BQ24735: Simultaneous 6 A SYS Output and 3 A Single-Cell Li-Ion Charging

Kevin Makovy1

Part Number: BQ24735
Other Parts Discussed in Thread: BQ28Z610-R1, BQ24773, BQ24610

Hello,

I'm looking for some suggestions on a power management design.

I would like to use a fuel/gas gauge IC (BQ28Z610-R1) combined with a compatible I2C-controlled battery charger capable of supplying 6 A "system" output while simultaneously charging a single-cell Li-Ion battery at 3 A.

Input can be either 5 V USB or < 15 V wall adapter.

Are you able to recommend any battery chargers that meet these specifications or are these current requirements too high?

Thanks,

Kevin

over 5 years ago

0 Kedar Manishankar over 5 years ago

TI__Mastermind 24075 points

Hi Kevin,

What kind of topology are you looking for? If adapter is not present, would you want your battery to directly supply the 6A system load or would you want your system rail to be lost while adapter is disconnected. Are you looking for system voltage to be regulated near battery voltage (NVDC architecture), or directly tied to adapter or battery voltage (direct powerpath)?

What would maximum possible wall adapter voltage be? This will help me narrow down based off of charger IC input voltage ratings.

0 Kevin Makovy1 over 5 years ago in reply to Kedar Manishankar

Prodigy 140 points

Hey Kedar,

I appreciate the help. If no adapter is present - I would like for the battery to directly supply the 6 A system load. NVDC architecture would be ideal.

The maximum adapter voltage is 15 V.

Thanks again for the help,

Kevin

0 Kedar Manishankar over 5 years ago in reply to Kevin Makovy1

TI__Mastermind 24075 points

Hi Kevin,

Forgot to ask but what charge regulation voltage are you looking for? Is it 1S Li-ion?

0 Kevin Makovy1 over 5 years ago in reply to Kedar Manishankar

Prodigy 140 points

Yup - 4.2 V - 1S Li-Ion

Thanks,

Kevin

0 Kedar Manishankar over 5 years ago in reply to Kevin Makovy1

TI__Mastermind 24075 points

Hi Kevin,

NVDC architecture is highly integrated, so the power loss across the integrated FETs is quite high and generally not suited for such high current requirements. With that being said, you can take a look at BQ24773 which is the closest to satisfying your system conditions. We have more options if using direct powerpath topology, with the down-side of this topology being that VSYS can range between VADAP and VBAT. If that is acceptable I can give you more options, but let me know if BQ24773 satisfies your requirements.

0 Kevin Makovy1 over 5 years ago in reply to Kedar Manishankar

Prodigy 140 points

Hey Kedar,

Thank you for the NVDC option - direct powerpath toplogy is OK to use.

I can change the downstream power architecture if there is a better direct powerpath option available.

Thanks again,

Kevin

0 Kedar Manishankar over 5 years ago in reply to Kevin Makovy1

TI__Mastermind 24075 points

Hi Kevin,

You can take a look at BQ24610 as it can handle your high current requirements.

Power management

Power management forum

BQ24735: Simultaneous 6 A SYS Output and 3 A Single-Cell Li-Ion Charging