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LM5050-1-Q1: Use of LM5050-1 for ORing negative Power?

Part Number: LM5050-1-Q1
Other Parts Discussed in Thread: LM5050-1, LM5051

Hello,

Can I use LM5050-1 For ORing negative voltages? If yes how? if no then, are there any other negative ORing controllers available?

Regards

Vishal Kakade

  • Hello Vishal,

    LM5050-1 is not recommended for negative voltage ORing.
    LM5051 and TPS2352x devices support ORing negative power rails.

    However, TPS2352x has support for hot-swap as well.

    Regards,
    Kari.
  • Hello Kari,

    I want a negative  ORing controller which can work from -5V to -20V. 

    I have one more doubt, Other than Voltage drop and Power dissipation, what is the advantage of using LM5050-1?

    Regards

    Vishal Kakade

  • Hi Vishal,

    LM5051 can work at -5V VIN with UVLO -4.5V.
    Power Vcc pin from VIN directly as shown in Figure 29 of datasheet of LM5051. Rbias resistor can be chosen based on the calcuations shown in the datahseet and may not be needed here as Vin is 5V. Direcly tie the Vcc pin to Vin and leave "LINE" floating.

    Advantages of using LM5050-1 against a simple diode are power dissipation reduction, less forward drop of 22mV allows downstream power rails more voltage room to operate. Next, it saves cost and size of heat sink required with diodes. Reverse leakage across temperature is much higher with power diodes whereas with LM5050-1 + NFET, reverse leakage is relatively less across temperature.

    Let me now if you require more details.
    Could you let me know more about the application this would be used?

    Regards,
    Kari.