MIC3291 Datasheet, PDF (5/17 Pages) Micrel Semiconductor – 1.2MHz PWM White LED Driver with Internal Schottky Diode and Single-Wire Linear Brightness Control

Micrel, Inc.
Typical Characteristics
Feedback Voltage
vs. Brightness Level
275
250
225
200
175
150
125
100
75
50
25
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
BRIGHTNESS LEVEL (0-15)
100
90
80
70
60
50
40
30
20
10
0
0
6 Series White LED
Efficiency
V_IN = 4.2V
V_IN = 3.6V
V_IN = 2.8V
L = 22µH
C_OUT = 0.27µF
5
10
15
20
25
WHITE LED CURRENT (mA)
Peak Switch Current
vs. Input Voltage
1000
900
800
700
600
500
400
300
200
2.5 3 3.5 4 4.5 5 5.5
INPUT VOLTAGE (V)
6 Series White LED
Efficiency
100
90 ^VIN ^{= 2.8V}
80
70
60
50
V_IN = 4.2V
40
V_IN = 3.6V
30
20
L = 10µH
10
C_OUT = 0.27µF
0
0
5
10
15
20
25
WHITE LED CURRENT (mA)
100
90
80
70
60
50
40
30
20
10
0
0
3 Series White LED
Efficiency
V_IN = 3.6V
V_IN = 4.2V
V_IN = 2.8V
L = 22µH
C_OUT = 0.27µF
5
10
15
20
25
WHITE LED CURRENT (mA)
Input Current
vs. Input Voltage
350
L=10µH
300
250
6 LEDs
200
150
100
50
3 LEDs
0
2.5 3 3.5 4 4.5 5 5.5 6
INPUT VOLTAGE (V)
MIC3291
100
90
80
70
60
50
40
30
20
10
0
0
3 Series White LED
Efficiency
V_IN = 2.8V
V_IN = 3.6V
V_IN = 4.2V
L = 10µH
COUT = 0.27µF
5
10
15
20
25
WHITE LED CURRENT (mA)
Feedback Voltage
vs. Input Voltage
260
258
256
254
252
250
248
246
244
242
240
2.5 3 3.5 4 4.5 5 5.5 6
INPUT VOLTAGE (V)
Current Limit
vs. Input Voltage
1
0.95
0.9
0.85
0.8
0.75
0.7
0.65
0.6
2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1 6.6
INPUT VOLTAGE (V)
September 2010
5
M9999-092810
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