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BQ25890EVM

p karunakar
Prodigy 150 points
Other Parts Discussed in Thread: BQ25892, BQ25890

Can you please confirm following things for BQ25890EVM.

  1. JP1  Description: For bq25892 input current setting: Low: adaptor port; High: USB input

Factory Setting: bq25890/5: Not installed; bq25892: short PSEL to LOW

 

      1. Current limiting can be set via Software IINLIM (REGISTER) OR HARDWARE ILIM PIN 10 (BQ25890).
      2. Whether in BQ25890EVM R19 potentiometer is used for current limiting(hardware current limiting)?
      3. Any modifications are required for bq25890 JP1 ? As it is mentioned Not installed so...
      4. Suppose initially current is limited to 700ma via hardware (resistor connected to ILIM pin) and whether in later case can be changed to 1000ma via software keeping same value of resistor connected to ILIM PIN?

 Whether bq25890 will limit current to 700ma or 1000ma?

2.Can you please tell usage of JP6? i.e

                Can you elaborate more on below lines?

                 “USB current limit selection pin during buck mode and PSEL is high/ Not installed Enable pin       during boost mode”

3.Whether JP7 must be shorted to LOW?  i.e to enable the charge CE must be pulled low 

4. What should be IR compensation resistor value  and IR Comp voltage clamp value?

5. In EVM there is no pot connected  for TS pin Y?

  • 0
    TI__Expert 8230 points

    Hello,

    See my comments below:

    1.  For a bq25890EVM, JP1 shouldn't be installed on a new EVM. You can install it if you are evaluating the D+/D- detection on the device. Potentiometer R19 is indeed used for input current limiting on the ILIM pin. By default on a new EVM, R19 should be set such that the input current limit will be ~500mA. The bq25890 will use the lowest value between the ILIM pin and the I2C input current limit register to set the actual limit. Assuming the ILIM pin is enable (I2C bit), if you set the ILIM pin to 700mA and then change the I2C register to 1000mA, the input current limit should be 700mA. If you wish to modify the I2C register while keeping the same resistor, you can disable the ILIM pin via I2C and then modify the input current limit register.
    2.  JP6 is used to pull the OTG pin low and disable OTG via hardware.
    3. JP7 is not required as there is a 10k pull-down installed in parallel with JP7, so CE is always pulled low and charging is enabled.
    4. This depends on your test setup. You can measure the trace impedance between the BAT pin and the battery terminal; and using the charge current you can calculate the voltage drop due to IR.
    5. No pot for TS pin, just a fixed resistor network to simulate the temperature profile thresholds.

    I recommend you review the bq25890EVM User's Guide ( SLUUBA2B) that covers all of the previously discussed in detail.