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INA220: abnormal output when VCC5V drop to 2.2V and recovery

Part Number: INA220

Hi Expert, 

my customer is using INA220 in power monitor module, but we meet an issue, could you help to give some advice? thanks.

here is the schematic, VCC5V is 5V. but sometimes when poweroff the board, VCC5V will drop to 2.2V.

if the power input recovery to 48V, VCC5V recovery to 5V, but the voltage detector won't have 48V warning, still low voltage. when make VS pin drop to 1.5V and recovery to normal mode, it will work. could you give some advice?

BR

Chi

  • Hi Chi,

    what a confusing schematic... What components are mounted? The green or white?

    Where's the shunt? Is it a low side or high side current measurement? What is the "VBUS" voltage? What is the "VIN+" voltage?

    What do you mean by "recovery"? Where is the "voltage detector"? What is "normal mode"? Where does "VCC5V_A" come from?

    Kai

  • Hey Chi,

    If I understand you correctly, then I would think that maybe the device is not fully shutting down at 2.2V.  Since behavior is undefined in this supply range, it is hard to say what will happen.  My suggestion would be to send a register reset command (on reg 0x00) after you power it back up to help ensure that the device is at a known state.

    Regards,

    Mitch