LM5122: Multi-phase synchronous BOOST control chip

Jojo Wang

Part Number: LM5122

Hi,

I want to use LM5122 to build a 4-phase BOOST circuit in order to reduce the current ripple.Which of the following waveforms should the SYNCIN / RT signal give?

1、

2、

For the purpose of small current ripple, the second feeling is better. But I don't know if it is feasible for the LM5122.

And for the LM5122, how does the multi-phase synchronous BOOST achieve current averaging.

over 5 years ago

0 Youhao Xi over 5 years ago

TI__Guru* 78170 points

Hi Jojo,

Thank you for considering the LM5122. Please refer to the datasheet figure 34 for 4 phase interleave operation. If you really want to use 4 clock signals, both of yoru approaches works, if your 1st option has proper phase angle for each signal.

Thanks,

Youhao Xi, Applications Engineering

0 Jojo Wang over 5 years ago in reply to Youhao Xi

Prodigy 150 points

Hi Youhao,

Thank you for answering my questions.And,for multi-phase BOOST, how does the LM5122 distribute the current of each phase?

Thanks,

Jojo Wang

0 Jojo Wang over 5 years ago in reply to Youhao Xi

Prodigy 150 points

Hi Youhao,

Sorry, I didn't express clearly in the above response.If the second 4 clock signal method is used, Would it cause too much current deviation for each phase?

Thanks,

Jojo Wang

0 Youhao Xi over 5 years ago in reply to Jojo Wang

TI__Guru* 78170 points

Hi Jojo,

No, the clock would not cause additional current deviation. As I mentioned earlier, you don't need four clocks. You just need two out of phase clock signals per figure 34 of the datasheet.

Thanks,

Youhao

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LM5122: Multi-phase synchronous BOOST control chip