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.