MC34262_11 Datasheet, PDF (14/19 Pages) ON Semiconductor – Power Factor Controllers

Input = 115 VAC, Output = 175 W
MC34262, MC33262
Input = 230 VAC, Output = 175 W
2.0 ms/DIV
2.0 ms/DIV
Figure 23. Power Factor Corrected Input Waveforms
(Figure 21 Circuit)
500 V
400 V
Without Overvoltage Comparator
26%
432 V
400 V
With Overvoltage Comparator
8%
0V
200 ms/DIV
0V
200 ms/DIV
Figure 24. Output Voltage Startup Overshoot
(Figure 21 Circuit)
2X Step-Up
Isolation
Line
Transformer
115 Vac
Input
Neutral
Autoformer
AC POWER ANALYZER
HI
PM 1000
IO
W VA PF Vrms Arms _A
0 1235
Vcf Acf Ainst FREQ HARM
LO
7 9 11 13
HI
V
LO
Voltech
RFI Test Filter
T
0.005
0.1
1.0
0.005
0 to 270 Vac
Output to Power
Factor
Controller Circuit
Earth
Figure 25. Power Factor Test Set−Up
An RFI filter is required for best performance when connecting the preconverter directly to the ac line. The filter attenuates
the level of high frequency switching that appears on the ac line current waveform. Figures 20 and 21 work well with
commercially available two stage filters such as the Delta Electronics 03DPCG5. Shown above is a single stage test filter
that can easily be constructed with four ac line rated capacitors and a common−mode transformer. Coilcraft CMT3−28−2
was used to test Figures 20 and 21. It has a minimum inductance of 28 mH and a maximum current rating of 2.0 A. Coilcraft
CMT4−17−9was used to test Figure 22. It has a minimum inductance of 17 mH and a maximum current rating of 9.0 A. Circuit
conversion efficiency h (%) was calculated without the power loss of the RFI filter.
http://onsemi.com
14