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bq51003 Vout termination condition.

HsinHung Lee
Intellectual 300 points
Other Parts Discussed in Thread: BQ51003

Hi,

We're using the bq51003 for new design. Would you help to tell us the priority and condition that will cause the Vout be terminated by M1 MOSFET?

And What does the VIABS,FB/ VREF,IABS/ VIN,FB means? And how do I check the Vout termination condition when it is triggered.

Stanley

  • 0
    TI__Guru* 75486 points
    Hello Stanley
    Is this a termination with TX restart or very short drop in output voltage?
    What is voltage at RECT doing during this time?
    What is output current?

    Vout termination is most often caused by an output current overload, output current limit tripping. This is set by resistors value from ILIM to gnd.
    It could also be Adaptive Communications Limit reducing output current during comm time at higher currents, it can be disabled using EN1 / 2 pin.
    A couple of conditional will cause Voltage at RECT pin drops below OUT resulting in output voltage dropping. During FOD conditions the TX will reduce power to the RX to try and operate in a safe area. This will show up as a low RECT voltage. If the coupling between RX and TX is poor and load is high RECT voltage will be low.

    The three control ckts:
    1.) VILIM is the output current limit set by resistor on ILIM pin
    2.) VIABS is absolute max output current that is set internally
    3.) VIN,DPM will only enable output when input voltage above the target, used at start up.
  • 0 in reply to Bill Johns
    Intellectual 300 points

    Dear Bill,

    I run the dynamic loading test,

    and I  apply the dynamic loading as below settings:

    high load= 100mA/10ms; low low load= 40mA/10ms; RX Imax=500mA, 

    as you see the charging behavior on the Vout will suddenly drop and recover , and the Vrect keep output for 1.5s.

    is the Vrect's behavior normal or not? can bq51003 support this dynamic loading?

    Thanks

    Stanley