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TPS2663: Thermal protection will be triggered during startup

Sagen Lu
Prodigy 60 points
Part Number: TPS2663

TPS26630 input voltage 48V, output current setting 5A, When the power is turned on, thermal protection sometimes occurs.

The load capacitance is about 490uF.  if the capacitance value is reduced, the protection will not be triggered.

adjusting Cdt/dv will also trigger protection.

  • 0
    TI__Guru* 79071 points

    Hi Sagen,

    Thanks for reaching out. I will get back by wednesday EOD on this.

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    TI__Guru* 79071 points

    Hi Sagen,

    Please share a waveform showing VIN,VOUT and input current during startup. 

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 60 points

    Hi. Kunal

    Please reference as below.

    CH1: efuse_output Current, CH3:DC48V_IN, CH4:efuse_output voltage

  • 0 in reply to Sagen Lu
    Prodigy 60 points

    Hi. Kunal

    We have used the TPS26630_33EVM BOARD for this test.

     The EVM board's D2 TVS Diode was removed. The OVP & UVP settings were changed to 60V and 18V.  When no load, the EVM board's output is okay.

    1.  When our circuit (about 490uF) is connected to the output side, the efuse enters thermal protection mode and fails to start up upon powering on, as shown in Fig. 1. & Video.1

    2. Removing capacitor C4 from the EVM board and connecting a large capacitive load also results in power start-up failure. as shown in Fig. 2&  Fig. 3

    (CH1: efuse_output Current, CH3:DC48V_IN, CH4:efuse_output voltage)

    <Fig. 1>

    FIG1

    <Fig. 2>

    Fig 2

    <Fig. 3>

    <Video>

  • 0 in reply to Sagen Lu
    TI__Guru* 79071 points

    Hi Sagen,

    1. How much dvdt cap you have tried with?

    2. In addition to load cap is there some other load that is drawing current?

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 60 points

    Hi. Kunal

    1. How much dvdt cap you have tried with?

     -> Used 22nF & NC on EVM Board Test.

    2. In addition to load cap is there some other load that is drawing current?

     -> no other load.

  • 0 in reply to Sagen Lu
    TI__Guru* 79071 points

    Hi Sagen,

    Have you removed default caps on EVM? Or you are adding 490uF in addition to these caps?

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 60 points

    Hi. Kunal.

    If remove EVM 1000uF and connect our circuit with 490uF, that should be okay.

    Regarding the application of this component, we are encountering unstable phenomena. How can we design it to provide a stable output with an unknown capacitance?

  • 0 in reply to Sagen Lu
    TI__Guru* 79071 points

    Hi Sagen,

    There will be a limit to max cap what device can support charging during startup. How much can be the max cap in your case?

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 60 points

    It is 490uF.  But we still encounter instability situations.

  • 0 in reply to Sagen Lu
    TI__Guru* 79071 points

    Hi Sagen,

    With only 490uF at output coming from your board sometimes you don't see device starting up?

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Prodigy 60 points

    Hi. Kunal.

    With only 490uF at output coming from your board sometimes you don't see device starting up?

    ->Yes

  • 0 in reply to Sagen Lu
    Prodigy 60 points

    Can we discuss this directly using email.?

  • 0 in reply to Sagen Lu
    TI__Guru* 79071 points

    Yes Sagen.

    Regards

    Kunal Goel