XC9133 Datasheet, PDF (1/15 Pages) Torex Semiconductor – Step-Up DC/DC Converter-LED Backlight Driver

XC9133 Series
Step-Up DC/DC Converter-LED Backlight Driver
ETR0413-002
˙GENERAL DESCRIPTION
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 2.4Њçis used. A low profile and small board area solution can be achieved using a chip
inductor and a small ceramic output capacitor CL=0.22ЖF 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.
˙APPLICATIONS
˔For White LED driversç
˔Mobile phonesç
˔PDAsç
˔Digital cameras
ç
˙FEATURES
Input Voltage Range : 2.5V ~ 6.0V
Output Voltage Range : Up to 17.5V externally set-up
Reference voltage 0.2V +5%
Oscillation Frequency : 1.0MHzʶ20%
ON Resistance
: 2.4Њ
High Efficiency
: 85%
3 white LEDs in series
Control
V_IN=3.6V, I_LED=20mA
: PWM control
Stand-by Current
Output Capacitor
: I_STB=1.0ЖA (MAX.)
: 0.22ЖF, ceramic
Lx Limit Current
: 360mAÊ¢TYP.Ê£
Lx Overvoltage Limit : 19V (TYP.)
Packages
: SOT-25
USP-6C (under development)
˙TYPICAL APPLICATION CIRCUIT
˙TYPICAL PERFORMANCE
CHARACTERISTICS
˔XC9133B02A Series
100
90
L：VLF3010S
LED：NSCW100 x 3
SBD：XBS053V15R,C_L：TMK316J224KF
80
NR3015
70
60
50
40
30
20
10
VIN=3.0V
0
0
5
10
15
20
25
30
LED Currrent : ILED (mA)
1/15