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About internal feedback resistance value of TPS62172

Satoshi
Guru 19645 points
Other Parts Discussed in Thread: TPS62172

Please let me know about internal resistance value and accuracy of TPS62172.

【Background】

Customer evaluating two TPS62172 devices, but input current (= efficiency) are different.

（12Vin⇒3.3Vout/44mA: Difference of Input current are 1mA, = 4% efficiency）

Measurement environment is the same.

Test point and test method are correct.

⇒I think that cause is depend on internal feedback resistance.

Best regards,

Satoshi

  • 0
    TI__Guru**** 150650 points
    Can you confirm that you have 2 circuits, each uses the same components, and the efficiency is 4% different at the same operating point?

    You could swap the ICs and see if the efficiency is the same with the IC or the PCB. The external components might be varying to create this difference.

    4% difference is likely normal in PFM mode. In any case, the few uA of current drawn by the FB divider is not the cause of the efficiency difference.

    Can you post the raw data of the measured efficiency? Did you add a large input cap per this app note: www.ti.com/.../slva236.pdf