Philips PM2813 Power Supply User Manual


 
5 - 36 Users Manual
Remote sensin
g
(loads in parallel):
The followin
g
dia
g
ram shows the wirin
g
scheme.
If remote sensin
g
is used, locate the distribution terminals (DT) as near as
possible to the load terminals.
CAUTION: To prevent noise pickup, twist the sense wires and shield them from
the environment.
5.6.4 Tips for Remote Sensin
g
Applications
Prevent Output Noise
It is advised to twist or to shield the sense leads to minimize the pickup of
envirionmental noise. If the sense leads are twisted, run them parallel and close
to the load leads. In environments with heavy noise, it may be necessary to shield
the sense leads. Connect the shield to
g
round at the power supply end only.
Prevent Instability
The impedance of the load leads to
g
ether with the capacitance of the load can form
a filter , which may cause a phase shift in the sense feedback loop. This can cause
instability or even oscillations, which must be prevented. If there is doubt about the
stability of the output, you can check this with an oscilloscope. There are no simple
rules to prevent instability for all circumstances, but the followin
g
g
uidelines are
valid most often:
1. Use short leads with low resistance for the load and the sense connections.
2. Twist the load leads to
g
ether to minimize additional inductance.
3. Twist the sense leads to
g
ether (or shield them) to minimize interference with
the environment.
4. Keep the load capacitance as small as possible.
Fi
g
ure 5.6.6 Remote Sensin
g
withTwo Loads in Parallel
+S
+V
V
S
LOAD
+
ST5867
LOAD
+
DT+
DT