Step-Down Switching Regulator Design
Jernfors, Olli (2022)
Jernfors, Olli
2022
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-202204114938
https://urn.fi/URN:NBN:fi:amk-202204114938
Tiivistelmä
The goal of the thesis project was to design two different step-down switching regulators which would be measured for their line and load regulation. EMC measurement was also done for the PCBs since switching regulators are prone to produce interference.
First step was to choose IC regulators and do the calculations from their datasheets for the right components to get the wanted values for voltage and current of the load. Next the designs were done and tested on a breadboard to measure the output voltages with different line voltage and load resistance to see if the calculations and designs are correct. Then the designs were made on PCB and the measurements were repeated. The circuit boards were also EMC measured afterwards. The IC regulators chosen were LM78S40 and LM2575.
The regulators were tested, and both were working as they should. For EMC the ICs were measured for emission with the point of interest being the switching frequencies of the regulators. At the end it could be seen that there was a distinguishable difference in the operation of the IC regulators. LM78S40 had too much ripple and was causing some unexplainable interference, while LM2575 had no ripple at all, and its switching frequency was found.
First step was to choose IC regulators and do the calculations from their datasheets for the right components to get the wanted values for voltage and current of the load. Next the designs were done and tested on a breadboard to measure the output voltages with different line voltage and load resistance to see if the calculations and designs are correct. Then the designs were made on PCB and the measurements were repeated. The circuit boards were also EMC measured afterwards. The IC regulators chosen were LM78S40 and LM2575.
The regulators were tested, and both were working as they should. For EMC the ICs were measured for emission with the point of interest being the switching frequencies of the regulators. At the end it could be seen that there was a distinguishable difference in the operation of the IC regulators. LM78S40 had too much ripple and was causing some unexplainable interference, while LM2575 had no ripple at all, and its switching frequency was found.