TPS25927: The outpt capacitor of TPS259271

takahiko yokota

Mastermind 7135 points

Part Number: TPS25927

My customer evaluate TPS259271.

They use 47uF output capacitor and it is connected 1000uF as input capacitor of load.

Could they use this device with this method?

Best regards,

Yokota

over 6 years ago

0 Praveen GD over 6 years ago

TI__Guru 57737 points

Hi Yokota,

There is design calculator for this part which helps you in design. You can download the design calculator in the below link.
www.ti.com/.../toolssoftware

Please enter all the cells in yellow in the design calculator. Choose the IC as TPS25927.
Consider all the capacitance connected to the output rail as the Cout (Total Output Capacitance).
Upload the design calculator here after entering the cells in yellow.

0 Praveen GD over 6 years ago in reply to Praveen GD

TI__Guru 57737 points

Hi Yokota,

Were you able to download the Design Calculator and enter your parameters. Once you enter all the cells in yellow, please upload it here for us to review.

0 takahiko yokota over 6 years ago in reply to Praveen GD

Mastermind 7135 points

Hi Praveen-san

I'm sorry for my late reply.

I attached TPS259271's calculator written the spec.

TPS2592xx-Design-Calculator-RevA.xlsx

Best regards,

Yokota

0 Praveen GD over 6 years ago in reply to takahiko yokota

TI__Guru 57737 points

Hi Yokota,

The device will have a successful startup if

the device starts up with No-Load. That is your load should not draw any current until Vout reaches close to Vin.
Use a 10nF dVdT Capacitor.

I have uploaded the updated calculator where you can see that the device will have a glitch free start up.

6862.TPS2592xx-Design-Calculator-RevA.xlsx

0 takahiko yokota over 6 years ago in reply to Praveen GD

Mastermind 7135 points

Hi Praveen-san

Thank you for your support.
I'll evaluate based on attached document.
Please let me ask further questions.
The output capacitor is recommended 1000uF in "6.3 Recommended Operating Conditions".
Could I use 1000uF capacitor in what the conditions?

Best regards,
Yokota

0 Praveen GD over 6 years ago in reply to takahiko yokota

TI__Guru 57737 points

Hi Yokota,

High capacitance at the Output generally causes startup issues. As per calculator you will have successful startup if you have no-load. So, you can continue with 1047 uF capacitance at the Output.

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TPS25927: The outpt capacitor of TPS259271