BQ24075T: BQ24075T vs BQ24074

Lim Phang Moh

Intellectual 270 points

Part Number: BQ24075T
Other Parts Discussed in Thread: BQ24074

Hi,

Looking at the datasheet, in order to use BQ24075T on an existing design for BQ24074, I need to:

Replace the ITERM resistor with a zero ohm resistor to tie SYSOFF to GND to enable it.
Reduce input voltage to maximum 6V.

I think that is all to make it to work?

Due to BQ24074 shortage, I think this is the only way.

over 2 years ago

0 Anthony P Pham over 2 years ago

TI__Mastermind 23170 points

Hi Lim,

Yes, those two changes would need to be made. Another additional change is that you'll need to introduce a resistor divider network on the TS pin. You can find this information in the Battery Pack Temperature Monitoring section of the BQ24075T datasheet.

You'll need to configure as below:

Feel free to also attach a snippet of the new schematic with changes and I can take a look at it to ensure functionality but these should be the only changes.

Best Regards,

Anthony Pham

0 Lim Phang Moh over 2 years ago in reply to Anthony P Pham

Intellectual 270 points

Hi Anthony,

So, if I currently have a 10K resistor pulled down to GND to disable the TS functionality on the BQ24074, I need to add a pull-up to VIN with 200K resistor and replace the 10K resistor with a 49.9K resistor on the BQ24075T, am I right?

Thanks.

0 Lim Phang Moh over 2 years ago in reply to Lim Phang Moh

Intellectual 270 points

I attached here the schematic. I'm putting an option such that either BQ24074 or BQ24075T can be used.

0 Anthony P Pham over 2 years ago in reply to Lim Phang Moh

TI__Mastermind 23170 points

Hi Lim,

Yes that would be correct!

Best Regards,

Anthony Pham

0 Anthony P Pham over 2 years ago in reply to Lim Phang Moh

TI__Mastermind 23170 points

Hi Lim,

If you're having it so that either the BQ24074 or the BQ24075T can be used, are you going to have different voltages going to IN?

I see that you have mentioned the input voltage among the differences for the two devices. My concern is that the TS network, if you don't decide to switch it between a 10k resistor and the voltage divider network, the voltage at the TS pin for the BQ24074 may fall out of the valid charge range.

Leaving the voltage divider is fine for the BQ24074 but you will be having some current go from VEXT to to TS.

For reference the voltage at the TS pin needs to be between 300 mV and 2100 mV for the device to charge the battery for the BQ24074 while the BQ24075T range needs to be between 12.5 % and 25 % of the VEXT voltage

Best Regards,

Anthony Pham

0 Lim Phang Moh over 2 years ago in reply to Anthony P Pham

Intellectual 270 points

Hi Anthony,

The resistor network will be installed accordingly depending on which IC is mounted. If BQ24074 is used, only the 10K is mounted. If BQ24075T is used, then 49.9K and 200K will be mounted. The input voltage for both case will be similar 4.5-6 V.

+1 Anthony P Pham over 2 years ago in reply to Lim Phang Moh

TI__Mastermind 23170 points

Hi LIm,

In that case, everything should be good to go!

Best regards,

Anthony Pham

0 Lim Phang Moh over 2 years ago in reply to Anthony P Pham

Intellectual 270 points

Hi Anthony,

Thank you very much.

Ordering them IC now as they are in stock.

Power management

Power management forum

BQ24075T: BQ24075T vs BQ24074