Posted by Circuits Arena on Saturday 30 April 2016
Adjustable 0-100V 50 Amp SMPS Circuit Diagram is the artlcle explaining Adjustable 0-100V 50 Amp SMPS Circuit Diagram The switching supply is powered with IGBT transmitters and is further controlled by UC3845...
Adjustable 0-100V 50 Amp SMPS Circuit Diagram
The switching supply is powered with IGBT transmitters and is further controlled by UC3845 circuit.
The mains voltage goes straight through the EMC filter which is further checked and filtered on C4 capacitor.
The relay coil and fan, taken from AT or ATX power supply is powered
from 12V. The power is obtained via the resistor from 17V auxiliary
supply.
It is ideal to select R1 so that the voltage at the fan and the relay
coil limits to 12V. The auxiliary supply on the other hand uses TNY267
circuit and R27 facilitates protection from under-voltage of auxiliary
power.
The power will not turn on if the current is less than 230V. The UC3845
control circuit results to 47% duty cycle (Max.) with the output
frequency of 50 kHz. The circuit is further powered with the help of the
zener diode, which actually helps to reduce the supply voltage and even
helps to shift the UVLO threshold of lower 7.9V and upper 8.5V to 13.5V
and 14.1V respectively.
The source initiates the power and starts working on 14.1V. It never
goes below 13.5V and further helps to protect IGBT from desaturation.
However, the original threshold of UC3845 should to set as low as
possible.
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| 12V input supply may be acquired from an ATX power supply |
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| +U1 and -U1 may be derived from mains 220V input after appropriate rectification and filtration |
Also, please remember to place diodes D5, D5 ', D6, D6', D7, D7 ',
transistors T5 and T6 on heat sink along with the bridge. Care should be
taken to place snubbers R22 + D8 + C14, capacitors C15 and diodes D7
close to IGBT. The LED1 signals the operation of the supply and LED2
signals the error or the current mode.
