• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 135 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM76003: Will the Vin has voltage because of Vout?

Dong Ba
Intellectual 815 points
Part Number: LM76003

LM76003,When VIn is not connected, but there are other supply connected to Vout. That is, Vout has voltage but Vin is not connected.

Will the Vin has voltage because of Vout or any power consumption because of the Vout?

  • 0
    TI__Genius 10655 points

    Hello Ba Dong,

    This device has a feature known as pre-bias start up meaning that the device can begin its normal soft start sequence even when there is a voltage present on VOUT. In order for this to happen however, the internal circuitry of the device needs to be powered and the device needs to be enabled meaning that the EN pin would need to be tied to an external source, and BIAS would need to be tied to VOUT as long as VOUT is between 3.3V-18V as per the datasheet. I'm not sure if this will still work if VOUT>VIN.

    When there is no voltage present at VIN but there is a voltage present at VOUT, then there exists a current path through the High Side MOSFET (HSFET) body diode to the input voltage source. This can cause damage to the HIGH Side MOSFET if current does indeed flow through this path. A diode or some other protection must be used in order to protect the input power source from this reverse current flow.

    Testing this on an EVM would be the best way to ensure that this device can indeed operate under the desired conditions. The EVM can be obtained here:

    https://www.ti.com/tool/LM76003EVM-500K

    Does this answer your question?

    Regards,

    Harrison Overturf