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TPS65145 - in case of rectifier diode broken

Hirotaka Matsumoto
Guru 27585 points
Other Parts Discussed in Thread: TPS65145

Hi all

Would you mind if we ask TPS65145?
Please refer to the attachment file.
7701.20160705_TPS65145PWP_Reference.pdf

In this circuit, there is the rectifier diode(D1).
We guess that the broken rectifier diode  has two patterns. - Open and short
If the diode is broken, we guess that TPS65145 operates the followings;

Open : SW voltage rise up.(Due to open of the rectifier diode(D1), FB pin can't detect the voltage.)
            According to OCP protection, TPS65145 shuts down. 

Short(low impedance) : We can't imagine, however Vout can't get correct(normal) voltage.(Because of Vout > SW,  the output current may flow to SW pins.)

If our assumption is not correct, could you give us some comment.

Kind regards,

Hirotaka Matsumoto

  • 0
    Guru 27585 points

    Hi team

    We only need some suggestion.

    Kind regards,

    Hirotaka Matsumoto 

  • 0 in reply to Hirotaka Matsumoto
    TI__Expert 8010 points
    Hello Hirotaka Matsumoto,

    In case of a short-condition of the rectifier diode during normal operation the converter will shutdown.
    This will happen as the output capacitor will discharge into the switch, the output voltage will decrease and then the UVP
    will kick in and turn off the device. This will be a latched condition and in order to power up the device again it will require to cycle the input voltage. It will unlikely cause destructive behavior.

    The condition of an open of the rectifier diode is more critical, as there will be no current path for the inductor to continue flowing. At some stage the internal PMOS (in parallel to the rectifier diode) will break through and result in malfunctioning or rather the device will get damaged.

    Best Regards,
    Ilona
  • 0 in reply to Ilona
    Guru 27585 points

    Ilona san

    Thank you for your very kind reply!
    We got it!

    Kind regards,

    Hirotaka Matsumoto