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TCA6424A: Sleep mode confirm

Amelie Zheng
Genius 10865 points
Part Number: TCA6424A
Other Parts Discussed in Thread: TCA6424

Hi Team,

In data sheet, it is necessary to set all IOs as inputs to achieve lower power consumption. Is there any other way to make IOs not need to be set as inputs to achieve lower power consumption? Or some ports keep the output high, and other ports are set as input, can the power consumption be reduced?


TCA6424ARGJR's IO is all used as output GPIO application (output high or output low) in normal working mode,
Some modules cannot be powered down when the system is in sleep mode, and their power is controlled by the IO of TCA6424ARGJR, so the output is high even in sleep mode;
The whole system has low power consumption requirements, and it is not possible to set all the IOs of TCA6424ARGJR as inputs to reduce its power consumption, so customer would like to confirm whether there are other ways to make all or part of the IOs of TCA6424ARGJR can be set as output and function. Consumption is reduced to a minimum;

  • 0
    TI__Genius 15345 points

    Hello,

    This is an interesting predicament. In general input ports will see less current consumption on the device because the TCA6424 is not supplying the current for these pins.  

    The current consumption that you see from an output port is going to come down to how much current your output pin is going to consume. If all your output ports are going to draw current at the same time you will see a bigger spike in power consumption from the device. If they are going off and on at different intervals you will see less power consumption. There is nothing you can really do from the TCA6424 side, it will supply as much current as your output pins are drawing.

    Now if you decided to make some of your ports input ports when the output functionality is not being used you will need to have resistors that reference them to GND or VCC. If you leave these pins floating then there is a chance you could potentially turn on the gate of the ports and see shoot through current. This would increase your current consumption.

    In general it is best to reference these ports to VCC, you will see less current consumption that way.

    If you have output ports that don't have predictable on and off states then it is best to keep these ports set as output ports. It is especially important that you don't make any output ports that could float input ports. Once again this could increase your current consumption.

    In general, you could also decrease your current consumption by decreasing the load you are driving, for instance if you had a series resistor, increasing that resistance would lead to less current consumption.

    If this answered your question don't forget to hit the button. If you have any more questions let me know.

    Best,

    Chris