LM3555

2.2 µH

COUT

10 µF

CIN

10 µF

IND

PGND

VIN

VLED

SW

TORCH

STROBE

I2C/EN

SCL/EN1

SDA/EN2

VBAT

SGND

VOUT

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27

LM3555

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SNVS594G – DECEMBER 2008 – REVISED APRIL 2016

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM3555 is a white-LED driver for LED camera flash applications. The dual high-side current sources allow

for grounded cathode LEDs. The LM3555 can adaptively scale the maximum flash level delivered to the LEDs

based upon the flash configuration, whether it be a single LED or two LEDs in series.

8.2 Typical Application

Figure 50. LM3555 Typical Application

8.2.1 Design Requirements

For typical white-LED driver applications, use the parameters listed in Table 10.

Table 10. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Input voltage range

2.5 V to 5.5 V

Number of LEDs

1 or 2 LEDs in Series

Output current range

60 mA to 500mA