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TPS65982: TPS65982, HV_Gate1 and HV_gate2

Satoshi Yone
Expert 3600 points
Part Number: TPS65982

Hi, Team,

Can TPS65982 enable both HV_Gate1 and HV_Gate2?

The current flows through a NMOS body diode, then it cause power loss and thermal. So a customer wants to avoid it.

Best Regards,

Satoshi Yone

  • 0
    TI__Genius 12990 points
    Hi Yone-san,

    HV_gate1 and HV_gate2 on the external path of the 82 are not controlled by GPIO they are controlled by an internal charge pump which is controlled by internal circuitry. However you can configure both HV_gate1 and HV_gate2 to be both ON or both OFF via the app config tool by selecting the external power path as a source or sink.

    note: with both FETs ON or both OFF there should be no current flowing through the back to back body diodes.
    Can you explain how the current is flowing through NMOS body diode? is this reverse current?

    Thanks
  • 0 in reply to Jeffrey Mueller
    TI__Expert 3600 points
    Hi, Jeff,

    Thank you for your answer for the question. The customer tried selecting the external power path as a source or sink, but one-side NMOS turns on not both.

    The customer tried PP_EXT Configuration(0x28). Is there any other configuration to be both ON or both OFF via the app config tool?

    Best Regards,
    Satoshi Yone
  • 0 in reply to Satoshi Yone
    TI__Genius 12990 points
    Hi Satoshi-San,

    If a reverse current condition exists, the FET with the body diode opposite to the normal current flow will be shut off to prevent current from reaching the other side. This happens when the voltage on the VBUS side opposing current flow is greater then the voltage on the VBUS side going with the flow of current. For example, when used as a source (current flows from PP_EXT to VBUS or left to right) HV_GATE1 will be OFF, with the body diode blocking reverse current (from right to left). The voltage on VBUS sink side is greater than source side. The external back to back NFETs need to be implemented in a common-drain connection or will not work.

    are you using a RSENSE resistor to sense VBUS voltage? (x982 only supports 5 or 10 mOhm RSENSE).
    are you seeing a RCP event in the host GUI?

    Thanks