I agree with you that 18F1220 has too weak ADC. dsPICs have faster
ADCs. Silabs C8051Fxxx has much better ADC performance. Maybe you
can look at that as well. Keil offers free 4K C compiler for
it.

What do you mean by PFC metering? Does it mean to measure the power
factor and THD? Then perhaps a DSP is the way to go. Please have a
look at TMS320F2407 or better with an external fast ADC.

For energy metering, Microchip has an application note based on
a 16F873A.

We have HP 6811A AC power source/analyzer and I like it. But it
is quite expensive.

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.

Regards,
Xiaofan

-----Original Message-----
From: Martin Klingensmith [mailto:martin-distlists@nnytech.net]
Sent: Sunday, July 10, 2005 6:58 AM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] AC current sensing

I've decided that one of the Allegro sensors is probably the best thing 
to use. I should have figured, I have a couple sitting right here but I 
didn't think about them as I have as of now only used them for DC 
applications [though I realize they work just fine for AC or DC]

The application is an AC load analyzer/meter including PFC metering and 
energy/power calculations.
I'm planning on using an 18F1220 but I fear the ADC may not be fast 
enough to measure a signal having a bad PF [watch the current through a 
CFL sometime for fun]
I do believe the rest of the '1220 should be plenty fast considering it 
runs at 40MHz and has a hardware multiply.
I'm open to any comments/criticism.

--
Martin Klingensmith
-- 

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