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UCC29002: Bode Plot on outer loop for control chip

Part Number: UCC29002

Hi team,

My customer is using UCC29002 in their design and trying to run loop response for this Current Share IC.  They have looked through the application notes which indicate that we have done this, but it looks like it is less clear to the customer on how they ran the data or how to check its loop for stability.

Do we have information on this we measured the loop stability?

Thank you in advance for your support!

Errol

  • Hi Errol,

    all we have already put on-line. The load share loop should be at leas one decade below the power unit loop. The aim is not to allow current share loop to influence the power loop.

    the loop stability you mentioned is about power module or the current share loop?

    usually we just need to test the power module loop and follow the calculator of UCC29002 to design the external circuit

  • Hi David,

    I am awaiting a response from the customer but I am assuming it has to do with the current sharing loop.   I just sent a calendar invite and wanted to know if it is possible to have a call with my customer to explain how we do this.  Would it be possible to have a call in the next day or 2?

    Best regards,

    Errol

  • Hi David,

    I have the following from my customer in regards to the power module/current loop question:

    "How to measure the power module loop is well known to us and there are no questions about that.  And while we can follow the equations in the data sheet for the part, we wanted to follow the calculation up with a direct measurement of the current share loop Bode plot.  I have come up with a method of doing this, but wanted to know if you had a suggested method that avoids problems that might occur.  One potential problem results from realizing that the literature refers to this setup as a Master/Slave relationship.  The Master would not have an active UCC29002 circuit as it tends to put out a higher current.  The Slaves have active UCC29002 circuits causing them to produce the same current as the Master.  Trying to measure the Master would produce nothing as it is not active.  Likewise it is necessary to measure a Slave to confirm the Bode plot characteristics.  I was wondering if there is an easy way to ensure that the circuit I am trying to measure is a Slave and the two circuits are not trading back and forth the Master/Slave relationship?

    So my questions are: 

    1. Am I viewing the situation with this device (particularly the Master/Slave relationship) correctly?

    2. Do you have a suggested circuit setup for measuring the current share loop Bode plot?

    3. Is there is an easy way to ensure that the circuit I am trying to measure is a Slave and the two circuits are not trading back and forth the      Master/Slave relationship?

    4. Do you know of other potential problems making this measurement?

     

    I see Figure 4 in the spec sheet is such a Bode plot (app note slua128 (STDZ001A)), so I assume you did address these items at sometime in the past."

    Thank you so much for your support!

    Errol

  • Hi Errol,

     since we already discussing this case through email and Webex. Let me close the post.