USB Battery Charger Vbus Voltage Detection Circuit
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Solution Overview
Problem
Existing battery chargers for portable electronic devices using the USB Vbus terminal face challenges in detecting device connection without increasing complexity and cost, as they require large controllers for data communication-based detection.
Innovation Solution
A battery charger with a controller that detects device connection by monitoring voltage changes at the USB Vbus terminal, using a switching device and a controller to output a voltage and determine connection status, thereby simplifying the structure and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data communication-based connection detection is used, then connection detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the connection detection function from complex data communication protocols and implements it through simple voltage level detection on the Vbus line. This removes the need for USB data communication controllers while maintaining reliable connection detection, directly resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent replaces the electronic data communication system with a simpler electrical voltage detection mechanism. By monitoring voltage levels on the power line rather than exchanging data packets, the system achieves connection detection with minimal complexity while maintaining reliability.
2Reliability
If data communication-based connection detection is used, then connection detection reliability is improved, but system cost increases
Solution Approach 1:
The patent removes the expensive USB data communication controller hardware and associated firmware complexity, retaining only the essential voltage detection functionality. This extraction of the core detection function while eliminating unnecessary components directly reduces system cost while preserving connection detection reliability.
Solution Approach 2:
The patent uses simple, inexpensive voltage detection circuitry instead of expensive USB communication controllers. The minimalistic approach using basic voltage threshold detection provides sufficient reliability at a fraction of the cost of implementing full USB data communication protocols.
3Power
If USB Vbus terminal is used for power supply, then charging current sufficiency is improved, but power consumption increases
Solution Approach 1:
The patent performs preliminary voltage level detection on the Vbus line before enabling full charging operation. By detecting connection status and voltage levels in advance through simple threshold detection, the system can activate charging only when appropriate, avoiding unnecessary power consumption while maintaining sufficient charging current when needed.
Solution Approach 2:
The patent implements dynamic control of the charging circuit based on real-time voltage detection results. The charging transistor is switched on or off based on the detected voltage level, creating a dynamic system that adapts power consumption to actual charging needs, thus reducing wasted energy while maintaining adequate charging current capability.
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 efficient detection of device connection and charging without the need for complex data communication, simplifying the system and reducing costs while maintaining effective charging functionality.
Implementation Method 1
a first detection to detect a change in a voltage at the Vbus terminal by outputting a first voltage to the Vbus terminal
Data Source
AI summary
There is offered a battery charger for a portable electronic device that has a simple structure and is capable of detecting that the portable electronic device is connected to the battery charger. A first power supply line is connected to a positive terminal (+) of a rechargeable battery, while a ground line is connected to a negative terminal (−) of the rechargeable battery. An output transistor is connected between the first power supply line and a second power supply line. The output transistor is connected to a Vbus terminal of a USB connector through the second power supply line. A controller outputs a voltage of an H level to the Vbus terminal to detect a change in a voltage at the Vbus terminal, and judges whether the portable electronic device is connected to the USB connector based on a result of the detection. The controller turns the output transistor on when the portable electronic device is judged to be connected to the USB connector.