BQ24295: Schematic Review

Matt Staniszewski

Part Number: BQ24295
Other Parts Discussed in Thread: BQ24296M

Hi,

I originally posted a review for the BQ24296M, but decided to switch to the BQ24295 when I realized I could utilize the boost on PMID as my 5V output rather than have a separate boost converter. Here's the updated schematic:

Let me know if it looks OK.

Best,

Matt

over 5 years ago

0 Ning T over 5 years ago

TI__Guru 52591 points

Hi,

The bq24295 circuitry does not have obvious issue. Please double-check with the EVM schematic at www.ti.com/.../sluuao5b.pdf.

Thanks,

Ning.

0 Matt Staniszewski over 5 years ago in reply to Ning T

Intellectual 360 points

One follow-up question. I'm using the EVM and set up the circuit above. I've fixed ILIM at ~890ohm using the POT on the board. I see the battery is charging at up to 500mA. However, the draw on VBUS has no limit; I can go well above 500mA (I reached about 2A) and there's no limit.

Doesn't ILIM also limit how much current the BQ24295 draws on the VBUS pin? Or do I have to set something else? I have tried both tying a 200ohm resistor to D+/D- (Charger, 3A) and leaving them disconnected (default, 500mA).

Let me know.

Thanks,
Matt

0 Joel Hernandez II over 5 years ago in reply to Matt Staniszewski

TI__Mastermind 25800 points

Hey Matt,

The effect of the input current limit is to reduce the charging current in order to regulate the input current. However, if you are drawing power from PMID separately, you can exceed the current limit because the charger is only regulating current going to the system output.

Regards,
Joel H

0 Matt Staniszewski over 5 years ago in reply to Joel Hernandez II

Intellectual 360 points

Hi Joel,

Thank you for the explanation, I was afraid of that. What would be your best suggestion to limit the VBUS current to the device?

Best,

Matt

0 Ning T over 5 years ago in reply to Matt Staniszewski

TI__Guru 52591 points

Matt,

Please connect the input to VBUS pin.

Thanks,

Ning.

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BQ24295: Schematic Review