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TPS61088: Output current not exceeding 1.8A, designed for 5V/5A

Ram Raut
Prodigy 30 points
Part Number: TPS61088

Tool/software:

Hi Team,

I have designed a boost converter to power a Raspberry Pi from a Li-ion battery, but the output of the TPS61088 does not exceed more than ~1.8 A.
As soon as the current exceeds 1.8 A, the voltage drops to less than 3.5 V.I hooked up a bench power supply to VBAT(3.6V) and checked the output through an electronic load; the results are still the same.
Am I making any visible mistake in the schematic, or could it be due to current saturation in the inductor?
I tried changing R51 to 50K, but it did not changed much. 
Btw, EN pin is driven by TPS3840DL31DBVR.

Your support would be highly appreciated.


Thanks
Shrawan


  • 0
    TI__Mastermind 19110 points

    Hi Ram,

    Expert who supports this device is on holiday now.

    This E2E thread will be supported after the holiday.

    Regards

    Lei

  • 0 in reply to Lei Zhong
    TI__Guru 66350 points

    Hello Shrawan,

    The current limit can only be reduced when increasing the resistor on VILIM, you cannot increase it above the values given in the electrical characteristics of the datasheet.

    Please try to increase the switching frequency and check if then the maximum output current increases. This points to the peak current limit.

    Please check as well if the inductance of the inductor decreases with current which is typical. It might help to select an inductor that has a lower inductance reduction.

    Best regards,
    Brigitte