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TPS2HB35-Q1: Schematic check and how to use SEL1, SEL2 and DIA_EN

Matthew Pole
Intellectual 300 points
Part Number: TPS2HB35-Q1
Other Parts Discussed in Thread: TPS27SA08-Q1, TPS27SA08, TPS2HB16-Q1, TPS1HB08-Q1,

Hi all, I want to check if copying the datasheet example is that is needed?

I have diodes on the power supply entering the board so I assume I don't need the ground protect?

Also, how do the SEL's and DIA_EN work? Can I just pull them up or down and still have diagnostics instead of routing to uC? Thanks!

  • 0
    TI__Mastermind 32650 points

    Hi Matthew,

    I have one major concern: It looks like you are using this device with a 24V input voltage. This device is rated for 12V automotive applications. It is not rated for 24V automotive applications. The maximum voltage that is supported is 18V with respect to the current limit. I would recommend looking at TPS27SA08-Q1. This device clamps current at 20A. Please note that while this device will protect at higher voltages it will not support the 60V load dump required for 24V ISO compliant. External clamping must be used here.

    SEL and DIA_EN can be pulled high or low externally and the device will function as expected. They do not have to be connected to a MCU. With an upstream diode, the GND network is not necessary.

    I noticed that you have no connection to the SNS pin voltage? Are you planning to use the SNS voltage? 

    Thanks,

    Shreyas

  • 0 in reply to Shreyas Dmello
    Intellectual 300 points

    Hi Shreyas,

    Ah I see, I got suckered in by the 36V continuous max current. I skipped past the 18v section. Do you know of any automotive part that would allow up to 32v? Or would I be better off stepping my 20-32v input down to 12v? This HS switch would be used for driving Gigavac contactors

    Thanks!

  • 0 in reply to Matthew Pole
    TI__Mastermind 32650 points

    Hi Matthew,

    It really depends what you mean by allow 32V. As you may have seen with HB35, we spec the load dump compliance up to 40V. Some of our devices like the mentioned TPS27SA08-Q1 can also do higher voltage DC(24V) but do not support 24V load dump(which is 60V). Some our of older TPSxHxxx series of devices, support 32V DC but are only built to a max of 40V (once again for the auto 12V load dump spec)

    At this time please take a look at the following devices as they might work (but will all require external clamping for auto load dump for 24V auto systems). TPS1H100, TPS1HC30, TPS1HC100, TPS27SA08.

    Finally, if you do have the option to buck down to 12V, that will increase the number of devices that will support your application and will allow you to chose an R_on that is more appropriate for your load.

    Thanks,

    Shreyas

  • 0 in reply to Shreyas Dmello
    Intellectual 300 points

    Hi Shreyas,

    So by 32V I mean that my system have a 12-32V supply voltage range so I am looking for a device that can operate HV gigavac contactors at any voltage in that range. I am happy to have clamping outside.

    as for stepping down is there any set of components that will be ok with stepping 12-32v down to 12v and driving inductive loads with that 12v supply without causing any issues? 

    what do you suggest as the best route? 

    thanks again! Appreciate the help!

  • 0 in reply to Matthew Pole
    TI__Mastermind 32650 points

    Hi Matthew,

    For those DC voltages, the only option might be TPS1H100 which is a single channel, 100mOhm device. I do not think it will work for your application current. Therefore stepping down might be the best option.

    I cannot comment on DC-DC converters as that is handled by a different team. Please look at the TI converters here:

    https://www.ti.com/power-management/non-isolated-dc-dc-switching-regulators/step-down-buck/overview.html 

    Then please tag a potential device in a new E2E post and it will be directed to the right team for the fastest and most accurate response.

    Thank you for your interest in TI High Side Switches.

    Shreyas

  • 0 in reply to Shreyas Dmello
    Intellectual 300 points

    Hi, I will ask the question over on the DCDC side and see what they suggest. Lastly If I can drop down to 12V then what HS switch would you suggest for driving the HV contactors? I need to drive 4 contactors all together (would have had 2x HB35’s) thanks!

  • 0 in reply to Matthew Pole
    TI__Mastermind 32650 points

    Hi Matthew,

    This depends on the output current required by the contactors. For multi channel, we offer TPS2HB16-Q1 as well. For single channel, we offer TPS1HB08-Q1. The expected currents will dictate the on resistance chosen and the current limits set. Also note the amount of inductive energy these contactors will require to dissipate on the OFF event. If it is large, external inductive clamping might be required.

    Thanks,

    Shreyas

  • 0 in reply to Shreyas Dmello
    Intellectual 300 points

    So at 12V it will have a closing current of ~3A at 12v supply and ~7A at 32V and both will be less than 150mA continuous current when closed. They are also internally PWM driven so no back EMF when the coil opens.

  • 0 in reply to Matthew Pole
    TI__Mastermind 32650 points

    Hi Matthew,

    At 12V, 3A TPS2HB16-Q1 and TPS2HB35-Q1 will both be good options. 

    Thanks,

    Shreyas