High-Efficiency, Wide Brightness

Range, CCFL Backlight Controller

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7

5.40

5.10

0.01

0.1

10

100

5.15

5.30

5.35

MAX1996 toc10

1

5.20

5.25

NORMAL OPERATION

SHUTDOWN

4.6

4.0

4.1

4.4

4.5

4.2

4.3

-15

-40

60

35

10

85

MAX1996 toc11

TEMPERATURE (

°C)

5.32

5.33

5.31

5.35

5.36

5.34

4.40

4.45

4.35

4.55

4.60

4.50

NORMAL OPERATION

SHUTDOWN

Typical Operating Characteristics (continued)

PIN

NAME

FUNCTION

1

ILIM

and GND. The current-limit threshold measured between LX_ and GND is 1/5th the voltage at ILIM;

0.2V.

2

REF

2V Reference Output. Bypass REF to GND with a 0.1µF capacitor. REF is discharged to GND when

shut down.

3

MINDAC

4

GND

System Ground. The GND input to the maximum and minimum current-limit comparators. The

comparators sense the low-side FET NL1 and NL2 for zero-current crossing and current limit.

5

MODE

Interface Selection Input and Sync Input for DPWM Chopping. The average voltage on the MODE

pin selects one of three CCFL brightness control interfaces:

minimum brightness.

maximum brightness.

An AC clocking signal superimposed on the DC average MODE pin voltage can be used to

synchronize the DPWM chopping frequency. See Synchronizing the DPWM Frequency.

6

CRF/SDA

Reference and Serial Data Input. In analog interface mode, pin 6 is the reference input to the 5-bit

brightness control ADC. Bypass CRF to GND with a 0.1µF capacitor. In SMBus interface mode,

SDA is an SMBus serial data input/open-drain output.

Pin Description