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TPS4H000-Q1: Outputs short to 16V vbat

Mohamed Hellal
Intellectual 2295 points
Part Number: TPS4H000-Q1
Other Parts Discussed in Thread: LM74700-Q1

Hi,

I would like to know if there is another way to support the outputs short to Vbat, like 16Vmax, rather than having serial schottky diodes at the outputs because these diodes bring a voltage drops and  TPS4H00-Q1 VCC supply is 5V here, and customer is asking to have min 4,5Vout to supply LEDs.

Do you have any ideas how this can be supported here ?

Thanks,

Mohamed 

  • 0
    TI__Genius 12410 points

    Hello,

    Are you worried about reverse current? That is what the diode is for on the output to stop reverse current flowing through the part. This is an NFET where the body diode faces back towards the supply. During a reverse battery event the channel will turn on to lower the power dissipation but there is no way to stop the current without an extra circuit.

    You can implement an ideal diode that TI has that can sit on the supply which has ~20mV drop. Something like the LM74700-Q1.

    However, if you have a diode at each of the outputs, the schottky diode voltage drop should be low. There are 200mV drop diodes at <1A.

  • 0 in reply to Cameron Phillips
    TI__Intellectual 2295 points

    Hi, 

    The concern is more against a short-circuit to Vbat at the output (different then reverse polarity), I agree it can be done with a serial schottky but the drop is not very welcome in this application.

    Do you see any potential possibility to support this protection in a different manner than with external serial diodes ? 

    Thanks, 

    Mohamed 

  • 0 in reply to Mohamed Hellal
    TI__Genius 12410 points

    Hello,

    I can only tell how to protect the device because if it is shorted to16V when 5V is on the input then there will be reverse current flowing through the device that would damage. IN that case you would nee something to block current back through the device.

    You would need and OVP switch at your load to turn it off it it saw 16V is the only other way I can think of doing what you are asking.