how can I change the bq24773 charge current without bqStudio

winningbear

Other Parts Discussed in Thread: BQSTUDIO, BQ24773, ENERGIA

I can change the charge current through bqStudio,but when I restart the EVM, the charge current will become to 0A. Now I want to set a specific charge current at 5A ,and it won't be back to POR state(0A) when I restart the EVM.How can I do?Can I change the POR state?How can I do if i can change?

over 8 years ago

0 David Wiest Jr over 8 years ago

TI__Genius 11480 points

Hi,

You cannot change the default POR state for the bq24773. You will have to write the charge current to the register after power up.

0 winningbear over 8 years ago in reply to David Wiest Jr

Prodigy 190 points

Thank you for your reply,I am a green hand in battery area.I want to use bq24773 to make a fast charger,so how can I write register without SMBus and computer?

0 David Wiest Jr over 8 years ago in reply to winningbear

TI__Genius 11480 points

Hi,

You will need to program a micro controller to communicate. If you are unfamiliar with this, you might consider looking into an MSP430 and using Energia as your IDE. The Wire library is good for simple projects to "get your feet wet", so to speak.

0 winningbear over 8 years ago in reply to David Wiest Jr

Prodigy 190 points

I am using bq24773EVM to text charge current.The text battery is Panasonic 18650(single cell),I set charge current 3008A,charge voltage 4028mV.The battery begin voltage is 3.8V. But the charge current only can reach the maxcurrent at 1A, what is the matter?

0 Wang5577 over 8 years ago in reply to winningbear

TI__Guru 56650 points

What is the charge output voltage and output cable/wire and battery internal resistance? If the charger output voltage is 4.028V, the current is 1A, that indicates the charger reaches the charge voltage setting and runs the constant voltage mode. The charge current is depended on the output resistance.

0 winningbear over 8 years ago in reply to Wang5577

Prodigy 190 points

Thanks for your replies.I have texted again,the charger output voltage is 4.2V and the current is 1.5A when I set charge current at 3008mA and charge voltage at 4.2V on bqStudio.The current won't always be 1.5A,it will decrease slowly.Could you tell me the reason about that?

0 Wang5577 over 8 years ago in reply to winningbear

TI__Guru 56650 points

This is debugging work:
1. Is charger output voltage or current abnormal? You think the charge currnet is abnormal.
2. Does charger work at voltage regulation or current regulation? You can check the charger output voltage is 4.2V which matches the bqstudio setting. So, charger is in voltage regulation loop that also indicates not in current regulation loop. A simple quesion: if charger output is 4.2V and battery is also fully charged at 4.2V, what is the charging current at this condition?

0 winningbear over 8 years ago in reply to Wang5577

Prodigy 190 points

Oh,thank you for your help,I understand .the battery always work at voltage regulation,thank you very much.

0 winningbear over 8 years ago in reply to Wang5577

Prodigy 190 points

Hi wang,
Can I disable the bq24773 "POR" function?Because I want to set a specific charge current or voltage once,it will never be reset even though repowerring .I hope the chip can work without the controller.Or I should choose a standalone chip?

0 Wang5577 over 8 years ago in reply to winningbear

TI__Guru 56650 points

bq24773 "POR" cannot be disabled. But, some register values are kept if the battery powers VCC pin up. Please check 0x14H and 0x15H register value after recycling the input power.

Power management

Power management forum

how can I change the bq24773 charge current without bqStudio