MP023GS-Z Design Performance

AC-DC Power Converters
1

Good day,

we have 12VDC/1A AC-DC adapter design that is based on MP023 (attached schematic). The design was created using EV023-S-00A reference design. We just completed the Input Characteristics Test which shows quite a low PF level. I’m wondering if we have any simple solution that can help us to increase it. Do our test results look normal in general?

Thank you in advance.

Merged_document
Merged_document1920×7174 551 KB

2

Hey Pulse Prototyping, happy to see you in the forums today.

Looking at your tests results and high yield of current harmonics which is certainly indicative of a low power factor. I am sure you already thought about power factor correcting methods such as the following:

  • Installing capacitors in parallel with any inductive loads such that they may counteract the lagging reactive power from any inductive load sources such as the output of your transformer. The EV023-S-00A has a bit more capacitors. However, this would only really try and match the phase between your voltage and current when your root cause is at the input rectification stage.
  • Installing a PFC controller at the input side rectifier that will help correct your input correct waveform.
  • We have all in one solution like the MPX2001 off the top of my head that would satisfy your requirements and give you a fuller solution. This option would be viable if your product volume isn’t too high.

For the latter two options, I can help you find a more tailored solution depending on your needs.

Hope this helped,

Best,
Krishan

3

Given the schematic, shows no PF correction circuity, your results are to be expected. Why did you think the PF would be high? What requirement are you attempting to meet? I thought under 30W there was no PF requirement, but that may have changed. At 12W the standard solution is usually a boundary mode boost converter taking the incoming AC to 380VDC or so ( for a universal input). Everybody makes such a chip even MPS 44018 for example.