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TIDA-01513: Addendum of TIDA-01513

Louis Huang
Prodigy 50 points
Part Number: TIDA-01513
Other Parts Discussed in Thread: TPSI2140-Q1

Hello Ti,

The addendum of TIDA-01513 application note provides the two-point isolation leakage error detection and also can calculate the Risop、Rison.
The method can meet the ISO6469-1 for get the each terminal to chassis resistance value.
In the ISO6469-1 standard also have define that the measuring device used in this test shall have an internal resistance above 10 M ohm.
But the simulation example of TIDA-01513 addendum that the internal resisatance not meet the internal resistance define.
Do you know the internal resistance design for the isolation resistance design is the must be meet requirement?

  • 0
    TI__Prodigy 80 points

    Which device do you mean that can not meet the requirement? The internal resistance of our device TPSI2140-Q1 is absolutely above 10M ohm. And could you also attach the original requirement of ISO6469-1.

  • 0 in reply to Bing Zou
    Prodigy 50 points

    Hello Bing Zou,

    Below is the TIDA-01513 example and which I mean is both of HV+ to chassis and HV- to chassis are 1.18Mohm. The total internal resistance not have 10Mohm.  

    Could you let me know which you mean the TPSI2140-Q1 internal resistance how to meet 10M?

    Here is capture from ISO6469-1 for internal resistance 10Mohm.

  • 0 in reply to Louis Huang
    TI__Prodigy 80 points

    Hi Louis,

    The 10M requirement here does not mean the discrete components, it says measurement device or voltmeter, that should mean a device with an ADC which can measure the voltage like MCU.y

    For the TPSI2140-Q1 internal resistance, you can check it in the datasheet, calculate it with the current of OFF states. 

  • 0 in reply to Bing Zou
    Prodigy 50 points

    Hello Bing Zou,

    We will use the TI solution to implement the isolation resistance measurement and the measure method is a kind of measure device. Hence, we consider the method need have an internal resistance 10Mohm.
    Here is capture from HP34401A multimeter.

    For the TPSI2140-Q1 internal resistance, could you please explain detail for me?

  • 0 in reply to Louis Huang
    TI__Prodigy 80 points

    Hi Louis,

    I think the reason why it set 10Mohm for the measurement device is to ignore the influence of it. And here in the schematic is a kind of input, is was considered. So i think we could not take it as a measurement device, it could be a measuring method. Or you take it as a measurement device, but the internal resistance should not be the resistor in the circle, it should be the resistance of TPSI2140-Q1 plus it.

    For TPSI2140-Q1, you can get to current and voltage in OFF states in the datasheet, and the R=V/I, you can calculate it.

  • 0 in reply to Bing Zou
    Prodigy 50 points

    Hello Bing Zou,

    Thanks for your reply.
    Yes, I think so.
    Using the TPSI2140-Q1 example to discuss, the internal resistance is SW1(TPSI2140-Q1)+R3+SW2(TPSI2140-Q1)+RDIV1+RDIV2 and should be equal or above 10Mohm.

    For this kind of desing of TPSI2140-Q1, I have some questions below:
    1. If consider the internal resistance(include TPSI2140-Q1 in the loop) is 10Mohm, the loop current will only have 0.1mA even low. It have any need to pay attention for the desing?
    2. Have simulation model can provide for TI Pspise of TPSI2140-Q1?
    3. What is the differrent of the switch current(Is1,s2) and repetitive avalanched rating(Iava)?
    4. Have any characteristic curve can provide for design reference? Ex.: Rds(on),Id...