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Max driving current driving capability of BQ24253 with 5V, 2A input supply

Siddalingayya CG
Prodigy 20 points
Other Parts Discussed in Thread: BQ24253, TPS63020

Hello all,

I have designed battery management circuit using BQ24253. I want to get 5V, 1.5A output across BQ24253.

I have taken ref design from the data sheet. Please find the attached circuit diagram.

I have given output of Battery charger BQ24253 to Buck-Boost converter TPS63020.

Finally I want to get 3 different voltage outputs: 5V (for USB ckt), 3.3V (ICs and other passives) and 19.2V (LED back light driving).

Issue: Output voltage of BQ24253 is getting dropped to 2.3volts and not able to drive all the loads simultaneously.

I want to get output of 4.5V and max current of 1.5A at BQ24253 terminal.

Kindly request forum members to suggest a solution.

This is used in some handheld device.

Thanks,

siddu

6371.BQ24253 for Power supply design.PDF

  • 0
    TI__Genius 13700 points

    Hello Siddu,

    The most likely culprits could be drooping on the input source. What is the input voltage when the output voltage is only 2.3V? Also how much current are you drawing at that time?

    Also the fact that VDPM is programmed to 5V with a 5V input is also creating a potential issue. There is an inherent voltage drop that will occur across the device. The range for the VDPM for a 5V USB input is given below. Try adjusting your resistor divider of R2 & R4 to hit 4.45V to see if this feedback loop is creating your issue.

    Looking at your schematic I noticed that you ILIM resistor is right on the edge of triggering the ILIM short condition. I would recommend setting it to a value within the acceptable range of the device by setting your OCP to 2A with a 240-270 ohm resistor.