SMPSSolution provide information to help you solve various issues related to switching mode power supplies (SMPS). Currently, many electronic device design and development manufacturers are lacking experienced engineers. SMPSSolution have begun disclosing information to resolve the current situation where product development is delayed due to the inability to address various issues in the development of SMPS. You can download various design know-how materials created based on 35 years of analog high-frequency electronic circuit design experience and past design data. In addition to past designs, we also have circuit diagrams, parts lists, board diagrams, and Gerber data using new devices. SMPSSolution have them ready for you, so you can start prototyping, assembling, and evaluating them right away. https://smpssolution.com/ © SMPS Solution January-25 1/16 SMPSSolution solve AC-DC SMPS problems

Solves the noise problem of SMPS. SMPSSolution propose solutions to the conduction noise and radiation noise of SMPS. Introduction of SMPS design method. This section introduces the steps involved in deciding on SMPS specifications, creating a prototype, and evaluating the design. Provides design data for SMPS. SMPSSolution provide performance data of SMPS that have been actually prototyped and evaluated. We help train SMPS design engineers. It contributes to improving the technical level of SMPS design engineers. Help those who want to become SMPS designers. It provides useful information for engineers who wish to become SMPS designers. Cause analysis and suggestions for SMPS recall problems. SMPSSolution obtain recalled SMPS and provide data on cause analysis and improvement proposals. © SMPS Solution Overview January-25 2/16

・ Specifications Client request. Check safety standards. ・ Selection of the main device Select a main device that satisfies the power supply specifications. ・ Transformer design Calculates and draws transformers to specifications and selected main devices. ・ Schematics and bill of materials Create a schematic and bill of materials from the main device datasheet and transformer calculation results. ・ PCB design Design a PCB board for the power supply board prototype. ・ Switching waveforms Check the switching waveform for any abnormalities in operation. ・ Regulation and efficiency Check if the input/output characteristics and efficiency are as specified. ・ EMC noise Check if the EMC noise satisfies the specification. ・ Output noise Check if the output ripple and spike noise meet the specifications. ・ Protective function Check the operation of overload protection and output overvoltage protection. ・ Dynamic characteristics Check the rise waveform and control characteristics of the output voltage. ・ Temperature rise and life Calculate the temperature rise of key components and estimated lifetime of electrolytic capacitors. ・ De-Rating Check margin for maximum ratings for all components. ※Reliability tests and safety tests are omitted because they are not the job of design engineers. © SMPS Solution Design procedure Explain the design procedure of Offline Switch mode Power Supplies. January-25 3/16

・ Input specification ・ Protection AC Rated input voltage（AC100V～240V） Output over current protection AC input voltage range（AC85V～276V） Output over voltage protection Rated input frequency (50/60Hz) Thermal Shutdown ・ Output specification ・ Safety Approval Rated output voltage Safety standards Rated output current Minimum creepage Rated output power Leakage current Output voltage range ・ Insulation specification Output current range Withstand voltage Peak output power Insulation resistance ・ Efficiency ・ Operating ambient temperature ・ Output ripple noise Average ・ EMC noise Range Conducted emission ・ Others Radiated emission Standby power Harmonic current emissions Inrush current Immunity noise Estimated product life © SMPS Solution Specifications Offline Switch Mode AC-DC Power Supplies. January-25 4/16

※These ICs are just a few examples. There are countless ICs for AC-DC switching power supply. ●What is important about selecting an IC is - Technical support and design example data - User-friendly datasheets with PCB design examples - Cost, lead time, and purchase history © SMPS Solution January-25 5/16 Selection of the main device Select main IC (built-in MOSFET) Flyback topology is recommended for 50W or less. 2W FSQ500L ON Semiconductor TO223-4L 700V MOSFET PWM Flyback 8W FSB117H ON Semiconductor DIP-8 700V MOSFET PWM Flyback 10W TNY288P Power Integrations DIP-7 725V MOSFET Simple ON/OFF Flyback 5W TNY284D Power Integrations SOP-7 725V MOSFET Simple ON/OFF Flyback 5W Viper16 ST Micro DIP-7 800V MOSFET PWM Flyback 15W TNY290K Power Integrations eSOP-12B 725V MOSFET Simple ON/OFF Flyback ST Micro DIP-7 800V MOSFET PWM Flyback TO223-4L SOP-7 DIP-7 eSOP-12B 10W Viper26

File name ： EMC-solution-at-Transformer.pdf EMC noise can be reduced by replacing the transformer without changing the power supply circuit or PCB layout. Introducing a method to solve EMC noise by improving the transformer structure. © SMPS Solution Transformer design Provides a transformer calculation sheet and transformer drowing. January-25 6/16

Provides reference designs for schematics and bill of materials. File name：Bill-of-material-manual.pdf Introducing know-how on selecting appropriate parts for switching power supplies. © SMPS Solution January-25 7/16 Schematics and bill of materials

Board design know-how for switching power supplies with low noise and stable operation. File name：PCB-design-manual.pdf ・ PCB creepage distance ・ Basic rules for power supply PCB board design ・ Primary side main parts placement and pattern ・ Secondary side main parts placement and pattern ・ Copper through-hole VIAs in switching current roop ・ Primary Clamp Circuit ・ Capacitor near main IC ・ Output voltage detection circuit Conduction noise in the Average PCB Design Conduction noise in the Best PCB Design © SMPS Solution 8/16 PCB design January-25

MOSFET voltage and current. The photo below is a photo taken during the measurement. Current is measured by cutting the copper foil pattern and using a current probe. Secondary rectifier diode voltage and current. File name：Magnetic-saturation-manual.pdf © SMPS Solution Switching waveforms After assembling the switching power supply board and checking the operation, check the switching waveform of the main part. Use an oscilloscope to check the voltage and current waveforms, and check whether the maximum ratings of the main components are exceeded and whether magnetic saturation has occurred. January-25 9/16 This file explains the measurement of magnetic saturation, the situations that tend to occur, and how to improve it. When magnetic saturation occurs in the transformer core, there is a high possibility that efficiency will deteriorate, unstable operation, and element destruction will occur.

© SMPS Solution Regulation and efficiency Below is an example of an exam form (Bias = auxiliary winding voltage) January-25 10/16

Conduction noise File name：Conduction-noise-summary.pdf File name：Low-band-noise-solution.pdf File name：Middle-band-noise-solution.pdf File name：High-band-noise-solution.pdf Radiation noise An antenna is used to measure the radiation noise. File name：Radiation-noise-solution.pdf © SMPS Solution January-25 11/16 EMC noise Measure the noise that is transmitted from the power supply equipment and output through the input line. This file introduces methods for suppressing radiated electromagnetic noise. Explains the equivalent circuit for conducting noise measurement and the causes of noise generation. The method of suppressing conduction noise differs depending on the frequency band. See below for noise countermeasures for each frequency band.

Output noise includes ripple noise and spike noise. Ripple noise Spike noise © SMPS Solution Output noise January-25 12/16 Typical measurement method. We recommend measuring ripple and spike noise with a resistive load. If the noise level is lowered too much, the output voltage will become unstable. The noise level fluctuates depending on the measurement environment.

Overload protection Overvoltage protection ↑Vout Iout → © SMPS Solution Increase the load current until the output voltage drops and check at which point the overload protection works. January-25 13/16 Protective function Short-circuit the part circled in red in the circuit diagram below to perform an overvoltage protection test. The test is performed by shorting the circuit during normal operation with the rated input/output.

Output start up characteristics Record the rising waveform of the output voltage and check for overshoot or abnormal vibration. How to improve output voltage overshoot and stability. As shown in the circuit diagram below, increase or decrease the constants of R65 C69 R69 to find the best value. If the adjustment of R65 C69 R69 does not improve the problem, there is an adjustment method specific to the main IC, so please contact the IC manufacturer. © SMPS Solution Dynamic characteristics January-25 14/16

Calculate the life of an electrolytic capacitor using the formula on the left. It was provided by an electrolytic capacitor manufacturer. L = Electrolytic capacitor life T1 = Maximum allowable temperature for electrolytic capacitors Lo = Basic life of electrolytic capacitor T2 = Electrolytic capacitor case tempera © SMPS Solution Temperature rise and life Calculate temperature rise and estimated life using a form like the one below. January-25 15/16 Measure the temperature by attaching a thermocouple as shown in the photo below. When measuring the temperature of an electrolytic capacitor, insulate the top surface with tape and then attach the thermocouple. For coils and transformers, the temperature is measured by attaching a thermocouple to the windings.

© SMPS Solution January-25 16/16 De-Rating This file explains the purpose and concept of De-Rating and how to measure and calculate the voltage, current, and power consumption of each component in a switching power supply. File name：De-Rating-manual.pdf Below is an example of a De-Rating table. Basically, De-Rating is performed for all parts in the parts list.