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UCC28051 output current drift

tsutomu ueno
Intellectual 520 points


Hi     everyone.

My customer   used  UCC28051DR.

I  want   check  the  output current drift  this view.

  ＜conditions＞

        ①　MUL-pin　；　0.2V　FIX

　　　②　Vo＿sns　；　2V　FIX

　　　③　Current　sensing-Register　；　Rcs；　1/3Ω

　　　④　output　current　deta　waveform　；　Zerocrosstalk

◆View

　①　Vcs＝0.67×（Comp-2.5）×（MUL+0.075）

　　　Io＝1/2×（Vcs／Rcs）

　　　Engeer　think　output　drift　current　560～840mA　range？

　　　that　using　ucc’neighboor　comp　is　4.5～5.5V　range,  and fix  range MUL , CS,  Vo_sns.

　

　②　Can　you　controls　current　output　method　a　Volume　Resister　to　MUL？

　

　③　comp　drift＝output　drift

　　　Is　it　eases　high　output　capabilly　COMP　　to　 the  supply　capabilly　REF-voltagecomp’s　output　capabilly　include？

 

   from  Ben.

  • 0
    TI__Guru* 86286 points

    The multiplier gain constant (K) is a tested parameter and can be found on page 4 of the data sheet.  This parameter is specified from 0.43 to 0.87 with a typical of 0.65.  With this information the multiplier output voltage could vary +34% to -31% roughly.  However based on the output power the voltage loop will correct for errors in the multiplier and this is generally not an issue in the typical application.

    Regards,

  • 0 in reply to Mike O'
    Intellectual 520 points

    Hi MIke.

    Thank you for reply.    It was very helpful.

    Sorry . Question No3 that I write was not good.

    Once again NO3.

    ③　Comp　drift　has　given　Vout　drift.

    　　in　this　case.

    　　Comp　output　spec　＜　REF-voltage　good　capabilly　output

    　　Can　be　stop　the　Vout’drift　include　the　REF？

     

    Regard.　　　　　from　Ben

    　　　

     

     

  • 0 in reply to tsutomu ueno
    TI__Guru* 86286 points

     

    The comp voltage should be adjusted by the voltage amplifier feedback to control the output voltage.  I am surprised that this is drifting.  How much is the drift and under what test conditions?

    Regards,

  • 0 in reply to Mike O'
    Intellectual 520 points

    Hi   Mike.

    Thank you  for  returns.

    I  check for customer  that   the reply got from Mike.

    If let me consult for my customer 's  relation between comp drift and ref-voltage.

    Regards              from   Ben