YB1315 Datasheet, PDF (1/10 Pages) YOBON TECHNOLOGIES,INC. – High Efficiency Charge Pump White LED Driver

Preliminary YB1315
High Efficiency Charge Pump White LED Driver
Description
The YB1315 charge pump is designed to
drive up to 5 white LEDs with regulated
constant current in backlight display
application. The device can provide up to
25mA per LED for a total 5 channels. The
output current can also be combined into
one single channel with 125mA output
current for flash-light applications. The
input voltage ranges from 2.7V to 5.5V and
is ideal for applications powered by a
single Li-Ion or 3 to 4 NiCd, NiMH or
Alkaline batteries.
YB1315 monitors the power-supply input
voltage and LED forward voltage and
current, and does an automatic selection to
a switching mode that is optimized for the
power conversion efficiency as well as
battery operating time. The 1MHz fixed
frequency switching allows for tiny external
components, and the regulation scheme is
optimized to ensure low EMI and low input
ripple.
Internal soft-start circuitry effectively
reduces the in-rush current. YB1315 also
provides short circuit protection,
over-temperature
protection
and
over-voltage protection. In shutdown mode,
the shutdown current is less than 1μA.
YB1315 is available in a TQFN-16 3x3
package.
Features
„ Voltage Input Range From 2.7V to 5.5V
„ Drives From 3 to 5 LEDs at Up to 25mA
Each
„ Fractional Conversion Modes for High
Conversion Efficiency, 1x and 1.5x
„ 1MHz Internal Oscillator
„ Thermal Protection Shutdown
„ Output Short-circuit Current Limit and
Over-Voltage Protection
„ Under-Voltage Lockout with Hysteresis
„ Automatic Soft-Start Reduces In-Rush
Current
„ 3mm x 3mm TQFN Package
Applications
„ White LED Backlighting
„ Handheld PCs and PDAs
„ Mobile Phone
„ DSC and DV flash light application
Typical Application Circuit
VIN
VOUT
1uF
VIN = 2.7V
to 5.5V
C1+
D1
0. 47µF
C1-
D2
0. 47µF
C2+
D3
YB1315
C2-
D4
1µF
EN1
EN2
GND
D5
ISET
PGND
Figure 1: Typical Application Circuit
YB1315 Rev.0.1
www.yobon.com.tw
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