Wide Brightness Range

CCFL Backlight Controllers

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3

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

DAC AND ERROR AMPLIFIER

DAC Resolution

Guaranteed monotonic

5

Bits

MINDAC Input Voltage Range

0

2

V

MINDAC Input Bias Current

-1

1

µA

MINDAC Digital PWM Disable

Threshold

MINDAC = VL

2.4

2.9

4

V

CSAV Input Voltage Range

0

0.8

V

188

194

200

2

6.25

16

CSAV Regulation Point

93

100

110

mV

CSAV Input Bias Current

-1

1

µA

CSAV to CCI Transconductance

100

µmho

CTFB Input Voltage Range

0

2

V

CTFB Input Bias Current

-1

1

µA

CTFB Regulation Point

570

600

630

mV

CTFB to CCV Transconductance

30

40

50

µmho

TIMERS AND FAULT DETECTION

Chopping Oscillator Frequency

No AC signal on MODE, not synchronized

24

28

32

kHz

No AC signal on MODE

205

220

235

32kHz AC signal on MODE

250

Digital PWM Chop-Mode Frequency

100kHz AC signal on MODE

781

Hz

MODE to DPWM Sync Ratio

128

No AC signal on MODE

2.06

2.33

2.73

32kHz AC signal on MODE

2.05

Lamp-Out Detection Timeout Timer

(Center-Tap Voltage Stuck at

Maximum) (Note 1)

lamp-out

threshold

100kHz AC signal on MODE

0.66

s

CSAV Lamp-Out Threshold

50

75

100

mV

Fault-Detection Threshold on CCV

(Note 2)

0.4

1

V

No AC signal on MODE

332

291

259

32kHz AC signal on MODE

256

Shorted Buck-Switch Detection

Timeout Timer (UL1950 Protection)

(Note 3)

detection

threshold on CCV

100kHz AC signal on MODE

82

ms

Lamp Turn-On Delay

After

SH/SUS or SH forces device on or SH rises

4

ms

MODE Operating Voltage Range

-5.5

11

V

MODE = GND Threshold

(min Brightness = 0)

To sync DPWM oscillator, not in shutdown

(Note 4)

0.6

V

MODE = REF Threshold

(max Brightness = 0)

To sync DPWM oscillator, not in shutdown

(Note 4)

1.4

2.6

V

MODE = VL Threshold

(MAX1739 SMB Interface Mode)

To sync DPWM oscillator, not in shutdown

(Note 4)

VL - 0.6

V

MODE AC Signal Amplitude

Peak to peak (Note 5)

2

V

MODE AC Signal Synchronization

Range

Chopping oscillator synchronized to MODE AC

signal

32

100

kHz