This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC28910: ultra wide input buck converter, output 5V, 1A.

Part Number: UCC28910
Other Parts Discussed in Thread: UCC28911

Hello,

I don't have much experience in building power supplies but I am building a digital input card and I came to this power supply problem.

I want to build ultra input range power supply based on buck converter with the following specifications:

Input voltage: 12 to 160 VDC or more.

Output: 3.3V or 5V or 12VDC.

Output current: 500 mA or better 1A.

 

I searched on TI web site, and I found some application notes using "UCC28910" to build buck converter power supplies with inputs 85 to 265 V and with limited output current of only 100 mA.  Although I could not find the maximum current supported by the chip but drain current peak is 700 mA so the chip must support much more.

https://www.ti.com/lit/an/snva750/snva750.pdf?ts=1687606794636

I think the application note limited the input current to 100 mA due to the heat dissipation consideration but if we short the I peak pin to ground then how much the output current could reach?

Also, I understand that non-isolated buck converter support wide input range as long as the input voltage is higher enough than the output voltage. Accordingly, the input of the circuit in the application note can accept 24V if we changed the output voltage settings to 12V for example. Is this correct?

How the above modifications may affect the circuit noise and EMI?

So, please guide us which chip is better to use for our design. And where we can find useful application notes with similar requirements.

Thanks in advance.

  • Hi,

    There are several factors which are going to limit operation for the above specifications using UCC28911.

    The UCC28910 , due to the limitation of the Rds(on) of the internal FET, the load current and power capability will be limited when Vin is under 100 V. Additionally, those devices are intended for flyback applications, so the internal max duty cycle limit of 42% for the free-wheel diode will inherently limit the average load current to160mA especially running it in buck mode. Therefore we would not recommend using UCC28910 for this buck type apllication. Instead, you could use a Flyback design with external FET, configured for a non-isolated output, this would be able to handle higher power and current. You need to use general purpose PWM controllers like UCC2813, UCC28C4x devices for this purpose.

    https://www.ti.com/lit/df/tidrlx3/tidrlx3.pdf?ts=1687769108288&ref_url=https%253A%252F%252Fwww.ti.com%252Freference-designs%252Findex.html

    Please reopen this thread with new part number so that it will be assigned to the correct product expert to help you.

    Thank you

  • Hi Harish,

    Thanks for your reply and for the explanations. Yes, I understood that there is no solution available in the market with built-in FET to cover this wide voltage range and 1A load. The input in my application is DC only (12 - 135 VDC).

    Anyway, I need to study more before selecting new IC.

    Thanks again.

  • Hi Mohammad,

    Please let us know if you require any further help by opening a new post on the part which works for you. I will close this post for now.

    Thank you

    Regards,

    Harish