Mariss' power supply circuit

I finally found the .pdf file and had a look.
As I understand it the circuit will perform shunt regulation
using PWM at 120 hz. Duty cycle will vary from 0-100% over a
couple volts diff between the filter cap and transformer secondary
peak. I think it will modulate with a raised cosine law. Right?

Question: what is the on resistance of the Fet you selected? Just
want to calculate heat sink thermal resistance. Also, what happens
in a line power undervoltage scenario?

And as a little FMEA thing, what would be the most likely part to fail?
Would it be the fet if say the primary mains went very high? Would it
fail open or shorted? (I currently have a floating neutral argument with
my Georgia Power supplier and their electrical feed)

I want to publicly thank you for publishing this as open source.
I appreciate your weekend efforts.
These things cost about $300 from other suppliers.

Les

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.rabun.net/~leswatts/wattsfurniturewp.html
engineering page:
http://www.rabun.net/~leswatts/shop.html

----- Original Message -----
From: "mariss92705" <mariss92705@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, June 16, 2002 3:54 PM
Subject: [CAD_CAM_EDM_DRO] Re: Power Supply Circuit


> Hi,
>
> OK, here's my Saturday's project. I posted a "Power supply
> circuit.pdf" in the files section of this list.
>
> It wound up being different than what I started with. Sensing current
> was too crude. Instead this circuit compares the power supply voltage
> against the xformer secondary voltage. It pulse width modulates the
> dump resistor and has a very nice proportional response. The PWM goes
> from 0% to 100% as the power supply voltage climbs to 2V above the
> nominal voltage. It has been tested and works very well.
>
> Mariss