• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 857 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

UCC39002: UCC39002 high voltage high side current sense

UCC39002: UCC39002

user6002119
Prodigy 20 points
Part Number: UCC39002
Other Parts Discussed in Thread: UCC29002

Hello Experts,

I have a question as attached file. Would you answer it, please?The main topology can work normally with
load, but the parallel current sharing is very unstable. Is there any problem with the circuit of
accessories? Is there any effect on current sharing if the primary and secondary sides are not isolated?
In addition, whether it can provide some low side high voltage application circuit reference

Best RegardsUCC39002.pdf

  • 0
    TI__Genius 13660 points

    Hello,

    UCC39002 can be used for both isolated and non-isolated application.

    But in your application, the output voltage is 150 V greater than 15V. The maximum VDD of the UCC39002 is 15 V. For higher-voltage applications greater than 15V, use the application solution as recommended in Figure 5 of the datasheet. A Zener clamp on the VDD pin is provided internally so the device can be powered from higher voltage rails using a minimum number of external components. The CSA inputs must be adjusted so as to not exceed their absolute maximum voltage ratings.

    Low side current sense:

    Or you also can use high side current sense:

    Regards,

    Teng

  • 0 in reply to Teng Feng
    Prodigy 20 points

    Hello Experts,

    Will the length of the connecting wire output to the load end affect the current sharing effect? Whether the output of the two parallel modules should be connected together nearby or not, because it is found that the length of the output line has a great influence on the current sharing effect, especially the negative end of the output. At the moment of switching from no-load to full load, there is a serious uneven current. How to solve it? As shown in the attachment

  • 0 in reply to user6002119
    TI__Genius 13660 points

    Hello,

    Yes, the length of the output line will affect the current sharing balance.  Because Voltage drops on Load Share line is dominated by the sum of the current sensing (RCS) and external PCB resistances (REXT). Please ensure RCS and REXT are identical. If RCS and REXT are identical then the current sharing will be affected only by differences in the UCC29002 current amplifier gain (AM and AS). Please ensure that all the current amplifier have the equal gain, and each current amplifier is self-balance. Since UCC29002 load share is a low bandwidth controller,  a slow response at load transition is unavoidable. A high bandwidth will to instability of the system.

    Regards,

    Teng