MIC2297_08 Datasheet, PDF (5/11 Pages) Micrel Semiconductor – 40V PWM Boost Regulator White LED Driver

Micrel
MIC2297
Typical Characteristics (continued)
Efficiency for 10 LEDs
vs. LED Current
85
80
VIN = 4.2V
75
70
VIN = 3.2V _{VIN = 3.6V}
65
60
55
50
45
40
L = 15µH
350
10
20
30
40
LED CURRENT (mA)
Efficiency for 9 LEDs
vs. LED Current
80
VIN = 4.2V
75
70
VIN = 3.6V
VIN = 3.2V
65
60
55
50
45
L = 6.8µH
400 _{5 10 15 20 25 30 35}
LED CURRENT (mA)
Efficiency for 9 LEDs
vs. LED Current
85
80
VIN = 4.2V
75
70
VIN = 3.2V _{VIN = 3.6V}
65
60
55
50
45
40
L = 15µH
350 _{5 10 15 20 25 30 35 40}
LED CURRENT (mA)
LED Current
vs. Duty Cycle
35
30
4V
5V
3V 2V
25
20
2V peak PWM
15
10
5
PWM = 20kHz
RSENSE
00 _{20 40 60 80 100}
DUTY CYCLE (%)
L1 = Murata LQH32CN100K11
L1
C1
1µF, 16V
C3
0.22µF, 10V
PWM
VIN
SW
EN
OVP
MIC2297BML
REF
COMP
BRT
AGND PGND FB
C4
0.1µF, 10V
C2
0.47µF, 50V
Mach 2008
5
M9999-032708