I know there are many techniques to protect over-voltage on the power supply. However, it does not apply to my case as it only provides single polarity voltage protection. Additionally, I want to achieve that with as little amount of components with small size as possible. In the other words, I want to design hardware to protect against a kind of harmful device called USB killer in a compact size with a little cost.
The schematic is shown below to demonstrate my idea:
Here HOST is known to provide constant 5V. Device may charge via the 5V power line and discharge to provide a short high voltage pulse: V_u (aka Unknown Voltage) could be 110V or -110V or higher. This is to protect HOST against the high voltage from Device.
Let's assume that HOST can tolerate the maximum voltage from -5V to 15V for a short period of time. I use 1 Ohm resistor to get the current and protect the circuit from the over-current with a 10A fuse.
Will this circuit protect against such a device? How effective is this protection?