USB Energy Harvesting Controller Circuitry for Low-Current Sources
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Solution Overview
Problem
USB specifications require a minimum current threshold for energy sources connected via dedicated charging ports, which prevents energy harvesting from alternative sources that provide less than 500 milliamps, limiting the ability to utilize energy sources like solar cells and other alternative energy sources.
Innovation Solution
An energy harvesting controller circuitry detects the current provided by an energy source and connects it directly to the user equipment's battery if it falls below the threshold, enabling energy harvesting while inhibiting normal USB operations, and switches to normal USB mode when the current exceeds the threshold, allowing normal operations such as boot-up and charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If USB specifications require a minimum current threshold for energy sources connected via dedicated charging ports, then normal USB operations can be ensured, but energy harvesting from alternative sources that provide less than 500 milliamps is prevented
Solution Approach 1:
The system dynamically switches between two operational modes based on the detected current level from the energy source. When current exceeds the threshold, the system operates in normal USB mode; when current falls below the threshold, the system transitions to energy harvesting mode. This dynamic adaptation allows the system to maintain reliability for standard USB devices while becoming compatible with low-power alternative energy sources like solar cells.
Solution Approach 2:
The system changes its operational parameters based on the energy source characteristics. By detecting whether the provided current exceeds a predetermined threshold, the system adjusts its mode of operation accordingly. This parameter-based differentiation enables the system to optimize performance for both high-current USB devices and low-current alternative energy sources without compromising either functionality.
2Adaptability or versatility
If the system connects energy sources directly to the battery when current is below threshold, then energy harvesting is enabled, but normal USB operations are inhibited
Solution Approach 1:
The system extracts the energy harvesting function as a separate operational mode distinct from normal USB operations. When low-current energy sources are detected, the system isolates the energy harvesting path by inhibiting normal USB operations, allowing direct connection to the battery. This separation enables the system to capture energy from alternative sources without interfering with the standard USB charging pathway.
3Ease of operation
If the system allows normal USB operations when current exceeds threshold, then standard charging and boot-up functions work properly, but energy harvesting from alternative sources is not utilized
Solution Approach 1:
The system continuously monitors the current provided by the energy source and uses this feedback to determine the appropriate operational mode. By comparing the detected current against a predetermined threshold, the system receives feedback about the energy source type and adjusts its behavior accordingly. This feedback mechanism ensures that energy harvesting opportunities are captured when appropriate while maintaining normal USB functionality when standard power sources are available.
Data Source
AI summary
In some example embodiments, there may be provided a method, which may include determining, by controller circuitry, whether an energy source provides at least a threshold current; connecting, when the energy source provides at least the threshold current, the energy source to interface circuitry to enable a normal mode of operation at the user equipment; and connecting, when the energy source does not provide at least the threshold current, the energy source to the battery. Related system, methods, and articles of manufacture are also disclosed.