Scott,
Thank you very much.
Barry
----------------------
From: "Lacey,Scott" <sla...@foxboro.com>, Date: Thu, 4 Nov 1999
14:52:57
-0500
Barry,
In a switchmode supply, the primary side dc voltage = 1.414 times the rms
value of the ac input. This is then switched (at 100kHz or so) into the
primary of a ferrite core transformer. The output pulse has an amplitude that
is at a fixed ratio to the input voltage. The regulator circuit adjusts the
pulse width to maintain a constant voltage at the output capacitor(s),
regardless of load. The worst case is heavy load at low input voltage. The
pulse width may reach the design limitation before the regulator is satisfied.
Hope this is some help.
Scott Lacey
-----Original Message-----
From: Bl Ma
Sent: Thursday, November 04, 1999 2:13 PM
To:
Cc: EMC/PS IEEE Group
Subject: RE: 90V & 47Hz - Is this a realistic combo
Mark,
Please pardon my ignorance. I have a silly question.
It seems to me that the purpose of brownout is to save energy by
reducing
voltage. Why do you test your power
supply "down to 85 Vac at 50/60 Hz at the maximum specified operating
temperature with high humidity
conditions present" instead of "up to 106 Vac ..."? Higher voltage
would
consume more energy and produce
more heat inside the power supply.
Barry Ma
Anritsu
---------------------
From: "Mark Schmidt" <>, on 11/4/99 9:45 AM:
Eastern Japan Voltage 100 Vac @ 50Hz. (Tokyo,Kawasaki, Sapporo,
Yokohoma and
Sebdai)
Western Japan Voltage 100 Vac @ 60Hz. (Osaka, Kyoto, Nagoya,
Hiroshima)
I also agree with Tania and the brown-out conditions that exist in
Japan. It
is my understanding that 90
Vac is quite common, personally I would test down to 85 Vac at 50/60 Hz
at
the maximum specified operating
temperature with high humidity conditions present.
----------------------
From: "Grant, Tania (Tania)", on 11/3/99 4:40 PM:
Ages ago when I worked at another company that shipped products to
Japan,
their unwritten rule was to design
in power supplies that operated without problems at 85 Vac, and that
had
better be designed/tested down to 80
Vac, because of the continued brown-out conditions in Japan. It seems
nothing much has changed.
I don't remember what was stated about the frequency tolerance.
Tania Grant,
Lucent Technologies, Communications Applications Group
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