TPSM84624: Can I make two modules output common ( Short) and power single load . One module will be ON at a time.

Hi Dilip,

Are both TPSM84624 configured to have the same output voltage? What are the input voltages to each module?

In general I think connecting the outputs together and enabling one module at a time is fine, so long as the set output voltage of one module is not higher than the input voltage of the disabled module. This is probably an unlikely scenario, but, for example, say module #1 is 12Vin to 6Vout and module #2 is 5Vin to 3.3Vout. If module #2 is disabled and module #1 is enabled, then the 6V output of module #1 will cause current to flow back through the HS FET body diode of the disabled module #2 since it will have output voltage higher than its input.

If both modules are set to the same output voltage, it may be more practical and cost effective to just use a power mux or power switches in front of a single TPSM84624 to switch between the different input sources.

Regarding protection features, the TPSM84624 has pre-bias startup feature that is beneficial in this muxing scenario. When one module is disabled and then the second one enabled, the second module will not turn on its LS FET to discharge the residual voltage on the common output node, preventing excessive negative current from flowing in the inductor that would otherwise flow if the module did not have pre-bias startup.

Regards,
Kris

Hi Kris,

    The input to the regulators will be the same voltage and so will the output voltage set on the regulators.

And anyway, as an abundant precaution we will switch off the inputs to both regulators, toggle the enables and then power them up simultaneously.

We are trying to keep component count low due to space, so no power muxes.

regards,

kalpak

Hi Kalpak,

Just to clarify, do you mean toggle the input sources at the same time, or toggle the TPSM84624 enable on at the same time? I understood from the original post that only one TPSM84624 will be enabled at a time.

Can you please help me understand the purpose of having the two modules with same input and output but only using one at a given time?

Regards,
Kris

I am trying to present a simplified picture of both regulators being TPSM84624 .

In reality one of the regulator will be of some other type.

Both will have the same supply but only one will be enabled at one time.

And to reiterate, the enabling will be not on the fly.

Supply will be switched off before the enable is toggled.