AS1340 查看數據表（PDF） - Unspecified

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产品描述 (功能)

比赛名单

AS1340

50V, Micropower, DC-DC Boost Converter

Unspecified 

AS1340

Datasheet - Application Information

9.5 LED Power Supply Application

The AS1340 can also be used for driving LEDs. Just simply connect the LEDs between the pins LX and FB. (see Figure 29).

Figure 29. LED Supply Application

VIN = 2.7V

to 5.5V

C1

0.1µF

On

Off

2

VCC

3

SWVIN

6

SWOUT

L1

4.7µH

4

AS1340

POK

1

EN

D1

5

LX

COUT

1µF

8

FB

ILED

R2

100

7,9

GND

The output voltage is adjusted automatically to the required voltage of the LEDs. This voltage depends on the forward voltage (VF) of the used

LEDs and the Feedback Voltage VFB.

Calculate VOUT by:

VOUT = VFILED  n + VFB

(EQ 3)

Note: The brightness of the LEDs can directly be adjusted by setting the current ILED via the corresponding R2.

Calculate R2 by:

Where:

VFB = 1.25V

n .... number of LED’s

ILED = V-----F---B--

R2

(EQ 4)

www.ams.com/DC-DC_Step-Up/AS1340

Revision 1.20

11 - 17

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