Microsemi

Integrated Products

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

Page 8

Copyright

© 2001

Rev. 1.0d, 2005-03-14

LX1990

Dual Programmable LED Current Sink

TM

®

DIMMING METHOD S

VDD

ENA

ISET GND

I

OUTA

I

OUTB

PWM

R

SET

VDD

ENA

ISET GND

I

OUTA

I

OUTB

ON / OFF

R

MIN

R

STEP

VDD

ENA

ISET GND

I

OUTA

I

OUTB

3V

R

MIN

R

MAX

Figure 5 – PWM on Enabled

(Lowest IQ)

Figure 6 – Precision 2 Steps

Figure 7 – Manual Control

VDD

ENA

ISET GND

I

OUTA

I

OUTB

ON / OFF

R

SET

PW M

VDD

ENA

ISET GND

I

OUTA

I

OUTB

1K

C

SLOPE

5K

10K

100K

PWM

2N2222A

8.2nF

VDD

ENA

ISET GND

I

OUTA

I

OUTB

6.3K

2N2222

10K

100K

PWM

ON / OFF

1V /

DIV

10µs / DIV

10mA /

DIV

1V /

DIV

20µs / DIV

10µA /

DIV

1V /

DIV

20µs / DIV

10mA /

DIV

Figure 8 – PWM Dimming Totem Pole

Output

Figure 9 – PWM – Low EMI

Wide Range

Figure 10 – PWM – Wide Range 500:1 +