TPS552882-Q1: TPS552882QWRPMRQ1 Output Voltage Instability

Amit Nagarkar

Part Number: TPS552882-Q1

Hello Team,

We are using the TPS552882QWRPMRQ1 buck-boost regulator in our design. The input voltage range is 3.3V to 4.2V, and the expected output is 3.8V at 3A.

However, we are observing instability at the output when powering on the device — the output voltage varies, and in some cases, we are getting a constant 4.8V instead of 3.8V.

Could you please help us analyze and resolve this issue?

Regards,

Amit

2 months ago

0 Colin Chen 2 months ago

TI__Mastermind 22421 points

HI,

Give me some time to check.

Colin

0 Amit Nagarkar 2 months ago in reply to Colin Chen

Prodigy 40 points

Hi Colin,

Thank you for your response.

Please find the image of the schematic.

Regards,

Amit

0 Colin Chen 2 months ago in reply to Amit Nagarkar

TI__Mastermind 22421 points

Hi Amit,

Could you test the SW1 and SW2, Vout waveforms?

It can help us to confirme the instability issue.

Thanks,

Colin

0 Amit Nagarkar 2 months ago in reply to Colin Chen

Prodigy 40 points

Hi Colin,

Ok, we will test.

After using a 1 µH inductor, we observed output voltage instability, noise, and heating issues. After changing the inductor to 4.7 µH, the output voltage became stable. Could you please confirm if the inductor value can affect the regulator’s performance?

Regards,

Amit

0 Colin Chen 2 months ago in reply to Amit Nagarkar

TI__Mastermind 22421 points

Hi Amit,

Yes, 1uH would make the loop unstable, and the inductor current ripple is also too large.

We suggest using 4.7uH inductor.

Thanks,

Colin

0 Amit Nagarkar 2 months ago in reply to Colin Chen

Prodigy 40 points

Hi Colin,

Thank you for your response.

However, according to the Webench simulation, the recommended inductor value is 1 µH. Could you please confirm whether it is acceptable to use a 4.7 µH inductor instead?

Regards,

Amit

0 Colin Chen 2 months ago in reply to Amit Nagarkar

TI__Mastermind 22421 points

Yes, i comfimed.

Thanks,

Colin

0 Amit Nagarkar 2 months ago in reply to Colin Chen

Prodigy 40 points

Thanks, Colin.

Regards,

Amit

0 Amit Nagarkar 2 months ago in reply to Amit Nagarkar

Prodigy 40 points

Hi Colin,

Here what we observed if we use 1A load continuously after 5 to 10 min ic is getting heated and output is getting unstable.

Regards,

Amit

0 Colin Chen 2 months ago in reply to Amit Nagarkar

TI__Mastermind 22421 points

Hi Amit,

Did the EVM work stable at 1A load? If so, please reduce the driver resistor from 10ohm to 1ohm in below marked.

Thanks,

Colin

0 Amit Nagarkar 2 months ago in reply to Colin Chen

Prodigy 40 points

Thanks, Colin.

Will update and check.

Regards,

Amit

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TPS552882-Q1: TPS552882QWRPMRQ1 Output Voltage Instability