Battery Power Supply Circuit for Sleep-Load Capacity Utilization
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Solution Overview
Problem
Lithium and lithium-ion batteries used in IoT devices and high power consumption applications have limitations such as being hazardous, restricted in transportation, and expensive, while batteries with non-flat discharge curves and high internal resistance, like alkaline batteries, have limited utilization due to inefficiencies in power supply systems.
Innovation Solution
A battery power supply circuit that includes a voltage downconverter, current limiter, and capacitor tank, controlled by a controller to optimize battery capacity utilization and extend battery life by managing current and voltage levels, and incorporating a buck-boost converter to handle batteries with varying voltages, and a low power mode for sleep operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional power supply systems are used with alkaline batteries (non-flat discharge curve, high internal resistance), then battery availability and safety are improved, but battery capacity utilization is limited
Solution Approach 1:
The system performs preliminary charging of the capacitor tank before the load is activated. The voltage converter charges the capacitor tank to a threshold voltage (up to 95% of desired output voltage) while current limiting is active, then removes current limiting to immediately further charge to the desired output voltage. This preliminary action prepares the power supply in advance, maximizing battery capacity utilization while protecting alkaline batteries with non-flat discharge curves.
Solution Approach 2:
The system dynamically adjusts current limiting based on the charging state of the capacitor tank and load requirements. The controller activates current limiting during initial charging, then removes it when the threshold voltage is reached, allowing the system to adapt to the battery's discharge characteristics and maximize capacity utilization.
2Ease of operation
If voltage converter is kept on continuously to maintain output voltage, then power availability to load is improved, but battery discharge due to capacitor tank parasitic self-discharge occurs
Solution Approach 1:
The voltage converter is operated periodically rather than continuously. It is enabled before the load is activated to charge the capacitor tank, then disabled when the load is turned off or enters sleep mode. This periodic operation eliminates battery discharge caused by parasitic self-discharge during idle periods while ensuring power availability when needed.
Solution Approach 2:
The voltage converter is enabled in advance before the load is activated, charging the capacitor tank to the desired output voltage. This preliminary charging action ensures immediate power availability when the load wakes up or activates, while allowing the converter to be disabled during idle periods to prevent parasitic discharge.
3Duration of action of stationary object
If current limiting is applied continuously to protect battery, then battery life is improved, but power delivery capability to load is reduced
Solution Approach 1:
Current limiting is dynamically controlled based on the charging phase. The controller activates current limiting during initial charging of the capacitor tank to protect the battery, then removes current limiting when the threshold voltage is reached, allowing full power delivery capability to the load without compromising battery life.
Solution Approach 2:
Current limiting is applied preliminarily during the charging phase before load activation. This preliminary protection preserves battery life, after which current limiting is removed to enable full power delivery capability when the load requires it.
4Ease of operation
If capacitor tank is charged to 100% desired output voltage immediately, then power availability is improved, but battery capacity utilization decreases
Solution Approach 1:
The capacitor tank is charged to a threshold voltage (up to 95% of desired output voltage) as a preliminary step while current limiting is active, then current limiting is removed to immediately further charge to the desired output voltage. This two-stage preliminary charging maximizes battery capacity utilization while ensuring adequate power availability.
Solution Approach 2:
The charging process is dynamically divided into two stages: initial charging to threshold voltage with current limiting, then rapid charging to desired voltage without current limiting. This dynamic approach optimizes both battery capacity utilization and 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 solution maximizes battery capacity utilization, extends battery life, and allows the use of widely available and safer battery types by efficiently managing power delivery and storage, while maintaining low temperature performance and handling batteries with different voltage profiles.
Implementation Method 1
a voltage downconverter connected in series to a battery and generating a voltage smaller less than the battery voltage
Implementation Method 2
a capacitor tank connected in series to the current limiter for providing an output voltage to the load
Data Source
AI summary
A battery power supply (BPS) circuit to power an intermittently powered load, optimized to maximize battery capacity utilization and extend battery life, while offering low temperature performance. The BPS includes a voltage converter connected to a battery for generating a voltage greater or less than the battery voltage, a current limiter configured to limit current in a current limiting mode and to provide a shunt in a noncurrent limiting mode, a capacitor tank for providing an output voltage to the load and first charged to a voltage up to 95 or 100% (depending upon the operation of the BPS) of a desired output voltage, and second charged to the desired output voltage when the current limiter is shunted. Optionally, a relaxation/stabilization period is then applied before the load is enabled to maximize battery life. The BPS also provides a low power mode of operation while the load is disabled or in a sleep mode of operation.