UCC2975, UCC2976, UCC2977

UCC3975, UCC3976, UCC3977

SLUS499A – NOVEMBER 2001 – REVISED JANUARY 2002

5

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mode select

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Shutdown threshold voltage

2.45

2.50

2.65

Restart threshold voltage

0.3

0.5

0.7

Open lamp detect enable threshold voltage

UCC2975

UCC2976

UCC2977

1.3

1.5

1.6

V

Open lamp detect enable threshold voltage

UCC3975

UCC3976

UCC3977

1.4

1.5

1.6

V

MODE pull-down current

200

250

300

mA

No lock threshold voltage

2.4

2.5

2.6

V

functional block diagram

The UCC397x family of controllers contain an error amplifier whose output is preconditioned at startup, a

precision window comparator used to form the VCO, and dual MOSFET drivers customized for half-bridge or

push-pull operation. The part includes a frequency lock retry circuit, low current shutdown, and open lamp fault

protection.

UDG–01053

Figure 4

OPEN/SD

+

2.5 V

+

0.5 V

+

1.5 V

SQ

Q

R

SLEEP

PWRUP

SHUT DOWN

RESET

OPEN LAMP

PWRUP

FAULT

INIT

OSC

COMP

FB

+

FAULT

COUNTER

RESET

COUNT

FAULT

SLEEP

NO LOCK

SQ

R

INIT

SLEEP

REF

UVLO

+

2.5 V

0.1 V

+

INIT

ERROR

AMPLIFIER

1.5 V

1.4 V

1.5 V

+

1.7 V

+

0.7 V

SQ

R

1.75 V

DQ

Q

CK

GND

OUTN/OUT2

OUTP/OUT1

VDD

SLEEP