Sensor-Guided Battery Power Switching for Longer RTC Backup Life
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Solution Overview
Problem
Batteries used for power retention in devices like Real Time Clocks (RTCs) have limited lifetimes due to factors such as discharge depth, temperature, and load variations, and are sensitive to operating conditions, necessitating a solution to extend their life cycle.
Innovation Solution
A battery monitoring module that switches between power modes based on sensor data and predefined curves, managing discharge speed, load, and environmental conditions to optimize battery usage, including a switch with a controllable slew rate and a current limiter to prevent overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the battery is used to power the device continuously, then the device can operate without interruption, but the battery lifetime is reduced due to continuous discharge cycles
Solution Approach 1:
The system implements periodic switching between power sources (battery and power supply) based on predefined curves and sensor data. The battery monitoring module alternates between connecting the battery to the device and connecting the power supply to the device, creating a periodic action pattern that extends battery life while ensuring continuous operation.
Solution Approach 2:
The system changes operating parameters by monitoring temperature, load, and battery voltage, and adjusts the power source connection accordingly. Predefined curves represent voltage depending on discharge and environmental data, allowing the system to adapt parameters dynamically to optimize both battery lifetime and operational reliability.
2Power
If the battery discharge speed is increased to meet high load demands, then the device can operate under higher load conditions, but the battery lifetime is reduced due to fast discharge
Solution Approach 1:
The system dynamically adjusts the discharge rate by monitoring load conditions and comparing them against predefined curves. The battery monitoring module can switch between battery and power supply based on real-time load demands, allowing the system to handle high load conditions when necessary while preserving battery lifetime by avoiding sustained fast discharge.
Solution Approach 2:
The power supply acts as an intermediary that shares the load burden with the battery. When high power is needed, the system can connect the power supply to handle the demand, preventing the battery from undergoing excessive fast discharge that would reduce its lifetime.
3Reliability
If the battery is charged frequently to maintain operation, then the device can maintain power availability, but the battery lifetime is reduced due to limited charge cycles
Solution Approach 1:
The system performs preliminary action by proactively switching to the power supply before the battery is fully discharged, based on predefined voltage curves and sensor data. This prevents deep discharge cycles that would require frequent recharging, thereby extending battery lifetime while maintaining continuous power availability.
Solution Approach 2:
The battery monitoring module continuously monitors battery voltage, temperature, and load conditions, and uses feedback from sensor data to determine when to switch power sources. This feedback mechanism ensures power availability is maintained while optimizing charge cycle usage to extend battery lifetime.
4Speed
If the switch has high switching speed to respond quickly to power demands, then the device can maintain stable operation, but inrush current peaks occur that reduce battery lifetime
Solution Approach 1:
The system applies beforehand cushioning by controlling the slew rate of the switch to limit inrush current peaks. The switch is designed with a maximum slew rate to prevent sudden current surges when switching between power sources, cushioning the battery from harmful current peaks while maintaining adequate switching speed for stable operation.
5Adaptability or versatility
If the battery operates at high temperature to maintain performance, then the device can operate in harsh environments, but the battery lifetime is reduced due to temperature sensitivity
Solution Approach 1:
The temperature sensor and predefined curves act as intermediaries that mediate between environmental conditions and battery operation. The system monitors temperature and uses predefined voltage curves for different temperature values to determine optimal switching points, allowing the device to operate in harsh environments while protecting the battery from temperature-induced lifetime reduction.
Data Source
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AI summary
The invention relates to a system for controlling supply of a device (104). The device can be a power retention device that requires to be permanently powered. To this end, it can be alternatively powered by a power supply (140), in a first mode, or by a battery (102), in a second mode. At least one sensor (110-114; 105) of the system acquires data related to the battery, such as environmental data, the voltage of the battery or the discharge current of the battery. Based on the data and at least one characteristic curve of the battery, a battery monitoring module is configured to switch between the first and second modes to improve the lifetime of the battery.