TPSM846C23: Switch from parallel operation to normal operation

Sagar Kumar

Part Number: TPSM846C23

Tool/software:

I am using TPSM846C23MOLR in parallel operation but now want to remove slave part to save the cost. Please let me know do I need to remove slave part only or need to remove o/p caps and other circutry of slave part as well to switch from parallel to normal operation?

Thanks

Sagar

6 months ago

0 Eileen Hernandez Hernandez 6 months ago

TI__Expert 5698 points

Hi Sagar,

Yes you will need to remove anything related to the secondary phase. If you keep secondary COUT, then that would be accounted in the primary single phase. If you don't want to remove secondary COUT, you can also try cutting trace to VOUT:

Same principle applies to CVIN.

Regards,

Eileen

0 Sagar Kumar 6 months ago in reply to Eileen Hernandez Hernandez

Prodigy 50 points

Hi Eileen,

Thanks for your reply so we need to remove CIN caps of slave as well

Thanks

Sagar

0 Eileen Hernandez Hernandez 6 months ago in reply to Sagar Kumar

TI__Expert 5698 points

Sagar,

If you're ok with the primary device having twice the input caps in primary then no, but it's best to just have components for single device.

Regards,

Eileen

0 Sagar Kumar 6 months ago in reply to Eileen Hernandez Hernandez

Prodigy 50 points

Hi Eileen,

Will twice input caps degrade the primary performance in any way like overshoot etc?

Thanks

Sagar

0 Eileen Hernandez Hernandez 6 months ago in reply to Sagar Kumar

TI__Expert 5698 points

Sagar,

There's pros and cons to keeping them, but overall you should be ok if kept. Having double the capacitance at single phase can improve VOUT stability as more CIN will reduce ripple and noise that could come through VIN, it may add a small delay at startup however that is not an issue, VIN doesn't directly affect control loop.

The real concern would be increased inrush current however you would need a significant amount of CIN to cause that, most likely you were using a normal amount already and that won't be an issue.

Regards,

Eileen

0 Sagar Kumar 6 months ago in reply to Eileen Hernandez Hernandez

Prodigy 50 points

Hi Ti Team,

I am using the external clk on sync pin in parallel operation see below image-

If I remove this circuitry along with slave IC what will be the consequence? Whether standalone power module works?

Thanks

Sagar

+1 Eileen Hernandez Hernandez 6 months ago in reply to Sagar Kumar

TI__Expert 5698 points

Hi Kumar,

You can remove this in a single phase setting and should have no impact. This is typically more for parallel operation, this is just a Frequency synchronization pin. As you can see in DS, the typical application schematic has it disconnected on single phase:

Regards,

Eileen

0 Sagar Kumar 5 months ago in reply to Eileen Hernandez Hernandez

Prodigy 50 points

Hi Ti Team,

Attaching the schematic of parallel operation, Please let me know how can i disable the slave without physically remove it from the board.

Thanks

Sagar

0 Eileen Hernandez Hernandez 5 months ago in reply to Sagar Kumar

TI__Expert 5698 points

Hi Sagar,

To disable slave device you can try:

- Depopulate R37 to disconnect ISHARE

- Need to disconnect VSHARE, there is no resistor to disconnect so you will need to cut trace.

- You will need to depopulate COUT+CIN unless you are ok with twice the capacitance for one phase.

- Depopulate R482 to disconnect SYNC

- Disconnect anything else that I may have missed that connect between both phases.

Regards,

Eileen

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TPSM846C23: Switch from parallel operation to normal operation