LTC3787polyphase application


I would like to use LTC3787 for polyphase application boosting 5 batteries (each 14.7V) to 26V.

My question is whether the single LTC3787 (it has two phases) can receive 2 different power sources (batteries in my case) or the input should be the same?

The second (complimentary) question: is it possible to connect LTC3787 ICs in parallel without any limit?

The third (bonus) question: the evaluation board for LTC3787 (P/N DC2001A) uses four phased design. Is it possible to separate inputs (cutting the board) ans achieve one output -4 inputs design.

It is probably possible to cut input trace, but may be there are some other shortcomings on the way?

Thanks in advance!

  • Hi, 

    The typical applications shown in the datasheet of LTC3787 are only are only for a single power source. Two power source configuration is not mentioned in the datasheet. This configuration may work in an actual circuit, but problems will probably occur in the compensation and control of the two converter. The two boost converter of LTC3787 are controlled only buy one error amplifier compensator. Thus, If you are going to use two different power source, then they must be almost identical with the same performance and behavior at an instant of time, and voltage level. This way, the controller will see it as a single power source. This already answers your third question.

    As for your second question, it is mentioned in page 20 of the datasheet that "a total of 12 phases can be cascaded to run simultaneously out-of-phase with respect to each other" to achieve a higher output current.