Current Selectable USB Charger With Crossover Switch
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Solution Overview
Problem
Conventional USB chargers are not interchangeable due to device-specific current requirements, leading to the need for multiple chargers, as electronic devices only accept charges if the charger's D+ and D− pins match their specifications, limiting compatibility.
Innovation Solution
A current selectable USB charger with a crossover switch and voltage dividers that can selectively set the voltages on the D+ and D− pins to match different current capabilities, allowing the charger to adapt to various devices by swapping voltages and regulating current through a current limiter circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a USB charger is designed with fixed voltage settings on D+ and D- pins, then the charger can provide stable current output, but the charger is not compatible with multiple devices requiring different current specifications
Solution Approach 1:
The patent applies the dynamics principle by making the voltage configuration on D+ and D- pins changeable rather than fixed. A switch mechanism allows the charger to dynamically reconfigure the voltage connections between the power supply and the USB connector pins, enabling adaptation to different device current requirements while maintaining a single charger design
Solution Approach 2:
The patent implements universality by designing a single charger that can serve multiple devices with different current specifications. Through the switch mechanism, the same charger hardware can present different voltage configurations on the USB connector, allowing it to function as both a 1-ampere and 2.1-ampere charger depending on the connected device
2Adaptability or versatility
If multiple USB connectors are provided on a single charger to support different current outputs, then device compatibility is improved, but the charger size and complexity increase
Solution Approach 1:
Instead of providing multiple physical connectors, the patent makes a single USB connector universal by enabling it to present different voltage configurations through the switch mechanism. This allows one connector to replace what would otherwise require multiple connectors, reducing the charger's size and complexity
Solution Approach 2:
The patent changes the electrical parameters (voltage levels) on the USB connector pins rather than changing the physical connector itself. By switching the voltage configuration on the same connector, the charger can adapt to different devices without requiring multiple physical interfaces, thereby minimizing size
Data Source
AI summary
A current selectable USB charger includes a USB (universal serial bus) connector, a crossover switch, a pair of voltage dividers and a power supply. The power supply provides preferably a +5 volt DC voltage to the pair of voltage dividers. The pair of voltage dividers includes a first voltage divider and a second voltage divider, each being formed of a pair of series-connected resistors. The voltage on the junction of the series-connected resistors of the first voltage divider is selectively provided, through the crossover switch, to one of the D− pin and the D+ pin of the USB connector. The voltage on the junction of the series-connected resistors of the second voltage divider is selectively provided, through the crossover switch, to one of the D+ pin and the D− pin of the USB connector.