This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ25713: why does the charger read inductance value before the converter starts up?

Part Number: BQ25713

Hi,

i want to know why does the charger read inductance value before the converter starts up?

i can't find more description about inductance detection in the datasheet.

9.3.5.1 Inductance Detection through IADPT Pin
The charger reads the inductance value through the resistance tied to IADPT pin before the converter starts up.
The resistances recommended for 1uH, 2.2uH and 3.3uH inductance are 93kΩ, 137kΩ and 169kΩ, respectively.
A surface mount chip resistor with ±3% or better tolerance must to be used for an accurate inductance detection.

Best regards,

Shubiao

  • Hi Ian,

    Thanks for reaching out. 

    BQ25713 is a highly integrated power converter/charger with various modes of operation.  To allow engineers to design with ease, the IC needs to know the inductance value to cover all the use cases and accommodate all the different operating conditions.

    Hope this helps.

    Regards,

    Peng

    *If my answer solves your question, please press "This Resolved My Issue" on the thread. 

  • Hi Peng,

    Do the operation modes mean buck, buck-boost, boost mode? 

    how does the inductance affects the operation mode? would you kindly share any notes or document to explain it?

    How bq25713 works if the IADPT pin resistor is not assembled? or with a wrong resistance?

    Best regards,

    Shubiao 

  • Hi Shubiao,

    Yes but there is more to it. There is also the different input voltage conditions, output voltage conditions, load conditions, OTG, etc. You need the correct IADPT resistance to work.

    Typically, in power converter, magnetics (inductor) is a very important parameter and will affect the power stage frequency response as well as thermal & efficiency. For example, with a smaller inductor, peak current will be higher and efficiency will be different due to the inductor AC loss.

    This is a very good tool to understand operation for different power converters.

    https://www.ti.com/tool/POWERSTAGE-DESIGNER 

    For our ICs, this is proprietary information. Please follow the datasheet. If the IADPT pin is not assembled or if it is the wrong resistance, the converter will not perform great in certain conditions and may not work at all. Typically, the more integrated an IC is (easier to use), the more you want to reference the EVM. BQ25713 is a fairly integrated power converter.

    Thanks and I hope this helps,

    Peng

    *If my answer solves your question, please press "This Resolved My Issue" on the thread.