LT3474/LT3474-1
TYPICAL APPLICATIONS
Step-Down 1A LED Driver with PWM Dimming
LED Current in PWM Mode
V
IN
I
LED1
500mA/DIV
6V TO 36V
C3
0.22μF
6.3V
C1
2.2μF
50V
L1
10μH
V
BOOST
SW
IN
SHDN
V(PWM)
5V/DIV
D1
LT3474
R
BIAS
OUT
T
REF
V
1ms/DIV
PWM
C2
2.2μF
6.3V
ADJ
R1
80.6k
V
LED
C
C4
GND
3.3nF
LED1
M1
R2
10k
PWM
C5
0.1μF
3474 TA01
D1: B140HB
C1 TO C3: X5R OR X7R
M1: Si2302ADS
Step-Down 1A LED Driver with
Two Series Connected LED Output
Efficiency, Two LED Output
95
V
IN
90
85
80
12V TO
36V
V
= 12V
= 24V
IN
C3
C1
2.2μF
50V
L1
10μH
0.22μF
V
BOOST
SW
IN
V
IN
10V
SHDN
D1
LT3474
75
70
R
T
BIAS
OUT
REF
V
R1
ADJ
C2
2.2μF
10V
PWM
LED
65
60
55
33.2k
V
C
C4
0.1μF
GND
LED1
LED2
1A
LED
CURRENT
200
400
LED CURRENT (mA)
800
0
1000
600
3474 G01
3474 TA02
D1: MBRM 140
C1 TO C3: X5R OR X7R
3474fd
18
Linear [ Linear ]
