APW7209 Datasheet, PDF (1/14 Pages) Anpec Electronics Coropration – 1MHz, High-Efficiency, Step-Up Converter for 2 to 10 White LEDs

APW7209
1MHz, High-Efficiency, Step-Up Converter for 2 to 10 White LEDs
Features
• Wide Input Voltage from 2.5V to 6V
• 0.3V Reference Voltage
• Fixed 1MHz Switching Frequency
• High Efficiency up to 88%
• 100Hz to 100kHz PWM Brightness Control Fre-
quency
• Open-LED Protection
• Under-Voltage Lockout Protection
• Over-Temperature Protection
• <1µA Quiescent Current during Shutdown
• SOT-23-6 Package
• Lead Free and Green Devices Available
(RoHS Compliant)
Applications
• White LED Display Backlighting
• Cell Phone and Smart Phone
• PDA, PMP, MP3
• Digital Camera
Pin Configuration
SOT-23-6 Top View
LX 1
GND 2
FB 3
6 VIN
5 OVP
4 EN
General Description
The APW7209 is a current-mode and fixed frequency
boost converter with an integrated N-FET to drive up to 10
white LEDs in series.
The series connection allows the LED current to be iden-
tical for uniform brightness. Its low on-resistance of N-
FET and low feedback voltage reduce power loss and
achieve high efficiency. Fast switching frequency(1MHz
typical) allows using small-size inductor and both of in-
put and output capacitors. An over voltage protection
function, which monitors the output voltage via OVP pin,
stops switching of the IC if the OVP voltage exceeds the
over voltage threshold. An internal soft-start circuit elimi-
nates the inrush current during start-up.
The APW7209 also integrates under-voltage lockout, over-
temperature protection, and current limit circuits to pro-
tect the IC in abnormal conditions.The APW7209 is avail-
able in a SOT-23-6 package.
Simplified Application Circuit
V_IN
C1
4.7µ F
OFF ON
L1
22µH
6 _VIN
LX ¹
2
GND
OVP ⁵
APW7209
4
EN
FB ³
V_OUT
C2
1µF ^{Up to}
10
WLEDs
R1
15Ω
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and
advise customers to obtain the latest version of relevant information to verify before placing orders.
Copyright © ANPEC Electronics Corp.
1
Rev. A.3 - Jul., 2008
www.anpec.com.tw