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TPS65800

Simon Luetzelschwab
Prodigy 10 points
Other Parts Discussed in Thread: TPS63031, TPS61241, TPS61200

Hi,

I want to use a TPS65800 to power a datalogger.

Inputs are to different 5V sources.

As Outputs I need :

5V 200mA

3,3V 50mA (for ADC)

3,3V 300mA

I thougt I could use the internal regulators of the TPS to generate the two 3,3V supplies. But as I want to use an LiPo with its minimum voltage of 2,5V the internal regulators of the TPS wouldn't work. So I thougt to boost the outputvoltage of the TPS (2,5 to 4,2V) to 5V and feed it into the internal regulators of the TPS. Is this possible? or how I could create 3,3V with the TPS , with only 2,5V available from the lipo.

Thanks for you help

best regards Simon

  • 0
    TI__Guru**** 150880 points

    Yes, if the input to the LDOs or buck converters are less than their output voltage of 3.3V, then the LDOs or buck converters will not output 3.3V.  They can only decrease the input voltage.

    If you just need those 3 rails and a charger, then I recommend the bq2403x family of power path chargers.  This IC would charge the battery and power the system.  On its OUT pin, you would need a small boost converter for the 5V (TPS61241 or TPS61200) and a buck-boost converter (TPS63031) for the 3.3V.  A small LDO (TPS79933, TLV70033, etc.) would then go on the 5V to create the 3.3V for your ADC.

    Is a solution like this acceptable for you?  It would be smaller and likely cheaper than using only a fraction of the PMU.