UCC2912

UCC3912

PROGRAMMABLE HOT SWAP POWER MANAGER

SLUS241D − MARCH 1994 - REVISED NOVEMBER 2003

6

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APPLICATION INFORMATION

UDG-93019-4

Figure 2. Load Current, Timing-Capacitor Voltage, and Output Voltage of the UCC3912 Under Fault

Conditions.

estimating maximum load capacitance

For hot-swap applications, the rate at which the total output capacitance can be charged depends on the

maximum output current available and the nature of the load. For a constant-current current-limited controller,

the output will come up if the load asks for less than the maximum available short-circuit current.

To ensure recovery of a duty-cycle from a short-circuited load condition, there is a maximum total output

capacitance which can be charged for a given unit ON time (fault time). The design value of ON or fault time

can be adjusted by changing the timing capacitor CT.

For worst-case constant-current load of value just less than the trip limit; COUT(max) can be estimated from:

C

OUT(max) [

I

MAX *

I

LOAD

28

103

CT

V

OUT

where VOUT is the output voltage.