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Original question:

TPS43061 Inductor DCR Current Sensing

TPS43060: current sense comparator ISNS

user6045872
Prodigy 40 points
Part Number: TPS43060
Other Parts Discussed in Thread: LM5155, TPS40210

it is possible to connect ISEN- pin to gnd, and ISEN+ pin to sense resistor in mosfet source path?

  • 0
    TI__Mastermind 40080 points

    Dear sir,

    The sensed signal from the input line is more clean than from the low side FET. If from the low side FET, there need to add addtional filters.  So suggest you keep the sense resistor in series with the inductors.

    The expert for this part  is on US holiday and they'll reply you after back to the office.

  • 0 in reply to Helen chen
    Prodigy 40 points
    But I have Vin> 200VDC and a classical non synchronous boost.
    I don't know current sense common mode range.
  • 0 in reply to user6045872
    TI__Mastermind 21720 points
    Hello,

    As Helen mentioned it is not recommended to move the current sense signal for load side current sensing.
    It sounds like the design is for a high voltage application and a non-synchronous boost is better suited for these kind of applications. I recommending taking a look at the LM5155.
    Thanks,
    Garrett
  • 0 in reply to Garrett Roecker
    Prodigy 40 points

    I have very wide input voltage range from 15V to 400V and discontinuous conduction mode boost. I need a minimum duty cycle of 1% and i can't do that with frequency higher than 50kHz..  Also i need adaptive soft start with duration of few second.

    Can you recommend some controller for this application?

    With TPS40210 is hard to get adaptive SS, LM5155 is perfect but duty cycle is greater than 1%...

  • 0 in reply to user6045872
    TI__Guru* 78110 points
    What is your output voltage? If you consider a boost, and your input voltage can be 400V, do you mean your output >400V? We just need to understand what exactly you want to do, then we may be able to propose properly.

    Thanks,
    Youhao Xi, Application Engineering
  • 0 in reply to Youhao Xi
    Prodigy 40 points

    Yes, the output voltage in this case is 390VDC. Input is 15 to 360VDC. The output power is 50W. I need an universal industrial input range from 24VDC to 255VAC.

    Thank you!

  • 0 in reply to user6045872
    TI__Guru* 78110 points
    Thank you for the explanation. This requires a large inductor. I just did a quick calculation, if you choose 100kHz switching, and 11uH inductor (Isat>12A), then 15Vin will take 80% duty to produce 390V, and 360Vin takes 3.3% duty. Not sure how do you get 1% duty. The LM5155 can achieve 3% duty (333ns ON time vs its 50ns min ON time).

    Thanks,
    Youhao