Texas Instruments LM3409HV, User Manual

Page: 12 / 14

I
L
ED
(
A
)
V
PW
M2
(
V
)
14
12
10
8
6
4
2
0
-2
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
I
LED
2 é s/DIV
V
PWM2
I
L
ED
(A)
V
PW
M
2
(V)
7
6
5
4
3
2
1
0
-1
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0
-0.4
I
LED
200 ns/DIV
V
PWM2
I
L
ED
(
A
)
V
EN
(V)
14
12
10
8
6
4
2
0
-2
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
I
LED
10 é s/DIV
V
EN
I
L
ED
(A)
V
EN
(V)
7
6
5
4
3
2
1
0
-1
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0.0
-0.4
I
LED
2
é s/DIV
3.5 é s
V
EN
Typical Waveforms
www.ti.com
8 Typical Waveforms
T
A
= +25°C, V
IN
= 48V and V
O
= 42V.
Figure 6. 20kHz 50% EN pin PWM dimming Figure 7. 20kHz 50% EN pin PWM dimming (rising
edge)
Figure 8. 100kHz 50% External FET PWM dimming Figure 9. 100kHz 50% External FET PWM dimming
(rising edge)
12 AN-1953 LM3409HV Evaluation Board SNVA390D – May 2009 – Revised May 2013
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