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UCC29002: UCC29002

ghasem aghdam
Intellectual 455 points
Part Number: UCC29002

Hi there,

I would like to parallel two isolated DC/DC module with 53 V input voltage, 28 V output voltage, 25 A output current capability by using UCC29002.

Besides remote sense pins (+Sense and -Sense), the products have an output voltage adjust pin (Vadj). This pin can be used to adjust the output voltage above or below output voltage initial setting by using an external resistor.

To increase the voltage the resistor should be connected between the Vadj pin and +Sense pin and to decrease the output voltage, the resistor should be connected between the Vadj pin and –Sense pin.

I'm just wondering how I should connect ADJ pin of the UCC29002 (pin 5)? Should I connect it to Vadj pin of the module?

Thank you very much in advance!

BR,

Ghasem

  • 0
    TI__Mastermind 34465 points

    Hello Ghasem,

    If I understand you correctly, your power module has these pinouts:

    If this is correct, you will not need to use the Vadj input.

    You can connect the UCC29002 as shown in Figure 5 of the data sheet.

    Because your output voltage is greater than the VDD range of the UCC29002 you will need to use the RBIAS1 ,RBIAS2 resistors and the NPN transistor.

    Hope this helps

    Regards

    John

  • 0 in reply to John Griffin1
    Intellectual 455 points
    Hi John,

    Many thanks for your reply.

    Yes, you are totally correct. My modules have the same pin-out as you drew.

    The Modules have 28 V initial output voltage (if Vadj pin is left open) and output adjust range is 14-35 V. To increase the voltage the resistor should be connected between the Vadj pin and +Sense pin and to decrease the output voltage, the resistor should be connected between the Vadj pin and –Sense pin.

    Just for clarification: Do you mean I have to skip ADJ pin of the UCC29002 (pin 5) or Vadj pin of the module? Of course if I skip ADJ pin of the UCC29002 (pin 5), I must limit voltage on that pin by using NPN transistor.

    BR,
    Ghasem
  • 0 in reply to ghasem aghdam
    TI__Mastermind 34465 points
    Hi Ghasem,
    Yes you are correct.
    Do not use the ADJ pin on your modules.
    Regards
    John
  • 0 in reply to John Griffin1
    Intellectual 455 points
    Hi John,

    Thank you very much for the confirmation.

    As said before, the Modules have 28 V initial output voltage (if Vadj pin is left open) and output adjust range is 14-35 V.

    If I skip the ADJ pin on my modules, what output voltage I should expect? 28 V (initial output voltage if Vadj pin is left open)?

    Should I use ADJ pin on my modules If I wish to run the modules in parallel at 25 V output?

    BR,
    Ghasem
  • 0 in reply to ghasem aghdam
    TI__Mastermind 34465 points
    Hi Ghashem,
    The UCC29002 is a current sharing controller and it does this by making small changes to the output voltage.
    It was not intended for use as a variable output voltage controller.
    If you want to vary the output voltage over this wide range then the UCC29002 is not a suitable device.

    Regards
    John
  • 0 in reply to John Griffin1
    TI__Mastermind 34465 points

    Hi Ghashem,

    I am going to close this post since it has been over two weeks without a response.

    Please open a new post if you have further queries.

    Regards

    John