AP5725_10 Datasheet, PDF (1/17 Pages) Diodes Incorporated – WHITE LED STEP-UP CONVERTER

AP5725
WHITE LED STEP-UP CONVERTER
Description
Pin Assignments
The AP5725 is a step-up DC/DC converter specifically
designed to drive white LEDs with a constant current. The
device can drive 2 ~ 6 LEDs in series from a Li-Ion cell.
Series connection of the LEDs provides identical LED
currents resulting in uniform brightness and eliminates the
need for ballast resistors. For driving higher number of LEDs,
AP5725 also supports a single feedback of parallel
connected multiple strings of equal number of LEDs.
The AP5725 switches at 1.2MHz that allows the use of tiny
external components. A low 0.25V feedback voltage
minimizes power loss in the current setting resistor for better
efficiency.
(Top View)
SW ¹
6 VIN
(Top View)
GND 2
FB 3
SW 1
5 OVP
V_IN 2
74 _{EN OVP 3}
6 GND
5 FB
4 EN
SOT26 / TSOT23-6
DFN2020C-6
Features
Applications
• High efficiency: 84% typical
• Fast 1.2MHz switching frequency
• Current limit and UVLO protections
• Internal thermal shutdown
• Internal Over Voltage Protection
• Integrated soft-start function
• SOT26, TSOT23-6 and DFN2020C-6: Available in
“Green” Molding Compound (No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
• Cellular Phones
• PDAs, Hand held Computers
• Digital Cameras
• MP3 Players
• GPS Receivers
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
Typical Application Circuit
V_IN
ON OFF
PWM Dimming
L1
22uH
D1
C _IN
1uF
V_IN
SW
AP5725 ^OVP
EN
FB
GND
C_OUT
1uF
2~6 LEDs
RSET
12
AP5725
Document number: DS31844 Rev. 3 - 2
Figure 1. Typical Application Circuit
1 of 17
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July 2010
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