1
GENERAL DESCRIPTION
The regulator is a general purpose 24V DC to 13.2V
DC regulator, e.g. to be used for supply of VHF
radiotelephones.
The regulator is a serial regulator with excellent
noise performance.
1.1
TECHNICAL DATA
The regulator is controlled from the connected VHF
unit by the on/off button.
Input Voltage
21.6 to 31.2V DC
Output Voltage
13.2V DC
Output Current
Max. 8A DC
Operation Temperature
Range
15°C to +55°C
Fuse
8 Amp. 5 x 20mm
Current from on/off
Terminal
Less than 15 mA DC
1.2
PRINCIPLE OF OPERATION
The regulator is a linear serial regulator where most
of the loss is dissipated in resistors. It is provided
with a terminal for remote shut-down. If the on/off
terminal is connected to the -terminal, the regulator
is on. If the on/off terminal is disconnected, the
regulator is off.
1.3
CIRCUIT DESCRIPTION
The output voltage is regulated by the integrated
voltage regulator IC1. The output voltage is 12V DC
plus the forward voltage over diodes D5 and D6:
approx. 13.2V DC in total if T4 is conducting. If the
output voltage drops the current through IC1 and R5
increases. An increase in voltage across R5 will
result in an increase in current in T1 and the resis-
tors R10 - R23 resulting in an increase in the output
current. T1 delivers most of the output current and
FC1 only a small driver current.
If the input voltage is low and the output current is
high, the voltage across R10 -R23 results in T1
going into saturation. The voltage across R4 in-
creases and when the voltage across R4 and V
BE
Of
T1 is greater than approx. 1 Volt, T3 starts to
conduct base current to T1. This transistor then
shunts the remaining current to the output, bypass-
ing R10 - R23.
COMPONENT LOCATION
View from component side with upper side tracks.
PCB rev. 24613G
View from component side with lower side tracks.
R10
R11
R12
R13
R14
R15
R16
R3
C3
D3
D2
R8
R9
R7
R4
R5
R23
R22
R21
R20
R19
R18
R17
C5
C2
D6
R6
IC1
B-T2
T4
C4
C1
E-T2
E-T1
C-T1
B-T1
E-T2
D5
C-T2
T3
R2
R1
F1
D1
R10
R11
R12
R13
R14
R15
R16
R3
C3
D3
D2
R8
R9
R7
R4
R5
R23
R22
R21
R20
R19
R18
R17
C5
C2
D6
R6
IC1
B-T2
T4
C4
C1
E-T2
E-T1
C-T1
B-T1
E-T2
D5
C-T2
T3
R2
R1
F1
D1
When the input voltage and the output current are
high, T1 is nearly saturated. When the input voltage
is low and the output current is high, the resistors R1
- R3 will result in saturation of both T1 and T2. The
combination of T1 in saturation and T2 delivering
the remaining output current divides the total loss,
so the main loss is in the resistors giving low loss in
the semi-conductors and a lower junction tempera-
ture, resulting in a higher reliability for the whole
regulator.
T4 is used to switch the regulator ON and OFF. If the
ON/OFF input is disconnected T4 is OFF and the
base currents to T1 and T2 are zero and the current
through IC1 will also be reduced to zero. The stand-
by current consumption is then less than 10 micro
amp. If the ON/OFF input is connected to - input, T4
goes into saturation and the regulator starts.
In case of a short-circuit over the output R5 and D3
limits the current through IC1 and T4 to approx. 250
mA and R1 - R3 and D3 limits the current through T1
and T2 to approx. 15 Amp. The temperature of the
1.4
PARTS LIST
REGULATOR
ECI A/S
5-0-24613G
600416
POSITION
DESCRIPTION
MANUFACTOR
TYPE
PART NO.
C1
CAPACITOR ELECTROLYTIC 47uF -10/+50% 63V
ERO
EB 00 FL 247 J
14.552
C2
CAPACITOR MKT
0.22uF 10% 63V
ERO
MKT1818
11.090
C3
CAPACITOR MKT
0.22uF 10% 63V
ERO
MKT1818
11.090
C4
CAPACITOR ELECTROLYTIC 47uF -10/+50% 63V
ERO
EB 00 FL 247 J
14.552
C5
CAPACITOR MKT
100nF 10% 100VDC
PHILIPS
2222 371 28104
11.180
D1
DIODE
MOTOROLA
MR750
25.219
D2
DIODE SCHOTTKY
THOMSON-CSF
BAT43
27.600
D3
DIODE ZENER
PHILIPS
BZX79C7V5
26.539
D5
DIODE
1N4148 HIGH SPEED
PHILIPS
1N4148-143
25.131
D6
DIODE
1N4148 HIGH SPEED
PHILIPS
1N4148-143
25.131
F1
FUSE
8AF 250V Ø5x20mm
ELU
171 100 8AF
45.561
IC1
VOLTAGE REGULATOR
+12V
MOTOROLA
MC7812CT
31.260
R1
RESISTOR POWER
1R0 OHM 10% 6.5W
VITROHM
1R0 10% TYPE 296-0
05.725
R2
RESISTOR POWER
1R0 OHM 10% 6.5W
VITROHM
1R0 10% TYPE 296-0
05.725
R3
RESISTOR POWER
1R0 OHM 10% 6.5W
VITROHM
1R0 10% TYPE 296-0
05.725
R4
RESISTOR
47 OHM 5% 0.6W
BEYSCHLAG
MBB 0207-00-BX-47R
03.167
R5
RESISTOR PMF
27 OHM 5% 3W
PHILIPS
2322 195 13279
04.660
R6
RESISTOR MF
1k0 OHM 5% 0.4W
PHILIPS
2322 181 53102
01.200
R7
RESISTOR MF
1k0 OHM 5% 0.4W
PHILIPS
2322 181 53102
01.200
R8
RESISTOR MF
10k OHM 5% 0.4W
PHILIPS
2322 181 53103
01.225
R9
RESISTOR
2.2 KOHM 5% 0.6W
DRALORIC
SMA 0207 STK100-2K
03.208
R10
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R11
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R12
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R13
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R14
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R15
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R16
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R17
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R18
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R19
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R20
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R21
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R22
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
R23
RESISTOR POWER
6R8 OHM 10% 6.5W
VITROHM
6R8 10% TYPE 296-0
05.730
T1
TRANSISTOR DARLINGTON
TEXAS
MJ2501
29.235
T2
TRANSISTOR DARLINGTON
TEXAS
MJ2501
29.235
T3
TRANSISTOR AF
BC547B NPN TO-92
PHILIPS
BC547B
28.067
T4
TRANSISTOR
BD140-10
AEG
BD140-10
29.066
DIAGRAM
This diagram is valid for PCB rev. 24613G
140mm
7.5mm
7.5mm
90mm
7.5mm
7.5mm
105mm
155mm
25332A
UP
4 pcs. ø3.5mm
78mm
DIMENSION AND DRILLING PLAN
The regulator must only be mounted vertically.
Free distance must be kept to allow circulation.
cooling surface will increase and activate the thermal
protection circuit inside IC1 and lower the output
voltage, even though a short-circuit of the output
should be avoided.
The diode D1 protects against reverse input volt-
age. A fuse will blow in case of reverse input.
TECHNICAL MANUAL
FOR
24V/12V REGULATOR
N420
Doc. No.: M420GB Issue: D/0339
