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Original question:

LM66100: Reverse polarity protection with TVS diode and polyswitch

LM66100: Control for CE pin

Shunsuke Nagata
Genius 13070 points
Part Number: LM66100
Other Parts Discussed in Thread: TPS22916, TPS2121, TPS2113A, TPS2115A

Hi, 

Could you please give me advice for control to CE pin? I would like to use LM66100 without control signal to CE pin.

I would like to support below working:
Supply Power ON -> Rise VIN -> Turn on internal FET -> Supply power OFF -> Decrease VIN -> Turn off internal FET..

If CE pin short to GND (Always active), will device can support above sequence? I guess Internal FET may be turned off due to low input voltage.
I don't want to use external component (such as resister divider between VCC and GND for CE)

Regards,
Nagata.

  • 0
    TI__Mastermind 32650 points

    Hi Nagata-san,

    Are you looking for an ideal diode device or a load switch? Your control sequence seems to indicate that you are looking for a switch rather than an ideal diode as you want to have control of turn on and turn off. Please refer to the TPS22916 and similar devices if this is the case.

    For LM66100, the control structure uses VIN and CE as the two reference voltages. Whenever VIN > CE the device turns ON and when CE > VIN, the device turns off. Depending on how the CE pin is connected, the device will protect against different situations. For eg, connecting CE to GND results in an always on device that protects against reverse polarity or incorrect supply configuration events. The device will be off whenever GND > VIN. If Ce is connected to VOUT, this will result in a reverse current protection nature as VOUT > VIN during reverse current. These configurations are described in the LM66100 datasheet in Section 8.3 and Section 9.

  • 0 in reply to Shreyas Dmello
    TI__Genius 13070 points

    Hi, Shreyas -san,

    Thank you for your information. I would like to use LM66100 for diode-OR instead of SBD. If you have plan to have ACTIVE high in CE pin, I can control turn ON / OFF from external components. Is there a device which support Active high in CE pin?

    I'm trying to set as below system:

    When Power supply to VIN1 and no supply to VIN2, Turn on LM66100 of VIN1 side and turn off VIN2 side.
    When Power supply to VIN2 and no supply to VIN1. Turn on VIN2 side and turn off VIN1 side.
    When Power supply to VIN1 and VIN2, turn on one of side and turn off another side.

    -> It may complicated.  But if there is a device which support active high CE pin. I can control it.

    Regards,
    Nagata.

  • 0 in reply to Shunsuke Nagata
    TI__Mastermind 32650 points

    Hi Nagata-san,

    LM66100 is built for OR-ing two supplies as well. This takes two LM66100s and connects the CE of one device to the VIN of the other device. Please refer to the Applications section (Section 9) in the datasheet for more information. The LM66100 EVM also has a example schematic for OR-ing. The device will automatically chose the highest voltage at any given time and pass it to the output.

    If you want to select which rail is chosen, you will need to use a PowerMUX device like TPS2113A, TPS2115A or TPS2121 depending on your application requirements.