Power Supply Circuit With Capacitor Support for Peak Current
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Solution Overview
Problem
Limited power sources, such as 12V accessory power outlets in automobiles and USB ports, restrict the types of electrical devices that can be powered due to their limited current capacities, making them less useful.
Innovation Solution
A circuit that includes a power converter and a capacitive element, where the power converter limits current flow and the capacitive element temporarily supports increased current demand, allowing the power converter to operate within safe limits and enabling the capacitive element to discharge during peak power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power converter with current limit is used to protect the power source, then the power source is protected from damage, but the load cannot receive sufficient current during peak power demands
Solution Approach 1:
The capacitive element is pre-charged during periods when the load demand is low, storing energy in advance. When the load requires peak power, the capacitor discharges to supplement the limited current from the power converter, thereby meeting the load's peak demand without exceeding the power converter's current limit.
Solution Approach 2:
The capacitive element acts as an intermediary between the power converter and the load. It absorbs excess current when available and releases it when needed, mediating the mismatch between the power converter's limited current output and the load's variable current demands.
2Power
If the power converter operates at maximum current limit continuously, then the load can receive maximum power, but the power source may be damaged or overloaded
Solution Approach 1:
Energy is stored in the capacitive element in advance during low-demand periods, preparing a reservoir of power that can be deployed during peak demands. This eliminates the need for the power converter to continuously operate at its maximum current limit, thereby preventing overcurrent damage.
Solution Approach 2:
The capacitive element serves as a cushion that absorbs the shocks of peak power demands. By having this energy buffer in place beforehand, the system can handle sudden high-current demands without transmitting harmful overcurrents to the power source.
3Power
If a second power source is added to provide additional current, then peak power demands can be met, but the device complexity increases
Solution Approach 1:
The capacitive element serves multiple functions: it acts as an energy buffer during peak demands, a current source during high-power periods, and a trickle-charge storage device during low-power periods. This multi-functionality eliminates the need for a separate second power source, maintaining system simplicity while achieving peak power capability.
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
This configuration enhances the ability to supply power to devices with varying demands, reducing peak power drawn from limited power sources and maintaining the power source's longevity by limiting its usage during high-demand periods.
Implementation Method 1
an RC circuit including a capacitor C and a resistor R in series with the power converter
Data Source
AI summary
A circuit to supply power to a load incorporates a first power source, a second power source that may be detachable, a power converter and at least one capacitor (capacitive element), where the first power source is capable of powering the load when charged, where the second power source is not capable of powering the load, but the second power source is capable of trickle-charging the first power source at a time when the first power source is not powering the load, where the power converter may impose a limit on a flow of current through the power converter, and where the at least one capacitor may cooperate to temporarily support a flow of additional current that circumvents the power converter at a time when the load attempts to draw a relatively greater amount of current.