Power-On Reset Circuit Segmentation for Voltage Drift
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Solution Overview
Problem
Conventional power-on reset (PoR) circuits face issues with accuracy due to threshold voltage drift and reliability due to complex interactions in bandgap reference voltage circuits, leading to potential malfunctions and improper resets.
Innovation Solution
A PoR circuit design incorporating a power supply voltage detector and a holding circuit to ensure stable reference voltage generation, with the power supply voltage detector being controllable and capable of being shut down to reduce power consumption, while the holding circuit maintains the detection results to ensure continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PoR circuit based on bandgap reference voltage circuit is used, then measurement precision is improved, but device complexity increases and reliability deteriorates
Solution Approach 1:
The PoR circuit is segmented into distinct functional modules: power supply voltage detector, holding circuit, reference voltage generator, and reset determination circuit. This segmentation allows the complex bandgap reference circuit to be isolated and controlled, reducing overall system complexity while maintaining precision.
Solution Approach 2:
The power supply voltage detector acts as an intermediary between the power supply and the reference voltage generator. It monitors voltage levels and controls the enabling of the bandgap reference circuit, preventing direct harmful effects of unstable power supply on the precision circuitry.
2Measurement precision
If a PoR circuit based on bandgap reference voltage circuit is used, then measurement precision is improved, but reliability worsens due to component interactions
Solution Approach 1:
The power supply voltage detector provides beforehand cushioning by monitoring voltage levels before they can harm the reference voltage generator. It prepares enablement signals in advance to protect the precision circuit from unstable power conditions, preventing malfunctions before they occur.
Solution Approach 2:
The circuit implements feedback through the holding circuit that monitors the detection signal and maintains the enablement signal state. This feedback mechanism ensures the reference voltage generator is only active when power supply voltage is sufficient, improving reliability while maintaining precision.
3Reliability
If the power supply voltage detector is continuously operated, then reliability is improved, but use of energy increases
Solution Approach 1:
The power supply voltage detector operates periodically rather than continuously. The holding circuit maintains the enablement signal state between detection cycles, allowing the detector to be disabled during stable operation while maintaining system reliability through periodic monitoring.
Solution Approach 2:
The circuit dynamically adjusts the operation state of the power supply voltage detector based on system needs. The detector is enabled when voltage monitoring is required and can be disabled when the holding circuit maintains the current state, optimizing power consumption while preserving reliability.
Data Source
AI summary
A power-on reset circuit arranged to generate a reset signal according to a power supply voltage includes: a power supply voltage detector, a holding circuit, a reference voltage generator and a reset determination circuit. The power supply voltage detector is controllable by the reset signal, and arranged to detect a level of the power supply voltage to generate a detection signal. The holding circuit is arranged to output an enablement signal according to the detection signal, wherein the holding circuit selectively maintains a level of the enablement signal according to a level of the detection signal. The reference voltage generator is controllable by the enablement signal to selectively output a reference voltage. The reset determination circuit is arranged to output the reset signal according to the power supply voltage and the reference voltage.