USB-C Power Supply Switch Isolation for Overvoltage Protection
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Solution Overview
Problem
USB-C cables using USB-PD technology face issues with voltage regulation, leading to potential damage from excessive voltage delivery, which can degrade electronic devices due to the inability to effectively isolate the connector from the power converter when voltage exceeds a setpoint value.
Innovation Solution
A device with a low dropout linear voltage regulator and a switch control circuit, including a hysteresis comparator and differential amplifier, is used to compare the input voltage with a threshold voltage, controlling the switch to isolate the connector when the voltage exceeds the threshold, thereby protecting the device from excessive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power converter is used to deliver power over USB-C cable, then power transmission capability is improved, but voltage regulation difficulty increases leading to potential damage from excessive voltage
Solution Approach 1:
The system is segmented into distinct functional blocks: a power converter block for power transmission, a detection block for voltage monitoring, a control block for switch management, and a protection block for isolation control. This segmentation allows each block to perform its specific function optimally while maintaining overall system reliability through coordinated operation.
Solution Approach 2:
A switch is introduced as an intermediary element between the power converter and the connector. This switch acts as a controllable mediator that can isolate the connector from the power converter when voltage exceeds safe levels, preventing direct damage while allowing normal power transmission when conditions are safe.
2Productivity
If voltage regulation is relaxed to allow higher power delivery, then power transmission efficiency is improved, but risk of electronic device damage increases
Solution Approach 1:
The system implements a feedback mechanism where the detection block continuously monitors the voltage level and provides this information to the control block. The control block adjusts the switch state based on the detected voltage, creating a closed-loop feedback system that maintains power transmission efficiency while preventing excessive voltage damage through real-time monitoring and adjustment.
Solution Approach 2:
The system applies preliminary anti-action by detecting voltage levels before they reach dangerous thresholds and preemptively activating the isolation mechanism. The control block is configured to open the switch when voltage exceeds a predetermined safe level, preventing the harmful effect of excessive voltage before it can damage electronic components.
3Reliability
If isolation mechanism is added to protect from overvoltage, then device protection capability is improved, but system complexity increases
Solution Approach 1:
The protection functionality is merged with the existing power transmission system by integrating the detection block, control block, and isolation switch into the power delivery pathway. Rather than adding a separate complex protection system, the solution combines monitoring and protection functions within the existing architectural framework, reducing overall system complexity while maintaining effective protection.
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
The solution effectively maintains the output voltage within safe limits, preventing damage to electronic components and ensuring reliable power delivery while protecting against voltage increases, thus enhancing the safety and efficiency of USB-C power transmission.
Implementation Method 1
a low dropout, LDO, linear voltage regulator connected between the first and third terminals, wherein the regulator is configured to provide the second voltage from the first voltage
Implementation Method 2
the control circuit of the switch comprises a hysteresis comparator, a first input of which is connected to the first terminal, a second input of which is connected to the third terminal
Implementation Method 3
a second circuit configured to supply, to the fourth terminal, a signal representative of the difference between the value of the second voltage and the threshold value
Data Source
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AI summary
This description relates to a device (10) comprising: a first terminal (19) for receiving a first DC voltage (Vsc); a switch (SW) selectively connecting the first terminal (19) to a second output terminal (Vbus) of the device; a control circuit (14) for the switch comprising a third terminal (M-VDD) for receiving a second DC voltage (Vdd); and a low-dropout linear voltage regulator (16), LDO, connected between the first and third terminals, the regulator being configured to provide the second voltage from the first voltage.