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1.5mA quiescent current found on TPS62730 in Auto BYPASS SWITCH range

Other Parts Discussed in Thread: TPS62730, TPS62733

Hi,

In my design with 2.3-2.4V input in no load, tps62730 is supposed to be Auto BYPASS SWITCH mode. However, I found it entered PWM and caused 1.5mA on the input. If the input is less than 2.3V or higher than 2.5V, the quiescent current is normal in uA level. Could you give comment on what may trigger the PWM mode?

Thanks

  • Hi Di Wang1,

    please find my comments and questions below:

    1. TPS62730 automatically enter bypass mode once battery voltage (input voltage) falls below 2.2V. It means that input voltage range 2.3V-2.4V cannot cause entering bypass mode. Question: What is input voltage range for your application?
    2. If there is no output current(no load connected to the output) TPS62730  operating quiescent current is in range 23uA-40uA. Is there any load connected to TPS62730 during testing?
    3. Would you please share schematic?
    4. Which kind of device are you using for measuring input current?

    Best regards

    Lubomir

  • Thank you, Lubomir.

    1.The input range is 2.1V~~3.1V;

    2. It was absolutely no load, no any connect for evaluation;

    3. There was no operation on ON/BYP (UP_EN_+2V7_TXD network). The inductor is CBL2012T4R7M()

    The capacitors are 0603 package.

    4. This multimeter Keysight 34410A. 

  • Hi Di Wang1,

    1. Input voltage range is 2.1V-3.1V. Output voltage is labeled: VDC-2V7.
      • Is output voltage 2.7V?
      • What is acceptable variation of the output voltage?
      • What is maximum output current for application?
    2. The part number TPS62730 is used in thread: 1.5mA quiescent current found on TPS62730 in Auto BYPASS SWITCH range but I see TPS62733in schematic.
      • Which part is really used?
    3. Are there any resistors (which are not in the schematic above) for example sense resistors connected to nets VBAT-ON or VDC-2V7?
    4. I measured input current on the EVM (evaluation module) and it is in line with datasheet. Would it be possible for you to order EVM: http://www.ti.com/lit/ug/slvu455a/slvu455a.pdf and measure it? then we will be sure that we are measuring the same power supply.
    5. Pin #1 is STAT pin. It is not START pin as it is labeled in schematic.

    Best regards

    Lubomir Fenic