XC9116 Datasheet, PDF (1/22 Pages) Torex Semiconductor – Step-Up DC/DC Converter-Backlight LED Driver

XC9116 Series
Step-Up DC/DC Converter-Backlight LED Driver
ETR0407-002
■GENERAL DESCRIPTION
The XC9116 series is a fixed frequency, constant current step-up DC/DC converter ideal for driving LEDs used in backlighting
applications on cellular phones, PDAs and digital cameras etc. Output voltage of up to 17.5V can be derived, therefore, four
white LED’s in series can be driven. Since an LED current can be set up by an external resistance when LEDs are in-series
connection, all white LEDs can be turned on equably. A network of two parallel legs with three in each LED can be also
driven. Luminance of the LED's is controlled by changing the duty cycle of a PWM signal applied to the CE pin. Efficiency is
high with the XC9116 through the high 1.0MHz switching frequency and the low feedback reference voltage, ensuring the RLED
losses are minimal. In addition, an internal MOSFET with an RDSON of 2.0 Ω is used. A low profile and small board area
solution can be achieved using a chip coil and an ultra small ceramic output capacitor (CL) of 0.22µF.
The 'B' type of XC9116 has an additional fault detection circuit. If the LEDs are disconnected or damaged in such a way that
prevents feedback, excess or run away output voltage is prevented by stopping the drive to the internal MOSFET.
■APPLICATIONS
●For White LED drivers
○Mobile phones, PHS
○PDAs
○Digital still cameras
■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 : 1.0MHz, ±20%
ON Resistance
: 2.0Ω
Efficiency
: 86% (XC9116B Type)
: 84% (XC9116D Type)
(VIN=3.6V, ILED=20mA when
driving 3 white LEDs in series)
Control
: PWM control
Standby current
: ISTB=1.0µA (MAX.)
Load Capacitor
: 0.22µF, ceramic
Lx Limit Current
: 325mA
Lx Overvoltage Limit : XC9116B series
No Lx Overvoltage Limit : XC9116D series
■TYPICAL APPLICATION CIRCUIT
VIN
2.5V~6.0V
SD
XB0ASB03A1B
L:22uH
VLF3010A
■TYPICAL PERFORMANCE
CHARACTERISTICS
●XC9116B Type
VIN
Lx
CIN
1uF
100Hz to
10kHz
CE
FB
VSS
RLED
10ohm
20mA
CL
0.22uF
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