EE 413 Solution Fall 2009 Midterm Exam 1

EE 413 Last Name: Solution Fall 2009 Midterm Exam 1 First Name: Instructions: 1. This is a closed-book, closed-note exam. There is a separate equation sheet and data sheet for the International Rectifier IRFP4310ZPbF HEXFET. No other study materials should be visible or accessible during the exam. 2. Be certain to check all parameter values that you use, as many ofthe values differ slightly from the ones used in the lecture notes and/or homework assignments. 3. A significant fraction of your score for each problem will be based on the manner in which you develop your solution. It should be logical and neat. 4. You have 90 minutes to complete the exam. 5. You must turn in all pages of the exam. Do not write below this line: Problem 1 (20 points) Problem 2 (20 points) Problem 3 (20 points) Problem 4 (20 points) Problem 5 (20 points) TOTAL (100 points) 1 1. An International Rectifier IRFP4310ZPbF HEXFET is used in an application in which f, = 500 kHz, D=0.6,and Ip(om) =100 A. Estimate the junction temperature T,, if the total switching energy is 2 μJ, ROSA =1°C/W, T = 25°C, and typical values are used for all other parameters. -2 Pa = DRAsn) Iolon)Do + fo ETs + Asswle Tj = 100 °C TJ ReJC Recs RASA TA Rps(6m) 14.8 2(1.6) = 7.66 w2 P₁= (0.6)(7.6& ms2)(100A)² + (500 k2 )2,J) = 47.1 W T= TA + (Resc +Recs RSA) Pa = (25 °c) +(0.54 + 0.24 +1 °C/0X47.1w) = 109 C Assume Tj = 115°C Roscon)= (4.8 m2)1.75) = 8,4 Mr PA = 51.4 w T₃ = 116 °с T 120 °C