AP5724 Datasheet, PDF (1/16 Pages) Diodes Incorporated – WHITE LED STEP-UP CONVERTER

Features
• Inherently Matched LED Current
• 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 and DFN2020C-6: Available in “Green”
Molding Compound (No Br, Sb)
• Lead Free Finish/RoHS Compliant (Note 1)
AP5724
WHITE LED STEP-UP CONVERTER
General Description
The AP5724 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. The
AP5724 switches at 1.2MHz that allows the use of tiny external
components. A low 0.1V feedback voltage minimizes power loss
in the current setting resistor for better efficiency.
Applications
• Cellular Phones
• PDAs, Hand held Computers
• Digital Cameras
• MP3 Players
• GPS Receivers
Typical Application Circuit
V_IN
ON OFF
PWM Dimming
L1
22uH
D1
C _IN
1uF
V_IN
SW
AP5724 ^OVP
EN
FB
GND
C_OUT
1uF
2~6 LEDs
RSET
5
Figure 1. Typical Application Circuit
AP5724 Rev. 1
1 of 16
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JUNE 2009
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