BQ25756: TI's battery charger IC solution

Conor

Part Number: BQ25756
Other Parts Discussed in Thread: BQ25155, BQ25798

Hi,

Are there any applicable products for TI's battery charger?

Requirements:
・Lithium polymer battery 1 cell
・Input voltage max: 8V or higher
・Charging voltage: 4.2V
・Battery temperature monitoring function
・Over-charge and over-discharge protection
・Charging current monitoring function
・Voltage remaining monitor function

Prerequisites:
Charging current (at CC): 100mA or more
With LDO: 2V to 3V

We have set the remaining battery level monitor function and charge current monitor function as requirements, However, if it is too difficult to build in the battery charger, we would like to know about external components.

Thanks,

Conor

over 1 year ago

0 Jing Zou over 1 year ago

TI__Mastermind 20240 points

Hi Conor,

What is the input voltage range? You only mention 8V or higher. What is the max input voltage can go?

0 Conor over 1 year ago in reply to Jing Zou

Guru 10050 points

Hi Jing,

Jing Zou said:
What is the input voltage range?

Regarding the input voltage range, the current solar cell specifications are as follows.
- Lower limit voltage: undecided
- Upper voltage limit: 8 V

Therefore, the product should be able to operate from as low a voltage as possible.

Thanks,

Conor

0 Charles Harthan over 1 year ago in reply to Conor

TI__Intellectual 1710 points

Hi Conor,

Based on your requirements, I recommend BQ25155: www.ti.com/.../BQ25155

This part comes with 500mA charge current, integrated LDO, integrated ADC (for measuring battery voltage and charge current) and 20 Vin absolute max.

For your input voltage range, does the charger need to operate with an 8V Vin or does it just need to support 8V?

Regards,

Charles Harthan

0 Conor over 1 year ago in reply to Charles Harthan

Guru 10050 points

Hi Charles,

Charles Harthan said:
For your input voltage range, does the charger need to operate with an 8V Vin or does it just need to support 8V?

BQ25155 is a linear charger specialized for wearable products that assumes 5V USB input. As for the input voltage range, the specification of the solar cell that will be used is the upper limit voltage: 8V, so the input voltage must be operated at a maximum of 8V. Please let me know if there are any products that support an input voltage of 8V or higher and have a built-in LDO of 2V or higher.

Thanks,

Conor

0 Charles Harthan over 1 year ago in reply to Conor

TI__Intellectual 1710 points

Hi Conor,

I see. We do not have a charger with 8V operating Vin that has an integrated LDO with 2V or higher.

A product that could be useful to you is BQ25798 which is a buck-boost charger that supports solar cell input. This part comes with a sys pin that is separate from the battery, and you can connect an external LDO to the sys pin to provide that extra voltage rail.

Regards,

Charles Harthan

0 Conor over 1 year ago in reply to Charles Harthan

Guru 10050 points

Hi Charles,

Charles Harthan said:
Based on your requirements, I recommend BQ25155: www.ti.com/.../BQ25155

As cost is a priority in our application, we would like to consider using an LDO to step down from 8 to 5 V and input 5 V to the BQ25155.
Is the BQ25155 the best solution for the conditions I have sent?

Thanks,

Conor

0 Charles Harthan over 1 year ago in reply to Conor

TI__Intellectual 1710 points

Hi Conor,

Yes, since your Vin to the IC is 5V now, I would recommend BQ25155 here.

Regards,

Charles Harthan

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BQ25756: TI's battery charger IC solution