AC Adapter Charging Circuit with Dynamic Voltage Control
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Solution Overview
Problem
Current charging systems, such as those using USB interfaces, face challenges in efficiently delivering power to devices due to limitations in standardized communications interfaces, leading to inefficiencies and power losses, as they often operate in constant current mode and require power negotiation, which does not match the exact power needs of downstream devices.
Innovation Solution
The implementation of a switched mode power supply (SMPS) with feedback mechanisms that adjust voltage levels based on detected drops in supply voltage, allowing for optimal power delivery by maintaining a substantially constant supply voltage for the DC charger circuit, and a control circuit that manages power paths between the system load and battery, ensuring maximum current allocation to both.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standardized communications interfaces (USB) are used for charging, then convenience and compatibility are improved, but power delivery capability deteriorates due to current limits
Solution Approach 1:
The patent segments the power delivery function by introducing a separate AC adapter with USB interface that bypasses the standard USB current limits. The AC adapter creates an independent power path from AC mains through its internal rectifier and regulator circuits directly to the battery, while the USB interface maintains only communication and low-power charging functions. This segmentation allows high-power charging without modifying the standard USB specification.
2Adaptability or versatility
If power negotiation protocols are implemented, then adaptability to different devices is improved, but charging speed deteriorates due to negotiation overhead
Solution Approach 1:
The AC adapter performs preliminary power establishment by providing full power immediately upon connection without requiring negotiation protocols. The adapter assumes the downstream device can accept maximum power and begins charging immediately. This preliminary action eliminates negotiation overhead and achieves maximum charging speed from the moment of connection.
3Adaptability or versatility
If predetermined voltage increments are used for power delivery, then compatibility with existing standards is improved, but efficiency deteriorates due to voltage mismatch
Solution Approach 1:
The AC adapter implements dynamic voltage adjustment through its control circuit that continuously monitors battery voltage and charging current. The regulator circuit dynamically adjusts the output voltage to match the exact requirements of the battery at any given moment, rather than providing fixed voltage increments. This dynamic adaptation maximizes charging efficiency while maintaining compatibility with different battery types.
4Productivity
If maximum current is allocated to battery charging, then charging speed is improved, but system load performance deteriorates due to current starvation
Solution Approach 1:
The AC adapter segments the power distribution by providing dedicated high-current paths for both battery charging and system load operation simultaneously. The internal circuitry includes separate current allocation circuits that can deliver maximum current to the battery while also providing sufficient current to the system load, rather than forcing a choice between the two. This segmentation resolves the current starvation problem.
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 enables efficient and rapid battery charging by optimizing power delivery, reducing charging time and minimizing power losses, as the system dynamically adjusts voltage and current allocation to meet the device's power needs without the need for negotiation protocols.
Implementation Method 1
a switched mode power supply (SMPS) configured to operate with energy supplied from the AC power source via the power supply input terminal, the SMPS configured to generate a supply voltage for a direct current (DC) charger circuit supplied by the SMPS
Implementation Method 2
the SMPS further configured to adjust a voltage level of the supply voltage depending on a feedback signal applied at a feedback input to the SMPS; input terminals configured to receive signals from the DC charger circuit, wherein at least one of the received signals is an analog signal responsive to a drop in the supply voltage in the DC charger circuit
Data Source
AI summary
The present technology relates to systems and methods for rapidly charging a battery of a device when the device is attached to an AC adapter. Some embodiments of the present disclosure describe an activation circuit in an AC adaptor and a detection circuit in a downstream device that cooperatively ensure optimal power delivery. Some embodiments of the present disclosure describe a device with a system load, a battery, and a control circuit, wherein the control circuit is configured to provide the battery with a charging current of Ibat=Imax−Isys when the device is in a USB compliant mode of operation and a charging current of Ibat=Imax when the device is connected to an AC adapter.