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UCC28220: UCC28220 Application Question

GaryC
Expert 3295 points
Part Number: UCC28220
Other Parts Discussed in Thread: LM5032

I’m writing for the following questions.

(1)   I would like to apply UCC28220 in interleaved 2-FET forward converters while Dmax < 0.5 for each channel.

à Can Dmax < 0.5 (e.g. 0.48) be achieved by setting an appropriate resistor value for Pin=8/9?

à How to achieve 70kHz switching frequency for each channel while Dmax=0.48?

(2)   Will there be other TI controller IC specially for 2-FET forward interleave purpose? (OR recommended controller IC)

 

Figure 13 refers to switching frequency while Figure 14 refers to oscillator frequency.

However, when RCHRG=RDISRG=10.2k, frequency from Figure 13 (i.e. ~500kHz) and frequency from Figure 14 (~500kHz) should refer to the same frequency.

Please clarify the following questions.

à Figure 13 refers to switching frequency of each channels or oscillator frequency?

à Figure 14 refers to switching frequency of each channels or oscillator frequency?

BR,

Gary

  • 0
    TI__Mastermind 34465 points

    Hello Gary,

    It is a little bit confusing when you mention "2 Fet forward converter"

    This term is normally used to refer to the following:

    I dont think this is what you mean and your requirement is for a two channel interleaved forward.

    If this is so then the UCC28220 or the LM5032 high voltage dual interleaved current mode controller.

    I think the UCC28220 is a better fit for your application because you can easily set the maximum duty cycle with this part

    You can do this by using Equations 1,2 and 3 in the data sheet

    Your final question refers to Figure 13 and Figure 14.

    If you use the above equation with 10.2 kOhm resistors then the nominal oscillator frequency is 1MHz and the switching frequency is 500kHz.

    This means that Figure 14 is mislabelled. It should refer to the switching frequency variation with temperature

    So at 25C you will expect to get 500kHz switching frequency.

    Thank you for pointing out this error in the data sheet. I will try to get this corrected ASAP.

    Regards

    John