W-52 Datasheet, PDF (9/11 Pages) Copal Electronics – CMOS White LED Driver

W-52
TYPICAL APPLICATION CIRCUITS
(The application diagrams below are shown for the TSOTï23 packages.)
VIN
L₁ 6.8 H
D1
6
1
VIN
SW
C1
4.7 F
W-52
5
SHDN
3
LED
RSET
2.5 V DC 60.40 k
DIMMING
CONTROL
4
R_SET
1.50 k
GND
2
15 mA
C2
2.2 F
Figure 16. Two LEDs with DC Level Dimming Control
VIN
L_{1 6.8 H}
D1
85
6
1
VIN
SW
80
C1
4.7 F
W-52
5
SHDN
3
LED
C2
75
1F
RSET
4
GND
2
15 mA
70
2.5 V DC ^{60.40 k}
DIMMING
CONTROL
65
R_SET
1.50 k
60
0
Figure 17. Three LEDs with DC Level Dimming Control
VIN
L₁ 6.8 H
D1
85
C1
80
4.7 F
6
1
VIN
SW
75
W-52
PWM
DIMMING
5
SHDN
3
LED
C2
70
CONTROL
RSET
GND
15 mA
1F
4
2
65
R_SET
1.50 k
60
0
Figure 19. Four LEDs with PWM Dimming Control
V_IN = 4.2 V
V_IN = 3.0 V
5
10
15
20
LED CURRENT (mA)
Figure 18. Efficiency ï Three LEDs
V_IN = 4.2 V
V_IN = 3.0 V
5
10
15
20
LED CURRENT (mA)
Figure 20. Efficiency ï Four LEDs
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