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TPA3121D2

toshi-e2e
Genius 4850 points
Other Parts Discussed in Thread: TPA3121D2, TPA3121D2EVM

Hi all,

My customer has some questions about TAP3121D2 as follows;

1. When PVCC=10V , RL=8-ohm and f=1kHz,
      
        1-1. What is the maximum power?
     
        1-2  About the PVCC Power-Supply Decoupling capacitor, 470uF
                 what is the maximum ripple current?   

        1-3   How to calculate the life of the 470uF capacitor? 

2.  Even PVCC is lowered to 8V, it seems that TPA3121D2 works normally without shutdown.
       When it became PVCC = 8V,  what happens to the operation of the output?

Regards,
Toshi
        

  • 0
    TI__Expert 5000 points

    Hi, Toshi

                For question 1.1, you can find the answer in datasheet Figure14 and Figure 23.

                For question 1,2 , I think this depend on their system, if you use a  inductor with larger value as the output filter, the ripple current should also be smaller. Also depend how much output power they will use. I strong suggest them to test it with TPA3121EVM by themselves.

                For question 1.3, this is decided by the vendor of capacitor, if you decided the current/voltage/temperature. Customer can ask their capacitor vendor for answer. For example:  

           I am not sure if customer use PVCC=8V (which datasheet can't support), maybe cause OC fault /PWM frequency change/THD+N deterioration ......

  • 0 in reply to Peter Cao
    TI__Expert 5000 points
    Hi, Toshi
    For the question 1-2, I will check it with TPA3121D2EVM, but need your check with customer-----how much output power of the ClassD they need?
  • 0 in reply to Peter Cao
    Genius 4850 points

    Hi Peter-san,
    thanks for your support.

    I will check the output power which they need.

    Thanks and regards,
    Toshi

  • 0 in reply to toshi-e2e
    Genius 4850 points
    Hi Peter-san,
    their target output power is 1.5W with PVCC=10V.

    Anyway,
    They have an additional question about OC fault.
    When OC fault occurred, how does TPA3121D2 operate?

    Regards,
    Toshi
  • 0 in reply to toshi-e2e
    TI__Expert 5000 points

    Hi, Toshi-san

           I will update the ripple current test result to you next Monday. 

           For Over current protection behavior: when the current increase to OCP point, the output stage will come into Hiz.

    After the Over current event, the driver will keep in Hiz about 220ms, then will switching again. This behavior will continue until the short been move away.

  • 0 in reply to Peter Cao
    TI__Expert 5000 points

    Hi, toshi-san

           TPA3121D2EVM's 470uF capacitor's UHE1V471MH06 is UHE1V471MHD6 , you can find datasheet in below link:

    http://products.nichicon.co.jp/en/part_search/part_list.cfm   

          Rated ripple current is 1.45A, Endurance time is 10000hours