sc4540 Semtech Corporation, sc4540 Datasheet - Page 13

• Manufacturer Part Number: sc4540
• Description: High Ei Ciency Boost Converter For Up To 10 Leds
• Manufacturer: Semtech Corporation

Applications Information (continued)
Application Circuit for Alternate Input voltages
The typical applications circuit for the SC4540 is shown in
Figure 2. The performance data and specifi cations included
in this document are for the typical application circuit
(Figure 2). The SC4540 can be used with input voltages
lower than 4.5V (see Figure 3). The Inductor, L1, will need
to be adjusted to allow proper operation for input volt-
ages between to 2.8V to 5.5V. The SC4538 datasheet
should be consulted for the performance of the lower
input voltage circuit.
E n a b le a n d
d im m in g
P W M
4 .5 to 1 2 V
C
4 7 n F
C O M P
Figure 2 — Typical Application Circuit
2.2μF
C
IN
1 .2 7 k Ω
R
C O M P
R
IS E T
5 6 μH
IN
C O M P
IS E T
L 1
E N
SC 4540
G N D
L X
O U T
D
B L
C
1 μF
O UT
E n a b le a n d
Figure 3 — Low Input Voltage Application Circuit
d im m in g
P W M
2 .8 V to 5 .5 V
C
4 7 n F
C O M P
2.2μF
C
IN
1 .2 7 k Ω
R
C O M P
R
IS E T
2 2 μH
IN
IS E T
C O M P
L 1
E N
SC 4540
G N D
L X
O U T
D
B L
SC4540
1 μF
C
O UT
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