Step 1: System simulation and transformer design Step 2: Transformer construction Step 3: System design finalization 3.1 STEP 1 – System simulation and transformer design In this step, the system design outlined below is based on the simulation/calculation output: Transformer design (primary inductance, turns ratios of all windings). Design of core Rectangular core: It is used for core type distribution transformer and small power transformer for moderate and low voltages and shell type transformers. In core type transformer the ratio of depth to width of core varies between 1.4 to 2. In shell type transformer width of central limb is 2 to 3 times the depth of core. Reference 1 uses an Excel spreadsheet as the centerpiece of simple flyback-transformer design technique. With the spreadsheet, continuous or dis- continuous-mode flyback-transformer design takes less than 10 minutes. Compare this operation with the tedious, time-consuming task of manually number-crunching more than 50 independent parameters.
- Then we proceed to calculate as follows:. Primary area(pa)= Primary turns(n1) / (Primary turns per sqcm). Secondary area(sa)= Secondary turns(n2) / (Secondary turns per sqcm).
- Boost controllers (external switch) LM3017 — High Efficiency Low-Side Controller with True Shutdown LM3478 — 2.9740V Wide Input Range Boost/SEPIC/Flyback DC-DC Controller LM3478Q-Q1 — 40-V wide VIN low-side N-channel controller for switching regulators with 10-µA shutdown current LM3481 — 2.97V to 48V High-Efficiency Controller for Boost, SEPIC and Flyback LM3481-Q1 — 2.97-V to 48.
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Transformer Design Calculation Excel Formula
Supported products & hardware
Boost controllers (external switch)
LM3017—High Efficiency Low-Side Controller with True ShutdownLM3478—2.97~40V Wide Input Range Boost/SEPIC/Flyback DC-DC ControllerLM3478Q-Q1—40-V wide VIN low-side N-channel controller for switching regulators with 10-µA shutdown currentLM3481—2.97V to 48V High-Efficiency Controller for Boost, SEPIC and FlybackLM3481-Q1—2.97-V to 48-V high-efficiency controller for boost, SEPIC and flyback, AEC-Q100 qualifiedLM3488—2.97V to 40V Wide Vin Low-Side N-Channel Controller for Switching RegulatorsLM3488Q-Q1—40-V wide VIN low-side N-channel controller for switching regulators with 5-µA shutdown currentLM5020—13-100V Wide Vin, Current Mode PWM Boost, Flyback, Sepic ControllerLM5022—6-60V Wide Vin, current mode boost, SEPIC and Flyback controllerTPS40210-Q1—4.5-V to 52-V wide input range current mode boost controller with 700-mV reference voltageTPS40211-Q1—4.5-V to 52-V wide input range current mode boost controller with 260-mV reference voltageBoost converters (integrated switch)
LM2577—3.5-V to 40-V, 3-A low component count step-up regulatorLM2585—4-V to 40-V, 3-A step-up wide VIN flyback regulatorLM2586—4-V to 40-V, 3-A step-up wide VIN flyback regulator with frequency synchronizationLM2587—4V to 40V, 5A Step-Up Wide Vin Flyback RegulatorLM2588—4-V to 40-V, 5-A step-up wide VIN flyback regulator with frequency synchronizationLM2621—1.2V to 14V input voltage, 1A load current, step-up DC-DCLM2623—0.8V to 14V input voltage, 2A load current, step-up DC-DCLM2623-Q1—0.8-V to 14-V input voltage, 2-A load current, step-up DC/DC, AEC-Q100 qualifiedLM2735—520kHz/1.6MHz space efficient boost and SEPIC DC-DC regulatorLM2735-Q1—520-kHz, 1.6-MHz space efficient boost and SEPIC DC/DC regulator, AEC-Q100 qualifiedLM3578A—2-V to 40-VIN switching regulators in buck, boost, terminal, depending upon the applicationLM5000—3.1-40V Wide Vin, 2A Current Mode Non-Synchronous Boost RegulatorLM5001—3.1-75V Wide Vin, 1A Current Mode Non-Synchronous Switch Mode RegulatorLM5001-Q1—3.1-V to 75-V wide VIN, 1-A current mode non-synchronous switch mode regulatorLM5002—3.1-75V Wide Vin, 0.5A Current Mode Boost, Flyback, Sepic ConverterTL1451—Dual Pulse-Width-Modulation Control CircuitTL1451A—3.6V to 50V dual channel controller with Wide input voltage rangeTL1451A-EP—Enhanced Product Dual Pulse-Width-Modulation Control CircuitsTL1451A-Q1—3.6-V to 50-V dual-channel PWM controller, AEC-Q100 qualifiedTL5001—PWM Controller with wide input range, with ±5% tolerance on reference, operation –20°C to 85°CTL5001A—PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°CTL5001A-Q1—PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°CTL5001M—PWM Controller with wide input range, with ±5% tolerance on reference, operation –55°C to 125°CTPS43000—Multi-Topology (buck, boost, sepic) High Frequency DC/DC ControllerTPS55340—5-A, 40-V, wide VIN boost, flyback, & SEPIC converterTPS55340-EP—Enhanced integrated, 5-A, 40-V wide input range boost/SEPIC/flyback DC/DC regulatorTPS55340-Q1—Integrated, 5-A 40-V wide input range boost/SEPIC/flyback DC/DC regulator, AEC-Q100 qualifiedTPS61175—3-A ,40V High Voltage Boost Converter with Soft-start and Programmable Switching FrequencyTPS61175-Q1—3-A, 40-V high voltage boost converter with soft-start and programmable switching frequencyUC2572—Negative output Flyback pulse width modulatorBuck converters (integrated switch)
LM5015—4.25-75V, Monolithic Two-Switch Forward DC-DC RegulatorCurrent Transformer Design Calculation Excel
Flybuck converters
LM25017—7.5-48V Wide Vin, 650mA Constant On-Time Synchronous Buck RegulatorLM25018—7.5-48V Wide Vin, 300mA Constant On-Time Synchronous Buck RegulatorLM25019—7.5-48V Wide Vin, 100mA Constant On-Time Synchronous Buck RegulatorLM34925—7.5-100V Wide Vin, 100mA Integrated Secondary Bias Regulator for Isolated DC/DC ConvertersLM34926—7.5-100V Wide Vin, 300mA Integrated Secondary Bias Regulator for Isolated DC/DC ConvertersLM34927—7.5-100V Wide Vin, 600mA Integrated Secondary Bias Regulator for Isolated DC/DC ConvertersLM5017—7.5-100V Wide Vin, 600mA Constant On-Time Synchronous Buck RegulatorLM5018—7.5-100V Wide Vin, 300mA Constant On-Time Synchronous Buck RegulatorLM5019—7.5-100V Wide Vin, 100mA Constant On-Time Synchronous Buck RegulatorLM5160—LM5160 wide input 65V, 2A synchronous buck/Fly-Buck™ converterLM5160-Q1—Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ ConverterLM5160A—LM5160A Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ ConverterLM5161—Wide Input 4.5-V to 100-V, 1-A Synchronous Buck / Fly-Buck ConverterTPS55010—2.95V To 6V Input, 2W, Isolated DC/DC Converter with Integrated FETSTransformer Calculations Examples
PWM controllers & resonant controllers
LM2524D—40V, 0.2A 550KHz PWM controllerLM3524D—40V, 0.2A 350KHz PWM controller