Reset Signal Generation Circuit Voltage Threshold Adaptation
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Solution Overview
Problem
Existing reset signal generation circuits face instability when power voltage drops, leading to potential malfunctions due to narrow voltage hysteresis ranges and variations in power circuits, causing abnormal operations or malfunctions.
Innovation Solution
A reset signal generation circuit with a voltage conversion unit that adjusts voltage thresholds by using a voltage divider circuit to generate first and second voltages associated with power voltage changes, allowing for stable operation even at low power voltages by shifting the reset detection voltage to a higher potential side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the power voltage becomes a low voltage (3.3V), then the voltage range for reset operation becomes narrower, but the difference between first and second threshold voltages needs to be maintained for stability
Solution Approach 1:
The invention changes the parameters (voltage levels) generated by the two voltage generation circuits based on the power voltage conditions. The first voltage generation circuit generates a first voltage suitable for reset release detection, while the second voltage generation circuit generates a second voltage suitable for reset detection. By independently controlling these parameters, the system maintains adequate hysteresis difference even when operating at low power voltages like 3.3V, ensuring both adaptability and stability.
Data Source
AI summary
A power system includes a voltage detection IC which outputs a reset signal to a microcomputer when an input voltage is equal to or lower than a reset release voltage, releases outputting of the reset signal when the input voltage exceeds the reset release voltage, and outputs the reset signal to the microcomputer again after the input voltage exceeds the reset release voltage when the input voltage is equal to or lower than a reset detection voltage which is lower than the reset release voltage and a voltage conversion circuit which sets a first voltage associated with a change of a power voltage as the input voltage before start of operation of the microcomputer and sets a second voltage which is associated with a change of the power voltage and is lower than the first voltage as the input voltage after the start of operation the microcomputer.