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LM5050-1: A LM5050-1 controls multiple parallel MOS

Part Number: LM5050-1
Other Parts Discussed in Thread: LM74720-Q1, LM74800-Q1, LM74700-Q1

HI sir

I have a model that uses multiple OR-MOS (BSC010NE2LS,INFINEON,  )

I want to use one LM5050-1 to control multiple MOS

is this possible? Or you have better suggestions

TKS

  • Hi TKS,

    Yes, LM5050-1 can drive multiple FETs in parallel. May I know the following information so that I can suggest better parts for your application.

    • Vin Range:
    • Max load Current:
    • Features required: Reverse current blocking , ?
  • HI sir 

    Please refer to the following and i have one question

    Because I have different models, so there are different voltage and current,12V/66A is just one of the models

    How many multiple FETs in parallel in different models of FET that LM5050-01 can drive it

    • Vin Range:12V
    • Max load Current: 66A
    • OR-Mos: BSC010NE2LS*5PCS
    • Features required: Because the prototypes need to be used in parallel, it is necessary to Reverse current blocking
  • Hi TKS,

    LM5050-1 can drive multiple FETs in parallel. Given the constant Gate Source and Sink current, increasing the number of FETs in parallel increases the effective Ciss which leads to increase in Turn ON and Turn OFF times of the FETs. If these increase Ton and Toff are acceptable for the application, there should be no problem in using LM5050-1 to drive multiple FETs in parallel.

    If faster Ton and Toff times are required, you can consider using LM74810-Q1 (or) LM74720-Q1 in ideal diode only configuration as they have higher gate drive strength. 

  • HI sir

    If faster Ton and Toff times are required but not need Load Dump ,because our input voltage is from AC-DC, not from battery

    Is the LM7400 a better choice than the LM74810-Q1?

    TKS

  • HI TKS,

    The GATE drive strength of LM74700-Q1 is 11mA where as it is 20mA for  LM74800-Q1. You can decide between LM74700-Q1 and LM748001-Q1 based on this information. 

    LM74700-Q1:

    LM74800-Q1:

  • HI sir

    1: Can I ask a detailed question about the driver current ?

    How do I choose the correct driver IC  by calculating the drive current?

    This can help me to choose the correct driver IC in different CISS MOS

    2: Can LM74700-Q1 and LM748001-Q1 drive ciss 23500pF? Or need higher drive current 

    For example, there is a model as follows

    AC-DC power (Two power supplies in parallel)

    Input:90~264Vac

    Output V/A: 12V/66A

    OR-MOS:total ciss 23500pF   ( 5PCS MOS  in parallel) 

    TKS

  • Hi TKS,

    A decent approximation for calculating the Turn ON and Turn OFF times would be using the formula,

    i = C(dv/dt)

    Where,

    • i = I(GATE) , Use Source current for calculating Turn ON time and Sink Current for calculating Turn OFF time. 
    • C = total Ciss
    • dV = 10V 
    • dt = Turn ON time or Turn OFF time depending on the  I(GATE) source or sink current used

    You can choose the controller which provides acceptable Turn ON and Turn OFF times. 

    As I said earlier, both LM74700-Q1 and LM748001-Q1 can drive Ciss = 23500pF but the Turn ON and Turn OFF times would be increased. As Ciss is increased, the charge pump cap used for these devices has to be increased as per the formula below,