24-03-2008, 08:20 AM
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#17 (permalink)
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Uber Member
Join Date: Mar 2006
Posts: 4,937
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Quote:
Originally Posted by The Bear
That's not a single phase rectifier, and C1 isn't a part of a “smoothing” circuit to take out line ripple. It’s a part of the voltage doubler, and works in conjunction with C2 in order to cater for the US market where the line voltage is 110 volts.
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I stand corrected - I should have said C1 and C2 in series. I was considering the 220V input. In that case BR1 acts as a single phase rectifier and C1 + C2 provide smoothing. Note that they are shown as electrolytics which is typical for smoothing capacitors.
Smoothing is a compromise so won't be perfect and, from a 220Vac 50Hz supply, there will be a 100Hz component in the DC.
This is what I was looking for and shows it more clearly.
http://www.nxp.com/acrobat_download/applicationnotes/AN98091_1.pdf
I have a hard copy of it but was too idle to scan it in. |
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