PMIC Switching Between Energy Harvester and Primary Battery
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Solution Overview
Problem
Existing energy harvesting systems face challenges in ensuring continuous power supply to application circuits when the energy harvester and storage device cannot provide sufficient energy, due to unpredictable energy sources and varying environmental conditions, leading to potential power interruptions.
Innovation Solution
A Power Management Integrated Circuit (PMIC) with a voltage converter, a primary battery input, and monitoring and switching mechanisms to automatically switch between energy harvester and primary battery power sources based on predefined threshold values, ensuring continuous power availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system relies solely on energy harvester and storage device for power supply, then the system operates with simple architecture, but power interruptions occur when energy availability is insufficient
Solution Approach 1:
The system proactively integrates a primary battery as a backup power source before power interruptions occur. The battery is pre-configured in the power management circuitry to automatically activate when energy from the harvester and storage device becomes insufficient, preventing power interruptions rather than reacting to them.
Solution Approach 2:
The primary battery serves as a cushioning backup that compensates for potential energy shortages from the harvester and storage device. By having this reserve power source in place beforehand, the system ensures continuous operation even when environmental conditions reduce energy harvesting or when storage device capacity is depleted.
2Use of energy by moving object
If the PMIC uses a voltage converter with high power transfer efficiency, then energy utilization is optimized, but the system cannot operate when input voltage is insufficient for converter activation
Solution Approach 1:
The cold-start module is activated in the preliminary stage when the system first receives power input. It performs the essential function of generating sufficient voltage to activate the main voltage converter, after which the cold-start module is deactivated and the efficient main converter takes over for sustained operation.
Solution Approach 2:
The system operates in periodic phases: initially the cold-start module is active to bootstrap the system, then it deactivates and the main voltage converter becomes active for efficient power conversion. This periodic activation sequence ensures the system can start up even from very low input voltages while maintaining high efficiency during normal operation.
3Reliability
If the system integrates multiple power sources (energy harvester, storage device, primary battery), then power availability is ensured, but the system requires complex switching and monitoring mechanisms
Solution Approach 1:
The power management integrated circuit combines the functions of voltage conversion, power source selection, and system monitoring into a single integrated chip. This merging of multiple functions into one component achieves reliable multi-source power management while reducing overall system complexity compared to using separate discrete components for each function.
Solution Approach 2:
The PMIC is designed as a universal controller that can manage power from multiple sources (energy harvester, storage device, and primary battery) through its multiple input terminals. This multi-functional design allows a single component to handle diverse power sources and operating conditions, simplifying the system architecture while ensuring continuous power availability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The PMIC maintains continuous output power availability by switching to a primary battery when the energy harvester's energy storage signal falls below a threshold, allowing for broader primary battery selection and voltage compatibility, thus preventing power interruptions.
Implementation Method 1
The voltage converter comprises for example a DC-DC boost converter circuit
Implementation Method 2
The cold-start module typically comprises a charge pump
Implementation Method 3
Examples of energy harvester sources are photovoltaic cells (PV)
Implementation Method 4
Examples of energy harvester sources are photovoltaic cells (PV) or thermoelectric generators (TEG)
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2~3
AI summary
The present invention concerns a power management integrated circuit (PMIC) for managing energy from an energy harvester. The PMIC comprises a voltage converter and switches configured for switchable connecting an input of the voltage converter with either a first input terminal connectable to the energy harvester or with a second input terminal connectable with a primary battery. The PMIC further comprises a controller for driving the switches based on energy status signals related to the energy storage device and/or the energy harvester. The invention is also related to an energy harvesting system comprising a PMIC, an energy harvester connected to the first input terminal, an energy storage device connected to the output terminal and a primary battery connected to the second input terminal.