DS3991Z+PP Fast Delivery |IC PHOENIX CO.,LIMITED

DS3991Z+PP ,Low-Cost CCFL ControllerApplications♦ Strike Frequency BoostLCD PC Monitors♦ 100% to < 10% Dimming RangeLCD TVs♦ Low Cost♦ ..
DS3991Z+PP ,Low-Cost CCFL ControllerFeatures♦ CCFL Controller for Backlighting LCD PanelsThe DS3991 is a controller for cold-cathode fl ..
DS3992 ,Two-Channel, Push-Pull CCFL ControllerApplications♦ 100% to < 10% Dimming RangeLCD PC Monitors♦ 4.5V to 5.5V Single-Supply OperationLCD-T ..
DS3992Z-09N+ ,Two-Channel, Push-Pull CCFL ControllerFeatures♦ Two-Channel CCFL Controller for BacklightingThe DS3992 is a low-cost, two-channel control ..
DS3992Z-09N+T , Two-Channel, Push-Pull CCFL Controller
DS3992Z-09P+ ,Two-Channel, Push-Pull CCFL ControllerELECTRICAL CHARACTERISTICS(V = +4.5V to +5.5V, T = -40°C to +85°C.)CC APARAMETER SYMBOL CONDITIONS ..
EC2-12NU ,COMPACT AND LIGHTWEIGHT, SMALL MOUNTING SIZE, HIGH BREAKDOWN VOLTAGE
EC2-24 ,COMPACT AND LIGHTWEIGHT, SMALL MOUNTING SIZE, HIGH BREAKDOWN VOLTAGE
EC2-24NU ,COMPACT AND LIGHTWEIGHT, SMALL MOUNTING SIZE, HIGH BREAKDOWN VOLTAGE
EC2-4.5NJ ,COMPACT AND LIGHTWEIGHT, SMALL MOUNTING SIZE, HIGH BREAKDOWN VOLTAGE
EC2-4.5NU ,COMPACT AND LIGHTWEIGHT, SMALL MOUNTING SIZE, HIGH BREAKDOWN VOLTAGE
EC2-4.5TNU ,COMPACT AND LIGHTWEIGHT, SMALL MOUNTING SIZE, HIGH BREAKDOWN VOLTAGE

DS3991Z+PP
Low-Cost CCFL Controller
General Description
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.
The DS3991 converts a DC voltage (5V to 24V) to the
high-voltage (300VRMSto 1400VRMS) AC waveform that
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.
Applications
LCD PC Monitors
LCD TVs
FeaturesCCFL Controller for Backlighting LCD PanelsMinimal External Components RequiredLamp Fault Monitoring for Lamp-Open, Lamp-
Overcurrent, Failure-to-Strike, and Overvoltage
ConditionsAccurate (±5%) On-Board Oscillator for Lamp
Frequency (40kHz to 80kHz)Accurate (±5%) On-Board Oscillator for DPWM
Burst-Dimming Frequency (80Hz to 300Hz)Device Supply Undervoltage Lockout Inverter Supply Undervoltage and Overvoltage
LockoutsSoft-Start on Burst-Dimming Minimizes Audible
Transformer NoiseStrike Frequency Boost100% to < 10% Dimming RangeLow CostSingle-Supply Operation Range: 4.5V to 5.5VTemperature Range: -40°C to +85°C16-Pin SO Package (150 mils)
DS3991
TOP VIEW
VCC
BRIGHT
PWM_EN
LCM
SVMH
SVML
LOSC
POSC/PWM
VCC
SLOPE
OVD
VCC
VCC
GND
DS3991
Pin Configuration
Ordering Information
Rev 1; 2/08
+Denotes a lead-free package.
T&R = Tape and reel.
Typical Operating Circuits appear at end of data sheet.
PARTCONFIGURATION TEMP RANGEDIMMING FREQUENCY RANGE(Hz)PIN-PACKAGE
DS3991Z+PP Push-Pull -40°C to +85°C 80 to 300 16 SO (150 mils)
DS3991Z+T&R/PP Push-Pull -40°C to +85°C 80 to 300 16 SO (150 mils)
DS3991Z+HB Half-Bridge -40°C to +85°C 80 to 300 16 SO (150 mils)
DS3991Z+T&R/HB Half-Bridge -40°C to +85°C 80 to 300 16 SO (150 mils)
Low-Cost CCFL Controller
DS3991
ABSOLUTE MAXIMUM RATINGS
RECOMMENDED OPERATING CONDITIONS
(TA= -40°C to +85°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Voltage Range on VCC Relative to Ground..........-0.5V to +6.0V
Voltage Range on Any Lead
Other than VCC..............................................-0.5V to (VCC+ 0.5V),
not to exceed +6.0V
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-55°C to +125°C
Soldering Temperature............................Refer to the J-STD-020
Specification.
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Supply Voltage VCC (Note 1) 4.5 5.5 V
Input Logic 1 VIH 2.2 VCC +
0.3V
Input Logic 0 VIL -0.3 +0.8 V
BRIGHT, SVML, SVMH Voltage
Range VRA -0.3 VCC+
0.3V
LCM and OVD Voltage Range VRC (Note 2) -0.3 VCC +
0.3V
Gate-Driver Output Charge
Loading QG 20 nC
LOSC and POSC Loading COSC 20 pF
ELECTRICAL CHARACTERISTICS
(VCC= +4.5V to 5.5V, TA= -40°C to +85°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Supply Current ICC GA, GB loaded with 300pF 5 10 mA
Low-Level Output Voltage
(GA, GB) VOL IOL = 4mA 0.4 V
High-Level Output Voltage
(GA, GB) VOH IOH = -1mA 2.4 V
UVLO Threshold: VCC Rising VUVLOR 4.3 V
UVLO Threshold: VCC Falling VUVLOF 3.7 V
UVLO Hysteresis VUVLOH 100 mV
SVML Falling Threshold VSVMLT 1.94 2.00 2.06 V
SVMH Rising Threshold VSVMHT 1.94 2.00 2.06 V
SVML and SVMH Hysteresis VSVMH 150 mV
LCM and OVD DC Bias Voltage VDCB 1.35 V
LCM and OVD Input Resistance RDCB 50 k
Lamp-Off Threshold VLOT (Note 3) 1.65 1.75 1.85 V
Lamp Overcurrent Threshold VLOCT (Note 3) 3.25 3.35 3.45 V
Low-Cost CCFL Controller
DS3991
Note 1:All voltages are referenced to ground unless otherwise noted. Currents into the IC are positive; currents out of the IC are
negative.
Note 2:During fault conditions, if AC-coupled, LCM and OVD can go below ground by up to 1V for up to 1s.
Note 3:Threshold voltage includes the DC bias-voltage offset.
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +4.5V to 5.5V, TA= -40°C to +85°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Lamp Regulation Threshold VLRT (Note 3) 2.29 2.35 2.41 V
OVD Threshold VOVDT (Note 3) 2.25 2.35 2.45 V
Lamp Frequency LFOSCI 40 80 kHz
Lamp Frequency Tolerance LFTOLLOSC resistor ±0.1% over temperature;
measured from 0°C to +85°C -5 +5 %
Burst-Dimming PWM Frequency PFOSCI 80 300 Hz
Burst-Dimming PWM Frequency
Tolerance PFTOL POSC resistor ±0.1% over temperature -5 +5 %
SLOPE = 0 0 V BRIGHT Voltage: Minimum
Brightness VBMIN
SLOPE = 1 3.3 V
SLOPE = 0 3.3 V BRIGHT Voltage: Maximum
Brightness VBMAXSLOPE = 1 0 V
Gate-Driver Output Rise/Fall tR/tF CL = 600pF 100 ns
Typical Operating Characteristics
(VCC= 5.0V, TA= +25°C, unless otherwise noted.)
ACTIVE SUPPLY CURRENT
vs. SUPPLY VOLTAGE
DS3991 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
DPWM = 100%
DPWM = 50%
DPWM = 10%
SVM TRIPPED
GATE QC = 4.5nC
fLOSC = 49.6kHz
ACTIVE SUPPLY CURRENT
vs. TEMPERATURE
DS3991 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
VCC = 5.5V
VCC = 5.0V
VCC = 4.5VGATE QC = 4.5nC
fLOSC = 49.6kHz
DPWM = 100%
INTERNAL FREQUENCY CHANGE
vs. TEMPERATURE
DS3991 toc03
TEMPERATURE (°C)
FREQUENCY CHANGE (%)
DPWM FREQUENCY
LAMP FREQUENCY
Low-Cost CCFL Controller
PUSH-PULL TYPICAL OPERATION
AT VINV = 12.5V
DS3991 toc04
20μs
5.0V
20μs
5.0V
LCM
20μs
2.0V
OVD
20μs
2.0V
PUSH-PULL TYPICAL STARTUP
WITH SVM
DS3991 toc05
50ms
2.0V
50ms
5.0V
SVM
LCM
50ms
2.0V
OVD
50ms
2.0V
PUSH-PULL SOFT-START
AT VINV = 12.5V
DS3991 toc06
0.1ms
5.0V
0.1ms
5.0V
LCM
0.1ms
2.0V
OVD
0.1ms
2.0V
PUSH-PULL LAMP STRIKE,
EXPANDED VIEW
DS3991 toc07
50ms
5.0V
50ms
5.0V
LCM
50ms
2.0V
OVD
50ms
2.0V
PUSH-PULL BURST DIMMING
AT 133Hz, 10%
DS3991 toc08
1ms
5.0V
1ms
5.0V
LCM
1ms
2.0V
OVD
1ms
2.0V
PUSH-PULL BURST DIMMING
AT 133Hz, 50%
DS3991 toc09
1ms
5.0V
1ms
5.0V
LCM
1ms
2.0V
OVD
1ms
2.0V
DS3991ypical Operating Characteristics (continued)
(VCC= 5.0V, TA= +25°C, multilamp configuration, unless otherwise noted.)
Low-Cost CCFL Controller
DS3991
Low-Cost CCFL Controller
HALF-BRIDGE NORMAL OPERATION,
20μs
DS3991 toc10
20μs
5.0V
20μs
5.0V
LCM
20μs
2.0V
OVD
20μs
2.0V
HALF-BRIDGE SOFT-START
AT VINV = 12.5V
DS3991 toc11
50μs
5.0V
50μs
5.0V
LCM
50μs
2.0V
OVD
50μs
2.0V
HALF-BRIDGE LAMP STRIKE,
EXPANDED VIEW
DS3991 toc12
0.5ms
5.0V
0.5ms
5.0V
LCM
0.5ms
2.0V
OVD
0.5ms
2.0V
HALF-BRIDGE BURST DIMMING
AT 166Hz, 10%
DS3991 toc13
1ms
5.0V
1ms
5.0V
LCM
1ms
2.0V
OVD
1ms
2.0V
HALF-BRIDGE BURST DIMMING
AT 166Hz, 50%
DS3991 toc14
1ms
5.0V
1ms
5.0V
LCM
1ms
2.0V
OVD
1ms
2.0V
Typical Operating Characteristics (continued)
(VCC= 5.0V, TA= +25°C, single-lamp configuration, unless otherwise noted.)
DS3991
Low-Cost CCFL Controller
Pin Description
PINNAMEI/OFUNCTION
1 SLOPE I
BRIGHT Slope Select. This digital input determines the slope of the BRIGHT input when
an analog DC voltage is used to control lamp brightness (PWM_EN = 0).
SLOPE = 0: positive slope (0V = minimum brightness, 3.3V = 100% brightness)
SLOPE = 1: negative slope (0V = 100% brightness, 3.3V = minimum brightness)
2, 3, 4 VCC Connect to Voltage Supply. These pins should be connected to the voltage supply pin, VCC.
5 LOSC O Lamp Oscillator Resistor Adjust. A resistor (RLOSC) to ground on this pin sets the frequency
of the lamp oscillator (FLOSC). (RLOSC x FLOSC = 4.0E9). POSC/
PWM O/I
Burst-Dimming PWM Oscillator Resistor Adjust/PWM Digital Input. If PWM_EN = 0, a resistor
(RPOSC) to ground on this pin sets the frequency (FPOSC) of the burst-dimming PWM
oscillator (RPOSC x FPOSC = 4.0E6). If PWM_EN =1, a digital 80Hz to 300Hz PWM signal at
this input controls the lamp brightness.
7 BRIGHT I Lamp-Brightness Control. If PWM_EN = 0, a 0V to 3.3V analog DC voltage at this input
controls the brightness of the lamp.
8 PWM_EN I
PWM Lamp-Brightness Control Enable. This digital input determines whether the BRIGHT or
POSC/PWM input is used to control lamp brightness.
PWM_EN = 0 = PWM disabled (analog DC voltage applied at the BRIGHT input)
PWM_EN = 1 = PWM enabled (digital PWM signal applied at the POSC/PWM input) GA O MOSFET Gate Drive A. Drives a logic-level power MOSFET.
10 GB O MOSFET Gate Drive B. Drives a logic-level power MOSFET.
11 LCM I Lamp Current Monitor Input. Lamp current is monitored by a resistor placed in series with
the low-voltage side of the lamp.
12 OVD I Overvoltage Detection Input. Lamp voltage is monitored by a capacitor divider placed on
the high-voltage side of the lamp.
13 GND Signal Ground
14 VCC Voltage Supply, 4.5V to 5.5V
15 SVMH I
Supply Voltage Monitor High. The DC inverter-supply voltage is monitored by an external
resistor divider. The resistor-divider should be set such that it provides 2V at this pin for the
maximum allowable range of the DC inverter supply. Pulling this input above 2V turns the
lamps off and resets the controller. Connect to GND if not used.
16 SVML I
Supply Voltage Monitor Low. The DC inverter-supply voltage is monitored by an external
resistor divider. The resistor-divider should be set such that it provides 2V at this pin for the
minimum allowable range of the DC inverter supply. Pulling this input below 2V turns the
lamps off and resets the controller. Connect to VCC if not used.
DS3991
Low-Cost CCFL Controller
Main System Block Diagram
OVD
OVERVOLTAGE
DETECTION
LCM
LAMP CURRENT
MONITOR
80Hz TO 300Hz
EXTERNAL RESISTOR
LAMP FREQUENCY SET
VCC (4.5V TO 5.5V)
GND
CCFL
CONTROLLER
(SEE THE
CCFL CHANNEL
BLOCK
DIAGRAM)
EXTERNAL RESISTOR
BURST-DIMMING
FREQUENCY SET
ANALOG LAMP
BRIGHTNESS CONTROL
(PWM_EN = 0)
PWM LAMP
BRIGHTNESS CONTROL
(PWM_EN = 1)
SVML
SUPPLY VOLTAGE
MONITOR LOW
CHANNEL FAULT
CHANNEL ENABLE
MOSFET
GATE DRIVERS
LOSC
PWM_EN
BRIGHT
SLOPE
POSC
DPWM
SIGNAL
2.0V
40kHz TO 80kHz
OSCILLATOR (±5%)
80Hz TO 300Hz
OSCILLATOR (±5%)
POSITIVE OR
NEGATIVE SLOPE
SELECT
RAMP
GENERATOR
FAULT
HANDLING
SYSTEM
ENABLE/
POR
MUX
SVMH
SUPPLY VOLTAGE
MONITOR HIGH
2.0V
VREF
UVLO
DS3991
DS3991
Low-Cost CCFL Controller
CCFL Channel Block Diagram
GATE
DRIVERS
DIGITAL
CCFL
CONTROLLER
CHANNEL FAULT
LAMP FREQUENCY
(40kHz TO 80kHz)
BURST-DIMMING
PWM SIGNAL
CHANNEL ENABLE
MOSFET
GATE DRIVERS
LCM
LAMP CURRENT MONITOR
400mV
2.0V
LAMP OVERCURRENT
LAMP STRIKE AND REGULATION
LAMP OUT
1.0V
1.0V
OVD
OVERVOLTAGE DETECTOR
LAMP MAXIMUM VOLTAGE REGULATION
64 LAMP CYCLE
INTEGRATOR
OVERVOLTAGE
DS3991
Detailed Description
The DS3991 is available for both push-pull and half-
bridge drive topologies. In both drive topologies, the
DS3991 drives two logic-level MOSFETs. The DS3991
alternately turns on the two MOSFETs to create the high-
voltage AC waveform on the secondary. By varying the
duration of the MOSFET turn-on times, the controller is
able to accurately control the amount of current flowing
through the CCFL lamp. See the Typical Push-Pull
Application andTypical Half-Bridge Applicationfigures.
The DS3991 can also drive more than one CCFL lamp
per channel. The Typical Push-Pull Application, Multiple
Lamps Per Channel andTypical Half-Bridge Application,
Multiple Lamps Per Channelfigures show an application
driving three lamps.
A series resistor on the low-voltage side of the CCFL
lamp enables current monitoring. The voltage developed
across this resistor is fed to the lamp current monitor
(LCM) input on the DS3991. The DS3991 compares the
resistor voltage against an internal reference voltage to
determine the duty cycle for the MOSFET gates. See the
Main System Block Diagramand the CCFL Channel
Block Diagramfor more information.
Dimming Control
The DS3991 uses burst dimming to control the lamp
brightness. During the high period of the DPWM cycle,
the lamp is driven at the selected lamp frequency
(40kHz to 80kHz) as shown in Figure 1. This part of the
cycle is also called the burst period because of the
lamp-frequency burst that occurs during this time.
During the low period of the DPWM cycle, the controller
disables the MOSFET gate drivers so the lamp is not
driven. This causes the current to stop flowing in the
lamp, but the time is short enough to keep the lamp
from de-ionizing. Dimming is increased/decreased by
adjusting (i.e., modulating) the burst-period duty cycle.
At the beginning of each burst-dimming cycle, soft-start
slowly ramps the lamp current to reduce the potential to
create audible transformer noise.
There are two methods to control the duty cycle and
frequency of the burst-dimming DPWM. If the PWM_EN
pin is tied low, then the analog-control method is
enabled; a 0V to 3.3V analog voltage at the BRIGHT
input pin determines the duty cycle of a digital pulse-
width modulated (DPWM) signal. The frequency of the
DPWM signal is determined by the value of the resistor
tied from the POSC pin to ground. The slope of the
BRIGHT dimming input is either positive or negative
based on whether the SLOPE pin is tied low or high,
respectively.

Partno	Mfg	Dc	Qty	Available	Descript
DS3991Z+PP	MaximIC	N/a	800	avai	Low-Cost CCFL Controller
DS3991Z+PP	MaximIC ?	N/a	800	avai	Low-Cost CCFL Controller