TPS54331: TPS54331 Output Waveform

Sachin Tiwari

Part Number: TPS54331

Tool/software:

I am using the below circuit

J1 is Open

I an getting the following wave at the output.

What could be causing this variation ?

I tried changing C17 and L2 but it didnot help

Kindly suggest

0 Sachin Tiwari 11 months ago

I changed R10 to 56K and I get the following waveform

A little better. What are the optimal values to be used. Input 10V to 18V and Output 7.5 or 8V

0 Shipeng Cheng 11 months ago in reply to Sachin Tiwari

Hi Sachin,

How much is your load current when startup? Could you try short the L1?

Regards,

Shipeng

0 Sachin Tiwari 11 months ago in reply to Shipeng Cheng

I checked shorting L1 but the issue was still the same

I have a LDO connected on the output of Dc to DC

Below is the sch

The voltage from the TPS54331 is fed to the above circuit that generates 3.3V

I removed L4 and checked and the issue was still there.

As per your input, my guess is that the LDO is causing the variation in signal but I am not sure why and how this can be solved.

Any suggestion will be very helpful

0 Sachin Tiwari 11 months ago in reply to Sachin Tiwari

Shorting L3 also didnot help

0 Aurora Tie 11 months ago in reply to Sachin Tiwari

Hi,

It is currently a Chinese holiday, we will get back to you on 10/8. Thank you for your patience!

Aurora

0 Gui He 11 months ago in reply to Sachin Tiwari

Hi Sachin

I simulated using Webench and the Vo rising curve also has a slight twist. This should be normal and is not harmful to the system.

You can disconnect L1, connect Electronic load and do the start up test and see if the waveform is same.

Thanks and best regards.

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