For the past few years, I've been designing and building power electronics circuits as both a hobby and a learning experience. In this project, I'd like to share four of my favorite designs that have been thoroughly tested and successfully operated.

The collection includes two inverter designs based on the SG3525 controller and two Power Factor Correction (PFC) circuits based on the NCP1653. Together, they cover everything from a compact portable inverter to a high-power 2.5 kilowatt PFC converter.

All of the PCB boards shown in this project were manufactured by JLCPCB.

The second project is a much larger inverter capable of delivering up to 2.5 kilowatts.

Instead of using a single transformer, the design employs two transformers together with an H-bridge PWM output stage, allowing the inverter to handle much heavier loads.

Several protection features are included:

• Soft start / soft shutdown
• Input overvoltage protection
• Input undervoltage protection
• Over-temperature protection

The inverter can comfortably power motors, fans, power tools, and many other high-power AC loads.

The final project is a high-power 2.5 kilowatt PFC converter.

It is based on the same NCP1653 controller but uses a totem-pole MOSFET driver to achieve significantly higher output power.

The control circuit is powered by a separate 15–24 volt auxiliary power supply, while the boost inductor is constructed using two stacked ferrite cores to support the higher current without sacrificing efficiency.

This design has proven to be very stable during testing and is suitable for demanding high-power applications

The first project is a compact inverter that converts 12 volt DC into 220 volt AC.

The circuit is built around the SG3525 PWM controller and operates at a switching frequency of 34 kilohertz. It uses common MOSFETs such as the IRF3205 or IRFZ44, making the design inexpensive and easy to build.

Despite its small size, it is ideal for powering:

• Phone chargers
• LED lighting
• Small electronic equipment
• Portable devices

This is an excellent beginner project for anyone interested in inverter design.

The third project is an active Power Factor Correction circuit based on the NCP1653 controller.

The converter accepts an input voltage from 85 volt AC to 250 volt AC while maintaining a regulated 380 volt DC output.

The circuit includes:

• Integrated 15 volt auxiliary power supply
• Custom-wound boost inductor
• Easy-to-find components
• Stable output voltage
• Improved power factor
• Higher overall efficiency

This design is suitable for many switch-mode power supply applications.

ll PCB boards used in these projects were manufactured byJLCPCB.

After uploading the Gerber files, the finished boards arrived in approximately one week. The PCB quality exceeded my expectations, featuring precise drilling, clean solder masks, accurate silkscreen printing, and excellent overall manufacturing quality.

I've also shared the Gerber files so anyone interested can easily order the same PCB boards and build these projects.