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Linear power supply; 2 output voltages; Ground plane question.

M

Mike V.

Jan 1, 1970
0
I plan to have a transformer with two isolated outputs which are
rectified and regulated to give me two isolated voltages: 15V and 5V
with separate grounds.

The transformer will be on one end of the board. I need to put
separate ground planes underneath the 15V and 5V circuitry. My
question is: What about the power supply circuitry? The transformer
will also be on the board. Do I still need ground planes underneath
the transformer and bridge rectifiers and voltage regulators? Is it
better to put the power supply circuitry in the middle of the board,
then devote one side to 5V and the other to 15V circuitry? Or can I
keep the power supply on one side, 15V in the middle and 5V stuff on
the other side? If i do the latter, then i need to extend the voltage
rail trace across the board.

-Mike
 
J

John Popelish

Jan 1, 1970
0
Mike V. said:
I plan to have a transformer with two isolated outputs which are
rectified and regulated to give me two isolated voltages: 15V and 5V
with separate grounds.

The transformer will be on one end of the board. I need to put
separate ground planes underneath the 15V and 5V circuitry. My
question is: What about the power supply circuitry? The transformer
will also be on the board. Do I still need ground planes underneath
the transformer and bridge rectifiers and voltage regulators? Is it
better to put the power supply circuitry in the middle of the board,
then devote one side to 5V and the other to 15V circuitry? Or can I
keep the power supply on one side, 15V in the middle and 5V stuff on
the other side? If i do the latter, then i need to extend the voltage
rail trace across the board.

-Mike

You should have specific functions not only for ground planes, but for
ground traces. What is the function of the ground planes in these
circuits? When you answer that, it should be much clearer to you
where you need them and how they interconnect.
 
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