TI Chips TPS61042DRBR TPS61042 Constant Current LED Driver
Features
Current Source With Overvoltage Protection
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: 500 mA
Operates With Small Output Capacitors Down to 100 nF
Disconnects LEDs During Shutdown
No Load Quiescent Current: 38 μA Typ
Shutdown Current: 0.1 μA Typ
Available in a Small 3 mm × 3 mm QFN Package
Applications
White LED Supply for Backlight/Sidelight Displays
– PDA, Pocket PC, Smart Phones
– Handheld Devices
– Cellular Phones
Description
The TPS61042 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 (typ). 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 where the brightness can be controlled by an analog signal as well, as described in the application information section. 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 in case of a high impedance output (e.g. faulty LED).