LT3497

1

3497f

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Dual Full Function White

LED Driver with Integrated

Schottky Diodes

The LT

verter specifically designed to drive up to 12 white LEDs

(6 white LEDs in series per converter) from a Li-Ion cell. Se-

ries connection of the LEDs provides identical LED currents

resulting in uniform brightness and eliminating the need

for ballast resistors and expensive factory calibration.

The two independent converters are capable of driving

asymmetric LED strings. Accurate LED dimming and

shutdown of the two LED strings can also be controlled

independently. The LT3497 features a unique high side LED

current sense that enables the part to function as a “one

wire current source;” one side of the LED string can be

returned to ground anywhere, allowing a simpler 1-wire

LED connection. Traditional LED drivers use a grounded

resistor to sense LED current, requiring a 2-wire connec-

tion to the LED string.

The 2.3MHz switching frequency allows the use of tiny

inductors and capacitors. Few external components are

needed for the dual white LED Driver: open-LED protection

and the Schottky diodes are all contained inside the 3mm

× 2mm DFN package. With such a high level of integra-

tion, the LT3497 provides a high efficiency dual white LED

driver solution in the smallest of spaces.

Li-Ion Power Driver for 4/4 White LEDs

Converter) from a 3V Supply

Driving Asymmetric LED Strings

Two LED Strings

per Converter

× 2mm 10-Pin DFN Package

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

True Color PWM is a trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Efficiency

SW1

LT3497

GND

SW2

15

µH

10

Ω

10

Ω

1

µF

1

µF

3497 TA01a

1

µF

3V TO 5V

15

µH

CAP1

CAP2

LED1

LED2

CTRL1

SHUTDOWN

AND DIMMING

CONTROL 1

SHUTDOWN

AND DIMMING

CONTROL 2

CTRL2

OFF ON

OFF ON

LED CURRENT (mA)

0

50

55

60

65

70

75

80

4/4LEDs

510

15

20

3497 TA01b