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TPS1H000-Q1: Loss of ground issue

Sirui Zhu
Intellectual 2090 points
Part Number: TPS1H000-Q1
Other Parts Discussed in Thread: TPS1HTC30-Q1, TPS272C45, TPS274C65, TPS281C30

Hi team,

According to our application note Designing for Loss of Ground and Loss of Battery on Texas Instruments High-Side Switches, there will be an 200kohm path which may cause unwantted turn-on if an low-impedence path exist between power supply and GND.

My customer has used an e-fuse on the power supply, which has leak current and the low-impedence path. The app note also suggest TPSxHAxx and TPSxHBxx series has solved the internal 200kohm path issue, however customer needs 40Vin and ~1A load capability to drive loads. Could you please suggest a device that can meet customer's demand?

BR

Sirui

  • 0
    TI__Mastermind 32650 points

    Hi Sirul,

    We do not have many 40V DC compatible high side switch devices available at this time that are automotive rated. One solution is to use the steering diode fix as mentioned in the same application note in Figure 1-6 with the same device or a lower Ron device like TPS1H100 to avoid any possible damage during this double fault condition (loss of GND and simultaneous output short to GND).

    If the customer is willing to change their device, please look at TPS1HTC30-Q1. This is part of our new generation high voltage high side switches.

    Thanks,

    Shreyas

  • 0 in reply to Shreyas Dmello
    TI__Intellectual 2090 points

    Hi Shreyas,

    Customer doesn't really need automotive rated device since it's an industrial application. 

    Customer feedback adding the GND network didn't help with the issue, can I suggest them to increase the resistor, e.g., 4.7kohm, to increase the voltage drop between IC GND and module GND?

    Customer also want to know whether our new released device has solved the issue, but I can't tell which device is good. Could you please share how to tell whether a device have this internal parasitic path? 

    BR

    Sirui

  • 0 in reply to Sirui Zhu
    TI__Mastermind 32650 points

    Hi Sirui,

    The GND network that is needed for this situation is not the same as the GND network for other conditions. We recommend the following network:

    You cannot increase the resistance of the conventional GND network for the TPSxHxxx devices. The resistance must be kept to 1kOhm.

    Please note that all newer devices do not have this internal path. This path is limited to TPSxHxxx devices and their industrial versions. (HA, HB and HC devices along with TPS272C45, TPS274C65 do not have this leakage path) I would recommend looking at the new generation of high side switches that are meant to work to 60V like TPS1HTC30 and TPS281C30.

    Thanks,

    Shreyas