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TPS62270: Suitable regulator for prebiased operation

Ignacio Majcherczyk
Prodigy 170 points
Part Number: TPS62270
Other Parts Discussed in Thread: TPS628301

Tool/software:

Dear Forum

I need to know what DC/DC buck regulator to use for 1.8V output, 500mA absolute max current

and that can be prebiased at the output.

This regulator is to power an STM32L412 processor and the idea is that it operates with an LDO regulator in parallell

While the processor is in sleep mode, or in stop mode, the regulation is made with the LDO, when the processor goes up, and specially when is going to

write to an external qspi memory, the processor enables the DC/DC converter

What is the suggested converter for a case like this? If you also can suggest me an LDO for this operation it would be welcome also.

Best

Ignacio

  • +1
    TI__Mastermind 21580 points

    Hi Ignacio,

    A more safe and commonly used method is to have the LDO in series (in-between) the buck and your processor. The buck output can be regulated to about 100mV to 200mV more than what your processor requires. In this way the LDO will have enough dropout to clean the PFM switching ripple from the buck. Also you wouldn't loose too much efficiency with the lower dropout. If you go for this buck, LDO series approach you can choose TPS628301 as the buck. For the LDO can you kindly create a new post?

    Best regards,

    Varun