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TPS563209: Current Limit under VIN=5V, VOUT=1.2V, L1 = 2.2 µH

Part Number: TPS563209


My customer wants to know the current limit value (Min/Typ/Max) under VIN=5V, VOUT = 1.2V , L1 = 2.2 µH.  According to the datasheet P.5, we can find the following under VIN=12V, VOUT=1.05V.  But there is no Vin=5V, Vout=1.2V data.


So could you please let us know how to calculate Current limit value on his condition?

Thanks and best regards,


    The OCL spec. in datasheet is actually the valley value, so the typical output current limit value can be calculated with: I_limit=4.2+Ip-p/2

    In this case, VIN=5V, VOUT = 1.2V , L1 = 2.2 µH, then Ip_p/2=0.13A, so I_limit= 4.33A.

    You can also use this method to calculate Min/Max value.




  • Jared-san,

    Thank you for your reply, but I am confusing.

    In general, when current limit is detected on Valley Value timing by comparator, current limit is constant and independent of L. On the other hands, Icol is depend of L on the datasheet P.5.

    Could you please let us know where current does comparator observe?   Please advise us.

    Thanks and best regards,


    Your understanding are right, the valley value of current limit is constant, independent of L. 

    For TPS563209, the valley current limit is constant: I_limit_valley=4.2 A. In datasheet Page.5, the L and output voltage information are actually useless or should not be there.   

    And due to the output current is the average of inductor current, so the output current limit: I_limit_ouput= I_limit_valley + Ip-p/2;

    where, Ip-p/2=