Table of Contents
Advertisement
3-11 Each load should be connected t o the power
s u p p l y output terminals using s e p a r a t e pairs of
c o n n e c t i n g wires.
This w i l l minimize mutual
coupling e f f e c t s between l o a d s and w i l l retain full
advantage of the low output impedance of the power
supply.
Each pair of connecting w i r e s should b e
a s short a s p o s s i b l e t o reduce n o i s e pickup.
In
addition, a 0.
1
t o 1. Opf c a p a c i t o r should b e con-
n e c t e d between one terminal a n d t h e c h a s s i s , if
t h e supply is floated off of ground.
3-12
If load c o n s i d e r a t i o n s require t h a t t h e output
power distribution terminals be remotely located
from the power supply, then the power supply out-
put terminals should be connected t o the remote
distribution terminals v i a a pair of s h i e l d e d w i r e s
a n d e a c h load connected s e p a r a t e l y t o the remote
distribution terminals.
A 0.
1
t o 1. Opf c a p a c i t o r
should be c o n n e c t e d a c r o s s t h e remote distribution
terminals t o reduce high frequency coupling and
n o i s e .
3-1 3 OUTPUT CAPACITANCE
3-14 An internal c a p a c i t o r , a c r o s s the output ter-
minals of t h e power supply, h e l p s t o supply high
current p u l s e s of short duration during c o n s t a n t
voltage operation.
Any c a p a c i t a n c e added exter-
n a l l y w i l l improve the pulse current c a p a b i l i t y ,
b u t w i l l d e c r e a s e the s a f e t y provided b y the cur-
rent limiting circuit.
A
high current pulse may
damage load components before the average output
current is large enough t o c a u s e the current limit-
ing circuit t o operate.
3-15
REVERSE CURRENT LOADING
3-16 Active l o a d s connected t o the power supply
may a c t u a l l y deliver a reverse current t o the pow-
e r supply during a portion of i t s operating c y c l e .
An external source c a n n o t be allowed t o pump cur-
rent into the supply without l o s s of regulation and
p o s s i b l e damage t o the output capacitor.
To avoid
t h e s e e f f e c t s , i t
is
n e c e s s a r y t o preload the sup-
ply with a "dummy" load s o t h a t the power supply
delivers current through t h e entire operating c y c l e
of the load device.
3- 17 REVERSE VOLTAGE LOADING
3-18 A diode is connected a c r o s s the output ter-
minals.
Under normal operating conditions, the
diode i s reverse b i a s e d (anode connected t o neg-
a t i v e terminal).
If a reverse voltage is applied t o
the output terminals (positive voltage applied t o
negative terminal), t h e diode w i l l conduct, shunt-
ing current a c r o s s the output terminals and limit-
ing voltage t o the forward voltage drop of the
diode.
This diode protects the s e r i e s transistors
and the output electrolytic capacitors.
Advertisement
Table of Contents
