APW7208 Datasheet, PDF (1/16 Pages) Anpec Electronics Coropration – 1MHz, High-Efficiency, Step-Up Converter for 2 to 6 White LEDs

APW7208
1MHz, High-Efficiency, Step-Up Converter for 2 to 6 White LEDs
Features
General Description
• Wide Input Voltage from 2.5V to 6V
• 104mV 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 and TSOT-23-6 Packages
• Lead Free and Green Devices Available
(RoHS Compliant)
Applications
The APW7208 is a current-mode and fixed frequency
boost converter with an integrated N-FET to drive up to 6
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 feedback voltage reduces power loss and
achieves high efficiency. Fast 1MHz current-mode PWM
operation is available for input and output capacitors and
a small inductor while minimizing ripple on the input
supply. The OVP pin monitors the output voltage and stops
switching if exceeds the over-voltage threshold. An inter-
nal soft-start circuit eliminates the inrush current during
start-up.
The APW7208 also integrates under-voltage lockout,
over-temperature protection and current limit circuits.
The APW7208 is available in SOT-23-6 and TSOT-23-6
packages.
• White LED Display Backlighting
• Cell Phone and Smart Phone
• PDA, PMP, and MP3
• Digital Camera
Simplified Application Circuit
Pin Configuration
LX 1
GND 2
FB 3
6 VIN
5 OVP
4 EN
SOT-23-6 / TSOT-23-6
(Top View)
V_IN
C1
2.2µF
OFF ON
L1
22µH
6 _VIN
LX ¹
2
GND
OVP ⁵
4
EN
FB ³
V_OUT
C2
1µF _{Up to 6}
WLEDs
R1
5.1Ω
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.6 - Aug., 2011
www.anpec.com.tw