Step-Up DC/DC Converter-LED Backlight Driver
The XC9133 series is a fixed frequency, constant current step-up DC/DC converter which is optimized for LED backlight
applications in mobile phones, PDAs and digital cameras. Output voltage of up to 17.5V is possible so that four white LEDs
can be driven in series. Since the LED current is set by only one external resistor, all white LEDs placed in series can be
turned on at the same time. The new DC/DC Converter is also able to drive a network of two parallel banks of three LEDs.
LED dimming is controlled by adjusting the duty cycle of a PWM signal (10kHz Max.) applied to the CE pin.
Efficiency is high with a 0.2V low feedback reference voltage ensuring the RLED losses are minimal. In addition, an internal
MOSFET with a low RDSON of 2.4Ω is used. A low profile and small board area solution can be achieved using a chip
inductor and a small ceramic output capacitor CL=0.22μF as a result of the high 1MHz switching frequency.
If white LEDs are opened or damaged, the detector built in the Lx pin causes the IC to stop oscillating, preventing excessive
increase of the output voltage.
●For White LED drivers
●Smart phones / Mobile phones
●Mobile devices / terminals
●Digital still cameras
Input Voltage Range : 2.5V ~ 6.0V
Output Voltage Range : Up to 17.5V externally set-up
Reference voltage 0.2V +5%
Oscillation Frequency : 1.0MHz±20%
3 white LEDs in series
: PWM control
: ISTB=1.0μA (MAX.)
: 0.22μF, ceramic
Lx Limit Current
Lx Overvoltage Limit : 19V (TYP.)
Operating Ambient Temperature : -40℃～+85℃
Environmentally Friendly : EU RoHS Compliant, Pb Free
■TYPICAL APPLICATION CIRCUIT
LED：NSCW100 x 3
LED Currrent : ILED (mA)