Battery Pack Outrush Circuit for Startup Current Limiting
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Solution Overview
Problem
Devices and battery packs with low internal electrical impedance can cause damage when connected due to increased current flow, necessitating a solution to mitigate or prevent damage while maintaining low system impedance during operation.
Innovation Solution
Incorporating an outrush circuit with a resistor and switch in series and parallel configurations, respectively, that is controlled by an external signal to manage current flow, limiting current when necessary and allowing full current flow during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the battery pack uses low internal electrical impedance to supply electrical power, then the power delivery capability is improved, but the current flow increases causing damage to the connected device
Solution Approach 1:
The outrush circuit is activated in advance during the startup phase to limit current flow before the device is fully operational. The circuit proactively prevents harmful current spikes before they can damage the device, then automatically deactivates once the device is ready to receive full power.
Solution Approach 2:
The outrush circuit dynamically adjusts its state based on the operational phase of the device. During startup, the circuit is active to limit current; after startup completion, the circuit transitions to an inactive state to allow full power delivery. This dynamic behavior resolves the contradiction between limiting current and delivering power.
2Reliability
If the outrush circuit with resistor is activated continuously to limit current, then device damage is prevented, but system impedance remains high reducing power delivery
Solution Approach 1:
The outrush circuit operates periodically rather than continuously. It is activated during the startup phase when protection is needed, then deactivated during normal operation when full power delivery is required. This periodic activation pattern maintains both device protection and optimal power delivery.
Solution Approach 2:
The current limiting function is applied only during the preliminary startup phase when the device is most vulnerable. Once the device is operational, the protection circuit is removed from the circuit path, allowing the system to achieve its full power delivery capability without the resistor's impedance.
3Speed
If the switch is activated immediately upon receiving external signal, then full current flow is achieved quickly, but device damage may occur during startup
Solution Approach 1:
The outrush circuit is activated in advance during the startup phase to limit current flow before the device is fully operational. The circuit proactively prevents harmful current spikes before they can damage the device, then automatically deactivates once the device is ready to receive full power.
Solution Approach 2:
The outrush circuit applies preliminary counter-action by limiting current flow during startup to prevent the harmful effect of excessive current. This anti-action is applied before the harmful current can cause damage, then removed once the device is operational.
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
Prevents excessive current from causing damage to connected devices while ensuring sufficient power delivery, maintaining low system impedance and preventing device damage.
Implementation Method 1
The resistor is configured to be electrically connected to the first terminal or the second terminal and a power source... The resistor limits electric current to the second device
Implementation Method 2
When the first device receives the external signal, the switch is switched on after a startup time from receiving the external signal, such that the switch bypasses the resistor and replaces the resistor, and electric current from the power source substantially passes through the switch
Data Source
AI summary
A first device includes an outrush circuit including a resistor electrically disposed in series with first and second terminals of the first device and a switch electrically disposed in parallel with the resistor. The switch is controlled by an external signal received by the first device from a second device when the first device is communicably connected to the second device and the second device is electrically connected to the first and second terminals. When the first device receives the external signal, the switch is switched on after a startup time from receiving the external signal, such that electric current from a power source substantially passes through the switch. When the first device does not receive the external signal, the switch is switched off, such that electric current from the power source substantially passes through the resistor. The resistor limits electric current to the second device.