TPS2042, TPS2052

DUAL POWER-DISTRIBUTION SWITCHES

SLVS173A – AUGUST 1998 – REVISED APRIL 1999

21

POST OFFICE BOX 655303

APPLICATION INFORMATION

generic hot-plug applications (see Figure 34)

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 TPS2042 and TPS2052, 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 TPS2042 and TPS2052 also ensures the switch will be off after the card has been removed, and the switch

will be off during the next insertion. The UVLO feature guarantees a soft start with a controlled rise time for every

insertion of the card or module.

Power

Supply

Block of

Circuitry

TPS2042

GND

IN

EN1

EN2

OC1

OUT1

OUT2

OC2

0.1

µF

1000

µF

Optimum

2.7 V to 5.5 V

PC Board

Overcurrent Response

Block of

Circuitry

Figure 34. Typical Hot-Plug Implementation

reach these devices first after insertion. The typical rise time of the switch is approximately 2.5 ms, providing

a slow voltage ramp at the output of the device. This implementation controls system surge currents and

provides a hot-plugging mechanism for any device.