LM3409MY-NOPB Datasheet, PDF (7/43 Pages) Texas Instruments – PFET Buck Controller for High Power LED Drivers

LM3409, LM3409HV, LM3409-Q1
www.ti.com
SNVS602J – MARCH 2009 – REVISED MAY 2013
Typical Performance Characteristics (continued)
T_A = +25°C, V_IN = 24V, and characteristics are identical for LM3409 and LM3409HV unless otherwise specified.
Internal EN Pin PWM Dimming
External Parallel FET PWM Dimming
V_O = 17V (5 LEDs); V_IN = 24V
2.3
V_O = 17V (5 LEDs); V_IN = 24V
2.3
1.8
20kHz
1.4
1.8
100 kHz
1.4
0.9
1kHz
0.5
0.0
0
20
40
60
80 100
DUTY CYCLE (%)
Figure 15.
20kHz 50% EN pin PWM dimming
V_O = 42V (12 LEDs); V_IN = 48V ⁽⁵⁾
0.9
50 kHz
0.5
0.0
0
20
40
60
80 100
DUTY CYCLE (%)
Figure 16.
100kHz 50% External FET PWM dimming
V_O = 42V (12 LEDs); V_IN = 48V ⁽⁵⁾
14
2.0
12
1.5
10
1.0
8
I_LED
0.5
6
0.0
4
-0.5
2
-1.0
0
-1.5
-2
V_EN
-2.0
14
2.0
12
1.5
10
1.0
8
I_LED
0.5
6
0.0
4
-0.5
2
-1.0
0
-1.5
-2
V_PWM2
-2.0
10 és/DIV
Figure 17.
20kHz 50% EN pin PWM dimming (rising edge)
V_O = 42V (12 LEDs); V_IN = 48V ⁽⁶⁾
2 és/DIV
Figure 18.
100kHz 50% External FET PWM dimming (rising edge)
V_O = 42V (12 LEDs); V_IN = 48V ⁽⁶⁾
7
V_EN
2.8
6
2.4
5
I_LED
2.0
4
1.6
3
1.2
2
0.8
1
0.4
0
0.0
-1
-0.4
3.5 és
2 és/DIV
7
V_PWM2
2.8
6
2.4
5
I_LED
2.0
4
1.6
3
1.2
2
0.8
1
0.4
0
0.0
-1
-0.4
200 ns/DIV
Figure 19.
(5) The waveforms were acquired using the standard evaluation board from AN-1953 (SNVA390).
(6) The waveforms were acquired using the standard evaluation board from AN-1953 (SNVA390).
Figure 20.
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