Dual Shutdown Circuit Power Supply for Inrush Current Management
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Solution Overview
Problem
High-capacity portable power supplies face challenges with inrush currents when connected to power tools with capacitors, leading to potential overdischarge protection issues and inefficient battery protection circuit operation, particularly with lithium-ion batteries, which consume power even when not in use.
Innovation Solution
A power-supplying device with dual shutdown circuits on either side of the rechargeable battery and a monitoring unit that reduces power consumption by interrupting output when necessary, using FETs and photocouplers to manage current and voltage, and a battery protection IC that switches between active and standby modes to conserve power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power supply capacity is increased to accommodate more secondary cells, then the output current capability is improved, but the inrush current when connected to power tools with capacitors increases, triggering overdischarge protection circuits
Solution Approach 1:
The patent applies preliminary action by equipping the power supply with a monitoring unit that detects connection status before full power delivery. The control unit preemptively manages power output based on detected connection states, preventing inrush current from triggering protection circuits while maintaining high output capability. This is achieved through advance monitoring of terminal voltage and current conditions.
Solution Approach 2:
The patent implements feedback through a monitoring unit that continuously detects voltage and current at the power supply terminals. This feedback information is fed to the control unit, which adjusts power output in real-time. When inrush current is detected or connection status changes, the control unit modifies output to prevent protection circuit activation, enabling sustained high-power operation.
2Reliability
If a fuse or irreversible current-interrupting element is used to prevent output during short circuit, then the safety is improved, but the restoration of output after interruption becomes troublesome and time-consuming
Solution Approach 1:
The patent applies self-service through an automatic recovery mechanism. When short circuit or abnormal current is detected, the control unit automatically interrupts power output via the shutdown circuit. Once the abnormal condition clears, the system automatically restores normal operation without manual intervention. This eliminates the need for fuse replacement or manual reset operations.
Solution Approach 2:
The patent implements dynamics through a controllable shutdown circuit that can rapidly switch between on and off states based on real-time monitoring. The control unit dynamically adjusts power delivery, enabling quick interruption during abnormalities and swift recovery afterward. This dynamic response replaces static fuse protection with an adaptable electronic control system.
3Reliability
If the battery protection circuit continuously monitors the secondary battery to prevent overdischarge and overcharge, then the battery safety is improved, but the power consumption increases even when the power supply is not in use
Solution Approach 1:
The patent implements dynamics by making the monitoring unit controllable rather than continuously active. The control unit adjusts the monitoring circuit's operation state based on whether the power supply is currently in use. When not connected to a load, monitoring is reduced or suspended, conserving battery power. When in use, full monitoring activates to ensure safety. This dynamic operation maintains protection reliability while minimizing unnecessary power consumption.
4Use of energy by moving object
If the power supply is configured to simply shutdown the battery protection circuit when power is not being supplied to a power tool, then the power consumption is reduced, but the power supply may not be able to sufficiently deal with any kind of abnormality that may occur during this state
Solution Approach 1:
The patent applies preliminary action by maintaining a reduced-level monitoring capability even when the power supply is not actively powering a tool. The monitoring unit remains in a standby state, capable of detecting connection events or abnormal conditions that occur during idle periods. This preliminary monitoring ensures that abnormalities are detected and responded to promptly, maintaining safety without requiring full-power continuous operation.
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 device effectively manages inrush currents and prevents overdischarge/overcharge by efficiently interrupting power supply and reducing overall power consumption, ensuring reliable operation and extended battery life.
Implementation Method 1
a photocoupler (110A, 110B) positioned between the microcomputer (103) and the low-side shutdown circuit (109A, 109B)
Implementation Method 2
The low-side shutdown circuit (109A, 109B) includes n-channel FETs (7, 14)
Data Source
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AI summary
A power-supplying device includes a terminal, a rechargeable battery, a first shutdown circuit, and a second shutdown circuit. The terminal is configured to be connected to a power tool. The rechargeable battery is configured to output electrical power to the power tool via the terminal. The first shutdown circuit is positioned at a plus side of the rechargeable battery, the first shutdown circuit being configured to shutdown output of the rechargeable battery. The second shutdown circuit is positioned at a minus side of the rechargeable battery. The second shutdown circuit is configured to shutdown output of the rechargeable battery.