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bq24193 System Over-current Protection

Teik Hooi Teoh
Intellectual 655 points
Other Parts Discussed in Thread: BQ24193

Hi,

The datasheet briefly describe the system over-current protection under Battery Protection section.

Is this protection described for battery discharge under supplement mode (without VBUS input sources)?

There also seems to be no clear specifications on this protection:

What are the threshold voltage/current to trigger/release etc. ?

Is there a system over-current protection during system regulated with VBUS input source? What are the specifications?

  • 0
    Guru 22270 points

    Hello Teik,

    The data sheet specifies the registers that can be written to if you do not want to use the default parameters.  These are listed starting on page 17 of the bq24193 Datasheet.  In the Detailed Description section, it further describes these setting before you get to the Battery Protection section and they point to the registers need to control them.

    The threshold values (parameters) are set by the bit values in the register.  There are also more specs in the Electrical Characteristics section on page 9.  You can also try looking at the Manual for the EVM.  There may also be a Technical Reference Manual for the bq2419x family that would provide even more detail.

    Thanks,

  • 0 in reply to Greenja
    Intellectual 655 points

    Hi Geenja,

    I understand that the registers can be written with new values.

    However, they seem to be unrelated to system over-current protection settings.

    I could not find the related register settings or electrical specifications for it.

    Perhaps you can give me some pointers if I missed it.

    Regarding the Technical Reference Manual could you guide me to the link? Can't seem to find it. Thanks!

  • 0 in reply to Teik Hooi Teoh
    Guru 22270 points

    Hello Teik,

    The System over-current protection is based on the over-current limit that is set  either through hardware by the ILM resistor or through i2c in registers REG 00.  If there is an over-current fault then the REG 09 bit6 BOOST_FAULT will be set.  The same applies to the battery charging limits which are set through software REG 02/03/04.

    There doesn't seem to be a TRM for this device, but the datasheet provides the information you need for proper configuration of the registers.

  • 0 in reply to Greenja
    Intellectual 655 points

    Hi Greenja,

    If I understand correctly, the ILM pin or register REG00 setting are meant for VBUS maximum current limit. 

    However, if there is no input source to VBUS and charger is operating solely on battery, where only battery is supplying to the system load, there is still a system over-current protection according to datasheet.

    But there is no available information on the fault threshold level and conditions for it to be activated.

    I am interested to find out these information. Please help. Thanks!

  • 0 in reply to Teik Hooi Teoh
    Guru 22270 points

    Hello Teik,

    The over-current protection when the battery is connected would follow all the parameters in the Electrical Characteristics.  

    The Battery Charger section and Battery Over-Voltage Protection section and CHARGE OVER-CURRENT COMPARATOR on page 10 and 11.  These min/max values are what the bq24193 use to determine if there is a fault.

    From the Vshort row you can see that if the bq24193 see a voltage of 1.8V battery short condition exist.  You can find the Ishort battery short current in the same manner.

    The Electrical Characteristics section is a vital part of any datasheet.  If parameters are not given in Detailed Description section of the document then they can usually be found  in the Electrical Characteristics.

    Thanks,