
EL7513
Typical Performance Curves (Continued)
All performance curves and waveforms are taken with C 1 = 4.7μF, C 2 = 1μF, C 3 = 0.1μF, L = 33μF, V IN = 3.3V, V CNTL = 1V, R 1 = 5 Ω , 4 LEDs in a
series; unless otherwise specified.
V CNTL = 1V
35
30
25
20
15
10
5
16.0
15.8
15.6
15.4
15.2
15.0
14.8
14.6
14.4
14.2
0
0
0.5
1.0
1.5
2.0
2.5
14.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V CNTL (V)
FIGURE 3. I LED vs V CNTL
V IN (V)
FIGURE 4. I LED vs V IN
V IN
L
BAT54HT1
4.7μF
33μH
1μF
90
2 LEDs IN A SERIES
V IN = 4.2V
8
VIN
LX
4
85
V IN = 2.7V
VOUT
CS
3
7
80
V CTRL
2
1
CNTL PGND
COMP SGND
5
6
5 Ω
75
70
L=COILCRAFT LPO1704-333CM
0.1μF
5
10
15
20
25
30
I O (mA)
V IN
4.7μF
FIGURE 5A. 2 LEDs IN A SERIES
BAT54HT1
L
33μH
1μF
FIGURE 5.
90
FIGURE 5B. EFFICIENCY vs I O
3 LEDs IN A SERIES
8
VIN
LX
4
85
V IN = 4.2V
V IN = 2.7V
VOUT
CS
3
7
80
V CTRL
2
1
CNTL PGND
COMP SGND
5
6
5 Ω
75
70
L = COILCRAFT LPO1704-333CM
5
10
15
20
25
30
0.1μF
I O (mA)
FIGURE 6A. 3 LEDs IN A SERIES
5
FIGURE 6.
FIGURE 6B. EFFICIENCY vs I O
FN7112.5
December 22, 2008