IR3093

Page 21 of 39

07/15/04

Figure 8 – Operating Waveforms

Soft-start delay time

to allow the soft start. The soft start time

O

SS

O

SS

CHG

SS

V

t

V

t

I

C

*

10

*

60

*

6

(4)

time

respectively.

6

10

*

60

1

.

1

*

*

'

SS

CHG

SS

SSDEL

C

I

V

C

t

(5)

6

10

*

61

25

.

0

*

*

'

SS

DISCHG

SS

OCDEL

C

I

V

C

t

(6)

6

10

*

60

)

1

.

1

75

.

3

(

*

*





'

O

SS

CHG

SS

VccPG

V

C

I

V

C

t

(7)

Over Current Protection (OCP)

The current limit threshold is set by a resistor connected between the OCSET and VDAC pins. If the average

Current Sense Amplifier output plus VDAC voltage exceeds the OCSET voltage, the over-current protection is

triggered.

VCC

START-UP

NORMAL OPERATION

HICCUP OVER-CURRENT

PROTECTION

RE-START

AFTER OCP

CLEARS

POWER-DOWN

7.4V

UVLO

(12V)

5VUVL

4.36V

SS/DEL

3.75V

PWRGD

VOUT

IOUT

(5VUVL GATES

FAULT MODE)

(VCC GATES

FAULT MODE)

1.1V

(VOUT CHANGES DUE TO

LOAD AND VID CHANGES)

OCP

DELAY

OCP THRESHOLD