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LMG3100R017: Need Input current (Icc) vs Frequency graph

Sundar Raj A
Prodigy 71 points
Part Number: LMG3100R017
Other Parts Discussed in Thread: LMG3100R044,

Tool/software:

Please share the graph of Input current vs Frequency, Thank you 

  • 0
    TI__Expert 8553 points

    Hi Sundar,

    Thanks for reaching out.

    You can calculate based on the equation below:

    Ivdd = Ivddq + Fsw*k + Qg*Fsw*D

    From datasheet;

    Ivdd = 10mA, Ivddq = 0.17mA, Fsw = 500kHz, Qg = 7.3nC, D=50%, we can calculate k.

    k = 14.01*10^-9 A/Hz

    Then using the constant k in the equation, Ivdd can be calculated for different Fsw.

    Best,

    Pratik A.

  • 0
    Prodigy 71 points

    Hi Pratik,

    Thank you for sharing this information.

    I have one more question: In this MOSFET, how can we use the zero current switching (ZCS) option? How does it need to be configured?

  • +1 in reply to Sundar Raj A
    TI__Expert 8553 points

    Hi Sundar,

    This GaN IC doesn't have ZCD (zero current detection) option. To externally perform this you need to use a resonant converter topology like LLC or SRC and add a zero current detection circuit to detect the instant the current becomes zero. 

    For current based ZCD:
    1. Current Sensing: Place a low-value sense resistor in series with the GaN device's power line to minimize conduction loss, such as a 10mΩ resistor.
    2. Bias Voltage: Apply a bias voltage to one side of the sense resistor to ensure the sensed signal is always positive, regardless of current direction, according to OSTI.gov.
    3. Amplification: A high-bandwidth amplifier is needed to magnify the small voltage drop across the sensing resistor into a signal that can be easily processed.
    4. Comparison: Connect the amplified signal to a high-speed comparator, which will output a digital signal when the current crosses zero.
    5. Digital Output: The comparator's output is typically routed to a digital isolator and then to a microprocessor for further control. 

    Best,

    Pratik A.

  • 0 in reply to Pratik Adibatla
    Prodigy 71 points

    Hi Pratik,

    Thank you for sharing the information.

    Could you please explain how to calculate the K value?
    In my case, Ids is 35 A, the frequency is 3 MHz and 1 MHz, and the duty cycle (D) is 50%.
    How can we calculate Qg and K for this case?

    Regards,

    Sundar 

  • 0 in reply to Sundar Raj A
    TI__Expert 8553 points

    Hi Sundar, 

    Qg is fixed 7.3nC from datasheet and k is a constant = 14.01*10^-9 A/Hz.

    Now for different Fsw & D you can calculate the Ivvd as Ivddq is also constant.

    Best,

    Pratik A.

  • 0 in reply to Pratik Adibatla
    Prodigy 71 points

    Hi Pratik 

    Qg for LMG3100R017 is 20-29nC not 7.3nC, for the part LMG3100R044 Qg is 7.3 nC, Right?  Please find the attached for your reference, 

  • 0 in reply to Sundar Raj A
    TI__Expert 8553 points

    Hi Sundar,

    Apologies for any confusion. The datasheet values would be correct.

    Best,

    Pratik A.