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TPS563207EVM: TPS563207EVM OTP

Kiki Chang
Prodigy 10 points
Part Number: TPS563207EVM
Other Parts Discussed in Thread: TPS563207

We set up the test environment for TPS563207. Initially, the output current was set to 3.5A, which is higher than the datasheet's maximum value of 3A,but the current limit is 4A. However, it immediately triggered  and hiccup ,.I would like to know the behaiver of OTP.

(CH2: Vin/CH3: Iout/CH4: Vout)

To confirm the behavior of OTP causing Hiccup,I also do some tests as below. 

(CH2: Vin/CH3: Iout/CH4: Vout)

1.Heating by Hot air gun.

The frequency of V-out rising and falling is faster, approximately 40ms voltage drop compared to the original 448ms, which is 10 times shorter. The retry time has also increased from 22ms to 40ms. Why isn't V-out pulled directly low after OTP? Shouldn't the voltage be dangerous even with OTP?

2.Cooling by FAN.

Why does the retry time still remain at 22ms? The fan helps in faster cooling, so shouldn't it be shortened?

If 22ms is an internal natural cooling mechanism of the IC, is it possible for the temperature inside the IC package to decrease by 37℃ from 172℃ within such a short time?

  • 0
    TI__Expert 8100 points

    Hi Kiki,

    I have received email from your contacted FAE. Will have communications via email

    BRs

    Zixu

  • 0 in reply to Zixu Wang
    Prodigy 10 points

    Hi Zixu,

    I have already replied in the email and waited for a week, but I haven't received a response.

    I hope to receive your reply sooner.

    Here are the additional testing sections you previously mentioned.

    Testing conditions:

    Vin=12V,V-out=5V,I-out=3.5A

    The testing efficiency is approximately 81.98%.

    Real Vin

    Real lin

    Real Vout

    Real lout

    Real Pin

    Real Pout

    Real EFF

    12.11

    1.73

    4.907

    3.5

    20.95

    17.17

    81.98%

     

     Continuously draw a current of 3.5A using an electronic load machine.

    After approximately 6 minutes, I observed a Tc temperature of 141.9℃ on the oscilloscope's Hiccup waveform using an infrared thermometer.

     the internal temperature of the IC at this moment using the formula.

    PD=3.5*5/0.8198-3.5*5=3.84℃/W

    Tsen=3.84*0.9+141.9= 145.356℃  < 172℃ (thermal shutdown limit of datasheet)

    The waveform behavior as follows.

    (CH1:SW/CH2:IL/CH3:Iout/CH4:Vout)

    CH2:Inductor Valley current=1.92A < 3.3A(min)

    CH4:Output voltage threshold >65%

    None of the above conditions have reached the OCP criteria, so the observed behavior of Hiccup at this time is unlikely caused by OCP. Additionally, the temperature has not reached the OTP thermal shutdown threshold of 172℃.

    So we would like to discuss: Is this Hiccup behavior triggered by OTP or OCP ?

  • 0 in reply to Kiki Chang
    TI__Expert 8100 points

    Hi Kiki,

    Based on latest condition, I will analyze tested data and communicate via email.

    BRs

    Zixu