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The key part of any electronic device is the power supply. Any instability or malfunction of the power supply part causes the device to stop working or demonstrate weird behavior. In this article/video, I introduced an AC-to-DC flyback Switching power supply that converts 85V-260VAC to 5VDC-2.5A, which can be used in various applications. The 5V selection for the output makes it friendly for linear regulators that convert 5VDC to lower voltages. The maximum power delivery of this power supply is around 12W, which means it can handle 2.5A at 5V output. The controller chip is DK1203, which does not need any external supply, a startup resistor, or an auxiliary winding on the transformer. The ferrite core of the transformer is EE20. A potentiometer allows you to adjust the output voltage and set it exactly at 5.0V. To design the schematic and PCB, I used Altium Designer 23 and shared the PCB project with my friends for feedback and updates using Altium-365. The fast component search engine, Octopart, proved invaluable in quickly obtaining component information and generating the Bill of Materials (BOM). To ensure high-quality fabricated boards, I sent the Gerber files to PCBWay. I tested the board for voltage drop, current delivery, and output noise. I used Siglent SDL1020X-E DC Load and Siglent SDS2102X Plus oscilloscope to perform all tests. I am confident that building this circuit enhances your knowledge regarding switching power supply design, except for using it for real applications. Schematic + PCB + Transformer: https://www.pcbway.com/blog/technology/85V_260VAC_to_5VDC_2_5A_Flyback_Switching_Power_Supply_b7f49beb.html References : DK1203: https://grupoautcomp.com.br/wp-content/uploads/2016/11/Specification-IC-DK1203.pdf : 500mA Fuse: https://octopart.com/39211000440-littelfuse-39590771?r=sp : 07D471 Varistor: https://octopart.com/mov-07d471ktr-bourns-19184728?r=sp : 100nF X2: https://octopart.com/r463i310050m1k-kemet-50550056?r=sp : UU9.8 Choke: https://octopart.com/7355-h-rc-bourns-12614152?r=sp : MB6M Bridge: https://octopart.com/mb6m-e3%2F45-vishay-42761003?r=sp : 22uF-400V: https://octopart.com/eca2ghg220-panasonic-3578224?r=sp : RS1M Diode: https://octopart.com/rs1m-13-f-diodes+inc.-333072?r=sp : PC817 Optocoupler: https://octopart.com/pc817xnnsz1b-sharp-80823687?r=sp : TL431 Shunt: https://octopart.com/tl431acdbvr-texas+instruments-521839?r=sp : SS54 Schottky Diode: https://octopart.com/ss54-multicomp-18903925?r=sp : 470R-1206: https://octopart.com/cr1206-jw-471elf-bourns-3872844?r=sp
Flyback is the most common circuit topology to build galvanically isolated AC to DC or DC to DC converters. Flyback circuit is cheap and relatively easy to manufacture, therefore nowadays the majority of home or industrial appliances are powered using AC to DC Flyback converters. In general, a Flyback converter is suitable for low-power applications, mostly below 100W. In this article/video, I designed a cheap AC-to-DC flyback converter using a DK124 IC that can deliver up to 18W continuously. I calculated the transformer to handle 12V at the output which can be easily modified to reach other output voltages as well. The DK124 chip does not need any auxiliary winding or even an external startup resistor. The 220V Mains input has been protected using a MOV, an NTC, and a Fuse. The PCB board is single-layer and all components are through-hole. To design the schematic and PCB, I used Altium Designer 22. The fast component search engine (octopart) allowed me to quickly consider components’ information and also generate the BOM. To get high-quality fabricated boards, I sent the Gerber files to PCBWay. To test the power supply, I used Siglent an SDL1020X-E DC Load, an SDM3045X Multimeter, and an SDS1104X-E/SDS2102X Plus oscilloscope. Specifications Input Voltage Range: 85 to 265V-AC Output Power: 18W Continuous Output Voltage: 12V-DC Switching Frequency: 65KHz Reference: https://www.pcbway.com/blog/technology/220V_AC_to_12V_DC_18W_Switching_Power_Supply_81665a6c.html : DK124: https://grupoautcomp.com.br/wp-content/uploads/2016/11/Specification-IC-DK124.pdf : 10D561: https://octopart.com/mov-10d561k-bourns-19184788?r=sp : PC817: https://octopart.com/pc817x1j000f-sharp-39642331?r=sp : TL431: https://octopart.com/tl431aclpr-texas+instruments-521800?r=sp