Datasheet

ILED
5 mA/Div
Vcathode
100 mV/Div
REFIN
10 mV/Div
1 Ps/DIV
400 ns/DIV
ILED
50 mA/Div
NDRV (FET)
2V/Div
NDRV (NPN)
1V/Div
DIM
5V/Div
Vout
100 mV/Div
Vsw
20V/Div
ILED
200 mA/Div
400 Ps/DIV
200 Ps/DIV
Vout
200 mV/Div
ILED
5 mA/Div
VIN
5V/Div
NORMALIZED FREQUENCY
0.94
0.96
0.98
1.00
1.02
1.04
-40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
INPUT VOLTAGE (V)
EFFICIENCY (%)
50
60
70
80
90
100
5 9 13 17 21
100%
dimming duty
10%
50%
LM3431
www.ti.com SNVS547G –NOVEMBER 2007–REVISED MAY 2013
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
Unless otherwise specified the following conditions apply: V
IN
= 12V, T
J
= 25°C.
Efficiency vs. Input Voltage LED Current = 140 mA x 3, LED
Normalized Switching Frequency vs. Temperature (700 kHz) Vf = 25V
Figure 8. Figure 9.
Line Transient Response Dimming Transient Response
Figure 10. Figure 11.
LED Ripple Current NDRV Waveforms
Figure 12. Figure 13.
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