BQ25040: Using charger without host MCU

Angus Thomson1

Part Number: BQ25040
Other Parts Discussed in Thread: , BQ25170, BQ24040

I am using the bq25040 at a standalone battery charger for a single LiPo battery. There is no MCU on this board and I would like to program the fast charge current to ~500mA. It seems that this part is designed to be used with an MCU to set the current via the EN/SET pin, but in my case this isn't possible.

Can I set the charge current to be 500mA without needing to pulse this pin? It seems that the default current is USB500 (~400mA) without pulsing the pin, so I guess this is the only option, or am I missing something?

over 2 years ago

0 Nick Brylski over 2 years ago

TI__Mastermind 19195 points

Hello Angus,

The BQ25040EVM has a pulse generating circuit you can refer to: https://media.digikey.com/pdf/Data%20Sheets/Texas%20Instruments%20PDFs/BQ25040EVM_UG,4-2009.pdf

Is there a reason you have chosen this device? I would suggest looking at BQ25170 or BQ24040 as alternatives.

Best regards,

Nick

0 Angus Thomson1 over 2 years ago in reply to Nick Brylski

Prodigy 60 points

Hi Nick

Thanks for your reply. The only reason for choosing this device was availability - the two you mention in your message are out of stock everywhere! These are to be used in a new design which needs to be prototyped immediately - can you give me an idea whether either will be available soon?

Thanks

0 Angus Thomson1 over 2 years ago in reply to Angus Thomson1

Prodigy 60 points

To follow on from this, if I was to use this part (BQ25040) and do not provide any pulses on start-up, can you confirm that the charging current is set to 400mA?

Thanks!

+1 Nick Brylski over 2 years ago in reply to Angus Thomson1

TI__Mastermind 19195 points

Hi Angus,

Yes, if there are no pulses given the device will remain in the default USB500 mode, 400mA current limit.

I cannot speak on sourcing or lead times, best to reach out to your local TI sales rep. TI's fab capacity will be seeing some dramatic improvements this year so I am hoping for the best!

Thanks,

Nick

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BQ25040: Using charger without host MCU