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Original question:

BQ25606: BQ25606

BQ25606: Charge current and NTC protection question

Kami Huang60
Genius 3830 points
Part Number: BQ25606

Dear Sir/Ms.

The customer has a new case using a TI BQ25606, and would like to ask the following three questions:

1. When the resistance of RT1 & RT2 is 5.23K & 30.9K as follows, NTC = 10K, would like to ask at this time
What is the low temperature protection & high temperature protection?
Is there a tool for easy calculation ?? Or is there a calculation formula ??
A: I have provided the formulas in Datahseet to clients. But the client asked extension questions.
Q1-2: If there is no excel tool for the first point,
Then when the resistance of RT1 & RT2 is 5.23K & 30.9K, NTC = 10K (datasheet EQ1 and EQ2), would you like to know what the low temperature protection & high temperature protection temperature is at this time?

2. Does this IC have OVP & OCP protection?
If yes, how much are they? Or can they be adjusted or fixed?
A: My answer is fixed. The client asked another extension question.
 
Q2-2: If my voltage battery is fully charged at 4.2V, what is the voltage point of OVP?

3. Is there a Re-charge for this one? If so, how much will it charge back when the voltage is adjusted?
I didn't find it in the specifications.

Best Regards,

Kami Huang

  • 0
    TI__Mastermind 25800 points

    Hey Kami,

    For question 1, the equations (1) and (2) in the datasheet in section 8.3.6.4 JEITA Guideline Compliance During Charging Mode describe how to calculate the two RT1 and RT2 values depending on the thermistor profile and their desired low and high temperature cutoff.

    The value of NTC = 10k is not helpful. The customer needs to provide the NTC value @ Hot Temp and the NTC value @ Low Temp in order to identify the correct RT1 and RT2 values for their temperature window. 

    For question 2, the battery OVP protection of the charger is a percentage of the charging regulation voltage. You can refer to section BAT PIN OVERVOLTAGE PROTECTION of the datasheet EC table. It cannot be adjusted. 

    For question 3, you can refer to parameter VRECHG of the datasheet EC table for the recharge voltage threshold.

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    Genius 3830 points

    Hello John,

    Just check with customer RD He think you solve their question.

    Thanks for your kindly help.

    Best Regards,

    Kami Huang

  • 0 in reply to Kami Huang60
    Genius 3830 points

    Hello John,

    One more question.

    When my battery exists, but I remove the power from the input terminal (VBus / Vin),
    Will the battery voltage be recharged to VBus / Vin at this time?
    My knowledge will not be right, please help me confirm it again, thank you !!

    Best Regards,

    Kami Huang

  • 0 in reply to Kami Huang60
    TI__Mastermind 25800 points

    Hey Kami,

    This is not the case. When VBUS is removed, the converter is disabled unless you have pulled the OTG pin high. When the OTG pin is pulled HIGH, the converter will operate in reverse boost mode to regulate VBUS to 5V from a lower voltage battery.

    But in this mode, the battery is not "recharged to VBUS". 

    Regards,

    Joel H