DC/DC Switching Regulator Circuit Designs

📌 A Deeper Dive into DC-DC Converters: Buck vs. Boost Topologies Beyond simple voltage conversion, buck and boost converters are sophisticated switched-mode power supplies whose performance hinges on the interplay of key components. Let's look at the core principles: ↘️ Buck Converter (Step-Down): In a buck topology, the switch (MOSFET) chops the input voltage. Switch ON: The inductor is connected to the input, and current ramps up, storing energy in its magnetic field (VL=Vin−Vout). Switch OFF: The input is disconnected. The inductor's collapsing field forward-biases a freewheeling diode, maintaining current flow to the load. The output voltage is regulated by the duty cycle (D): Vout=Vin×D. ↗️ Boost Converter (Step-Up): A boost topology reconfigures the energy transfer to increase voltage. Switch ON: The inductor is connected directly across the input, storing a significant amount of energy while the load is supplied by the output capacitor. Switch OFF: The switch opens, and the inductor's induced voltage adds in series with the input voltage (Vin+VL), forwarding biasing the diode and charging the capacitor to a higher potential. The relationship is defined by Vout=Vin/(1−D). Key Design Considerations: Duty Cycle (D): The primary control mechanism, adjusted by the feedback loop to regulate the output against load and line variations. Switching Frequency (fs): A critical trade-off. Higher fs allows for smaller inductors and capacitors (reducing ripple and physical size), but increases switching losses in the MOSFET, impacting overall efficiency. Transient Response: Sudden load changes can cause voltage droop or overshoot. The converter's ability to quickly adjust the duty cycle and restabilize depends on the control loop's bandwidth and the values of the output filter components (L and C). Understanding these principles is fundamental to designing robust and efficient power management systems. #PowerElectronics #SMPS #BuckConverter #BoostConverter #HardwareDesign #Engineering

🔧 PART 1: Half-Bridge DC-DC Converter Design (200W, 48V Output @ 150kHz) 🔧 I’ve started designing a 200W Half-Bridge DC-DC Converter with a regulated 48V output at 4.16A. The input voltage range is 180V AC to 240V AC, and I’m using the SG3525 PWM controller operating at 150kHz switching frequency. ✅ The transformer and output inductor designs are being calculated by hand using formulas from the excellent book ��Switching Power Supply Design and Optimization” by Sanjay Maniktala — a highly recommended resource for anyone serious about power electronics. 🎯 I’m currently evaluating magnetic components: Is the ETD29 core a suitable choice for the transformer at 200W and 150kHz? Is the EE25 core appropriate for the output inductor at 48V, 4.16A? I enjoy getting into the math and design details rather than relying purely on ready-made simulations or black-box modules. I’ll continue to share updates and results as the design progresses. Would love to hear thoughts from the community! #PowerElectronics #Engineering #ElectronicsDesign #HalfBridgeConverter #Magnetics #DC_DCConverter #SG3525 #Electronics #power_electronics #powerelectronics

🤩 Build your Own Isolated DC-DC Converter from Scratch 🤓 I used these isolated 5V/5V for my RS485 Bus I've recently shown how I designed my isolated RS485 bus using discrete and integrated solutions. ✅ Check it out: https://lnkd.in/eH6EreyD Now, let me show you how you can design your own 5V to 5V or 3.3V/3.3V DC to DC supply that can power 100-200mA load enough to supply the RS485 IC. 𝗛𝗼𝘄 𝗱𝗼 𝗜 𝗜𝘀𝗼𝗹𝗮𝘁𝗲 𝗣𝗼𝘄𝗲𝗿? I need to use a transformer to provide the galvanic isolation. This transformer is driven driven by a push-pull converter topology to generate the required output voltage. The converter uses transformer action to transfer power from the primary side to the secondary side. Of course, I need to make sure of the following: ✅the right turns ratio is used ✅saturation voltage is not exceeded ✅operating frequency range ✅Volt-Time product 𝗪𝗵𝗮𝘁 𝗧𝗿𝗮𝗻𝘀𝗳𝗼𝗿𝗺𝗲𝗿 𝗼𝗽𝘁𝗶𝗼𝗻𝘀 𝗱𝗼 𝗜 𝗵𝗮𝘃𝗲 𝗳𝗼𝗿 𝘁𝗵𝗶𝘀 𝗮𝗽𝗽𝗹𝗶𝗰𝗮𝘁𝗶𝗼𝗻? I consider both of these two options that are designed for this application: 7603900X by Wurth Elektronik 78253J by Murata 𝗛𝗼𝘄 𝗱𝗼 𝗜 𝗗𝗿𝗶𝘃𝗲 𝘁𝗵𝗲 𝗧𝗿𝗮𝗻𝘀𝗳𝗼𝗿𝗺𝗲𝗿 𝗶𝗻 𝗮 𝗽𝘂𝘀𝗵-𝗽𝘂𝗹𝗹 𝗰𝗼𝗻𝗳𝗶𝗴𝘂𝗿𝗮𝘁𝗶𝗼𝗻? I use p/n: SN6501 by Texas Instruments, it is a monolithic oscillator/power-driver, designed for small form factor, isolated power supplies in isolated interface applications. The device drives a low-profile, center-tapped transformer primary from a 3.3-V or 5-V DC power supply. The secondary can be wound to provide any isolated voltage based on transformer turns ratio 𝗪𝗵𝗮𝘁'𝘀 𝗶𝗻𝘀𝗶𝗱𝗲 𝘁𝗵𝗶𝘀 𝗰𝗵𝗶𝗽?🪄 SN6501 consists of an oscillator followed by a gate drive circuit that provides the complementary output signals to drive the ground referenced N-channel power switches. The internal logic ensures break-before-make action between the two switches such that they don't turn ON at the same time 🤔 𝗛𝗼𝘄 𝗱𝗼 𝗜 𝗿𝗲𝗰𝘁𝗶𝗳𝘆 𝘁𝗵𝗲 𝗧𝗿𝗮𝗻𝘀𝗳𝗼𝗿𝗺𝗲𝗿'𝘀 𝗼𝘂𝘁𝗽𝘂𝘁? I use a rectifier diode with a low-forward voltage to provide as much voltage to the converter output as possible. When used in high-frequency switching applications, the diode must possess a short recovery time. Schottky diodes meet both requirements. You can use p/n: MBR0520L by onsemi with a typical forward voltage of 275 mV at 100mA forward current. 𝗪𝗵𝗮𝘁'𝘀 𝗻𝗲𝘅𝘁? I need to regulate the output voltage of the transformer using a linear regulator. I can use TPS7X series by Texas Instruments for that while keeping in mind to provide the right input/output capacitance for my application. 𝗔𝗻𝘆𝘁𝗵𝗶𝗻𝗴 𝗲𝗹𝘀𝗲? I need to consider adding enough filtering after the diodes by using enough bulk capacitance. Also, add enough capacitance at the primary side of the transformer 𝗛𝗮𝘃𝗲 𝗾𝘂𝗲𝘀𝘁𝗶𝗼𝗻𝘀 𝗼𝗿 𝗶𝗱𝗲𝗮𝘀? ✍ Share them in the comments section #electronics #smps #hardware #pcb #iot #sensors #circuits #analog