Microsemi

Integrated Products

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 1

Copyright

© 2003

Rev. 1.2, 8/30/2006

LX1691

Enhanced Multi-Mode CCFL Controller

TM

®

DESCRIPTION

Microsemi’s

LX1691

is

a

cost

reduced, enhanced feature set, Direct

Drive CCFL (Cold Cathode Fluorescent

Lamp) Controller. Its architecture is

based on the very popular LX1689. By

limiting

advanced

processing, die size

and

package pin count is decreased while

improving dimming precision.

LX1691 based inverter modules can

be designed for virtually any CCFL

appliance from digital cameras and

PDA’s to big screen monitors and

driver viewable automotive displays.

New versatile dimming circuitry can

accept digital and analog control inputs

and provides six different dimming

modes that control both lamp current

amplitude and duty cycle, either simul-

taneously or separately. Designers can

select

normal

or

reverse

polarity

dimming and precisely program mini-

mum and maximum lamp currents with

resistors.

The LX1691 fault shutdown

feature is enhanced to include regu-

lation and shutdown for over voltage

and over current conditions.

Microsemi’s proven and patented

Direct Drive architecture works with

system voltages from 3 volts to more

than 50 volts, limited only by the

external power FET’s that drive the high

voltage transformer.

The LX1691 includes the Microsemi

proven and patented strike method that

allows significant efficiency gains while

guaranteeing strong striking power at all

operating temperatures. Our method

sweeps strike frequency smoothly up to

the unloaded resonant frequency of the

lamp and high voltage transformer.

This, coupled with the LX1691’s active

high output voltage regulation, produces

just

enough

strike

voltage

without

generating unpredictable high voltage

spikes that cause arcing and component

failures.

Competitive

devices

that

simply switch to a higher frequency for

striking do not have this “real time”

control over output voltage, and require

much more attention to transformer

design.

Protected by U.S. Patents: 5,615,093; 5,923,129; 5,930,121; 6,198,234; Patents Pending

KEY FEATUR ES

Simultaneous Amplitude And

Duty Cycle Dimming Modes

Resistor Programmable Min and

Max Lamp Currents

Digital Dimming Can Synch To

External Or Internal Clocks

100 ms Power On Delay

Open Or Shorted Lamp

Regulation & Shutdown

“On Chip” Full Wave Lamp

Current & Voltage Rectifiers

16 Pin TSSOP Package

Very Stable Oscillator with On-

Chip Timing Capacitor

Soft Start-Up Striking

Enhanced Digital Dimming

Resolution

BENEFITS

Low Component Count / Module

Cost / And Size

High “Nits/Watt” Efficiency

Operates Directly From a Single

Li-Ion Cell

Industries Safest And Highest

Performing Strike Voltage

Generation (Patented)

Tight Operating Frequency

Tolerance For Easier System

Level RFI Control

PRODUCT H I GHLIGHT

2

0

T1

T2

BRITE_IN

DD_CLK

+3V

Traditional Analog

+

T1

T2

_

2

0

BRITE_IN

DD_CLK

External Digital

T = 512 / DD_CLK Frequency

+

_

2

0

T1

T2

BRITE_IN

DD_CLK

Direct PWM (Analog)

+

T1

T2

_

2

0

BRITE_IN

DD_CLK

+3V

Internal Digital

T = 512 / Lamp Frequency

+

_

T

Lamp Current (mA)

Lamp Current (mA)

Lamp Current (mA)

Lamp Current (mA)

T

T

T

Four of Six Dimming Modes

PACKAGE ORDER INFO

PW

Plastic TSSOP

16-PIN

RoHS compliant / Pb-free

-40 to +85

2.8V

5.5V

LX1691IPW

Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1691IPW-TR)