Endymion
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I am considering to use Buck-Boost topology for Power Factor Correction but I'm having trouble finding much literature on it. My appliance is an LED fixture so it will always have a (fairly) constant load (150mA @ 30V). Since the input voltage range is going to be between 100-240 VAC and the output is 30V, using a Boost Converter with PFC is a bit unfeasible. I would prefer if the solution is single-stage due to space and cost. I want to avoud using a Flyback topology because at 240V input it will place a huge voltage stress on the power switch.
From looking at the waveform (page 10 and 11) of a Boost topology working in Critical Conduction Mode, the peak current is:
Ipk=(2 x √2 x Pin)/Vrms
My question is, does this result hold for Buck-Boost as well? I feel that it should because it is based on the waveforms and not on the topology. Another way to look at this would be that during ton, the Buck-Boost and the Boost topology's inductor both have Vin applied across them.
I am actually not considering the above linked part. I am considering Richtek RT7302. Unfortunately, for this IC, most of the literature is for Flyback topology and not for Buck-Boost - including their Excel Design Tool.
power-factor-correction
From looking at the waveform (page 10 and 11) of a Boost topology working in Critical Conduction Mode, the peak current is:
Ipk=(2 x √2 x Pin)/Vrms
My question is, does this result hold for Buck-Boost as well? I feel that it should because it is based on the waveforms and not on the topology. Another way to look at this would be that during ton, the Buck-Boost and the Boost topology's inductor both have Vin applied across them.
I am actually not considering the above linked part. I am considering Richtek RT7302. Unfortunately, for this IC, most of the literature is for Flyback topology and not for Buck-Boost - including their Excel Design Tool.
power-factor-correction