Data sheet, White led step-up converter ap3019a, Typical performance characteristics – Diodes AP3019A User Manual
Page 6: Wled forward voltage (v, Is 3.45v at i, Figure 4. efficiency vs. junction temperature, Figure 5. efficiency vs. input voltage, Figure 6. efficiency vs. led’s number
Data Sheet
WHITE LED STEP-UP CONVERTER AP3019A
May. 2010 Rev. 1.8 BCD Semiconductor Manufacturing Limited
6
Typical Performance Characteristics
WLED forward voltage (V
F
) is 3.45V at I
F
=20mA, unless otherwise noted.
Figure 4. Efficiency vs. Junction Temperature
Figure 5. Efficiency vs. Input Voltage
Figure 6. Efficiency vs. LED’s Number
Figure 7. Schottky Forward Current vs.
Schottky Forward Drop
3.0
3.5
4.0
4.5
5.0
70
72
74
76
78
80
82
84
86
I
OUT
=20mA, 8 LEDs,T
A
=25
O
C
C
IN
=1
µ
F, C
OUT
=0.22
µ
F, L=22
µ
H
Ef
ficiency (%)
Input Voltage (V)
-50
-25
0
25
50
75
100
73
74
75
76
77
78
79
80
81
82
83
V
IN
=3.6V, I
OUT
=20mA, 8 LEDs
C
IN
=1
µ
F, C
OUT
=0.22
µ
F, L=22
µ
H
Ef
ficie
n
cy (%
)
Junction Temperature (
o
C)
2
3
4
5
6
7
8
76
77
78
79
80
81
82
83
84
85
86
V
IN
=3.6V, I
OUT
=20mA,T
A
=25
O
C
C
IN
=1
µ
F, C
OUT
=0.22
µ
F, L=22
µ
H
LED's Number
Ef
ficien
c
y
(
%
)
0
200
400
600
800
1000
0
50
100
150
200
250
300
350
Schottky F
o
rwar
d Curr
ent (m
A
)
Schottky Forward Drop (mV)