1 Features

1• Current Source With 18-V Overvoltage Protection

• Powers up to 4 LEDs in Series

• Input Voltage Range: 1.8 V to 6 V

• Internal 30-V Switch

• Up to 85% Efficiency

• Precise Brightness Control Using PWM Signal or

Analog Signal

• Switching Frequency up to 1 MHz

• Internal Power MOSFET Switch 400 mA

• Operates With Small Output Capacitors Down to

100 nF

• Disconnects LEDs During Shutdown

• No Load Quiescent Current 38 μA Typical

• Shutdown Current 0.1 μA Typical

• Available in a Small 3-mm × 3-mm QFN Package

2 Applications

• White LED Supply for Display Backlight and

Sidelight in

– PDAs, Pocket PCs, Smart Phones

– Handheld Devices

– Cellular Phones

3 Description

The TPS61043 is a high-frequency boost converter

with constant current output that drives white LEDs or

similar. The LED current is set with the external

sense resistor (RS) and is directly regulated by the

feedback pin (FB) that regulates the voltage across

the sense resistor RS to 252 mV (typical). To control

LED brightness, the LED current can be pulsed by

applying a PWM (pulse width modulated) signal with

a frequency range of 100 Hz to 50 kHz to the control

pin (CTRL). To allow higher flexibility, the device can

be configured so that the brightness is controlled by

an analog signal as well, as described in Application

Information. To avoid possible leakage currents

through the LEDs during shutdown, the control pin

(CTRL) disables the device and disconnects the

LEDs from ground. For maximum safety during

operation, the output has integrated overvoltage

protection that prevents damage to the device by

limiting the output voltage to typically 18 V in case of

a high-impedance output (for example, faulty LED).

The TPS61043 device provides a solution for

applications where higher LED currents or more than

four LEDs in series must be powered.