Heating issue in TPS54340

Rajesh Gupta

Other Parts Discussed in Thread: TPS54340

Dear Team,

Develop the DC-DC board based on TPS54340 with Specs: INput: 13.5V, Output: 5V, 2.5A.

Attached is the Schematic driving at 500Khz, Facing the heating issue in the circuit about 70-75 C, Please advise suggestions to overcome the heating issue.

Here used the two diodes, One for reverse polarity at input and other is synchronous diode.

Best regards

Rajesh Gupta

over 8 years ago

0 Anston Lobo over 8 years ago

TI__Genius 16025 points

Hi Rajesh,

Thank you for the question! Allow me to redirect your TPS54340 query to the Non-isolated forum for application specific assistance.

Thanks,
Anston

0 JohnTucker over 8 years ago in reply to Anston Lobo

TI__Guru**** 191445 points

Webench suggests that your pcb should be around 44-46 deg. C. That is about 15 degree increase from baseline 30 C. Most likely your layout is not optimized with insufficient copper are for the IC and or catch diode.

0 priyank mani over 8 years ago in reply to JohnTucker

Intellectual 290 points

Dear John,

Thanks for your reply !!

1) I would like to know what should be the thermal area to take care of this heat generation.

2) what we have felt , if you mistakenly touch the the RT resistance , due to some body charge, Output of TPS54340 gets disturbed. and this is a major problem we are facing apart from heat generation.

kindly reply ASAP!!

0 JohnTucker over 8 years ago in reply to priyank mani

TI__Guru**** 191445 points

The RT pin is extremely sensitive. Touching it while the circuit is operating will certainly cause the switching frequency to be erratic.

You can use the thermal simulation inside of Webench to estimate the PCB copper area required. The basic thermal data calculated in webench as standard for TPS54340 uses 3" x 3" four layre pcb with 2 oz copper on each layer. That is a lot of copper area, hence the webench temperature estimate is very low.. You can edit the pcb in the thermal simulation to more closely match your available board area.