Soft Ferrites Applications High Power TPC SMPS Lighting TV & Monitors Filtering 9 Soft Ferrites Applications Shapes of magnetic cores depend on applications: • E cores and RM cores: They are used in computer, radio communication, interference suppression, SMPS for wide-band transformers, power transformers, pulse transformers. • U cores: They are used in TV applications, industrial and professional applications for wide-band transformers and high voltage transformer. Soft ferrite cores are used in a large band of applications, with different shapes and adapted materials. Today the main application areas are: ■ Power Application ■ Filtering Application APPLICATIONS ADVANTAGES DRAWBACKS Low power range (200W) Simples topology - low cost Poor current form factor Output current < 10A Multi-output capability Max operating frequency: 80kHz Typ. efficiency: 65 to 80% B - FORWARD CONVERTERS HOW DOES IT WORK? I1 D1 T L D2 C V2 V1 TR D3 I. POWER APPLICATION • High Power During “TR” on: “D1” is opened and the primary energy is directly transferred to the secondary through the transformer “T” and stored in choke “L”. During “TR” off: “D2” is opened and energy stored in “L” is returned to load. Remark: an important airgap is needed in the choke but low or no airgap is required in the transformer (low magnetizing energy returned to the input by the way of the auxiliary winding and “D3”). A power transformer transmits energy, transforms voltage to the required level and provides galvanic separation. It operates under conditions which require special power ferrites with low losses and high saturation levels. • SMPS The following table summarize the structures of a SMPS circuit. Three principle structures of a switched mode power supply circuits are: A - Flyback Converters B - Forward Converters C - Push-Pull Converters APPLICATIONS ADVANTAGES Power range typ.:100 to Low ripple output (built in 300W output current > 7A filter LC) DRAWBACKS Not optimized for multi-outputs High frequency capability High efficiency: up to 90% A - FLYBACK CONVERTERS In a flyback converter, all the energy to be transferred to the output capacitor and load is, at first, stored in the inductor. HOW DOES IT WORK? I1 T D C - PUSH-PULL CONVERTERS The push-pull converter is an arrangement of two forward converters operating in antiphase. For the same operating conditions and power throughput, its design can use a smaller transformer core. • Ballast C Ballast are used for fluorescent lamps. It limits the current and works like coil. Ballast resistance is calculated to obtain the arc voltage of the lamp and the right current to run with right conditions. For the best efficiency, dimensional and electromagnetic parameters of ferrite cores transmit the exact value of cathode current, lamp voltage and lamp current. V2 V1 TR During “TR” on: “D” is blocked and primary energy is stored in the transformer “T”. During “TR” off: “D” is opened and energy is returned to the load. Remark: an important airgap is needed in the magnetic circuit in order to prevent saturation. 10 TPC Inductor L Ballast Starter 220 50Hz Tube C Soft Ferrites Applications II. FILTERING APPLICATION High permeability materials represent soft ferrites used in the filtering application like EMI suppression, telecommunication, tuning, etc... To avoid this problem, inductive components are very effective, especially at high frequency. With high permeability material, inductors has high impedance for the interfering unwanted signal. • Telecommunication • EMI Suppression Electronic equipment development pollutes the environment of electromagnetic waves. For the best working of devices, laws will become more stringent in the near future. Most important applications in telecommunication, are filter coils and “pulse and signal transformer”. For those applications, a high quality factor (Q) is needed. Good wideband characteristics transmit analog signals or digital pulses without much distortion. III. FERRINOX MATERIAL: QUICK SELECTION GUIDE A complete description of power ferrite materials is presented pages 18 to 34. The following table summarize the typical applications. MATERIAL FOR POWER APPLICATIONS MATERIAL MAIN FEATURES APPLICATION CORE TYPE B2 Low losses for low frequency (25 to 150 kHz) Power transformers DC/DC converters E, U Cores and Toroids F1 Very low losses for medium frequency (50 to 250 kHz) and high flux density Power transformers DC/DC converters E, U, PQ, EP and RM Cores, Toroids F2 Very low losses for high frequency (100 to 500 kHz) Power transformers DC/DC converters E, U, RM and Planar Cores F4 Very low losses for high frequency (500 to 1.5 MHz) Power transformers DC/DC converters E and Planar Cores MATERIAL FOR TV TRANSFORMERS AND FLYBACK TRANSFORMERS MATERIAL MAIN FEATURES APPLICATION CORE TYPE B3 High flux density and negative power loss temperature slope at high temperature Noise suppression Chokes Broadband transformers Drivers Small E and U Cores B5 High flux density and low losses at high temperature (32 kHz) General purpose power Transformers Drivers E and U Cores Toroids TPC 11 Soft Ferrites Applications IV. DC BIAS CORE SELECTION CURVES LI2 VS AL To prevent saturation of the magnetic circuit in a choke, the following curves provide the AL limit before saturation of most E, U, RM and FM cores (corresponding to a 20% inductance drop) at 25°C and 100°C operating temperatures. • Draw a horizontal line at the Y axis coordinate corresponding to the required LI2 max value: L : Inductance required (mH) Imax : Peak current • Any core whose line intersects with this horizontal line may be used. • Draw a vertical line at this intersection to get the AL value. In the same way, the following curves provide the maximum applicable ampere turns on a core before saturation: • Draw a vertical line at the X axis coordinate corresponding to the required AL value 12 • The intersection with the LI2 line of the required core indicates NI max value by calculating: NI max = √(LI2 / AL) Notes: 1. These graphs are valid for B1, B2, F1. 2. Increase by about 10% the LI2 max value for B3, B5. 3. The lower and upper core limits correspond to the optimum effective permeability range: 54 ≤ µe ≤ 300. V. DC BIASED INDUCTANCE • AL versus N x IS curves are given for the following cores in the U-core section: UR3513B - UR3513D - UR3513H - UR3915A UR4014A - UR4022A - UR4316A - UR4916A Note: These graphs are valid with a specific coil for each core only. TPC Soft Ferrites Applications (please see the respective curves at the end of this section) AL CURVES E CORES AL CURVES E CORES 10 10 E-2206A E-2005B E-2206A LI2 (mJ) at 100°C LI2 (mJ) at 25°C E-2005B 1 E-2006A E-1907A E-1905A E-1605A E-1605B E-1306A 0.1 1 E-2006A E-1907A E-1905A E-1605A E-1605B E-1306A E-1304A 0.1 E-1304A 0.01 10 100 0.01 10 1000 100 AL (nH) Figure 1 Figure 2 AL CURVES E CORES AL CURVES E CORES 100 100 E-4012A E-3509A E-3510A E-3510B LI2 (mJ) at 100°C LI2 (mJ) at 25°C E-4012A 10 1000 AL (nH) E-2507A E-4113A E-3213A E-3313A E-3611A E-3007B E-3008A 1 10 E-3509A E-3510A E-3510B E-2507A E-4113A E-3213A E-3313A E-3611A E-3007B E-3008A 1 E-2506A E-2506B E-2506C E-2507B 0.1 10 100 E-2506A E-2506B E-2506C E-2507B 0.1 10 1000 100 Figure 3 Figure 4 AL CURVES E CORES AL CURVES E CORES 1000 1000 LI2 (mJ) at 100°C LI2 (mJ) at 25°C 1000 AL (nH) AL (nH) E-6527A 100 E-5521A E-4220A E-4220B E-7032A E-5525A 10 100 E-6527A E-5521A E-4220A E-4220B E-7032A 10 E-5525A E-4916A E-4916A E-4215A E-4215B E-4215A E-4215B 1 10 100 1 10 1000 AL (nH) 100 1000 AL (nH) Figure 5 Figure 6 TPC 13 Soft Ferrites Applications AL CURVES EI CORES AL CURVES EI CORES 100 100 EI4012A 10 EI3011B EI2506C EI4215B EI3313A 1 EI4012A LI2 (mJ) at 100°C LI2 (mJ) at 25°C EI3510B 10 EI3510B EI3011B EI2506C EI4215B 1 EI3313A EI2206A EI2206A 0.1 10 100 0.1 10 1000 100 AL (nH) 1000 AL (nH) Figure 7 Figure 8 AL CURVES EC CORES AL CURVES EC CORES 100 100 EC7017A EC7017A EC5214A EC5214A 10 LI2 (mJ) at 100°C LI2 (mJ) at 25°C EC4112A EC3510A 1 EC4112A 10 EC3510A 1 0.1 10 100 0.1 10 1000 100 1000 AL (nH) AL (nH) Figure 9 Figure 10 AL CURVES ET CORES AL CURVES ET CORES 100 100 ET5419A ET5419A ET4916A ET4415A ET4916A ET4415A LI2 (mJ) at 100°C LI2 (mJ) at 25°C ET3913A 10 ET3411A ET2910A 100 0.1 10 1000 100 1000 AL (nH) AL (nH) Figure 11 14 ET3411A ET2910A 1 1 0.1 10 ET3913A 10 Figure 12 TPC Soft Ferrites Applications AL CURVES ER CORES AL CURVES ER CORES AL CURVES RM - FM CORES FM8770A 100 100 100 FM5039A ER4518B ER5519A ER5519B ER4518B ER5519A ER5519B RM1400B ER4821A ER5318A ER4518A ER5221A ER4013A ER3411A 1 ER3913A ER3913D 10 ER2811A ER4821A ER5318A ER4518A ER5221A ER4013A ER3411A 1 0.1 10 100 10 RM1000B RM0800B RM0600B 1 0.1 10 1000 LI2 (mJ) at 25°C 10 ER2811A LI2 (mJ) at 100°C LI2 (mJ) at 25°C ER3913A ER3913D 100 AL (nH) RM0500B 0.1 10 1000 100 AL (nH) Figure 13 Figure 14 AL CURVES RM - FM CORES 1000 AL (nH) Figure 15 AL CURVES U CORES AL CURVES U CORES FM8770A 100 100 100 RM1000B RM0800B 10 U-3126A RM0600B U-2513A U-1204A 1 1 RM0500B U-2007A U-2507A LI2 (mJ) at 100°C (mJ) at 25°C RM1400B 10 LI2 LI2 (mJ) at 100°C FM5039A 10 U-3126A U-2513A U-1204A 1 U-2007A U-2507A U-1105A U-1506A U-1706A U-1105A U-1506A U-1706A U-1606A U-1606A 0.1 10 100 0.1 10 1000 100 AL (nH) Figure 16 Figure 17 AL CURVES U CORES AL CURVES U CORES 100 1000 Figure 18 1000 U--141B U-9330A IU9330A 100 U--102A IU-102A U-4628A 10 LI2 (mJ) at 100°C U--141A U-9320A IU9320A U--126A IU-126A U-9316A IU9316A LI2 (mJ) at 25°C 0.1 10 AL (nH) AL (nH) 1000 1 10 1000 U--141A U-9320A IU9320A U--126A IU-126A U-9316A IU9316A 100 U--141B U-9330A IU9330A U--102A IU-102A U-4628A 10 100 1000 AL (nH) Figure 19 1 10 100 1000 AL (nH) Figure 20 TPC 15