Backup Power Multiplexer for Low-Power MCU Battery Life
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Solution Overview
Problem
Conventional power management solutions for low-power microcontroller units (MCUs) in IoT applications suffer from significant quiescent current drainage and inefficiencies due to continuous monitoring of power supplies, leading to unnecessary battery drain and complex power sequencing issues, with limited user flexibility in power source selection.
Innovation Solution
A software-controlled power supply multiplexer that adaptively switches between main and backup power supplies using existing voltage monitors, eliminating additional circuitry and allowing software-controlled power management, thereby conserving battery life and ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous voltage monitoring is implemented to detect power supply switching conditions, then power supply switching reliability is improved, but battery life is reduced due to quiescent current consumption
Solution Approach 1:
The patent extracts the voltage monitoring function from the main power domain and places it in the backup power domain, which is only activated when needed. This allows the main system to operate without continuous monitoring overhead, extending battery life while maintaining switching reliability when the backup domain is active.
Solution Approach 2:
The patent implements preliminary power supply switching before the main power supply completely fails by monitoring voltage thresholds in advance. This allows the system to transition to battery power proactively, ensuring reliable operation while minimizing unnecessary battery drainage through threshold-based triggering rather than continuous monitoring.
2Duration of action of moving object
If automatic power supply switching is implemented to extend battery life, then battery life is improved, but system flexibility is reduced
Solution Approach 1:
The patent implements a dynamic power supply architecture where the backup power domain can be selectively enabled or disabled based on system state and configuration. This allows the system to adapt between automatic switching mode (for battery conservation) and manual selection mode (for flexibility), resolving the contradiction between extended battery life and system adaptability.
Solution Approach 2:
The backup power domain is designed to serve multiple functions: it can automatically switch power sources to extend battery life, or it can be manually controlled to provide flexible power source selection. This multi-functionality allows the same hardware infrastructure to support both battery conservation and system flexibility requirements.
3Measurement precision
If additional voltage monitoring circuitry is added to monitor both main and backup power supplies, then power supply monitoring accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the voltage monitoring function into the existing backup power domain infrastructure, which already contains voltage monitoring capabilities for its operation. This eliminates the need for separate monitoring circuitry and reduces overall system complexity while maintaining accurate power supply monitoring through the integrated approach.
Solution Approach 2:
The existing voltage monitoring circuitry in the backup power domain is designed to serve multiple purposes: it monitors the backup power supply status for its own operation, and simultaneously monitors the main power supply voltage to detect switching conditions. This multi-functional design provides accurate monitoring without adding complexity.
Data Source
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AI summary
A method and system are provided for supplying power to a backup power domain by connecting a battery voltage to a supply terminal for a backup power domain in a low power microcontroller during a startup mode when a main supply voltage, by detecting application of the main supply voltage to the low power microcontroller at a predetermined safe voltage level, and by activating a selection control circuit to power the backup power domain in the low power microcontroller from the main power supply voltage or the backup power supply voltage based on a software-controlled configuration bit, where the selection control circuit is configured to connect, in response to the software-controlled configuration bit having a first user-selected value, the main power supply voltage to the supply terminal for the backup power domain when the main power supply voltage is smaller than the battery power supply voltage.