I have implemented the circuit provided in the datasheet for 5V output. Unfortunately, the output voltage rises to greater than 20V. I then purchased the dev kit EV175-S-00A and confirmed that it works without modification with an output voltage of 18V. I then modified the board by changing R3 from 95K to 18K. This should in theory give an output voltage of ~5V. However, when powered up the output rises to >20V, same as I observed in my previous test. Can the MP175 actually deliver 5V output, and if so how do I make it work? Input voltage is 120Vac.
Hello @sauger ,
Thank you for posting your question on the MPS Technical Forum.
The MP175 is mainly used for applications in which the output voltage is as low as 12V.
Nevertheless, I recommend checking the MP175L, which is a similar device (footprint and electrical specs) as the MP175. This IC can regulate output voltages as low as 5V.
Furthermore, the datasheet features a 5V/600mA application circuit for your reference.
Regards,
Edgar
Sorry I should be more clear. My custom design uses the MP175L and my design is identical to the schematic that you provided. I observed the output rising up to >20V. In order to remove my design from the equation I bought a Dev Kit which uses the MP175. I wasn’t aware that the MP175 was not meant for output down to 5V. Would it make sense for me to replace the MP175 with an MP175L on the Dev Kit to continue debug? All components on the Dev Kit are essentially the same as in the MP175L schematic shown for 5V output. And the resistor changed for 5V output.
Hi Sauger,
Thank you for providing details on your project.
Yes, the EVB for the MP175 has the same schematic as the one showed from the MP175L datasheet (Figure 10). There are some slightly differences in values for some of the capacitors, and populated diodes, but the overall layout is the same.
Given that, it makes sense to try and swap the MP175 with MP175L IC to continue your debugging process.
Regards,
Edgar