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LM5146: LM5146-Q1

Parth Shrivastava
Prodigy 60 points

Part Number: LM5146

Tool/software:

In the simulation, I have given an external bias supply to VCC Pin generated from output voltage and is >7.5V but when I tap on VCC, it still shows 7.5V. And also, there is no current in through VIN

  • 0
    TI__Genius 11865 points

    Hi Parth,

    • Can you please elaborate what you are doing here? 
    • What is the simulation that you have performed?

    Thanks,

    Best Regards,

    Taru 

  • 0 in reply to Taru Kapoor
    Prodigy 60 points

     

    I have provided external bias supply to VCC from DC/DC Output. Thus, when DC/DC Output reaches 15V, then VCC should transition from 7.5V to 12V but it remains at 7.5V extracting very high current to keep it at this level. (I believe the internal regulator is not turning OFF)

    The extra current is not going into Bootstrap Capacitor either

  • 0 in reply to Parth Shrivastava
    TI__Genius 11865 points

    Please share your simulation file. 

    Thanks,

    Best Regards,

    Taru

  • 0 in reply to Taru Kapoor
    Prodigy 60 points

    Hey,

    Actually, the Simulation File is a bit confidential, but I can share the Graphical Results with you

    Here, the Blue Line is the Voltage before 2.2Ohms, and Green one is VCC, the Red line is the current which is 506mA and is very large

    Actually If we back calculate,

    Icc = (8.615-7.5)/2.2 = 506mA, and when I change Zener voltage, the Icc current adjusts itself automatically to the value which will bring Vcc to 7.5V. The Output Bias supply should ideally give >7.5V and Icc should not be that much.

    Moreover, I have two Capacitors on VCC, 2.2uF and 100nF with Bootstrap Cap of 470nF and Bootstrap resistance of 2.2 ohms

  • 0 in reply to Parth Shrivastava
    TI__Genius 11865 points
    Parth Shrivastava said:

    Actually, the Simulation File is a bit confidential, but I can share the Graphical Results with you

    Can you atleast share an image of the LM5146 side of things? 

    If you dont want to post it on the forum - I have sent you a friend request - you can share that with me over there. 

    Thanks,

    Best Regards,

    Taru