TPS5430: TPS5430DDA - Technical Support

Amol Bagul

Part Number: TPS5430

Tool/software:

Hello,

I am working on to design power supply output 5VDC with the help of TPS5430DDA converter. Input voltage = 12VDC, Iout = 1.63A.

It was already in use in our design below the circuit.

The new design requires increase in Iout i.e. 1.63A. with that if I do the thermal analysis. considering

Iout = 1.631A, Vin= 12, Vout = 5V, TA= 35°C, θJA = 45 °C/W. The Junction temp. goes beyond operating range.

Did my calculations are correct? Need to know, how can I resolve the thermal issue? Do you recommend any other alternative instead? Is adding a resistor in parallel at the input a good way to reduce the 12V input and decrease heat dissipation?

Kindly help to move further.

Regards,

Amol B.

over 1 year ago

0 Frank De Stasi over 1 year ago

TI__Guru 72055 points

Hello

First you need to estimate the efficiency based on the data sheet curves.

Then you can estimate you power loss and calculate the required thetaJA.

You will probably get a smaller thetaJA than shown in the data sheet for the EVM if you use more copper area than the EVM.

Thanks

0 Amol Bagul over 1 year ago in reply to Frank De Stasi

Prodigy 80 points

Hello Frank,

Could you please give reference about power loss & calculation on thetaJA?

And Is it good idea to simulate the circuit using power designer webench? Does this gives the closest thetaJA?

ThanksSimulate_TPS5430DDAR_Startup.pdf

0 Frank De Stasi 11 months ago in reply to Amol Bagul

TI__Guru 72055 points

Hello

You can use Webench to estimate the power loss. Or use the efficiency curves in the data sheet.

I think that Webench makes an assumption about the thetaJA; it may not match your conditions.

The attached note should give you some guidance.

Thanks

0714.snva951.pdf

0 Frank De Stasi 11 months ago in reply to Frank De Stasi

TI__Guru 72055 points

Hello

I will close this post due to inactivity.

If you need further help, please open a new post.

Thanks

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TPS5430: TPS5430DDA - Technical Support