Rev 0; 1/08
Low-Cost CCFL Controller
DS391
General Description
Features
♦ CCFL Controller for Backlighting LCD Panels
The DS3991 is a controller for cold-cathode fluorescent
lamps (CCFLs) that are used to backlight liquid-crystal
displays (LCDs). The DS3991 is available for both
push-pull and half-bridge drive topologies.
♦ Minimal External Components Required
♦ Lamp Fault Monitoring for Lamp-Open, Lamp-
Overcurrent, Failure-to-Strike, and Overvoltage
Conditions
The DS3991 converts a DC voltage (5V to 24V) to the
high-voltage (300V
to 1400V
) AC waveform that
RMS
RMS
♦ Accurate (±±5% On-Board Oscillator for Lamp
is required to power the CCFLs. The push-pull and half-
bridge drive schemes use a minimal number of external
components, which reduces component and assembly
cost and makes the printed circuit board (PCB) design
easy to implement. Both drive schemes provide an effi-
cient DC to AC conversion and produce near-sinu-
soidal waveforms.
Frequency (40kHz to 80kHz%
♦ Accurate (±±5% On-Board Oscillator for DPꢀM
Burst-Dimming Frequency (80Hz to 300Hz%
♦ Device Supply Undervoltage Lockout
♦ Inverter Supply Undervoltage and Overvoltage
Lockouts
♦ Soft-Start on Burst-Dimming Minimizes Audible
Transformer Noise
Applications
♦ Strike Frequency Boost
LCD PC Monitors
LCD TVs
♦ 1005 to < 105 Dimming Range
♦ Low Cost
♦ Single-Supply Operation Range: 4.±V to ±.±V
♦ Temperature Range: -40°C to +8±°C
♦ 16-Pin SO Package (1±0 mils%
Ordering Information
PART
CONFIGURATION
Push-Pull
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
DIMMING FREQUENCY RANGE (Hz) PIN-PACKAGE
DS3991V+C
80 to 300
80 to 300
80 to 300
80 to 300
16 SO (150 mils)
16 SO (150 mils)
16 SO (150 mils)
16 SO (150 mils)
DS3991V+T&R/C
Push-Pull
DS3991V+
Half-Bridge
Half-Bridge
DS3991V+T&R
+Denotes a lead-free package.
T&R = Tape and reel.
Pin Configuration
TOP VIEW
SVML
SVMH
SLOPE
1
2
3
4
5
6
7
8
16
15
VCC
VCC
14 VCC
13 GND
12 OVD
11 LCM
Typical Operating Circuits appear at end of data sheet.
VCC
DS3991
LOSC
POSC/PWM
BRIGHT
PWM_EN
GB
GA
10
9
SO
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.