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Original question:

TIC12400: Requirement of 24 Active high channel

TIC12400: Requirement of 24 Active high channel

umamaheswar peta
Expert 1370 points
Part Number: TIC12400

Hi,

We have considered TIC12400-Q1 part in one of our Telematics design to read multiple inputs from vehicle.

We have few technical query as below,

  1. Is it possible to detect Short to Battery and Short to Ground for High side input ? If yes, please provide the details.
  2. Is it possible to detect Short to Battery and Short to Ground for Low side input ? If yes, please provide the details.

 Kindly help on this.

Best Regards,

Umamahesh

  • 0
    TI__Mastermind 22965 points
    Hi Umamahesh,
    One of my colleagues is looking into this and will follow up.

    Can you please share how the device is being used and what type of switches (along with resistance values) are being used?
  • 0
    TI__Intellectual 2355 points

    Hi umamaheswar ,

    Yes, it is possible to detect the conditions you described with TIC12400-Q1:

    The methods are explained as below:

    1. Short to battery for ground connected switch

    Using 2 Input pins ( one with a pull up source and one with a pull down sink) connected together with the same switch can allow short to battery for ground connect switch detection.

    Configuration as below:

    When Switch is connected to ground, the integrated ADC is able to determine if the switch network is in normal operation or short to battery. The truth table is as below:

    2. Short to ground for battery connected switch

    Similarly, with the same 2 input configuration, the truth table become the below:

    3. Short to ground for ground connected switch:

    • This can be achieved by using one input. By adding a resistor in series with the connected to ground switch, the ADC can distinguish if the input is shorted directly to ground or if the switch was closed.

    4. Short to battery for battery connected switch

    • This can be done if Vbat in the system is stable and using one input pin. If the Vbat level is consistent, adding a resistor in series with switch can enable the ADC to determine if the device is shorted to Vbat or the switch is closed.