Datasheet

LT3477
13
3477fc
APPLICATIONS INFORMATION
Figure 8a. 32V to 6 White LEDs: Buck Mode With PWM Dimming
Figure 8b. PWM Dimming Waveforms
2ms/DIV
I
LED
500mA/DIV
I
L
500mA/DIV
PWM
5V/DIV
3477 F08b
PV
IN
= 32V
6 LEDs
300mA
PWM FREQUENCY = 100Hz
BUCK MODE
I
SN1
I
SP1
V
IN
I
ADJ2
I
ADJ1
FBN
I
SP2
FBP
V
REF
C3
3.3μF
C1
2.2μF
V
IN
3.3V
C1: NIPPON NTS40X5R1H225M
C2: TAIYO YUDEN GMK316BJ105ML
C3: TAIYO YUDEN LMK316BJ335KL
L1: TOKO D53LC (PN# A915AY-100M)
D1: ZETEX ZLLS400
D2: DIODES INC 1N4148
NMOS1, NM0S2: ZETEX 2N7002
PMOS: SILICONIX Si2303BDS
LED1 TO LED6: LUMILEDS LXHL-BW02
C
C
0.1μF
C
SS
33nF
300mA
PMOS
3477 F08a
6.81k
NMOS1
NMOS2
100k
0
5V
100Hz
PWM
280k
10k
SW
D2
SS
GND
LT3477
I
SN2
R
T
SHDN
V
C
R
SENSE
0.33Ω
PV
IN
32V
L1
10μH
LED1
LED6
C2
1μF
D1
1k 1k
•
•
•
PWM