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BQ24193: Temperature settings for battery on TS pins

Aliasgar lightwala
Prodigy 50 points
Part Number: BQ24193

Datasheet specifies the below:

The resistor bias network has been updated as below.

RT2 = ((Vvref X RTHcold X RTHhot X (1/VT1 -1/VT5)) / ((RTHhot X (Vvref/VT5 -1) -RTHcold X (Vvref/VT1-1))

Select 0°C to 60°C range for Li-ion or Li-polymer battery,
RTHT1 = 27.28 kΩ
RTHT5 = 3.02 kΩ
RT1 = 2.27 kΩ
RT2 = 6.86 kΩ

Cool temperature is 0 to 10 degree C

Warm temperature is 45 to 60 degree C

Information needed.

1.What is the value of Vvref?

2. What is the temperature range for COLD & HOT?

3.How RTHT1 and RTHT5 is derived?

4.What is the value for RTHHOT AND RTHCOLD to calculate RT1 and RT2 respectively.

I am planning to test the temperature change by changing the value of the Resistor RT1 and RT2 ,howerver there are somany unknowns(mentioned above).

Iam confused, kindly help!

Best regards,

Ali

  • 0
    TI__Mastermind 19195 points

    Hello Ali,

    1. Vref is the pullup for NTC bias resistors, must be VREGN -- see EC table, JEITA THERMISTER COMPARATOR
    2. You can adjust the range to what is required by your application. 
    3. Refer to the datasheet for your selected NTC
    4. RTHHOT  = RTHT5, RTHCOLD = RTHT1

    We have a calculation tool you can refer to here: www.ti.com/.../slvrbe3

    Best regards,

    Nick

  • 0 in reply to Nick Brylski
    Prodigy 50 points

    Thank you nick. i will look into the tool

  • 0 in reply to Aliasgar lightwala
    Prodigy 50 points

    hello nick,

    i have one more question.

    What should be the charge termination current set?

    if we set the default 256mA(it takes more time to charge), we have single cell 10000mAh battery.

    Can you suggest what should be the thumb rule for charge termination current.?

    Note: Charging current is set to 3Amps.

    If increasing the charge termination current, will the battery be fully charged?

    Kindly help.

    Regards,

    Ali

  • 0 in reply to Aliasgar lightwala
    TI__Mastermind 19195 points

    Hi Ali,

    The lower you set the termination current the more fully charged the battery will be. Lower termination currents will take a longer time to finished charging. The battery datasheet may have some info on this. Many of our devices have termination set to 10% of fast charging current by default but increases the termination current is OK to do.

    Best regards,

    Nick

  • 0 in reply to Aliasgar lightwala
    Prodigy 50 points

    hello nick

    i have one more query below:

    In the datasheet: Recommended operating conditions states:

    ISYS: Output current = 4.5A

    Fast charging current= 4.5A

    Does the charger IC can deliver both the currents at the same time, meaning it can Charge with 4.5Amps as well it can source 4.5amps to the load?

    I believe charging current will reduce with increase in the load current.

    kindly correct me here if am wrong.

    Regards,

    Ali

  • 0 in reply to Aliasgar lightwala
    TI__Mastermind 19195 points

    Hi Ali,

    ISYS is combined charging plus load current on SYS. So if charging at 4.5A we do not recommend have any load on SYS.

    For future questions we ask that you make a new post as the original issue has been resolved.

    Best regards,

    Nick