UCC28951-Q1: UCC28951-Q1, UCC28950-Q1, UCC28951, UCC28950

Hello,

Your inquiry has been received and is under review.

Regards,

Hello,

I am wondering if your transformer turns ratio is off.  Could you double check it vs what Webex has suggested?

You might want to check the design with the application note and excel design tool.

The following link will bring you to the application note that goes through the step by step design process using the UCC28951.  You can find a link to the excel design tool inside the application note. 

https://www.ti.com/lit/pdf/slua560

Regards,

Dear Mike O,

Thank you for your quick response, but could you please guide me on how to enable the transformer turn ratio if it is off

Hello,

I had a typo.  I meant Webench not Webex.

The Webench design should have given you a transformer turns ratio based on your design requirements.

You  need to check this turns ratio vs what you put in your tina model.

Regards,

Hi Mike, I'll update all the details, cross-verify everything, and then get back to you with the result.

Hello,

Thanks for letting me know.

Regards,

Hi Mike, good evening. I’ve rechecked everything on my end and made the necessary changes according to the calculations, but it still isn’t working as expected. Please have a look at the TINA simulation file.16V to 48V converter.tsc

Hello,

Your inquiry is under review and I will get back to you shortly.

Regards,

Hello,

Could you share your excel file?

Regards,

Hello Mike, please find the compressed file which contains the Tina file design and the Excel sheet design calculations.16V to 48V converter.zip

Hello,

Thanks for sending the file and I will review it when I have a chance.

Regards,

Hello,

I am still working on this and will try to give you an answer today.

Regards,

Hello Mike, sure! I am also eagerly awaiting the working circuit for the 48V output.

Dear Sir,

I have made all the changes as per the MATCAD file received from TI, which is attached in the zip file. I have also made the required changes and checked each resistor value, entering them as per the calculations. Additionally, I have attached a screenshot of the waveform obtained after the transient response.

However, I am still not obtaining the 48V output with 30A current using a 1.6-ohm load. Please have a look at it.Design for the 48VDC.zip

Hello,

Your inquiry has been received and is under review.

Regards,

48V output Correction.zip

Dear Sir,

The output capacitor’s maximum operating voltage was 12V, which prevented my output voltage from exceeding 12V. After changing the output capacitor voltage to 100V, it started operating correctly. However, I have set my Error Amplifier non-inverting pin (EA+) to 2.5V so that when my output voltage reaches 48V, the voltage at the inverting pin (EA-) should not exceed 2.5V. Unfortunately, it is going up to 4V. Could you please guide me on why my output is exceeding 48V? I have attached a zip file for your reference, which contains the TINA file and screenshots of the output waveform for input voltages of 16V and 90V. In the waveform, VF1 is the voltage at the (EA-) pin, and the current is rising above 30A

Hello,

Your inquiry has been received and is under review.

Regards,

Hello,

I looked at your simulation file and your feedback capacitors seem to small.  You might want to check the compensation.

I also see the compensation capacitors (C3, C4) have an initial voltage across them.  This may be causing your design to over shoot. 

When I look at your simulation the output voltage is high and is decaying.   I would try resetting the vales to zero volts initially to see if the simulation improves.

Regards,