TPS61088: The efficiency at PFM and PWM mode with webench

Hirokazu Takahashi

Part Number: TPS61088

hello support team

The efficiency of TPS6188 will be same for both of PFM and PWM mode on normal load condition according to Figure 1 and 2 in datasheet.
But the efficiency by Webench is different each mode like below.
PFM mode : 95.5%
https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=12F89C75FBC72C1B

PWM mode : 90.6%
https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=188BC23973F8E161

Could you please check the Webench models and let me know the reason why they are different.

Best Regards,
Hirokazu Takahashi

over 6 years ago

0 Helen chen over 6 years ago

TI__Mastermind 40080 points

Dear Sir,

The modeling team will help on this case. Please wait in patience.

At 1A output condition, the eff. at the PWM and the PFM mode should be the same.

0 Hirokazu Takahashi over 6 years ago in reply to Helen chen

TI__Expert 8420 points

Hello Helen-san

Thanks for your support.
Do you have any update from the modeling team?

I guess that the PFM mode will be correct and Force PWM mode will be wrong. I want to confirm it at first because I want to proceed the study of PFM mode.

Best Regards,
Hirokazu Takahashi

0 Helen chen over 6 years ago in reply to Hirokazu Takahashi

TI__Mastermind 40080 points

Dear Sir,

The actual efficiency at Vin=4.5V Vo=12.5V/1A is around 93%, which is just between the Webench PWM and PFM efficiency curve. It is normal for the webench result doesn't match with the real efficiency.

I have assign the post to the Webench team, but didn't receive any reply yet. Please wait in patience.

0 Umayal Ramanathan over 6 years ago in reply to Helen chen

TI__Expert 5920 points

Hi Hirokazu-san,

We apologize for the delay in response.Thanks for reporting this issue.

We are able to replicate the issue.We are working to resolve the issue.We shall keep you updated on the fix.

Regards,

Umayal

0 Umayal Ramanathan over 6 years ago in reply to Umayal Ramanathan

TI__Expert 5920 points

Hi Hirokazu-san,

We are actively working to resolve issue w.r.t .efficiency mismatch between PFM and PWM mode in TPS61088.

We shall keep you updated on the same.

Thanks & Regards,

Umayal

0 Umayal Ramanathan over 6 years ago in reply to Umayal Ramanathan

TI__Expert 5920 points

Hi Hirokazu-san,

We have fixed the issue.The fix shall be available on ti.com by 1st August.

We shall let you know once the fix is available on ti.com.

Thanks & Regards,

Umayal

0 Umayal Ramanathan over 6 years ago in reply to Umayal Ramanathan

TI__Expert 5920 points

Hi Hirokazu-san,

The updates are now available on ti.com.

Thanks and Regards,

Umayal

0 Hirokazu Takahashi over 6 years ago in reply to Umayal Ramanathan

TI__Expert 8420 points

Hello Umayal-san

Thanks for reaching out

Best Regards,

Hirokazu Takahashi

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TPS61088: The efficiency at PFM and PWM mode with webench