USB PD Buck Converter Voltage Switching for Start-Stop Vehicles
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Solution Overview
Problem
Existing USB Power Delivery (PD) devices in automotive applications, using buck only DC-DC converters, fail to maintain output voltage higher than the input voltage during transient battery voltage dips, disrupting charging operations in start-stop vehicle modes.
Innovation Solution
A buck-only DC-DC converter design for USB PD devices that adjusts output voltage based on vehicle power state signals, switching between 9V for fast charge and 5V for normal charge modes during varying input voltages, ensuring continuous operation without interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a buck/boost DC-DC converter is used to generate voltages from 5V to 20V, then the output voltage can be maintained above and below the vehicle input voltage, but the device becomes more expensive, physically larger, and less energy efficient
Solution Approach 1:
The patent implements dynamic voltage negotiation between the USB PD device and the connected device, allowing the output voltage to adapt between 5V and 9V based on real-time conditions. The controller dynamically adjusts the DC-DC converter operation mode (buck or pass-through) depending on whether the vehicle battery voltage is above or below the threshold, enabling a simpler buck-only converter to achieve adaptability previously requiring complex buck/boost converters
Solution Approach 2:
The patent changes the operating parameters of the DC-DC converter based on vehicle battery voltage conditions. When battery voltage is above threshold, the converter operates in buck mode to step down to 9V for fast charging. When battery voltage drops below threshold, the system switches to pass-through mode maintaining 5V output. This parameter-based control allows a simpler converter design to achieve multiple voltage outputs
2Device complexity
If a buck-only DC-DC converter is used to reduce cost and complexity, then the device becomes more cost-effective and simpler, but the output voltage cannot be maintained higher than the input voltage during transient battery voltage dips
Solution Approach 1:
The system performs preliminary voltage negotiation with the connected USB device before actual power delivery begins. The controller pre-establishes the voltage contract (5V or 9V) based on predicted vehicle battery conditions, ensuring the simpler buck-only converter can maintain reliability by having the target voltage already determined before voltage transients occur
Solution Approach 2:
The patent implements continuous feedback monitoring of vehicle battery voltage by the controller. This feedback mechanism allows the system to detect voltage dips and switch between 9V buck mode and 5V pass-through mode in real-time, maintaining charging continuity and reliability despite using a simpler buck-only converter design
3Productivity
If the output voltage is switched between 9V and 5V based on vehicle power state, then fast charging and normal charging modes are supported, but the control complexity increases
Solution Approach 1:
The controller integrates multiple functions into a single component: voltage negotiation, voltage mode selection (buck or pass-through), and power management. This universal controller handles both 5V and 9V output modes, supporting both normal and fast charging through a single control unit, thereby managing control complexity efficiently while maintaining high productivity
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
Enables reliable and cost-effective USB PD operation in vehicles with start-stop technology, maintaining charging sessions across voltage transients while reducing device costs for consumers.
Implementation Method 1
a DC-DC power convertor (14) that receives an input voltage from a vehicle's electrical system
Data Source
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AI summary
An electrical power supply device (10) includes a DC-DC power convertor (14) receiving an input voltage (30) and producing a first output voltage (24) or a second output voltage (24) that is less than the first output voltage (24), the first and second output voltage (24) each less than the input voltage (30) and a device controller (16) in communication with the DC-DC power convertor (14). The device controller (16) has one or more processors and memory. The memory includes instructions which causes the device controller (16) to command the DC-DC power convertor (14) to output the first output voltage (24) when the input voltage (30) is equal to or greater than a threshold voltage (32) and which causes the device controller (16) to command the DC-DC power convertor (14) to output the second output voltage (24) when the input voltage (30) is less than the threshold voltage (32). A method (100) of operating the electrical power supply device (10) is also presented.