Issue 2 - July 2006

1

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© Zetex Semiconductors plc 2006

DN72

ZXLD1101 Driving 8 series LEDs

Description

This design note shows the ZXLD1101 driving 8 series connected LEDs. The input voltage ranges

from 4.2V to 5.2V with a maximum output current of 24mA at 5V input.

A typical schematic diagram is shown in Figure 1.

Figure 1

Schematic diagram

Ref.

Value

Part number

Manufacturer

Comments

U1

ZXLD1101E6

Zetex

LED Driver in SOT23-6

D1

1A

ZHCS1000

Zetex

1A Schottky in SOT23

L1

33 H

Generic

Generic

NOTES:

(1) R1 is set to zero. It shows the maximum output power characteristic of the LED driver. A regulated LED

current below the maximum value can be set by: ILED = VFB/R1, where VFB = 0.1V.

0

Generic

Generic

0805 size

C1

100 F

Generic

Generic

C2

1 F

Generic

Generic

C3

10 F

Generic

Generic

Table 1

Bill of materials

L1

D1

R1

C3

EN

GND

FB

LX

ZXLD1101

x8 LEDs

C2

C1