TPS61042 LED恒流驅動

　　The TPS61042 is a high frequency boost converterwith 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 LEDbrightness， 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 contro 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 eakage currents through the LEDs during shutdown， the control pin （CTRL） disables the device and disconnects the LEDs from ground. For maximumsafety during operation， the output has integratedovervoltage protection that prevents damage to thedevice in case of a high impedance output （e.g. faulty LED）。