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Original question:

BQ25504: Inductor change

TPS61200: Change in Vin source

Sanbab
Prodigy 30 points
Part Number: TPS61200
Other Parts Discussed in Thread: TPS61089

Hi,

I want to boost-up voltage from 0.4V to 4.2V using TPS61200. I am planning to have separate power rail(3.7V) for Vin and Vaux and source 0.4V connected to inductor and other side of inductor connected to L.

Will the chip work in the configuration ? The idea to have Vin and Vaux is to have a lower start-up and improve the gatedrive circuit control in the chip.

Regards,

  • 0
    TI__Mastermind 46905 points
    The device can't support this configuration: separate the VIN and the power source.

    if the 3.7V power rail can be higher than 4.5V, you can use TPS61089 for this configuration.
  • 0 in reply to Jasper Li
    Prodigy 30 points

    Hi,

    FYI i am using a solar cell...

    VCC Control and Gate Control blocks inside the chip are on a different rail - which can be powered by an external stable 3.7V. This way the internal gate control circuit and other modules are always biased. Vin is independent of Vout and there is a diode between VAUX and VOUT. The FETs in the chip are N-channel and technically I think its should be ok with my configuration and to have Vout to boost voltage from 0.3V-->4.2V with a lower startup. and  I plan to have this always turned ON. 

  • 0 in reply to Sanbab
    TI__Mastermind 46905 points
    you can have a look at 10.3.1 of the datasheet, the device need the input voltage to control the internal circuit. that is why we can't separate the VIN from the power supply.