Support Request for Custom Transformer Design – MPQ18913

DC-DC Power Converters
1

Hi,

I am designing an isolated DC/DC converter for 24V input and 24V output with a maximum output power of 5W. To achieve very low primary-to-secondary interwinding capacitance, I have selected the MPQ18913 controller.

I have purchased the EVQ18913-D-01A evaluation board along with several toroidal ferrite cores to build a custom transformer. The transformer used on the EVK board is well designed; however, it reaches temperatures above 50°C at just 3W load. Therefore, I would like to use a slightly larger core to achieve cooler operation.

To keep the BOM cost as low as possible, I prefer not to use a stock transformer.

I am attempting to replace the EVK board transformer with my own custom-wound transformer along with a suitable resonant capacitor. However, I have not been successful despite multiple attempts using different cores.

Below is the list of cores available with me for testing. I kindly request MPS to suggest a suitable core and the recommended turns for my application.

B64290L0038X087, B64290L0038X830, B64290L0044X830, B64290L0644X830, B64290L0044X027, B64290L0038X035, B64290A0044X087, B64290L0038X037, B64290L0742X087, B64290L0658X087, B64290L0044X049.

Thank you for your support.

Best regards,
Udhay

2

Given the following specifications that you have listed, I would implore you to evaluate the MID6W2424A module that integrates the transformer in the package.

It is capable of 6W with a 24V input where the integrated transformer is 1:1 which would yield you 24Vout with no problem. The level of isolation between the primary and secondary is 3kVRMS and is EN62368-1 Compliant.

This should save on the design, space, and operates between -40°C to +105°C Operating Ambient Temperature (TA) range.

Best,

Krishan