Offline Power Supply Controller Powered by Disconnected Capacitor
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Solution Overview
Problem
Existing low-power plug-in chargers and power supplies continue to consume energy even when not in use, leading to parasitic energy waste, as they remain connected to the AC power source unless manually unplugged.
Innovation Solution
An offline power supply with a controller powered by a separate capacitor that selectively disconnects the AC transformer when there is negligible load, recharging the capacitor as needed to maintain operation, effectively simulating unplugging by managing the connection to the AC power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the AC transformer remains connected to the AC power source, then the power supply can respond to charging requests instantly, but parasitic energy waste occurs continuously even when not in use
Solution Approach 1:
The system performs preliminary action by charging a capacitor during operation so that the controller can operate autonomously later without needing continuous AC power. This stored energy enables the system to maintain instant response capability while being able to disconnect from AC power to eliminate parasitic waste.
Solution Approach 2:
The controller is powered by the capacitor it previously charged, allowing it to autonomously monitor the DC bus voltage and control the switch without external power. This self-service capability enables the system to automatically disconnect and reconnect to AC power based on charging needs, eliminating parasitic waste while maintaining instant response.
2Loss of energy
If the controller is powered by the second power source (capacitor), then the switch can be selectively operated to disconnect AC power, but the controller needs initial power to start the charging process
Solution Approach 1:
The system uses periodic action by cycling the switch to connect and disconnect the AC transformer in controlled intervals. During these periodic connections, the capacitor is recharged; during disconnections, parasitic waste is eliminated. This periodic operation resolves the contradiction between needing initial power and eliminating continuous waste.
Solution Approach 2:
The system changes the power source parameter dynamically - transitioning from AC-powered controller to capacitor-powered controller. This parameter change enables the controller to operate autonomously and selectively disconnect AC power, reducing parasitic waste while managing the complexity through intelligent power source switching.
3Loss of energy
If the switch disconnects the primary-side circuit from the AC power source, then energy waste is reduced, but the system cannot recharge the capacitor or respond to charging requests
Solution Approach 1:
The controller continuously monitors the DC bus voltage as feedback to determine when capacitor charge levels are sufficient to disconnect AC power. This feedback mechanism ensures the system only disconnects when charging availability is maintained, resolving the contradiction between reducing energy waste and ensuring charging reliability.
Solution Approach 2:
The system dynamically adjusts its operation mode - connecting to AC power when capacitor charge is insufficient, and disconnecting when charge is sufficient. This dynamic behavior ensures charging availability is maintained while maximizing parasitic waste reduction, as the system adapts its power connection state based on real-time capacitor charge levels.
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 solution significantly reduces energy wastage by disconnecting the AC power supply when not in use, while ensuring quick reconnection and recharging of the capacitor to maintain functionality, thus minimizing standby power consumption.
Implementation Method 1
a transformer (20) connecting the primary-side circuit (16) and the secondary-side circuit (30)
Implementation Method 2
A second power source is charged during operation of the power supply circuit... when the second power source is a capacitor
Data Source
AI summary
An offline power supply includes a power supply circuit including a primary-side circuit for connecting to a first power source, a secondary-side circuit for connecting to a load, and a transformer connecting the primary-side circuit and the secondary-side circuit. A switch operates to selectively connect the primary-side circuit to the first power source. A second power source is charged during operation of the power supply circuit. A controller powered by the second power source has at least one input, and an output to selectively operate the switch based on the at least one input.