PSS, PSK Extended Data Sheet
Positive Switching Regulators (Benign)
REV. FEB 15, 2004
Page 3 of 15
Electrical Input Data
General Conditions:
TA = 25°C, unless TC is specified
Table 2: Input data
Input
PSS 5A14
PSS 1214
PSS 1214 1
PSS 2414
PSK 5A18
PSK 1218
PSK 1218 1
PSK 2418
Characteristics
Conditions
min typ max
Unit
Vi
Operating input voltage
Io = 0 – Io nom
8
40
1540
1940
2960
VDC
DVio min Min. diff. voltage Vi – Vo
TC min – TC max
2.9
345
Vi o
Undervoltage lock-out
7.3
12
Ii 0
No load input current
Io = 0, Vi min –Vi max
50
mA
ui RFI
Input RFI level, EN 55011/22
Vi nom, Io nom
A
AAA
dB (
V)
0.15...30 MHz
1 Output set to 15 V at R control input, see: Auxiliary Functions.
Control
circuit
Go–
Vo+
Gi–
Vi+
R
i
Io
Vo
I i
Vi
03020
Input
Filter
S+
CS
S–
30
32
26
28
24
4
6
20
22
14
16
18
8
10
Fig. 1
Block diagram
Functional Description
The switching regulators are designed using the buck con-
verter topology. The input is not electrically isolated from
the output. During the on period of the switching transistor,
current is transferred to the output and energy is stored in
the output choke. During the off period, this energy forces
the current to continue flowing through the output chocke
to the load and back through the freewheeling diode.
Regulation is accomplished by varying on/off duty cycle.
These
regulators
are
ideal
for
a
wide
range
of
applications, where input to output isolation is not
necessary, or where already provided by an external front
end (e.g. a transformer with rectifier). To optimise
customer’s needs, additional options and accessories are
available.
Input Filter and Fuse
An input filter and a fuse are incorporated in all modules as
standard. The filter reduces emitted electrical noise and
prevents oscillations caused by the negative input imped-
ance characteristic of a switched mode regulator. The input
fuse protects against severe defects.
The maximum permissible additionally superimposed rip-
ple
vi of the input voltage (rectifier mode) at a specified in-
put frequency
fi has the following values:
vi max = 10 Vpp at 100 Hz, or Vpp = 1000 Hz/fi 1 V
Inrush Current
The inrush current can reach very high values depending
on the source and input line conditions. The inrush current
into a switching regulator is limited by parasitic components
of the voltage source and power supply input only. This in-
put presents a very low impedance to such currents and
when driven from a low impedance source, e.g. a battery,
the inrush current can peak at several orders of magnitude
above the continuous DC input current. To protect series el-
ements such as switches or circuit brakers and rectifiers the
use of additional external current limitation device is recom-
mended.