BQ25505 Battery Management PSpice model

Ahmed Badr

Other Parts Discussed in Thread: BQ25505

Hi all,

I am asking about the PSpice model for the BQ25505 battery management circuit. I got the PSpice model from TI website, and put a DC voltage source input of 2V and an internal resistance 1kOhm, and a storage capacitor of 50uA connected to VBAT pin.

The undervoltage setting is at 1.77V which means that the main booster will work starting from this voltage. VOC_SAMP pin is connected to VSTOR which means an 80% MPPT setting.

So, as much as I understand, the input voltage will be set to 0.8*2=1.6V at main booster operation. However, I got the input voltage clamped at 0.1V (after 0.33V cold start voltage). I tried different input voltages 1V and 1.5V and still the input voltage seems to clamp at 0.1V during main boost.

Did anyone face the same problem? It seems the MPPT feature is not working.

Appreciate any help from you all,

Thanks in advance

over 9 years ago

0 Nikhil Gupta (Product Folder Models) over 9 years ago

TI__Mastermind 39210 points

Ahmed,

Can you share your complete PSpice project? It will help us debug your issue.

Regards,

0 Ahmed Badr over 9 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 30 points

Hi,

I am attaching here the circuit diagram and the waveforms of my project.

The PSpice stopped running after 2.3 sec, that's why the 50uF cap didn't reach the preset over voltage setting of 4.2V.

I was wondering about the input voltage that should be 80% of 2Vdc and not 0.1V.

Thanks for your reply

0 Nikhil Gupta (Product Folder Models) over 9 years ago in reply to Ahmed Badr

TI__Mastermind 39210 points

Ahmed,

It seems that you have increased the cap on some of the nodes. Since this model has to show switching behavior and also run for run time of several seconds, there are some known limitations that have been documented in the notes section. Can you use smaller cap values for your analysis? Also, I am unable to see the current through the R18 resistor. If R18 is too large then the drop across that R may not allow the Vin to rise up much.

Regards,

0 Ahmed Badr over 9 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 30 points

Hi Gupta,

Thanks for your reply. I tried different capacitors and lower R18 resistance, and still the input voltage clamps at 0.1V.

I don't really know what's happening here.

I am attaching here a case.

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BQ25505 Battery Management PSpice model