separate comparison circuits: a first comparison circuit that compares primary voltage with a reference voltage, and a second comparison circuit that compares secondary voltage with a reference voltage. This segmentation allows each circuit to accurately detect voltage decreases in its respective voltage domain, eliminating the measurement precision problem caused by voltage differences between primary and secondary sides
Data Source
AI summary
To provide a semiconductor device provided with a power-on reset circuit that can reliably detect decrease in power-supply voltage. The power-on reset circuit provided on the semiconductor device includes: a first comparison circuit that compares a primary voltage with a reference value; and a second comparison circuit that compares a secondary voltage with the reference value. The power-on reset circuit issues a reset signal based on comparison results of the first and second comparison circuits.