Industrial Environment
Switching Regulators, PCB & Chassis
PSR Series
PSR: Positive Switching Regulators
No input to output isolation
Single output of 5, 12, 15, 24 or 36 V DC/15...72 W
Input voltage up to 80 V DC
•
High efficiency up to 94%
•
Wide input voltage range
• Low input to output differential voltage
•
Very good dynamic properties
•
Input undervoltage lock-out
•
Parallel configurations possible
•
Continuous no-load and short-circuit proof
•
No derating
Safety according to IEC/EN 60950
C
PSR-Series
50
2.0"
25
1.0"
70
2.8"
Summary
The PSR series of positive switching regulators is de-
signed as power supply modules for electronic systems.
Their major advantages include a high level of efficiency
that remains virtually constant over the entire input range,
high reliability, low ripple and excellent dynamic response.
Modules with input voltages up to 80 V are specially de-
signed for secondary switched and battery driven applica-
tions. The case design allows operation at nominal load up
to 71°C without additional cooling.
Type Survey and Key Data
Table 1: Type survey
Output
voltage
U
o nom
[V]
5
5
5
5
12
15
24
36
1
Output
current
I
o nom
[A]
5
4
3
2
2.5
2.5
2
2
Input
voltage range
U
i
[V]
1
7...35
7...40
8...80
8...80
15...80
19...80
29...80
42...80
Input
voltage
U
i nom
[V]
20
20
40
40
40
40
50
60
2
Efficiency
2
Type
designation
PSA 55-7
PSR 54-7
PSR 53-7
PSR 52-7
PSR 122.5-7
PSR 152.5-7
PSR 242-7
PSR 362-7
Options
η
min
[%]
81
82
77
72
86
88
91
92
η
typ
[%]
83
83
79
74
87
89
92
94
-9, i, P, R, Y
-9, i, P, R, Y
-9, i, P, R, Y
Y
-9, i, P, R, Y
-9, i, P, R, Y
-9, i, P, R, Y
-9, i, P, R, Y
See also:
Electrical Input Data:
D
U
io min
.
Efficiency at
U
i nom
and
I
o nom
.
Non standard input/output configurations or special custom adaptions are available on request.
See also:
Commercial Information: Inquiry Form for Customized Power Supply.
Table of Contents
Page
Page
Electromagnetic Compatibility (EMC) ............................. 6
Immunity to Environmental Conditions ........................... 7
Mechanical Data .............................................................. 8
Safety and Installation Instructions ................................. 8
Description of Options ................................................... 10
Accessories ................................................................... 11
Summary .......................................................................... 1
Type Survey and Key Data .............................................. 1
Type Key .......................................................................... 2
Functional Description ..................................................... 2
Electrical Input Data ........................................................ 3
Electrical Output Data ...................................................... 4
Auxiliary Functions .......................................................... 5
MELCHER
The Power Partners.
Edition 4/4.99
1/11
PSR Series
Type Key
Switching Regulators, PCB & Chassis
Industrial Environment
PSR 12 2.5 -7 i R P Y
Positive switching regulator in case A01 ..................... PSR
Nominal output voltage in volt ................................... 5...36
Nominal output current in ampere ............................... 2...5
Operational ambient temperature range
T
A
–25...71°C ........................................................... -7
–40...71°C (option) .............................................. -9
Options:
Inhibit input ............................................................ i
Control input for output voltage adjustment
1
....... R
Potentiometer
1
..................................................... P
PCB soldering pins 0.5
×
1.0 mm ......................... Y
1
Option R excludes option P and vice versa.
Example:
PSR 122.5-7iPY = A positive switching regulator with a 12 V, 2.5 A output, ambient temperature range of
–25…71°C, inhibit input, potentiometer and PCB soldering pins.
Functional Description
The switching regulators are designed using the buck con-
verter topology. See also:
Technical Information: Topolo-
gies.
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 in the form of flux. During the off period, this energy
forces the current to continue flowing through the output,
to the load and back through the freewheeling diode.
Regulation is accomplished by varying the on to off duty
ratio of the power switch.
These regulators are ideal for a wide range of applica-
tions, 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.
03015
I
i
Input Filter
I
o
Vi+
Vo+
i (option)
Control circuit
R (option)
U
o
U
i
C
e
Gi–
Go–
Option P
Fig. 1
Block diagram
MELCHER
The Power Partners.
Edition 4/4.99
2/11
Industrial Environment
Electrical Input Data
Switching Regulators, PCB & Chassis
PSR Series
General Conditions:
T
A
= 25°C, unless
T
C
is specified
Table 2a: Input data
Input
Characteristics
Conditions
PSA 55
min typ max
PSR 54
min typ max
7
40
2
6.3
45
75
2.5
15
B
2
75
2.5
15
B
2
45
150
2.5
15
B
3
7.3
40
150
2.5
15
B
3
PSR 53
min typ max
8
80
3
7.3
40
mA
A
µs
PSR 52
min typ max
8
80
3
Unit
V DC
U
i
U
i o
I
i 0
I
inr p
t
inr r
t
inr h
u
i RFI
Operating input voltage
D
U
io min
Min. diff. voltage
U
i
–
U
o 1
Undervoltage lock-out
No load input current
Peak value of inrush current
Rise time
Time to half-value
I
o
= 0...I
o nom
T
C min
...T
C max
7
35
2
6.3
I
o
= 0,
U
i min
...U
i max
U
i nom
Input RFI level, EN 55011/22
U
i nom
,
I
o nom
0.01...30 MHz
Table 2b: Input data
Input
Characteristics
Conditions
PSR 122.5
min typ max
PSR 152.5
min typ max
19
80
4
7.3
35
150
2.5
15
B
3
150
2.5
15
B
3
35
150
2.5
15
B
3
12
35
150
2.5
15
B
3
PSR 242
min typ max
29
80
5
19
40
mA
A
µs
PSR 362
min typ max
42
80
6
Unit
V DC
U
i
U
i o
I
i 0
I
inr p
t
inr r
t
inr h
u
i RFI
1
Operating input voltage
D
U
io min
Min. diff. voltage
U
i
–
U
o 1
Undervoltage lock-out
No load input current
Peak value of inrush current
Rise time
Time to half-value
I
o
= 0...I
o nom
T
C min
...T
C max
15
80
3
7.3
I
o
= 0,
U
i min
...U
i max
U
i nom
Input RFI level, EN 55011/22
U
i nom
,
I
o nom
0.01...30 MHz
2
3
The minimum differential voltage
D
U
io min
between input and output increases linearly by 0 to 1 V between
T
A
= 46°C and 71°C
(T
C
= 70
°C
and 95°C)
With input filter FP 38 (connected between Uii and Gi, see:
Accessory Products)
and
C
e
= 470
µF/40
V
With input filter FP 80 (connected between Uii and Gi, see:
Accessory Products)
and
C
e
= 470
µF/100
V
External Input Circuitry
The sum of the lengths of the supply lines to the source or
to the nearest capacitor
≥100 µF
or to the nearest external
input filter which includes such a capacitor (a + b) should
not exceed 0.3 m (0.5 m twisted). An external input filter
(FP 38 or FP 80, see:
Accessory Products)
is recom-
mended in order to prevent power line oscillations and re-
duce superimposed interference voltages. See also:
Tech-
nical Information: Application Notes.
04016
+
Vi+
a
b
Gi–
Vo+
Go–
Fig. 2
Switching regulator with long supply lines.
MELCHER
The Power Partners.
Edition 4/4.99
3/11
PSR Series
Electrical Output Data
Switching Regulators, PCB & Chassis
Industrial Environment
General Conditions:
–
T
A
= 25°C, unless
T
C
is specified
– With R or option P, output voltage
U
o
=
U
o nom
at
I
o nom
Table 3a: Output data
Output
Characteristics
Conditions
PSA 55
min typ max
4.97
0
5.0
20
24
30
20
250
40
±1
±0.02
5.03
5.0
3
6.5
35
39
45
25
PSR 54
min typ max
4.97
0
4.0
15
19
30
20
200
40
±1
±0.02
5.03
4.0
5.2
25
29
45
25
PSR 53
min typ max
4.97
0
3.0
20
24
30
20
100
50
±1
±0.02
5.03
3.0
3.9
35
39
45
25
PSR 52
min typ max
4.97
0
2.0
20
24
30
20
100
50
±1
µs
mV/K
5.03
2.0
2.6
35
39
45
25
mV
mV
pp
Unit
V
A
U
o
I
o
I
oL
u
o
Output voltage
Output current
1
Output current limitation
response
1
Output
voltage
noise
Switching freq.
Total
U
i nom
,
I
o nom
U
i min
...U
i max
T
C min
...T
C max
U
i nom
,
I
o nom
IEC/EN 61204
2
BW = 20 MHz
U
i min
...U
i max
,
I
o nom
U
i nom
,
I
o
= 0...I
o nom
U
i nom
I
o nom
↔
1
/
3
I
o nom
IEC/EN 61204
2
U
i min
...U
i max
I
o
= 0...I
o nom
D
U
o U
D
U
o l
Static line regulation
Static load regulation
Dynamic
load
regulation
Voltage deviat.
Recovery time
u
o d
t
d
a
Uo
Temperature coefficient
D
U
o
/DT
C
(T
C min
...T
C max
)
±0.02
%/K
Table 3b: Output data
Output
Characteristics
Conditions
PSR 122.5
min typ max
11.93
0
2.5
30
35
50
35
180
60
±2
±0.02
PSR 152.5
min typ max
PSR 242
min typ max
PSR 362
min typ max
36.22
2.0
2.6
80 160
85 165
200 270
125 160
250
100
±5
±0.02
±8
µs
mV/K
mV
mV
pp
Unit
V
A
U
o
I
o
I
oL
u
o
Output voltage
Output current
1
Output current limitation
response
1
Output
voltage
noise
Switching freq.
Total
U
i nom
,
I
o nom
U
i min
...U
i max
T
C min
...T
C max
U
i nom
,
I
o nom
IEC/EN 61204
2
BW = 20 MHz
U
i min
...U
i max
,
I
o nom
U
i nom
,
I
o
= 0...I
o nom
U
i nom
I
o nom
↔
1
/
3
I
o nom
IEC/EN 61204
2
U
i min
...U
i max
I
o
= 0...I
o nom
12.07 14.91
2.5
3.25
45
50
75
45
0
2.5
40
44
15.09 23.86
2.5
3.25
75
80
0
2.0
45
24.14 35.78
2.0
2.6
95
0
2.0
50 100
150 220
120 160
210
80
D
U
o U
D
U
o l
Static line regulation
Static load regulation
Dynamic
load
regulation
Voltage deviat.
Recovery time
70 100
40
180
60
±3
±0.02
55
u
o d
t
d
a
Uo
Temperature coefficient
D
U
o
/DT
C
(T
C min
...T
C max
)
±0.02
%/K
1
2
3
See also:
Thermal Considerations.
See:
Technical Information: Measuring and Testing.
Linear derating from 5 to 4 A between
T
A
= 61°C and 71°C (T
C
= 85°C and 95°C).
05010
U
o
u
od
D
U
o I
D
U
o I
t
d
I
o
/I
o nom
1
u
od
t
d
t
0
≥10
s
≥10
s
t
Fig. 3
Dynamic load regulation.
MELCHER
The Power Partners.
Edition 4/4.99
4/11
Industrial Environment
Thermal Considerations
Switching Regulators, PCB & Chassis
Parallel and Series Connection
PSR Series
When a switching regulator is located in free, quasi-sta-
tionary air (convection cooling) at a temperature
T
A
= 71°C
and is operated at its nominal output current
I
o nom
, the
case temperature
T
C
will be about 95°C after the warm-up
phase, measured at the
Measuring point of case tempera-
ture T
C
(see:
Mechanical Data).
Under practical operating conditions, the ambient tem-
perature
T
A
may exceed 71°C, provided additional meas-
ures (heat sink, fan, etc.) are taken to ensure that the case
temperature
T
C
does not exceed its maximum value of
95°C.
Example: Sufficient forced cooling allows
T
A max
= 85°C. A
simple check of the case temperature
T
C
(T
C
≤
95°C) at
full load ensures correct operation of the system.
I
o
/I
o nom
Forced cooling
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
05031
Outputs of equal nominal voltages can be parallel-con-
nected. However, the use of a single unit with higher out-
put power, because of its power dissipation, is always a
better solution.
In parallel-connected operation, one or several outputs
may operate continuously at their current limit knee-point
which will cause an increase of the heat generation. Con-
sequently, the max. ambient temperature value should be
reduced by 10 K.
Outputs can be series-connected with any other module.
In series-connection the maximum output current is limited
by the lowest current limitation. Electrically separated
source voltages are needed for each module!
Short Circuit Behaviour
A constant current limitation circuit holds the output cur-
rent almost constant whenever an overload or a short cir-
cuit is applied to the regulator's output. It acts self-protect-
ing and recovers – in contrary to the fold back method –
automatically after removal of the overload or short circuit
condition.
U
o
/U
o nom
Convection cooling
T
C max
I
o nom
1.2
1.0
0.8
0.6
05033
I
o L
T
A min
50
60
70
80
90
100
T
A
[°C]
0.4
0.2
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
I
o
/I
o nom
Fig. 4
Output current derating versus temperature
Output Protection
A voltage suppressor diode which in worst case conditions
fails into a short circuit, protects the output against an in-
ternally generated overvoltage. Such an overvoltage could
occur due to a failure of either the control circuit or the
switching transistor. The output protection is not designed
to withstand externally applied overvoltages. The user
should ensure that systems with Melcher power supplies,
in the event of a failure, do not result in an unsafe condi-
tion (fail-safe).
Fig. 5
Overload, short-circuit behaviour U
o
versus I
o
.
Auxiliary Functions
LED Output Voltage Indicator
A yellow output indicator LED shines when the output volt-
age is higher than approx. 3 V.
The LED output voltage indicator is not available for
PSR 52.
MELCHER
The Power Partners.
Edition 4/4.99
5/11
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