Hi All,
I am currently doing a project on MOSFET, therefore, i need to understand the specification of the MOSFET in order to make a judgement whether this part can or cannot be used. However, I face some difficulty during the progress, and i need expert advises on the following matter:
Question 1: How to determine the gate current required for the calculation of the switching loss?
Background 1: I would like to find out the total power dissipation of the MOSFET. However, i am facing the difficulty on calculating the switching loss as i not understand the how to determine the "gate current" of the MOSFET. The confusion come from my understanding toward the operation of the ideal mosfet that there is no current flow to the gate of the mosfet. The drain source resistance is controlled by the gate voltage. Therefore, is the gate current required here referring to the specification "Gate-Source Leakage Current" stated in the datasheet? Please advise.
The document availabe at (page 4): https://pdfserv.maximintegrated.com/en/an/AN1832.pdf
Question 2: Why the On-resistance getting higher when the drain current higher under the constant gate voltage?
Background 2: I am thinking from the perspective of V=IR. When the voltage is kept constant, shouldn't that the On resistance value should be lower when the drain current increase? This characteristic below is belong to RENESAS, 2SJ648.
https://4donline.ihs.com/images/Vip...3-1.pdf?hkey=EF798316E3902B6ED9A73243A3159BB0
Question 3: Why does thermal resistance information is not specify on most of the mosfet datasheet?
Background 3: Need for determination of thermal effect of the mosfet on the actual applicatioin.
I am currently doing a project on MOSFET, therefore, i need to understand the specification of the MOSFET in order to make a judgement whether this part can or cannot be used. However, I face some difficulty during the progress, and i need expert advises on the following matter:
Question 1: How to determine the gate current required for the calculation of the switching loss?
Background 1: I would like to find out the total power dissipation of the MOSFET. However, i am facing the difficulty on calculating the switching loss as i not understand the how to determine the "gate current" of the MOSFET. The confusion come from my understanding toward the operation of the ideal mosfet that there is no current flow to the gate of the mosfet. The drain source resistance is controlled by the gate voltage. Therefore, is the gate current required here referring to the specification "Gate-Source Leakage Current" stated in the datasheet? Please advise.
The document availabe at (page 4): https://pdfserv.maximintegrated.com/en/an/AN1832.pdf
Question 2: Why the On-resistance getting higher when the drain current higher under the constant gate voltage?
Background 2: I am thinking from the perspective of V=IR. When the voltage is kept constant, shouldn't that the On resistance value should be lower when the drain current increase? This characteristic below is belong to RENESAS, 2SJ648.
https://4donline.ihs.com/images/Vip...3-1.pdf?hkey=EF798316E3902B6ED9A73243A3159BB0
Question 3: Why does thermal resistance information is not specify on most of the mosfet datasheet?
Background 3: Need for determination of thermal effect of the mosfet on the actual applicatioin.
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