BQ25170: BQ25170 lipo charger

Hi Ali

The BQ25170 would be a small simple solution that could possibly work. Battery is 1Ah and max output current is 100mA, this would require about 10 hours, long but possible.

BQ25170 is a linear charger, low cost and small but not high efficiency.  A switching converter would be more efficient but is larger and cost more.

Do you have a time requirement to complete the charge?

Hi Bill Johns

Thank you for your previous response.

I am working on a display system that will operate with concurrent battery charging. The idea is to charge the battery while the system is in use, as power is available only when water flows. Therefore, the system must be capable of simultaneous power consumption and battery charging.

The primary requirement is not necessarily to fully charge the battery but to maintain a balance where the power drawn is compensated by the charging input.

You may wonder about the system's power consumption. I have not yet calculated the exact power requirements, but the following components are part of the system:

1. Flow and temperature sensors
2. LCD (I am aiming to use a low-power consumption display)
3. Microcontroller (MCU)

The system will read sensor values and display the information on the LCD.

Do you have any suggestions or recommendations for managing the power and charging system under these conditions?

Thank you in advance for your help.

Hi Ali

We have power path devices that will charge the battery and provide current to system at the same time.

A couple of devices to look at:

1.) BQ25180 -  is a power path liner charger, see here

2.) BQ24133 - is also power path but switch mode converter with higher efficiency, see here

Some things to consider:

1.) What package type, BGA for small package OR QFN for ease of assembly.

2.) Software interface, is this stand alone with no MCU control OR will MCU be used to configure / control the devcie.

Hi Bill Johns

1: Easy assembly, NO BGA
2: Standalone, NO MCU

Less BOM count though but space isn't the issue 
Thanks

Hi Ali

Take a look at the BQ25185.

Hi Bill Johns

I am evaluating the BQ24133 and BQ25185 for my application and would like to know which would be the better option.

I assume the BQ25185 was suggested to minimize the BOM count. However, in my case, efficiency is the highest priority over other factors. Given this requirement, which of the two would be the better choice or if any other more efficient solution?

I appreciate any insights or recommendations.

Thanks
 

Hi Ali

Ali Khan said:

I assume the BQ25185 was suggested to minimize the BOM count. However, in my case, efficiency is the highest priority over other factors. Given this requirement, which of the two would be the better choice or if any other more efficient solution?

The BQ24133 is a switching converter and will be higher efficiency solution.  

Hi Bill Johns
After further checking of BQ24133, I found that it's minimum VIN is 4.5V. The turbine voltage rating is 3 to 6V.
Also, it is buck converter. Is there any Buck/Boost converter lipo charger available that can utilize all the available input power and charge the battery.

The turbine will generate 5V and 100mA ideally and Load current is around 100mA as well so i want to utilize all the available power to keep battery charge while using it.

Let me know if you need further explanation.
Thanks

Hi Ali

We do have a buck-boost charger, but it is overkill for 1 cell at 100mA.

A possible alternative is to use a two IC solution.  We have a buck-boost power supply family TPS630XX that could power the battery charger BQ25170.

Take a look at the TPS63020.

Hi Bill Johns
I agreed with you. I was also thinking to regulate input voltages for battery charger then use efficient charger to charge the battery.

The TPS63020 Vin Max is 5.5V and I need at least 6V because turbine will generate 3 to 6V output.

Thanks

Hi Ali

Couple of units to take a look at the:

1.) TPS63060 with input voltage range 2.5V to 12V

2.) TPS63070 with input voltage range 2V to 16V