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13.2 Dimming Performance
The LED driver is capable of matching or exceeding the dimming performance of an incandescent lamp.
Using a simple rotary TRIAC dimmer, smooth and near logarithmic dimming performance is achieved. By
varying the firing angle of the TRIAC dimmer and measuring the corresponding input and output
parameters, the dimming performance of the demonstration board driving 6 LEDs is summarized in
Table 5.
Table 5. Measured Efficiency and Line Regulation Data (with TRIAC Dimmer)
V
IN
(V
RMS
) V
O
(V) I
O
(mA) P
OUT
(W)
115.0 19.9 351 7.0
110.1 19.8 323 6.4
105.2 19.7 295 5.8
100.4 19.6 269 5.3
95.5 19.6 258 5.0
90.7 19.5 248 4.8
85.2 19.4 222 4.3
80.2 19.3 199 3.8
75.1 19.2 176 3.4
70.8 19.1 159 3.0
65.5 18.7 138 2.6
60.5 18.8 120 2.3
55.2 18.6 101 1.9
50.6 18.5 86 1.6
45.7 18.3 72 1.3
39.4 18.0 54 1.0
34.2 17.8 42 0.7
30.3 17.6 33 0.6
26.0 17.4 25 0.4
20.0 17.0 15 0.3
15.2 16.6 9 0.1
17
SNVA429C–August 2010–Revised May 2013 AN-2034 LM3445 -120VAC, 8W Isolated Flyback LED Driver
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