Maybe FFT is the way to go for PF analyzing. There must be some
experts in this list on how to do discrete FFT.

I am not so sure that we are looking at the same chip since 
IR1150 is specified for 75W to 3KW+ and it needs an external
power MOSFET (or IGBT) to work. Maybe you were looking at the
old chip with built-in power MOSFET. The chip never comes out.

3KW is "low power" and 240VAC is "low voltage" for electric power 
engineering. :) I normally do not want to deal with anything above
1kW and 253VAC and I think I will not have to do that any more. My
universal AC/DC power supply design now consumes only 0.7W and does
not need any power factor correction. Anyway, I think typical PFC 
application above 3kW will need require significant considerations
of the protection of the components.

It is okay to be used in flyback PFC applications. Low power
flyback PFC works in discontinuous conduction mode (DCM). One cycle
control typically works in continuous conduction mode (CCM). Still
the efficiency will not be as good as boost PFC. Single stage PFC
is still not so good as 2-stage boost PFC + DC-DC converter in
terms of efficiency.

The best paper for one-cycle control of single-phase PFC
is the following. BTW, Dr Lai is now with Intersil.

[1] Z. Lai, Keyue Smedley. "A Family of Power Factor
Correction Controllers". APEC '97. New York. IEEE 1997.

It also appears in IEEE Transactions on Power Electronics, 
Volume: 13 , Issue: 3, May 1998, Pages:501 - 510

The beauty of one-cycle control is that it scales very well.
It works for single-phase PFC/APF. IMHO IR is too late to
come out this IC to capture the market from others like TI. 

It also works for 3-phase PFC/APF. It will also works for 
high power multi-level PFC/APF. Let's wait to see some
companies come out with 3-phase PFC control IC with
one-cycle control.

Regards,
Xiaofan

-----Original Message-----
From: Martin K [mailto:martin-distlists@nnytech.net]
Sent: Tuesday, July 12, 2005 11:14 AM
...
Yes I should have said "PF analyzing" as PF correction metering makes no 
sense. I'm not sure how to actually analyze the PF from a piecewise 
signal, that is part of what I am researching.

...
> On a side note, IR has finally come out the new PFC control IC based 
> on the patented one-cycle control of Dr K.M. Smedley of University
> of California at Irvine. It is quite an interesting IC to look at
> if you are interested in low power PFC applications.

Is it just for low power? I thought it was for up to 4kW, if we were 
looking at the same chip. Very interesting indeed that only one inductor 
and a shunt resistor is needed now.

I've also been wondering if it is possible to make a flyback PFC for a 
specific application I have in mind. It seems as though it should work 
keeping in mind that the energy is transferred in the off time for both 
the boost and flyback topologies.

-- 
Martin K
http://wwia.org/
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist