VISHAY DALE www.vishay.com Magnetics Application Note IHLP Selection Example INPUT LREQ IDC I Freq. TAMB V-μs 0.54 μH 20 A 7.39 A 300 kHz 50 °C 4.14 0.46 IHLP SELECTED Step 1. IHLP-4040DZ-01 0.56 μH L DCR IHEAT ISAT RTH PHEAT ET100 K0 K1 0.56 μH 0.0017 30 A 49 A 26.96 °C/W 1.48 W 0.88 18.31 0.00340 VERIFICATION Step 2. B PK OPER 4.14 = ----------- x 100 = 470.5 G 0.88 Step 3. 300 000 f e = ---------------------------------------------- = 192 216.1 Hz 2 2 0.46 – 0.46 Step 4. PCORE = 18.31 x 192 2160.188 x 470.52.118 x 300 000 x 10-14 = 0.248 W Step 5. The core losses are 0.248 W which is less then 1/3 of PHEAT (0.493 W) Step 6. PCUallowed = 1.48 - 0.248 = 1.32 W Step 7. 274.5 + 50 R OPER = 0.0017 x ---------------------------- = 0.00213 259.5 2 P DC = 20 x 0.00213 = 0.852 W 300 000 x 0.00213 = 0.217 W Step 8. PTOTAL = 0.248 + 0.852 + 0.217 = 1.317 W Step 9. T = 1.317 x 26.96 = 35.51 °C TOPER = 50 + 35.51 = 85.51 °C Step 10. 7.39 I PEAK = 20 + ----------- = 23.7 A 2 ISAT = 49 A which is greater then the required 23.7 A Revision: 20-Mar-13 Document Number: 34252 1 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 APPLICATION NOTE 2 P AC = 0.00340 x 7.39 x Application Note www.vishay.com Vishay Dale IHLP Selection Example SELECTION CRITERIA 1. Limit core losses (PCORE) to 1/3 of total losses for 40 °C temperature rise (PHEAT). 2. Total copper losses allowed will be equal to PHEAT - PCORE. 3. Maximum component temperature should be kept 125 °C, 155 °C for -51 components. 4. Maximum T should be 40 °C (this can be exceeded provided caution is taken to insure max. temperature 125 °C/155 °C). 5. IPEAK ISAT (recommended, IPEAK can exceed ISAT with caution due to soft saturation of IHLP product). GOVERNING EQUATIONS ET ckt = --------------- x 100 ET 100 G 1. B PK 2. f0 f e = ---------------------------2 2 – 3. P CORE = K 0 f e 4. P AC = K 1 x I x 5. 274.5 + T AMB R OPER = R TYP. x -----------------------------------259.5 OPER Kf – 1 2 Hz B pk Kb x f 0 x 10 f 0 x R OPER – 14 W W A 2 W 6. P DC = I 7. P TOTAL = P CORE + P DC + P AC 8. T = P TOTAL x R TH C 9. T OPER = T AMB + T C DC x R OPER I 10. I PEAK = I DC + ----2 W A Notes (1) Equation #5 assumes a 40 °C temperature rise and will have the same units as R TYP. (2) For equations #3 f in Hz and B PK in G. (3) R OPER is based on a 40 °C temperature rise. (4) K is 1.188 for -01 material, 1.173 for -11 material, and 1.044 for -51 material. f (5) K is 2.118 for -01 material, 2.213 for -11 material, and 2.497 for -51 material. b (6) For IHLP-2525EZ-01 - K = 1.181 and K = 2.166. f b SELECTION PROCESS APPLICATION NOTE Note • This process assumes that the following is known: Required inductance, frequency, IDC, I, TAMB, and V-μs (ET) required. Step 1. Select inductor value based on controller data sheet recommendation and current (IDC) rating. Step 6. Use selection criteria #2 to determine allowable copper losses. Step 2. Determine peak operational flux density in Gauss using equation #1. Step 7. Determine actual copper losses using equations #4, #5 and #6. Step 3. Calculate effective frequency using equation #2. Step 8. Use equation #7 for total losses. Step 4. Determine core loss using equation #3 (see notes #1 and #2) and compare to selection criteria #1. Step 9. Step 5. If core losses are > 1/3 PHEAT select a larger inductor. Determine T using equation #8 and insure TOPER 125 °C (155 °C for -51 material) using equation #9. Step 10. Verify IPEAK is less then ISAT using equation #10 for the selected part (see selection criteria #5). DEFINITIONS ETckt V-μs product of the circuit f0 Switching frequency in Hz ET100 V-μs product at 100 Gauss from table #1 RTH Thermal gradient of IHLP from Table #1 PCORE Core losses in W fe Effective frequency in Hz PDC Losses due to the DCR of the inductor copper winding in W Duty cycle PAC- Losses in the coil due to AC effects K0 IHLP core constant from table #1 K1- AC loss constant from Table #1 Revision: 20-Mar-13 Document Number: 34252 2 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000