4.5 W Flash White LED Boost Driver

The NCP5050 is a high powered fixed frequency PWM boost converter optimized for constant current applications such as driving high-powered white LEDs. This device has been designed with high-efficiency for use in portable applications and is capable of driving up to 5 high power LEDs in series for camera flash or flashlight (torch) applications. To support the need of driving the LEDs in a high current pulse mode for flash as well as a continuous mode for focus or torch, a control pin and support circuitry is incorporated which allows the user to program two LED currents. The both output current are fully configurable via the use of 2 external resistors and this average current can be reduced by applying a PWM signal to the CTRL pin up to 50 kHz.

FEATUREs
• High Efficiency Up to 88% for 2 LED (VF = 3.5 V by LED) at 200 mA
• High frequency Dimming PWM Control
• Maximum Vout of 20 V
• 1.7 MHz PWM DC/DC Converter
• Shut Down Control Facility with True-Cutoff
• Open LED (Output Overvoltage) Protection
• 1.2 s Timer out Function
• Soft Start to Limit Inrush Current
• Small 3x3x0.8 mm WDFN Package
• These are Pb-Free Devices

Typical Applications
• White LED Flash (Camera Phone, Digital Still Camera, Personal Media Player)
• Portable Flash Lights
• Medium Size LCD Backlight (See Application Note AND8294/D for Details)