Dynamic Input Capacitor Switching for Fast Charger Volume Reduction
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Solution Overview
Problem
Conventional fast chargers face challenges in adapting to varying AC power voltages, leading to inefficiencies and increased volume due to fixed capacitance in their input filtering units, which affects charging performance and device size.
Innovation Solution
The design incorporates two first input capacitors and one second input capacitor with adjustable switch control, allowing the use of three capacitors only when necessary, reducing board width and volume while maintaining effective filtering across different voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed capacitance design is used in the input filtering unit to handle full-range input voltage (90-264 Vac), then the device can operate across all voltage ranges, but the device volume and board width increase due to requiring larger capacitors
Solution Approach 1:
The patent implements dynamic capacitance adjustment by using a control unit that switches between different capacitor configurations (first capacitor alone, second capacitor alone, or both in parallel) based on the detected input voltage range. This dynamic reconfiguration allows the filtering unit to adapt its capacitance value to match the current voltage conditions, achieving full voltage range compatibility without requiring the always-present large capacitance needed for universal operation.
Solution Approach 2:
The patent changes the capacitance parameter of the input filtering unit based on input voltage conditions. By detecting the input voltage range and switching between different capacitor combinations, the system adjusts the total capacitance value to be optimal for each voltage range, thereby reducing the required capacitor size for high-voltage operation while maintaining adequate filtering for low-voltage operation.
2Reliability
If larger capacitance is used in the input filtering unit to reduce voltage ripples, then the filtering performance improves, but the device volume increases
Solution Approach 1:
The system dynamically adjusts capacitance based on input voltage levels. During low-voltage operation where larger capacitance is needed for adequate filtering, the control unit connects both capacitors in parallel. During high-voltage operation where smaller capacitance suffices, the control unit uses only the appropriate capacitor, thereby maintaining reliable filtering performance across all conditions while minimizing volume.
3Reliability
If the input filtering unit is designed for highest input power and lowest voltage (90 Vac), then filtering is adequate for low voltage, but the device volume increases to accommodate the larger capacitors needed for this condition
Solution Approach 1:
The control unit detects input voltage and dynamically switches capacitor configurations. When low voltage (90 Vac) is detected, both capacitors are connected in parallel to provide adequate filtering. When high voltage is detected, the system switches to using only the appropriate capacitor, maintaining filtering adequacy for low-voltage conditions without permanently incorporating the large capacitance required for those conditions.
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 approach allows for a compact fast charging device that efficiently handles varying AC power voltages, enhancing charging performance and reducing capacitor usage, thereby shrinking the device's volume compared to conventional models.
Implementation Method 1
a bridge rectifier unit, being coupled to the AC power coupling interface and a first ground end, and being used for converting an AC power signal received from the AC power coupling interface to a pulsating DC voltage signal
Implementation Method 2
an input-end filtering unit, being coupled to the bridge rectifier unit and the first ground end, and being used for converting the pulsating DC voltage signal received from the bridge rectifier unit to a DC voltage signal
Implementation Method 3
a first CLC filter unit 14′ consisting of at least one choke coil Lin′ and a plurality of input capacitors Cin′
Implementation Method 4
a transformer unit, comprising a primary winding having a first electrical terminal and a second electrical terminal, a secondary winding having a first electrical terminal and a second electrical terminal, and an auxiliary winding having a first electrical terminal and a second electrical terminal
Implementation Method 5
an optical coupler 19′ consisting of an LED element LD′ and a phototransistor LT′
Implementation Method 6
an optical coupler 19′ consisting of an LED element LD′ and a phototransistor LT′
Data Source
AI summary
A fast charging device for mobile electronic device is disclosed. Particularly, an input-end filtering unit contained in the fast charging device is designed to comprise two first input capacitors, one second input capacitor, and one switch element. By such design, in case of a rated voltage of an input AC power being smaller than 110 Vac, the switch element is controlled to complete a switch-ON operation, so as to make the input-end filtering unit execute a signal filtering process by simultaneously using two first input capacitors and one second input capacitor. Moreover, in case of the rated voltage of the input AC power being in a range between 110 Vac and 264 Vac, the switch element is controlled to complete a switch-OFF operation, so as to make the input-end filtering unit execute the signal filtering process by merely using two first input capacitors.