BQ33100 / learning operation

Hello Nagai,

The CHGLVL0 and CHGLVL1 output pins are used to help set the charge current.  Section 8.3.3 of the datasheet gives an overview and Table 2 shows the relationship between the state of those pins and the charging voltage (V Chg Nominal, V Chg A, V Chg B and V Chg Max).

Table 40 MAC Command Summary Table shows the commands required to change the state of the CHGLVL0 and CHGLVL1 pins.  

The Application drawing in Figure 18 shows how to configure the solution.  The CHGLVL0 and CHGLVL1 pins control FETs that set the bias voltage on a Q1 that will control the charge voltage.

During learn, if the bq33100 determines that the capacitors are aging the device sets charge voltage to one "notch" higher than it is currently set.  It also sets a flag to notify the system that aging is occurring and it may be time to consider replacing the supercapacitor block.  If the charge voltage is V Chg Nominal, it will allow the system to change the charge current to V Chg A.  This allows the system to increase the energy storage in the supercapacitor to compensate for the aging capacitors.

Regards,

Dick

Hello Dick,

Thank you for response.
When discharge, what are statuses each port in Table-2?
As same as then chargeing time?
I want to understand about switching behavior sequence for  CHGLVLx with charging voltage.

Regards,
Nagai

Hi Dick,

   I have a question for you?

How can I calculate/know how long the learning will take?

Thanks,

Tony

Hi Tony,
You can time it.. it's gonna depend on the size of your capacitor and the amount of current your learn load draws as well as your charge current.
thanks
Onyx

Hi Onyx,

   Thanks, I have one more question.

How can I calculate below two calibration parameters for my supercap module?

Current Gain
CC Delta 

Thanks,

Tony

Hi Onyx,
What is the accuracy of Capacitance measurements with BQ33100?

Thanks,

Tony

Hi Tony,

Going by the method of measurement of the bq33100 which can be done with a high resolution scope for comparison purposes, the gauge accuracy is within +/- 5% 

thanks

Onyx

Hi Tony,
The gauge's calibration routine does the calculation of cc gain and cc delta for you when you do calibration. You do not have to calculate that your self.

thanks
Onyx

Hi Oynx,

   Thanks a again.

How is the repeatability of BQ33100 capacitance measurement?

For example, if I measured capacitance of a capacitor many many times, what is the deviation of my measurements?

Thanks,

Tony

The recommendation would be to test and see. If should be fairly consistent.
thanks
Onyx