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UCC3895: pmp9622 , UCC3895 cc-cv charger

Part Number: UCC3895
Other Parts Discussed in Thread: PMP9622

Hi team i got some questions about the pmp9622 

question 1 

is the R35 tied to ground( 0V ) or tied to 5V supply.
as the figure below. 

 


question 2
why is the r28 supplied from 6.3V is there a reason for it? 
Is it possible to supply from a 220-12V flyback converter and regulate the output of the flyback to 6.3V with adj regulator?

  


question 3 

how to achive the cc and cv is a  pwm filtered dc a methot? or dac? 
 and what is the range for it.

question 4  what if ı will limit my current to 40A and output voltage to 28V what must the shunt's resistors value be? 
How to calculate 


thanks in advance!


  • Hello,

    I am reviewing your inquiry and will get back to you shortly.

    Regards,

  • Hello,

    Please see my comments below.

    question 1 

    is the R35 tied to ground( 0V ) or tied to 5V supply.
    as the figure below. 
    >R35 should be tied to 5 V.
     


    question 2
    why is the r28 supplied from 6.3V is there a reason for it? 

    >This should be tied to the output voltage.  Not sure why the designer chose to tie it to the 6.3 V bias supply.


    Is it possible to supply from a 220-12V flyback converter and regulate the output of the flyback to 6.3V with adj regulator?

    >The bias supply flyback was design for an input range102VAC-132VAC Input so 220 V is out of the question.

    >These designs generally have 3 to 1 and 220-12 V input  is 8 to 1.  A 5 to 1 input range is more achievable.  I would reconsider your input range for the bias supply. 

      


    question 3 

    how to achive the cc and cv is a  pwm filtered dc a methot? or dac? 
     and what is the range for it.

    >The approach shown is typically what is used for a CC/CV with external amplifiers.

    >Not sure exactly what your question is, could you clarify for me please?

    question 4  what if ı will limit my current to 40A and output voltage to 28V what must the shunt's resistors value be? 
    How to calculate 

    >I reviewed the schematic and U6B is controlling the voltage across (Vc) those resistors to 100 mV.

    >If you are doing a 40A design R40//R41 = 100mV/40A = 2.5 mOhm 


    thanks in advance!

    I hope this helps and if it resolves your issue, please hit resolve.

    Regards,

  • Thank you for the answers sır ,

    İn question 2 , do you mean the r28 nust tied to the output of the charger ( main converter ) or of the aux supply?

    What i mean is in question 3 i have got a pwm and i will filter this pwm to a DC Signal by achiving a r-c-r-c configuration. Bu changing the duty i can change the dc value. İ just mean can use this methot bu varying the pwm duty to the tp14 and tp11 points 

    Regards!

  • Hello,

    In regards to 2.  The opto is generally tied to the output of the power supply/charger.

    In regards to 3.  If you want to adjust the output voltage and constant current regulation, this can be accomplished by using tp11 and tp14 and disconnecting the dividers off the reference.

    If I understand this correctly, you want to make these adjustments by sending a PWM signal to RC filters for averaging.  Then you use this average voltage to control the CV and CC levels.   Theoretically you should be able to do this.  Could you tell me why you want to go with this approach?

    Regards,

  • Hi Sır mike , thank you for helping my issue.

    Also for question 2 thank you again.But still there is problem in the question 3 i will show you my real schematic in a winrar file. 

    Of course i can tell why i want to go this aproach 

     C2.rar



    1- As you can see by tying the R44/R20 (R22/R48 are not connected) resistors i will work with the V_SET1 and I_SET1 these are my potentiometer output's for change the output voltage and current.
    2- By tying the R22/R48 (R44/R20 are not connected) resistors i will work with the V_SET2 and I_SET2 functions  these are my pwm output's from the uC. 

    the problem is 

    what do you mean with this disconnecting the dividers off the reference   
    the V_FB and I_FB functions are caming from the output voltage and current return do you mean the dividers on the V_FB and I_FB line?


    Regards

  • Hello,

    I am reviewing your inquiry and will get back to you shortly.

    Regards,

  • Hello,

    I do not have the WINRAR application.  So I will not be able to review your schematic.  Could you send it in a PDF?

    Regards,

  • Hello,

    I thought you were going to use an average voltage from the PWM ton control your current and voltage.  

    > If you were going to do this you could use single pole R C filters to average the PWM signals.  

    >I marked up the schematic to clarify what I had meant.

    After reviewing the schematic you sent and it looks like you are trying to adjust the CC and CV with V SET2 and ISET2 inputs.

    However, why do you you need so many low pass filters off of Q1 and Q2? 

    Regards,

  • thank you for you response sir ı have fixed the problem!


  • Hello,

    Thankyou for letting me know.  I was glad that I could help.

    Mike