AP8801_0912 Datasheet, PDF (1/11 Pages) Diodes Incorporated – 500mA LED Step-down Converter

Features
• LED driving current up to 500mA
• Operating input voltage up to 48V
• High efficiency up to 92%
• High switching frequency up to 500kHz
• PWM/DC input for dimming control
• Built-in output open-circuit protection
• SOP-8L and MSOP-8L are available in “Green”
Molding Compound (No Br, Sb)
• Lead Free Finish/RoHS Compliant (Note 1)
Applications
• Commercial & industrial lighting
• Small LCD panel backlight
• Appliances interior lighting
• Architecture Detail lighting
Typical Application Circuit
AP8801
500mA LED Step-down Converter
General Description
The AP8801 is a step-down DC/DC converter designed to drive
LEDs with a constant current. The device can drive up to thirteen
LEDs, depending on the forward voltage of the LEDs, in series
from a voltage source of 8V to 48V. Series connection of the
LEDs provides identical LED currents resulting in uniform
brightness and eliminating the need for ballast resistors. The
AP8801 switches at frequency up to 500kHz. This allows the
use of small size external components, hence minimizing the
PCB area needed.
Maximum output current of AP8801 is set via an external resistor
connected between the VIN and SET input pins. Dimming is
achieved by applying either a DC voltage or a PWM signal at the
CTRL input pin. An input voltage of 0.2V or lower at CTRL shuts
down the output at SW and puts the device into a low-current
standby state.
24V_DC
C₁ = 2.2μF
V_IN
CTRL
SET
AP8801
R_SET = 0.43Ω
D₁
GND
SW
L₁ = 100μH
Figure 1: Typical Application Circuit
AP8801 Rev. 4
DS31765
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www.diodes.com
DECEMBER 2009
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