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2 Phase operation in LTC7840 not working

I am designing a SEPIC/ BOOST Converter with LTC7840. To keep the input current waveform form battery steady i am trying to use 2 phase operation feature of LTC7840, unfortunately it is not working as expected. Ideally the two channels should be with 180Degree out of phase with each other with same duty cycle when circuit component son both channels are same, i.e. circuit of channel 2 is copy of circuit of channel 1 and PCB layout is also symmetric. I am trying to get the output of 60V and expected power output id 150W. But the system becomes unstable for power more than 15W and moves into DCM. Besides this though the duty cycle of both channels to be same but, in my testing it is found that channel turns off as soon as Channel 1 turns off hence a very small duty cycle as compared to channel 1.

Also the explanation of its Hiccup mode mentioned in the datasheet is not  clear to me, Could you please provide nay document on the Hiccup mode ?

Parents Reply
  • Hi Akshay,

    Sorry for late reply. Can you share clear PDF schematic that we can review? If you are doing parallel outputs (page 38 schematic), you may be encountering output current imbalance sharing. Another challenge is the power level. Please specify too your input and output voltage rating. 150W is not an easy task.

    Several sections in datasheet discuss the hiccup mode. It is a way during over-current protection for the IC to try to see if fault is still there or not, a sort of re-try mechanism.

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