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BQ25185: ABOUT BQ25185DLHR DATASHEET

Norihiro Yoshii
Prodigy 50 points
Part Number: BQ25185

Tool/software:

I want to understand about BQ25185DLHR  DATASHEET.

reference

www.ti.com/.../bq25185.pdf

1,

1, P7 About KISET



1.What is the meaning of the formula in KISET Charge current setting factor, ICHG = KISET / RISET?

I understand that the current that can flow through the SYS terminal is correct?

KISET here is TYP 300Ω

RISET is ISET terminal is data sheet P1
Do you mean Simplified Schematic 1K?


2, ILIM/VSET of data sheet P1
Table 8-1. ILIM and VBATREG Resistor Map on page 16 of the data sheet

Do you mean the register?

ILIM/VSET is interpreted as a resistance that determines the upper limit of current when charging.
Is that correct?

P16's
ILIM1100 has an upper limit of current when charging: 1100mA
Is it okay to charge the ILIM500 with an upper limit of 500mA?
What happens if the ILIM/VSET resistance values ​​are different?
I would like to use 9.1K, but it is difficult to obtain, so I am trying to use 10K. What will happen?
Example 1: There is no 9.1K, so use 10.0K
Regarding the above
please tell me.
  • 0
    TI__Intellectual 2200 points

    Hello Norihiro,

    Norihiro Yoshii said:
    1.What is the meaning of the formula in KISET Charge current setting factor, ICHG = KISET / RISET?

    The formula ICHG = KISET / RISET calculates the value of the external pull-down resistor required between the ISET pin and GND to set the desired fast charge current.

    KISET is typically 300ΩA, so using a 1k resistor on ISET would set the fast charge current to 300mA.

    Norihiro Yoshii said:
    2, ILIM/VSET of data sheet P1 Table 8-1. ILIM and VBATREG Resistor Map on page 16 of the data sheet Do you mean the register?

    The BQ25185 is a standalone (RC-settable) battery charger that operates without I2C communication and does not have registers. The device is configured using pull-down resistors.

    Norihiro Yoshii said:
    ILIM/VSET is interpreted as a resistance that determines the upper limit of current when charging. Is that correct?

    Yes, the input current limit and battery regulation voltage are configured using a pull-down resistor on the ILIM/VSET pin.

    Norihiro Yoshii said:
    What happens if the ILIM/VSET resistance values ​​are different?

    ILIM/VSET is the same pin, so there will only be one resistor connected to this pin.

    Norihiro Yoshii said:
    I would like to use 9.1K, but it is difficult to obtain, so I am trying to use 10K. What will happen? Example 1: There is no 9.1K, so use 10.0K Regarding the above please tell me.

    It is preferred to use a 9.1k resistor, as using a 10k resistor will likely result in ILIM and VBATREG being set incorrectly.

    Best regards,

    Alec Lehman

  • 0 in reply to Alec Lehman
    Prodigy 50 points 
    I got the answer and
What I understood and
If you have any questions, please refer to the URL below.
I compiled it into a PDF.
If there are any mistakes
please tell me

    www.dropbox.com/.../20241121ANS-BQ25185.pdf

  • +1 in reply to Norihiro Yoshii
    TI__Intellectual 2200 points

    Hello Yoshii-san,

    To answer your questions in the file:

    1. The resistor on ISET can be selected based on the desired fast charge current; the 1k resistor is shown as an example.
    2. Yes, the resistor on the ILIM/VSET pin corresponds to the resistor values in Table 8-1.
    3. ILIM500 means the input current limit will be set to 500mA; ILIM1100 means 1100mA.

    Best regards,

    Alec Lehman

  • 0 in reply to Alec Lehman
    Prodigy 50 points 
    As per the URL below, 
    ILIM/VSET will be implemented at 18K. As a result, I believe that if CE is pulled down, no further control is required. Is that correct?

    www.dropbox.com/.../20241126-BQ25185.pdf
  • 0 in reply to Norihiro Yoshii
    TI__Intellectual 2200 points

    Hello Yoshii-san,

    Yes, using an 18k resistor for ILIM/VSET will set the battery regulation voltage to 4.2V. This means the BQ25185 will stop charging the battery once it reaches 4.2V.

    Best regards,

    Alec Lehman