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TPS2662: Recovery from OVP

Takashi Onawa
Genius 13200 points
Part Number: TPS2662

Hi Team,

I have two quick question regarding OVP because there is not enough description in the datasheet about that.

1. What are the conditions for recovering from OVP?
2. Does the dv/dt of Soft start ever change when returning from OVP?

Regards,

Takashi Onawa

  • 0
    TI__Guru** 105361 points

    Hi Takashi,

    The device recovers from OVP if the Vin voltage falls below the set OVP falling threshold. While recovering from OVP, there is no dv/dt mode of operation. The device ramps the vout voltage similar to the case Cdvdt=OPEN. Ramps the Vout at the rate of 23.9V/0.664ms.

    Best Regards, Rakesh

  • 0 in reply to Rakesh
    TI__Genius 13200 points

    Rakesh-san,

    Thanks for your prompt response on this.

    OK, I understand there is no dv/dt mode of operation while recovering from OVP.

    Could you tell me the background why the device behaves as above?
    I need to explain that to close this issue.

    Regards,

    Takashi Onawa

  • 0 in reply to Takashi Onawa
    TI__Guru** 105361 points

    Hi Takashi-san,

    The devices are designed to support quick Vout recovery from transient Vin voltages to serve the load with minimum interruption. If dv/dt mode of operation is needed, the customer can reset the SHDNb pin. 

    Best Regards, Rakesh

  • 0 in reply to Rakesh
    TI__Genius 13200 points

    Hi Rakesh-san,

    Thanks, I understood the background and workaround.

    Sorry, I have one more quick question.

    My customer noticed that a startup delay is different from the estimated value in their own board evaluation. According to UVLO_tON(dly) spec, it should be estimated using equation 1 below  but It was 0.7ms longer than the expected value.

    Can you think of any reason why this value would be significantly different from the calculated value as below?

    UVLO_tON(dly) = 51 + 27.4 x C(dVdT) (Equation 1)
    C(dVdT) = 47nF

    UVLO_tON(dly) = 1.3ms

    On the other hand, They have seen  2ms start up slope at start up timing.

    Regards,

    Takashi Onawa

  • 0 in reply to Takashi Onawa
    TI__Guru** 105361 points

    Hi Takashi-san,

    Can you share the startup waveform (Vin, Vout, dVdT pin voltage) from the customer with C(dVdT) = 47nF

    Best Regards, Rakesh

  • 0 in reply to Rakesh
    TI__Genius 13200 points

    Hi Rakesh-san,

    I just sent the capture to you off line.

    Regards,

    Takashi Onawa

  • 0 in reply to Takashi Onawa
    TI__Guru** 105361 points

    Hi Takashi-san,

    I have received the test waveform. I will follow-up on email.

    Best Regards, Rakesh