AP2161/AP2171

1A SINGLE CHANNEL CURRENT-LIMITED POWER

SWITCH

AP2161/AP2171 Rev. 6

13 of 19

JUNE 2009

DS31564

www.diodes.com

Application Note

(Continued)

Generic Hot-Plug Applications

In many applications it may be necessary to remove modules or pc boards while the main unit is still

operating. These are considered hot-plug applications. Such implementations require the control of current

surges seen by the main power supply and the card being inserted. The most effective way to control these

surges is to limit and slowly ramp the current and voltage being applied to the card, similar to the way in

which a power supply normally turns on. Due to the controlled rise times and fall times of the

AP2161/AP2171, these devices can be used to provide a softer start-up to devices being hot-plugged into a

powered system. The UVLO feature of the AP2161/AP2171 also ensures that the switch is off after the card

has been removed, and that the switch is off during the next insertion.

these devices first after insertion. The typical rise time of the switch is approximately 1ms, providing a slow

voltage ramp at the output of the device. This implementation controls system surge current and provides a

hot-plugging mechanism for any device.