SOtM SPS1000 SERIES Operating Manual

CIRCUIT DESCRIPTION AND OPERATING MANUAL

CIRCUIT DESCRIPTION

Power Supplies SPS 1000 series are based on the primary switched AC/DC converters topology.
Power supplies of this technology have got a high efficiency factor. Simplified functional diagram is
shown in the fig.1.
S W ITCH
L U1
F 1
Input
N N1
filte r
P E
Option
The 230 AC line voltage is rectified by a bridge rectifier „U
capacitor „C ". RFI filters „F
f1
produced inside the power supply. When the unit is switched on, the electrolytic capacitor is charged
via NTC resistors. Inrush current is limited approximately to 60A/10ms. This must be taken into
account at a fusing of the line outlet. It is recommended to use 16A normal fuse or 10A slow one. The
rectified 230V AC (300V DC) is chopped by the inverter „S" which consists of four MOSFET
transistors and transformed to a lower voltage. The 50kHz power converter is of full bridge type. The
regulation of the output voltage (current) is achieved by pulse-width modulation varying duty cycle
(D=0÷80%) at the constant frequency.
POWER SUPPLIES SPS1000 SERIES
t
NTC C
U
f1
1
t
Input
re ct.
NTC
P TC1
R OV
M
F ans
M
speed
control
R S 232
U ž
:
0- 5V
ž I
:
0- 5V
"ON"
"OF F "
" protect the line and a load from a high frequency interference
1
TR
S U
2
Inverter Output
re ct.
P TC2
I
m
U m
R O
C ontrol
circuit
U I
ž ž
+5V
(Disable)
"OU TP U T"
"OF F " "ON"
S witch
F ig.1
" and smoothed by a large electrolytic
1
1
TL
C
F 2
f2
Output
filte r
I m
ZJ
Display unit
+5V
+
U2
I2
-
U m