TPS40210: how to get 2A current on the output

Bart

Part Number: TPS40210

Team,

our customer has TPS40210 in the design. The converter is used for Vin 10-20V, Vout 24V and the planned Iout max is 2A.

Unfortunately we can only establish 1.3A on the output. One of the remarks is that the used transistor is heating up significantly (as if it wasn't properly controlled by 8V voltage).

We can share the altium project files offline for faster troubleshooting.

Thanks for your help.

Kind regards,
Bartosz

over 7 years ago

0 Youhao Xi over 7 years ago

TI__Guru* 78190 points

Please email the altium file to my TI mailbox. Also, please share the waveforms of the following: switch node, FB, and COMP at both 1.3A and 2A load, under a given Vin.

0 Konrad Tomtas11 over 7 years ago in reply to Youhao Xi

Prodigy 30 points

This DCDC converter cant start under load 16.5Ohm, unloaded im getting 24V outputs

0 Youhao Xi over 7 years ago in reply to Konrad Tomtas11

TI__Guru* 78190 points

I reviewed the layout and the IC underpad seems not connected to GND but left floating. The IC underpad should be tied to GND.

In addition, the switching current takes a zigzag path, which may result switching noise attaching the ISNS pin and trip the over current protection. The parts of the following current loop should be placed closely with minimal spatial area to prevent noise issue:
RS-->T2-->D5--> C14-->GND-->RS.

You should also consider to add some ceramic capacitor on the output rail for better filtering.

0 Konrad Tomtas11 over 7 years ago in reply to Youhao Xi

Prodigy 30 points

Hi there is course of voltage on current capacitor :

problem still exist, we dont know how to solve it, i woudl like ask 4 your help

Konrad

0 Garrett Roecker over 7 years ago in reply to Konrad Tomtas11

TI__Mastermind 21720 points

Hi Konrad,

Please make sure that you are probing the output voltage with a short ground lead, as described in this blog. I notice that the voltage scale in both waveforms is relatively small. If probed with a large ground loop on the scope probe high frequency noise can be coupled into the measurement that might not be real.

Thanks,

Garrett

0 Konrad Tomtas11 over 7 years ago in reply to Garrett Roecker

Prodigy 30 points

short loop mesurment on gnd of TPS40210

0 Garrett Roecker over 7 years ago in reply to Konrad Tomtas11

TI__Mastermind 21720 points

Hi Konrad,

Did you mean to post a photo?

Thanks,

Garrett

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TPS40210: how to get 2A current on the output