TPS54618: quick questions around remote sensing for this device (and the TPS62160)

Michael T Schneider

Part Number: TPS54618
Other Parts Discussed in Thread: TPS62160, TPS62147, TPS62135

One of my customers is looking for some confirmation on the following:

Regarding implementing the approach laid out in "Remote Sensing for Power Supplies" (slyt467), to account for IR losses in the power-distribution-network from the SMPS to the SoC load, can we confirm if this approach is supported with the TPS54618QRTERQ1 and TPS62160QDSGTQ1?

If yes:

TPS54618QRTERQ1 has a VSENSE input from the resistor divider… thus the top resistor would be hooked to the load location and feed-back trace carefully guarded from noise with a cap at the VSENSE pin6 input. Right?
Any other guidance specific to this converter?

and...

TPS62160QDSGTQ1 has both a FB and VOS pin. Which would go to the load?
VOS is listed as voltage sense and connection for control loop circuitry
Looking for confirmation if one or both of these would be tapped off at the load

over 7 years ago

0 JohnTucker over 7 years ago

TI__Guru**** 191445 points

How far away are you remote sensing the load?

0 Michael T Schneider over 7 years ago in reply to JohnTucker

TI__Expert 3790 points

John,

The remote sense lines are all on the same PCB, in each case would be <2 inches… and probably closer to 1 inch.

0 JohnTucker over 7 years ago in reply to Michael T Schneider

TI__Guru**** 191445 points

Macael,

In that case no problem for TPS54618. On many EVMs I use the output connector as the point of regulation, typically around 1.5 inches away from the IC. You may not even need that bypass capacitor mentioned in the app note. You would need to be careful about the value if you use it. It will act like a feed forward capacitor and place a zero/pole pair in the loop. the 1 uF used would place that pair at a low frequency. I would place the FB resistor divider close to the FB pin though.

0 Michael T Schneider over 7 years ago in reply to JohnTucker

TI__Expert 3790 points

Thanks John, appreciate the help. I just noticed that the TPS62160 falls under a different product line I will look to them for confirmation.

Best Regards.

0 Chris Glaser over 7 years ago

TI__Guru**** 150710 points

For TPS62160, please connect VOS near the IC at the output cap and route the top FB resistor trace to the load.

As well, I recommend the new, much more accurate (1% vs. 3%) TPS62147/8. These are 2A versions of the TPS62135/6. If you are going through the effort to use remote sense to overcome some small IR drop, a more accurate device would be better.

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TPS54618: quick questions around remote sensing for this device (and the TPS62160)