MIC2297 Datasheet, PDF (5/12 Pages) Micrel Semiconductor – 40V PWM Boost Regulator White LED Driver

Micrel
Typical Characteristics
Supply Current
vs. Input Voltage
6
5.5
5
4.5
4
3.5
Not Switching
VFB = 1V
32 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
1200
1000
800
600
400
200
00
Switch Current
vs. Switch Voltage
VIN = 3.6V
500
1000
1500
SWITCH CURRENT (mA)
BRT Voltage
vs. Input Voltage
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.52 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
FB Voltage
vs. BRT Voltage
300
250
200
150
100
50
0
1000 1200
BRT VOLTAGE (mV)
May 2005
Max Duty Cycle
vs. Input Voltage
100
99
98
97
96
952 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
Switch Voltage
vs. Input Voltage
220
215
210
205
200
195
IFSWITCH = 0.5A
1902 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
FB Voltage
vs. Input Voltage
300
280
260
240
220
200
180
160
140
120
1002 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
Efficiency for 10 LEDs @ 20mA
vs. Input Voltage
80
78
76
74
72
L = 6.8µH
702 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
5
MIC2297
Frequency
vs. Input Voltage
800
700
600
500
4002 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
LED Current
vs. Input Voltage
20
18
16
14
12
102 _{3 4 5 6 7 8 9 10}
INPUT VOLTAGE (V)
LED Current
vs. BRT Voltage
30
25
20
15
10
5
RSENSE
0
1000 1200
BRT VOLTAGE (mV)
Efficiency for 10 LEDs
vs. LED Current
80
VIN = 4.2V
75
70
VIN = 3.2V
VIN = 3.6V
65
60
55
50
45
L = 6.8µH
400 _{5 10 15 20 25 30 35}
LED CURRENT (mA)
M9999-050305
[phone]