HP 900 Series - Figure:3-9. Power Supply Block Diagram

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S
Line Filter
(low
freq.)
f
Power Switch
1
Fuse
I
Comn:ercial I Line Filter
Line ~ (high freq.)
..
---.
V Sel
bridge
rectifier
& energYI--
storage
t
...
.
Transformer
~
~
~ rl DD~{ 2~eo.
.-rectifier r ~
1 rectifier ~ -12V
post reg.
....
--..
...
--..
~ +5V over
~I current
sensor
I----~~... rectifier IT.
switching 1oII~1-------------l
control
circuitry
oJ
~
+
+5V feedback ~
loop circuitry
E
+5V
overvoltage
protection + 1 2V
circuitry -1 2V
PURESET ~- ~es~f~ +5V
- I circuitry k--- + 1 2V