BQ24075: BQ24075 and BQ27750 compatible?

Dan Ringger

Part Number: BQ24075

Hello - I am working on the battery charging system of a product we are developing. We use the bq24075 to charge a single Li battery. Inside the battery is a bq27750 battery gauge chip. What can we expect the interaction of these two chips to be if you can answer, and is there a problem using them in this way?

over 5 years ago

0 Kang Kang over 5 years ago

TI__Mastermind 24870 points

Hello Dan,

They both run on I2C and have different I2C addresses. One charges the battery and the other gauges the battery capacity.

Thanks

0 Dan Ringger over 5 years ago in reply to Kang Kang

TI__Intellectual 1790 points

Hi Kang - The bq24075 does not have an I2C. Our problem is that we have seen situations where the battery is not charging. We need input on conflicts that are possible which could cause a failure to function as desired. We need to understand the characteristics of the interaction to avoid it if possible. Please respond.

0 Kang Kang over 5 years ago in reply to Dan Ringger

TI__Mastermind 24870 points

This is a chargers question. Please post to chargers forum. Closing on gauge forum.

As long as the gauge FETs are turned on, there is no reason the battery should not be charging.

0 Raheem over 5 years ago in reply to Kang Kang

TI__Mastermind 21590 points

Hello,

The BQ24075 is a standalone charger that doesn't need any communication. Whatever interaction occurs depends on the system.

0 Dan Ringger over 5 years ago in reply to Raheem

TI__Intellectual 1790 points

Thank you. So the issue the customer is seeing with the battery sometimes not charging doesn't have anything to do with BQ24075 and BQ27750 compatibility issues. Any suggests what the customer should look for in the charger circuit/configuration that may cause intermittent charging? Thx

0 Raheem over 5 years ago in reply to Dan Ringger

TI__Mastermind 21590 points

Hello,

Is the issue periodic? Can you post their schematic.

0 Dan Ringger over 5 years ago in reply to Raheem

TI__Intellectual 1790 points

The 24075 outputs to a bq27750 battery gauge. The /charge signal is always low (active) signifying charging, but the battery never charges. Shows charging for days, then try to run on the battery, no charge. I then take the battery to the lab and apply a simple diode charging circuit to it and it charges up. I will send schematic offline.

0 Raheem over 5 years ago in reply to Dan Ringger

TI__Mastermind 21590 points

Hello Dan,

What voltage is on TS pin?

What voltage is on SYSOFF?

0 Dan Ringger over 5 years ago in reply to Raheem

TI__Intellectual 1790 points

Sysoff is low, Ts is tied to 10K PTC thermistor. The pack is not hot, we have not measured that. But it is connected.

0 Raheem over 5 years ago in reply to Dan Ringger

TI__Mastermind 21590 points

Hello Dan,

It'll be good to know the exact voltage on the TS pin. Also what is the voltage on OUT and well as IN when the device isn't charging?

0 Dan Ringger over 5 years ago in reply to Raheem

TI__Intellectual 1790 points

Input is 5 volts but I have not measured the out nor have I seen it. I am getting this from the other folks. Like 8 of em. And the software guy says the charging line always shows charging, but again, I wasn’t privy. Just need some advice on where to look next to figure it out.

0 Raheem over 5 years ago in reply to Dan Ringger

TI__Mastermind 21590 points

Hello Dan,

The charge indicator will show charging if the device reduces charge current due to TS voltage outside charging threshold, the device being in DPPM mode or device is in thermal regulation or SYSOFF is high

Power management

Power management forum

BQ24075: BQ24075 and BQ27750 compatible?