TPS562201: TPS562201DDC AND TPS562208DDCR

Faisal Mufti

Part Number: TPS562201
Other Parts Discussed in Thread: TPS562208

Tool/software:

Hi ,

I have used the recommended design in the Datasheet and have used in the feedback resistor value 10k and 57.6k for generating around 5.4 V.

and used 3.3u H with DC resistance of 140mOhm and Capacitors two 10uF X7R. I am also using a Diode at the output before the load.

I can see ripple of around 200mV with load of around 40mA. I know TPS562201 works in PFM and has lower regulation in lower load region.

So I used TPS562208 which shows 38mV of ripple in Workbench simulation but I can see around 122mV.

It would be nice if you can suggest some improvements.

over 1 year ago

0 Colin Chen over 1 year ago

TI__Mastermind 21031 points

Hi,

My colleague Shipeng will reply to you later.

Colin

0 Shipeng Cheng over 1 year ago

TI__Genius 16960 points

Hi,

You should turn on the "20MHz bandwidth limit" in oscilloscope to measure ripple. Thanks.

0 Faisal Mufti over 1 year ago in reply to Shipeng Cheng

Prodigy 20 points

Thanks for the reply. It certainly helped . But I can still see some ripple and gitters after the diode.

As mentioned before we have a diode in series after the inductor and capacitors. Does a diode in series at the output before load effect the regulation.

0 Shipeng Cheng over 1 year ago in reply to Faisal Mufti

TI__Genius 16960 points

Hi Faisal,

Could you upload the waveform you get? Thanks.

0 Faisal Mufti over 1 year ago in reply to Shipeng Cheng

Prodigy 20 points

After diode

Before diode

The chopping you see, is transmission happening. And that has worst impact after the diode. As the current changes from 30mA to 100mA during transmission.

so I wanted to understand if the regulator is impacted by the diode or its just the drop of the diode.

Measurement is done in AC coupling mode

0 Shipeng Cheng over 1 year ago in reply to Faisal Mufti

TI__Genius 16960 points

Hi Faisal,

You should measure by the minimum loop, using a ring to measure on output capacitor. Thanks.

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TPS562201: TPS562201DDC AND TPS562208DDCR