Diodes AP8801 - Manual (Page 5)

AP8801
500mA LED STEP-DOWN CONVERTER
AP8801
Document number: DS31765 Rev. 7 - 2
5 of 14
www.diodes.com
June 2012
© Diodes Incorporated
Typical Characteristics (T
A
= +25°C, V
IN
= 60V, L =68µH unless otherwise stated.)
OUT
P
UT
CU
RRE
NT
DEVIA
T
ION (
%
)
SUPPLY VOLTAGE (V)
Figure. 8 LED Current vs. Input Voltage
6 12 18 48 24 30 36 42
10
-10
8
-8
-6
-4
0
2
4
6
-2
SUPPLY VOLTAGE (V)
Figure. 9 Efficiency vs. Input Voltage
6 12 18 48 24 30 36 42
E
F
F
IC
IE
N
C
Y
(%)
100
90
60
70
75
80
85
65
55
50
95
S
W
IT
CHING F
R
EQUE
NCY
(
k
Hz
)
700
0
100
200
500
600
300
400
SUPPLY VOLTAGE (V)
Figure. 10 Switching Frequency vs. Input Voltage
6 12 18 48 24 30 36 42
SUPPLY VOLTAGE (V)
Figure. 11 Duty Cycle vs. Input Voltage
6 12 18 48 24 30 36 42
D
U
T
Y
C
Y
C
LE
(%)
100
0
90
10
20
30
50
60
70
80
40
Figure. 12 Steady State Waveforms
Figure.13 Start-Up Showing LED Current Soft -Start