Microsemi

Integrated Products

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

Page 5

Copyright

© 2002

Rev. 1.0a,2006-11-13

PanelMatch

™

LXMG1618-05-2x

5V 2.2W CCFL Programmable Inverter Module

TM

®

TY PICAL APPLICATION

LXMG1618-05-2x

5V

SET

2

GND

V

HI

V

LO

BRITE

V

IN1

SLEEP

SET

1

0.65V

to

2.0V 2.7K

20K

DAC or

Pot

CCFL

TUBE

NC

NC

Figure 1

– Brightness Control

(output current set to maximum)

P.W.

10µs to 125µS

BRITE

LXMG1618-05-2x

~26 < P.W. < 100%

of period

PWM Signal

from System

Figure 1A

– PWM Brightness Control

LXMG1618-05-2x

SET

2

GND

V

HI

V

LO

SLEEP

SET

1

CCFL

TUBE

BRITE

5V

V

IN1

L

L

L

H

H

L

H

H

L=GND; H=Open

Figure 2

– Max Output Current

The brightness control may be a voltage output DAC or

other voltage source, a digital pot or 20K manual pot. The

inverter contains an internal 10K pull-up to 3V to bias the

pot add a 2.7K resistor to set the lower threshold voltage.

A 3.3V Logic Level PWM signal from a micro-controller

may also be used as shown in Figure 1A.

If you need to turn the inverter ON/OFF remotely, connect

to TTL logic signal to the

lamp current regulation. If both lamp wires have heavy

This wire is typically white.

desired maximum output current. Using these two pins in

combination allows the inverter to match a wide variety of

panels from different manufactures.

Generally the best

lamp lifetime and efficiency correlates with driving the

CCFL at the manufactures nominal current setting.

flexibility to adjust the current to the maximum allowable

output current to increase panel brightness at the expense

of some reduced lamp life.

Although the SET pins are designed such that just leaving

them open or grounding them is all that is needed to set the

output current, they can also be actively set. Using a open

collector or open drain logic signal will allow you to

reduce the lamp current for situations where greater dim

range is required, as an example in nighttime situations. In

conjunction with a light sensor or other timer the panel

could be set to higher brightness (maximum output

current) for daytime illumination and lower brightness

(minimum or typical output current) at nighttime. Since

the dim ratio is a factor the peak output current, using this

technique the effective dim ratio can be increased.

Conversely the SET inputs could be used to overdrive the

lamp temporarily to facilitate faster lamp warm up at initial

lamp turn on. Of course any possible degradation on lamp

life from such practices is the users responsibility as not all

lamps are designed to be overdriven.

The inverter has a built in fault timeout function. If the

output is open (lamp disconnected or broken) or shorted

the inverter will attempt to strike the lamp for several

seconds. After about 2 seconds without success the inverter

will shutdown.

In order to restart the inverter it is

supply.