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TPS1H000-Q1: Hysterisis for resetting the thermal shutdown and swing Functional consultation

wulu
Prodigy 30 points
Part Number: TPS1H000-Q1

Tool/software:

Hello，

The chip also has a thermal turn-off of the thermal swing function, the swing T(hys) is 10℃, but for our actual equipment, the load on the PCB board will be opened and closed at any time, which will lead to the entire onboard temperature is changing, it is easy to turn off the output because of the thermal swing function, whether the thermal swing function can turn off the detection? However, it is also written in the following figure that Thermal Behavior After Short to GND, so does the diagnosis start when the output is short-circuited to the ground， The temperature change has no impact on normal use?

  • 0
    TI__Expert 4900 points

    Hello, 

    I am checking on this now and will get back to you soon. 

    Thank you,

    Sarah

  • 0 in reply to Sarah Raines
    TI__Expert 4900 points

    Hello, 

    The above diagram is an example of what thermal behavior looks like "after short to GND". The thermal protection features described are active all the time, not just after a short to GND. 

    Thank you, 

    Sarah

  • 0 in reply to Sarah Raines
    Prodigy 30 points

    Hello,

    That is not suitable for our application scenario, is there a chip without thermal oscillation protection, please recommend it!

  • 0 in reply to wulu
    TI__Expert 4900 points

    Hello, 

    All of our high side switches have these thermal protection features. 

    A PCB where the load is expected to turn off and on at any time is a common application for these parts. 

    Please consider the Layout Guidelines in sections 10.1 of the data sheet.

    Thank you,

    Sarah

  • 0 in reply to Sarah Raines
    TI__Expert 4900 points

    I would also like to be clear that the device does not shut down with only 10C. It will only shut off if temperature rises above T_SD or if the FET temp rises 60C above the controller. The latter should really only be expected in a short to GND case. 

  • 0 in reply to Sarah Raines
    Prodigy 30 points

    Hello,

    I think you still haven't captured my concerns. After my equipment is turned on, for example, I have a high-power load whose heat loss is around 10W. When the equipment is in normal operation, the on-board temperature is 70℃ when the load is not turned on, while the on-board temperature is 85℃ when the load is turned on, and the load is switched on and off randomly when we use it. Will the process of this switch cause the TPS1H000-Q1 chip to enter the thermal oscillation protection?Or is the thermal oscillation detection time very fast, much faster than the actual application of heating and cooling time, and will not shut off the output because of thermal oscillation?I don't know if I understand this correctly?

    The actual temperature change of the equipment is shown in the following figure:

  • 0 in reply to wulu
    Prodigy 30 points

    Hello,

    To clarify, I have been wondering whether the parameter T (hys) will be turned off because of the switching action of my device load!

  • 0 in reply to wulu
    TI__Expert 4900 points

    Hello, 

    T_HYS is just the hysteresis of the thermal swing shutdown reset. The parameter for thermal swing shutdown is 60C, but its expected that it may take 60C - 10C before a "safe operating temperature" is recognized again.

    Thank you,

    Sarah

  • 0 in reply to Sarah Raines
    Prodigy 30 points

    Hello,

    I would like to know whether there is a time requirement for the thermal pendulum to identify the swing of 10C. The time is not indicated in the figure below. If the temperature rises and falls very slowly during the load switch according to normal use, will the output not be shut down due to the thermal swing?

  • +1 in reply to wulu
    TI__Expert 4900 points

    Hello, 

    This is not a specific time parameter. The idea is the thermal swing represents the difference in the temperature of the FET vs the rest of the logic. So you see if the temperature of the power FET increased rapidly there would be a large temperature difference. If that difference is > 60C the device will trigger Thermal Swing Shutdown. --> ΔT = T(FET) – T(Logic) > T(sw)

    The device will recover when the temperature difference is at least 60C - T_HYS (10C). --> ΔT = T(FET) – T(Logic) < T(sw) – T(hys)

    This is described in section "7.3.5.4.2 Thermal Swing" of the data sheet. 

    Thank you,

    Sarah