TPS22929 Reverse Current Protection

Hi T-kishi,

We missed this thread but are now moving this to the appropriate forum which is under "Load Switches". Please let us know if this question is still open or is no longer needed.

Thanks,
Alex

 Hi T Kishi,

If VIN and ON are both pulled to 0V, then the reverse current protection will be enabled. 

Are VIN and ON pulled down to 0V, or are they left floating?  Also, are VIN and ON connected to each other?

Thanks,

Alek Kaknevicius

Hi Alek

thank you for reply.

State "VIN" and "ON" are not inputted Voltage.So, "VIN" and "ON" will be Floating.

Is there a possibility of reverse flow when it is this state?

Regard 

T Kishi

I have a similar question:

We have a customer who is performing a simulation using the model of the TPS22929.  Vin is floated, but ON is held low.  Vout is set to ~3.0V.

They are seeing (IN SIMULATION) that the output discharge appears to be active, but we don't see VIN being bootstrapped up at all.

Would this be expected performance?  Should the output discharge actually be active when Vin < UVLO?

Thanks, Best, S. Dunbar, AFA Colorado

Hi S. Dunbar,

To test this functionality, I went down into our lab and applied 3V on VOUT with the ON pin pulled down low. When I did this, QOD was not enabled and the VIN voltage was floating at about 55mV.  As you suspect, VIN powers the QOD feature and without a high enough voltage on VIN, the QOD will not be active. Is this behavior only seen in simulations or is the customer also seeing it on their board?

Thanks,

Alek Kaknevicius

So far, this appears to only be in simulation- we're trying to figure out if it's safe to proceed.  We are trying to program an MSP430 downstream from the '22929, and we need to QOD to be inactive or it will overload the MSP430 FET tool power supply.

Perhaps the simulation model wasn't designed to cover this case?

Thanks for looking into this. 

Best, Steve

Hi Steve,

I'll reach out to our modeling team and see how the QOD is implemented in the model.

Thanks,

Alek Kaknevicius

Alek-

Would you have any update on this?  Thanks! -Steve

Hi Steve,

The modeling team confirmed that the QOD function of the model is only dependent on the ON pin voltage. This is different form actual silicon where the ON pin needs to be low and a VIN voltage needs to be present to enable QOD.

Thanks,

Alek Kaknevicius

Thanks for checking into this. Appreciate it. Best, Steve