inverting Buck-Boost support 3.6V~4.2V -> -5.3V/0.8A

Ann_Lien

Other Parts Discussed in Thread: TPS82130, TPS62826, TPS62130, TIDA-01423, TIDA-01457

Hello expert,

I would like to check if we have solution could support 3.6V~4.2V -> -5.3V/0.8A with inverting Buck-Boost topology. It would be better to have reference design for this application. Thanks a lot!

Best regards,

Ann Lien

over 4 years ago

0 Milos over 4 years ago

TI__Expert 7925 points

Hi Ann,

I couldn't find any buck-boost device matching the requirements, the most we can achieve for those voltages is around 200-300 mA.

There might be a suitable buck converter that can be configured as an inverting buck-boost, I will check with the buck team.:
http://www.ti.com/lit/an/snva856/snva856.pdf

Best regards,
Milos

0 Ann_Lien over 4 years ago in reply to Milos

TI__Genius 12670 points

Hello Milo,

Thanks for your help on this case and looking forward to seeing your feedback here :)

Best regards,

Ann Lien

0 Alfonso Furio over 4 years ago in reply to Ann_Lien

TI__Expert 3645 points

Hello Ann,

I found only this reference design that can fit your case. Here there is the link for TIDA-01457 based on the module TPS82130.

0 Ann_Lien over 4 years ago in reply to Alfonso Furio

TI__Genius 12670 points

Hello Alfonso,

It seems like we can use simple 3A converter solution to achieve it. May I use TPS62826 which is already used in their application to achieve 3.6V~4.2V -> -5.3V/0.8A application? Thanks a lot!!

Best regards,

Ann Lien

0 Milos over 4 years ago in reply to Ann_Lien

TI__Expert 7925 points

Hi Ann,

The TPS62826 cannot be used, its Vin_max is 5.5 V which is not high enough. When used in inverting buck-boost configuration, the Vin_max requirement is:

Vin_max = Vin + |Vout| = 4.2 + 5.3 = 9.5 V (for explanation check Figure 5 from the document I linked above)

You might use the TPS62130, check Section 9.3.3 from the datasheet, and this application note for calculations:
http://www.ti.com/lit/an/slva469c/slva469c.pdf

For your input/output voltages it should be able to provide at least 1 A, but double check with the buck team if there are any other concerns.

Best regards,
Milos

0 Alfonso Furio over 4 years ago in reply to Milos

TI__Expert 3645 points

Hello Ann,

Thanks, Milos, for the explanation. Last time you look for a solution with a reference design, and I provided the link of TIDA-01457. On the first page, it is specified that the solution works at around 1A. Also, tps62130 can be suitable for your application, but is available only a ref design that doesn't match your rails (TIDA-01423).
For specific support on these devices, please open a new thread, including the part number since I am supporting buck converter below 7V.

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inverting Buck-Boost support 3.6V~4.2V -> -5.3V/0.8A