AN47 参数 Datasheet PDF下载

AN47

I

OUT

vs V

ADJ

(R

S

=600m )

350

300

250

Series1

mA

200

150

100

50

0

0

0.5

1

V

1.5

2

2.5

Figure 2

V

IN

R1

4.7k

VR1

10k

Typical output current versus ADJ voltage with R

S

= 600m

ADJ

ZTLV431

ZXLD1350

GND

Figure 3

Typical circuit of DC voltage dimming

The ZTLV431 acts as a shunt regulator to generate an external 1.25V reference voltage. The

reference voltage is applied to pot VR1 to provide dimming voltage of 0-1.25V.

Using an external regulator affects the accuracy of the current setting. If a 1% reference is used

the LED current will be more accurate than using the internal reference.

© Zetex Semiconductors plc 2006