plugging or hot Swap (plugging or Hot Swap) refers to a technology that connects a device, such as a board or module, to or removes it from the working system without affecting the system. The protection design of live plug and remove can be divided into four levels according to the degree of impact on devices and signals during live plug and remove.

Level 1.0 protection

The circuit board with level 0 protection design should be switched off before the main power supply can be safely plugged in and out. It has no protection against transient current or sudden voltage, and can not enter the high resistance state when inserting the circuit board interface. If the circuit board is plugged in and out without a power failure in the system, the interface or other components on the board are likely to be damaged. Circuit boards that can only achieve level 0 protection cannot be plugged and unplugged.

Level 2.1 Protection (Partial Power Down)

A circuit board with a Level 1 protection design prevents damage to the circuit board by limiting the current between the live bus and the interface into which the circuit board is inserted when power is disconnected. This transient current limit ensures that the board can be plugged in and out without interrupting the main power supply, but the main system must suspend signal transmission during the plugged in and out period.

Insertion (Hot Insertion)

Circuit boards with a level 2 protection design have live plug and pull performance, which can prevent drive conflicts when inserting the circuit board. Level 2 protection design In addition to the capability of level 1 protection design, the signal end can maintain a high resistance state until the supply voltage rises to a specified value, and will output according to the set state after the supply voltage exceeds this specified value.

Live Insertion

A circuit board with a Level 3 protection design has no additional restrictions, constraints, or requirements on system power and signal when plugged in and out with live power. Live plugging and data exchange can be carried out synchronously, that is, under any circumstances, plugging and unplugging operations will not damage the data, certainly will not damage the device.

Currently, hot-swappable connectors basically follow the on-and-off design method. The power off sequence of different terminals is controlled by different terminal lengths to achieve convenient hot swap function.