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BQ25172: Clarification Request on VOUT_OVP and VRECHG Threshold Behaviors

Conor
Guru 12165 points
Part Number: BQ25172

Tool/software:

Hi,

We would appreciate your confirmation on the following three points regarding the BQ25172 device behavior:

  1. The datasheet defines both rising and falling thresholds for VOUT_OVP, suggesting a hysteresis mechanism.
    Could you confirm whether the device terminates charging when the output voltage exceeds the rising threshold (e.g., 1.70 V/cell), and resumes charging when the voltage drops below the falling threshold (e.g., 1.45 V/cell)?

  2. Our understanding is that VRECHG serves as the voltage threshold to initiate recharge when intermittent charging is enabled. Is this correct?

  3. When intermittent charging is disabled, it appears that the device still resumes charging once the battery voltage drops below VRECHG.
    Is it correct to say that VRECHG is used internally as the recharge trigger even in non-intermittent mode?
    Also, are there any other voltage thresholds that can trigger a recharge cycle?

Thanks,

Conor

  • 0
    TI__Guru* 75876 points

    Hi Conor

    Conor said:
    The datasheet defines both rising and falling thresholds for VOUT_OVP, suggesting a hysteresis mechanism.
    Could you confirm whether the device terminates charging when the output voltage exceeds the rising threshold (e.g., 1.70 V/cell), and resumes charging when the voltage drops below the falling threshold (e.g., 1.45 V/cell)?

    Bill J – Terminates charging above1.70V/Cell-Yes charge complete and fault is set (Blink at 1Hz).  Does NOT resume charging at 1.45V/cell. But fault will clear.

    Conor said:
    Our understanding is that VRECHG serves as the voltage threshold to initiate recharge when intermittent charging is enabled. Is this correct?

    Bill J – Yes

    Conor said:
    When intermittent charging is disabled, it appears that the device still resumes charging once the battery voltage drops below VRECHG.
    Is it correct to say that VRECHG is used internally as the recharge trigger even in non-intermittent mode?

    Bill J – No, with intermittent charging disabled unit will only charge one cycle. 

    Conor said:
    Also, are there any other voltage thresholds that can trigger a recharge cycle?

    Bill J – The TS pin can also be used to trigger a reset and start a recharge cycle.  Pull low then release.

  • 0 in reply to Bill Johns
    Guru 12165 points

    Hi Bill,

    Thank you for your reply.

    Bill Johns said:
    Bill J – Terminates charging above1.70V/Cell-Yes charge complete and fault is set (Blink at 1Hz).  Does NOT resume charging at 1.45V/cell. But fault will clear.

    Regarding VOUT_OVP in question 1, when the battery voltage drops to the falling threshold, will charging resume if I drop TS to LOW and release it, just like with normal charging?

    Or is a power-on reset of the IC required, etc.?

    Thanks,

    Conor

  • 0 in reply to Conor
    TI__Guru* 75876 points

    Hi Conor

    Conor said:
    Regarding VOUT_OVP in question 1, when the battery voltage drops to the falling threshold, will charging resume if I drop TS to LOW and release it, just like with normal charging?

    Bill J -- Battery voltage drops from 1.7V / Cell (OVP) to range of 1.45V - 1.33V / Cell.  Charge will not restart.  Also pulling TS low release will not restart charge.

    Conor said:
    Or is a power-on reset of the IC required, etc.?

    Bill J -- If the battery voltage is in range of 1.45V - 1.33V / Cell power on will not restart charge.  The battery voltage must drop below 1.33V / Cell before charge starts.