Datasheet

LT3478/LT3478-1
20
34781f
TYPICAL APPLICATIO S
U
16W, 12 LEDs at 350mA, Buck-Boost Mode LED Driver plus LT3003
LT3478-1
SHDN
V
REF
OUT
LED
CTRL2
CTRL1
OVPSET
PWM SS V
C
R
T
V
IN
V
S
LSW
C2
10µF
50V
C3
3.3µF
10V
R1
24k
R
T
69.8k
f
OSC
= 500kHz
100Hz
R2
100k
PWM
DIMMING RATIO = 200:1
L1: CDRH105R-8R2
D1: PDS560
D2: 7.5V ZENER
LEDs: LUXEON I (WHITE)
1.05A
D1
3478 TA04a
L1
8.2µH
V
IN
5V
3.3V
0V
V
S
12V TO 16V
C1
4.7µF
25V
V
C
V
C
V
OUT
V
OUT
C
C
0.1µF
C
SS
1µF
C4
1µF
LT3003
V
MAX
OT1
OT2
V
IN
PWM
GND V
EE
LED1 LED2 LED3
D2
V
S
(V)
EFFICIENCY (%)
90
85
80
75
70
50
55
60
65
3478 TA04b
12 LEDs
(4 SERIES x 3 CHANNELS)
LUXEON I (WHITE)
12 14 161513
V
IN
= 5V
I
LED
= 350mA
f
OSC
= 500kHz
PWM DUTY CYCLE = 100%
Effi ciency vs Input V
S
LT3478-1
SHDN
V
REF
OUT
LED
CTRL2
CTRL1
OVPSET
PWM SS V
C
R
T
V
IN
V
S
LSW
C2
3.3µF
25V
C3
3.3µF
10V
R1
24k
R
T
31.6k
f
OSC
= 1MHz
100Hz
R2
100k
PWM
DIMMING RATIO = 3000:1
L1: CDRH104R-5R2
D1: PDS560
LEDs: LUXEON I (WHITE)
1.05A
D1
3478 TA03a
L1
5.2µH
V
IN
3.3V
3.3V
0V
V
S
8V TO 14V
C1
4.7µF
16V
V
C
V
C
V
IN
V
OUT
V
OUT
C
C
0.1µF
C
SS
1µF
LT3003
V
MAX
OT1
OT2
V
IN
PWM
GND V
EE
LED1 LED2 LED3
V
S
(V)
8
EFFICIENCY (%)
90
85
80
75
70
3478 TA03b
10 1412
V
IN
= 3.3V
I
LED
= 350mA
f
OSC
= 1MHz
PWM DUTY CYCLE = 100%
15 LEDs
(5 SERIES x 3 CHANNELS)
LUXEON I (WHITE)
17W, 15 LEDs at 350mA, Boost LED Driver plus LT3003
Effi ciency vs Input V
S