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BQ25883: Overload- / short circuit protection at SYS output

Urs Niedermann
Prodigy 50 points
Part Number: BQ25883

Dear team, 

what is the maximum current at the SYS output  (rms / peak)?
Does this output have an overload / overcurrent / short circuit protection?
Will the device be destroyed if there is a short circuit at the SYS output?
Thank you & kind regards
Urs Niedermann

  • 0
    TI__Guru**** 166996 points

    Hi Urs,

    Per datasheet section 7.3 on page 6, the maximum RMS discharge current is 5A with peak discharge current for 1us of 9A.

    Per datasheet section 8.3.11.1.4, The charger device continually monitors and compares VBUS to VSYS to protect against a system short-circuit event. In the event that VSYS drops to within 250 mV of VBUS during operation, a short circuit event is flagged and the converter stops switching. The SYS_SHORT_FLAG or SNS_SHORT_FLAG bit is set and an INT pulse is asserted to the host. The device attempts to recover from this condition automatically.  

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Prodigy 50 points
    Hi Jeff,
    Thanks for your quick answer.
    I have already read the two notes.
    In my opinion the current specification refers to the BAT pin and not to the SYS pin. Do exactly 
    the same values apply to the SYS pin?
    In battery mode there is no voltage source connected to VBUS. So VBUS is high-impedance. 
    What about the detection of a short circuit at the SYS pin? The detection limit of 250 mV measured 
    against a floating potential might not work to switch off the switcher. 
    Thanks for clarifying the two points.
    Kind Regards,
    Urs

    Hi Jeff,

  • 0 in reply to Urs Niedermann
    TI__Guru**** 166996 points

    Hi Urs,

    Per datasheet section 8.3.13.2 Battery Over-Discharge Protection,  when the battery is discharged below VBAT_SHORT_HYS, the BATFET is turned off to protect battery from overdischarge.To recover from over-discharge, an input source is required at VBUS. When an input source is plugged in, the BATFET turns on. The battery is charged with IBAT_SHORT current when the VBAT < VBAT_SHORT, or pre-charge current as set in IPRECHG registers when the battery voltage is between VBAT_SHORT and VBAT_LOWV.

    Regards,

    Jeff