dsp sstc

Description: This project involves the development of a versatile digital signal processor (DSP) based generic driver and controller circuit for Solid State Tesla Coils (SSTCs). It is designed to support various topologies, including DRSSTC, OLTC, and PLL-SSTC, which can be implemented programmatically. Additionally, the controller can be utilized to debug switch mode supplies by functioning as a PWM signal generator. The DSP controller board will utilize one of Motorola/Freescale's miniature hybrid controllers from the 56800E series (specifically the 56F8322). These microcontrollers feature a DSP core operating at 60 MHz with a performance of 60 MIPS (17 ns per instruction). The 56F8322 is favored due to its on-board 6-channel PWM module and 6 timers, and it is currently available for sample order. The final version of the DSP board will enable operation as a feedback SSTC with immediate frequency tracking, including programmable hard limiting of the output frequency range (e.g., minimum 50 kHz, maximum 200 kHz) and automatic SSTC restart "kicks." The optical serial communication link is established using a cost-effective TFDU/TFDS/TFDT4100 IrDA transceiver module, which is adapted for standard serial data bit encoding rather than the IrDA pulse-length encoding. The TFDU4100 includes an internal transmitter diode with drive circuitry and a receiver diode with gain control and amplification for digital output, simplifying the design compared to discrete components. The PC side will require a second TFDU4100 along with minor circuitry to convert to 0V and 5V levels, disregarding the "official" RS-232 signal levels. The board output lines are driven by an open-collector 74LS07 / SN7407 logic buffer that supports output signal levels up to 30V, with a typical maximum transition delay of 20 ns. The DSP board already incorporates 10kOhm pull-up resistors. The DSP56858 Evaluation Module Users Manual contains a JTAG schematic, which utilizes a special MC74LCX244; however, a standard 74HC244 should also be compatible at 3.3V, albeit at a slower speed. A low-cost Developer Starter Kit (MC56F8300DSK) is available from Freescale for approximately $80, including all necessary development software and eliminating the need for a DIY JTAG adapter. Important considerations include updating the JTAG connector pin-out, replacing the LM317L and 78L05 with TO-220 packaged components due to power dissipation concerns, and ensuring that the LM317T has a 3.3V zener diode across the output, as the regulator may produce voltage spikes exceeding 9V at power-up, potentially damaging the DSP. Lab notes indicate that an audio-modulated 500 kHz PWM test source was created for a class-D audio amplifier project. It was observed that the built-in PWM module's frequency adjustment for frequencies above 100 kHz does not provide as fine-grained a resolution as desired, with a step size greater than 4 kHz, rather than a fixed sub-1 kHz resolution. However, the resolution remains satisfactory below 100 kHz.

The circuit design for this DSP-based controller emphasizes flexibility and programmability, allowing for a wide range of applications in driving various SSTC topologies. The choice of the 56F8322 microcontroller is critical, as its built-in features significantly reduce the need for additional components, thus simplifying the overall design. The integration of a 6-channel PWM module facilitates precise control over the output, essential for the operation of SSTCs, which require accurate frequency modulation to function effectively.

The communication between the DSP board and the PC through the TFDU4100 transceiver enhances ease of use, allowing for straightforward data transfer without the complications associated with traditional RS-232 levels. The open-collector output stage provided by the 74LS07 / SN7407 logic buffer ensures compatibility with higher voltage applications, enhancing the circuit's versatility.

Power management is addressed through the use of robust voltage regulators, with careful consideration given to component selection to prevent overheating and ensure stable operation. The incorporation of pull-up resistors is a standard practice that ensures reliable signal integrity across the board.

The project also includes provisions for debugging and testing, allowing for iterative development and refinement of the circuit. The ability to generate PWM signals is particularly useful for testing the circuit's response and performance in real-time, providing valuable feedback for further optimization.

Overall, this DSP-based driver and controller circuit is positioned to serve as a comprehensive solution for controlling Solid State Tesla Coils, with the potential for future enhancements and adaptations to meet evolving requirements in the field of high-voltage electronics.This is a project for a versatile, digital signal processor (DSP) based generic driver and controller circuit for Solid State Tesla Coils (SSTCs). Support for all new topologies (DRSSTC, OLTC, PLL-SSTC, . ) can be implemented programmatically. The same controller can serve to debug switch mode supplies, by functioning as a PWM signal generator.

Thi s DSP controller board will use one of Motorola/Freescale`s miniature hybrid controllers of the 56800E series (56F8322, datasheet ). These are very small microcontrollers with a DSP core, running 60 MHz with 60 MIPS (17ns per instruction).

The 56F8322 is preferred to others of the 56800E series as it has an on-board 6-channel PWM module and 6 timers, and is on Sample Order status. The final version of the DSP board will allow you to: operate as a feedback SSTC with immediate frequency tracking, including programmable hard limiting of output frequency range (e.

g. min 50kHz max 200kHz), and automatic SSTC restart `kicks` The optical serial communication link is achieved with a relatively cheap TFDU/TFDS/TFDT4100 IrDA transceiver module being `mis-used` for normal serial data bit encoding instead of the IrDA pulse-length encoding. The TFDU4100 has an internal transmitter diode with drive circuitry, and a receiver diode with gain control and amplifier for digital output, so it is simpler to use the module than a bunch of discretes.

The PC side will need a second TFDU4100, plus some small circuitry to convert to 0V and 5V (never mind the `official` RS-232 signal levels :-). The board output lines are driven by the open-collector 74LS07 / SN7407 logic buffer that allows up to 30V output signal levels and has a typical or max transition delay of 20ns.

10kOhm pull-up resistors are already included on the DSP board. 2) the DSP56858 Evaluation Module Users Manual dsp56858evmum_d. pdf also has a JTAG schematic on page 46/A-8. It uses a special MC74LCX244 but a normal 74HC244 should also be able to work from 3. 3V, just not as fast. There`s also a low cost Developer Starter Kit ( MC56F8300DSK ) that is available from Freescale for around $80. It comes with all necessary devel software, and does not require a DIY jtag adapter. Important notes: jtag connector pin-out needs to be updated, LM317L and 78L05 must be changed to TO-220 packaged ones because of power dissipation, and LM317T must have a 3.

3V zener accross the output as the regulator seems to create voltage spikes beyond 9V at power-up (can fry the DSP) Lab notes: already wrote an audio-modulated 500kHz PWM testsource (used in a class-D audio amp project), where it then became apparent that even with the 56F8322 the built-in PWM module`s frequency adjustment i. e. step size for freqs above 100kHz is not as fine-grained as I`d like. Step size was >4kHz, instead of a fixed sub-1kHz resolution. However at <100kHz resolution is fine.