Flyback Transformer Drivers

A solid-state flyback driver based on a micro solid-state Tesla coil circuit created by Steve Ward. The schematic is reprinted here with credits to Steve Ward. Instead of an air-core Tesla Coil setup, a flyback transformer is utilized. An IRFP450 MOSFET is employed, which has a current rating approximately 4A lower than the IRFP460 MOSFET. The transformer used is approximately 30V, 2A. A standard 8-pin socket is used instead of two 4-pin sockets for the two integrated circuits (TC4420 and 555 timer). This tube flyback driver is based on a vacuum tube Tesla coil (VTTC) and high-voltage generation circuits found in tube televisions. The schematic of the tube flyback driver includes a 6BG6 tube, which is a television output tube that drives the flyback transformer. The 12SQ7 serves as a high-gain amplifier that enhances feedback signals to oscillate the 6BG6 tube. The power transformer was salvaged from a small HP frequency counter and features 250V, 18V, and 7V windings. The 250V winding is connected to a voltage doubler, elevating it to approximately 600V, but it drops to around 300 to 400 volts under load. The 18V winding powers the 6V, 2.5A filament of the 6BG6 tube, which operates correctly, dropping to about 5V when loaded. The 7V winding is connected to another voltage doubler, raising the voltage to around 10V to 15V for the 12V filament of the 12SQ7. The circuit is self-resonant due to feedback triggering oscillations, eliminating the need for frequency alignment.

The solid-state flyback driver circuit leverages a micro solid-state Tesla coil design, which is a compact and efficient high-voltage generator. The choice of the IRFP450 MOSFET is significant as it balances performance and thermal management, allowing for effective switching at high frequencies while maintaining reliability. The flyback transformer, rated at approximately 30V and 2A, is integral to the operation of this driver, converting low-voltage input into high-voltage output, suitable for applications requiring substantial voltage levels.

The integrated circuits used in the design, TC4420 and 555 timer, play crucial roles in the generation and regulation of the oscillations necessary for the operation of the flyback transformer. The TC4420 provides the necessary drive to the MOSFET, ensuring rapid switching and efficient energy transfer, while the 555 timer is configured to create a stable oscillation frequency, which is vital for the flyback operation.

The use of a 6BG6 tube as the output stage enhances the circuit's capability to handle high voltages and currents, making it suitable for applications in high-voltage experiments or demonstrations. The 12SQ7 tube amplifies feedback signals, ensuring that the oscillations are sustained and stable.

The salvaged power transformer adds a layer of practicality to the design, providing multiple output voltages that are essential for the operation of the tubes. The voltage doubler circuits are critical in achieving the high voltages required for the flyback operation, allowing the system to operate effectively under load conditions.

Overall, this flyback driver circuit exemplifies the integration of solid-state components with traditional vacuum tube technology, showcasing a hybrid approach that capitalizes on the strengths of both technologies to achieve high-voltage generation efficiently. The self-resonant nature of the circuit, enabled by feedback mechanisms, simplifies the design process by negating the need for manual frequency adjustments, thereby enhancing user-friendliness and reliability.A solid state flyback driver based on a micro solid-state Tesla coil circuit created by Steve Ward. The schematic is reprinted here with credits to Steve Ward: microsstc. jpg. NOTES ON MY DESIGN: Instead of an air-core Tesla Coil setup, I used a flyback. Also I used a IRFP450 MOSFET, which is rated about 4A less than the IRFP460 MOSFET. The transformer I used is ~30V 2A. I used a standard 8-pin socket instead of two 4-pin sockets for the two ICs (TC4420 and 555 timer). This tube flyback driver is based on a vacuum tube tesla coil (VTTC) and high voltage generation circuits in tube TVs. Below is the schematic of the tube flyback driver. The 6BG6 tube is a TV output tube that drives the flyback transformer. The 12SQ7 is a high-gain amplifier that boosts the feedback signals to oscillate the 6BG6 tube. The power transformer was salvaged from a small HP frequency counter, and has 250V, 18V, and 7V windings.

The 250V winding is fed in a voltage doubler which brings it up to around 600V, but drops to around 300 to 400 volts loaded. The 18V winding feeds the 6V 2. 5A filament of the 6BG6 tube, which works alright and the voltage drops to about 5V loaded. The 7V winding is fed into another voltage doubler to bring up the voltage to around 10V to 15V for the 12V filament of the 12SQ7.

The circuit is self-resonant due to the use of feedback to trigger the oscillations so there is no frequency alignment necessary. 🔗 External reference