BQ33100: Do not pull CHG to low

Yuto Kitamura

Part Number: BQ33100

Tool/software:

Dear team,

We are suffering that CHG-pin do not pulled low and start charging. To understand the behavior, can you please help answer quesitons.

1. Can you tell me how to calculate the R4,5,6,7 to set Charging voltage to specific set voltage?

EVM user guide:

2. Is the evaluation software that works on Win11?

3. Can we set Chg voltage Nom, A, B and max via SMbus command?
If yes, how will be the set value by external resistors? Which is the higher priority?

Best regards,
Yuto

3 months ago

0 Diego 3 months ago

TI__Mastermind 25665 points

Hi Yuto,

1) The resistor size is dependent on the number of caps used in series. Please follow the recommend values from the chart.

2) I have not heard any problems with EVSW and Windows 11.

3) No there is not an SMbus cmd. Sections 8.3.3 and 9.2.2.2 in the datasheet discus charging.

BQ33100 Super Capacitor Manager datasheet (Rev. C)

Regards,

Diego

0 Yuto Kitamura 3 months ago in reply to Diego

TI__Expert 6455 points

Hi Diego,

Thanks for comments.

1. Then what is cause of our behavior? Why CHG is not pulled low?

2. How can we configure the charging voltage to specify to our system? I am not completely sure about it...

Best regards,
Yuto

0 Alan Frias 3 months ago in reply to Yuto Kitamura

TI__Mastermind 25225 points

Hello Yuto,

We will continue to work on your question, today is a national holiday, Memorial Day.

Thank you,
Alan

0 Yuto Kitamura 3 months ago in reply to Alan Frias

TI__Expert 6455 points

Hi Alan,

Thanks for reply. I look forward to the update tonight.

Yuto

0 Diego 3 months ago in reply to Yuto Kitamura

TI__Mastermind 25665 points

Hi Yuto,

The BQ33100 will determine a new ChargingVoltage() at end of the learning cycle based on the newly learned Capacitance. The following warnings will be set based on the changes in ChargingVoltage() and the capacitor's ability to provide the minimum power needs

Section 8.3.3 in the datasheet describes the chg lvl voltages and the parameters that need to be configured.

Regards,

Diego

0 Yuto Kitamura 2 months ago in reply to Diego

TI__Expert 6455 points

Hi Deigo,

We understand that we do not have to change the external components R4-7 in Fig.18 on datasheet even below condition - is it correct?
NOM 4.2V, MAX 5.0V, A 4.5V, B 4.7V

Additional question, if using 2 series capacitor, do we have to set R26 in Fig.18 to OPEN instead of 0ohm? Please kindly support that.

Best regards,
Yuto

0 Diego 2 months ago in reply to Yuto Kitamura

TI__Mastermind 25665 points

Hi Yuto,

You are correct please follow the evm schematic. R26 should be a 7.5 ohm resistor.

Regards,

Diego

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BQ33100: Do not pull CHG to low