18

LTC4212

4212f

OPERATIO

Figure 4. Power-Up with Overcurrent, Slow Comparator Trips the Circuit Breaker

ON

2.34V

TIMER

GATE

DC/DC

CONVERTER

OUTPUT

FAULT

PGT

PGI

PGF

4212 F04

12

3

4

5

6

7

8

9

10 11

13

12

1415

16

POWER GOOD TIMER

0.95V

0.65V

2ND TIMING

1ST TIMING

1ST TIMING

SOFT-START

ACTIVE

> 50mV, >18

µs

It consists of the time the FAULT pin takes to discharge

circuit breaker (Time Points 9 to 11), the time it takes the

1.316V (Time Points 11 to 12) and the elapsed time before

the external N-channel starts to conduct during the second

timing cycle (Time Points 12 to 16).

Sense Resistor Considerations

The fault current level at which the LTC4212’s internal

electronic circuit breaker trips is determined by a sense

pins and two separate trip points. The first trip point is set