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Buck boost dual regulated positive output

Naig
Prodigy 250 points
Other Parts Discussed in Thread: TXS0102, TPS63805, TPS61023, TPS63802, TPS610985

Hi,

I'm looking for a Buck Boost regulator with Dual positive output. Below are the specification:

Input: 3.0V (2 Alkaline AA Batteries operated).

Outputs: 3V@1A and 1.8V@1mA

What could be the possible solution for NB-IoT applications with sensors that has different voltage level?

Most of the ICs (modules and sensors) in our design needs 3V supply, but one of the sensor needs 1.8V supply.

I'm thinking to have separate buck converter for the 1.8V sensor and boost converter for the rest of the ICs.

What could be the best solution? 

Note: I'm using a level shifter TXS0102 for the I2C interface for the sensor (with 1.8V requirements), but I saw there is a buck converter with I2C interface. However, I'm not sure if it is applicable for my design.

Thank you.

 

  • 0
    TI__Mastermind 21565 points

    HI Naig:

    If the Vin is supplied by 2AA batteries, the voltage range will cover 3V. It means you need a buck-boost converter like TPS63805 to regulate 3V. And for 1.8V,1 mA, you could use a LDO. It's easier and lower cost than a DCDC converter. 

    Besides, may I know which sensor need 1.8V?  

  • 0 in reply to Minqiu Xie
    Prodigy 250 points

    Hi,

    Thank you for your response.

    What is the reason to use a buck-boost converter instead of a boost converter only? Also, I would like to use other packages than DSBGA if there is any.

    And for sensor that requires 1.8V, the supply current in measurement mode normally is 48mA not 1mA. Is there any reference design you could recommend similar to my applications for the power management? 

    BTW, the sensor that requires 1.8V I'm using is sgpc3.

     

  • 0 in reply to Naig
    TI__Mastermind 21565 points

    Hi Naig:

    I wonder if you need to regulate 3V all time, or is it ok just ensure it's no less than 3V. The voltage of two new batteries maybe high to 3.2V, larger than Vout. It's hard for boost converter to regulate Vout when it's lower than Vin. 

    If just want to keep Vout high no less than 3V, you can have a look at TPS61023 with pass through.

    If regulate 3V all time, you can choose TPS63802, which is QFN version.

  • 0 in reply to Minqiu Xie
    Prodigy 250 points

    Hi,

    It is not necessary to regulated 3V all the time, the supply voltage can be up to 3.3V. My concern is to boost the supply voltage when the Vin decrease it's voltage level. 

    Originally I'm using TPS610985 with 3.0Vout and has automatic pass-through function. 

    I think TPS61023 is not an option as it requires external resistor divider. as well as TPS63802.

  • 0 in reply to Naig
    TI__Mastermind 21565 points

    Hi Naig:

    Understand that, but TPS610985 can't handle 1A.

    TPS61023 is closest. But may I know why you can't accept the external resistor? It won't take much cost or solution size.