1.2 PRINCIPLE OF OPERATION
Theregulatorisa linear serialregulatorwheremost
of the loss is dissipated in resistors. It is provided
with a terminal for remote shut-down. If the on/off
terminalis 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
voltageregulatorIC1.Theoutputvoltageis 12V DC
plus the forward voltage over diodes D5 and D6:
approx. 13.2V DC in total if T4 is conducting. If the
outputvoltagedropsthecurrentthroughIC1andR5
increases. An increase in voltage across R5 will
result in an increase in current in T1 and the resis-
torsR10 -R23 resultingin anincrease inthe 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-
creasesandwhenthevoltageacrossR4andVBE Of
T1 is greater than approx. 1 Volt, T3 starts to
conduct base current to T1. This transistor then
shuntsthe 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,T1isnearly saturated. Whentheinput voltage
islowandtheoutputcurrentishigh,theresistorsR1
- 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,
sothe main loss is in the resistors giving low loss in
thesemi-conductors and a lower junction tempera-
ture, resulting in a higher reliability for the whole
regulator.
T4isusedtoswitchtheregulatorONandOFF.Ifthe
ON/OFF input is disconnected T4 is OFF and the
basecurrentsto T1and T2 arezero and thecurrent
throughIC1willalso be reducedtozero.The stand-
by current consumption is then less than 10 micro
amp.Ifthe ON/OFF inputisconnected to -input,T4
goes into saturation and the regulator starts.
In case of a short-circuit over the output R5 and D3
limitsthecurrent through IC1and T4 toapprox.250
mAandR1-R3andD3limitsthecurrentthroughT1
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
