AP8802_0912 Datasheet, PDF (7/16 Pages) Diodes Incorporated – 1A LED Step-down Converter

AP8802
1A LED Step-down Converter
Application Information (Continued)
Inductor Selection
This section highlights how to select the inductor suitable for the application requirements in terms of
switching frequency, LED current accuracy and temperature.
Switching Frequency @ ILED = 700mA
500
450
400
350
300
250
200
150
100
50
0
0
68
47
100
68
150
100
220
150
47
68
220
470
100
150
220
470
470
50
100
150
200
250
300
350
400
450
500
Inductor Value [uH]
Figure 4: Switching Frequency Vs Inductor Value
12V - 3 LEDs
24V - 5 LEDs
48V - 10 LEDs
The inductor influences the LED current accuracy that the system is able to provide. The following section
highlights how to select the inductor in relation to the device packages and the LED current, while maintaining
the chip temperature below 70˚C.
AP8802 Rev. 5
DS31766
7 of 16
www.diodes.com
DECEMBER 2009
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