Datasheet

NCL30000
http://onsemi.com
20
Load regulation from 12.3 to 52.5 (4 to 15 LEDs) for 115
and 230 Vac input is shown below in Figure 4. Efficiency for
this range is also shown. Note the tight regulation.
Efficiency is affected by the startup circuit losses in
proportion to load and influenced by higher line voltage.
320
330
340
350
360
370
380
12 17 22 27 32 37 42 47 52 57
LED Forward Voltage (Vdc)
LED Current (mA)
74%
76%
78%
80%
82%
84%
86%
Efficiency
115V LED Current
230V LED Current
115V Efficiency
230V Efficiency
Figure 33. LED Current and Efficiency at 115 and 230 Vac
Figure 34 shows the current regulation as a function of
output voltage (LED forward voltage). The control loop has
been designed to support 4 − 15 LED based on a forward
voltage that ranged from 2.6 − 3.5 V. The maximum on time
of the control loop has been configured to limit the
maximum power delivered. This is illustrated at the top of
the output voltage-current transfer function. At the bottom
of the curve, even with a short applied to the output, the
current is limited to less than 1 A.
0
5
10
15
20
25
30
35
40
45
50
55
60
0 100 200 300 400 500 600 700 800 900 1000
LED Current (mA)
LED Forward Voltage (Vdc)
Figure 34.
Protection
Region