I am working on building a lightning emulator to be used in development of an AS3935-based lightning detector. Here is the schematic of the AMS emulator (pdf attached). Sourec is the AMS AS3935 application note.
That device uses an AS1504 (obsolete) as a DAC and an AS1101 (LED driver) as a voltage controlled current sink. Draft1.pdf is a simulation using a current sink limited to 12 mA. The oscillation follows nicely the profile for the current sink, which is in red.
Both 16F and 24F PIC's come with built in 8-bit DAC's and op-amps. Unfortunately, I am quite ignorant of using op-amps as current regulators. There are several documents on using op-amps in that way, including a TI document ( sboa046 ) which includes this design:
I would use an appropriate resistor to give the give the control current. I have not tried to simulate it and wanted first to get opinions on that approach rather than using a separate chip, such as the AS1101.
Any comments, suggestions, or good links for providing that functionality using the built-in op-amps the PIC devices have? The AS1101 is only $1.16, so the issue is not really one of cost, but rather the simplicity of using just one chip.
Regards, John
Comment to moderators: I have a separate thread in Projects that also deals with this lightning detector, but I would like to keep that thread focused on the waveforms needed for emulation, rather than a sub-component of how to get them.
That device uses an AS1504 (obsolete) as a DAC and an AS1101 (LED driver) as a voltage controlled current sink. Draft1.pdf is a simulation using a current sink limited to 12 mA. The oscillation follows nicely the profile for the current sink, which is in red.
Both 16F and 24F PIC's come with built in 8-bit DAC's and op-amps. Unfortunately, I am quite ignorant of using op-amps as current regulators. There are several documents on using op-amps in that way, including a TI document ( sboa046 ) which includes this design:
I would use an appropriate resistor to give the give the control current. I have not tried to simulate it and wanted first to get opinions on that approach rather than using a separate chip, such as the AS1101.
Any comments, suggestions, or good links for providing that functionality using the built-in op-amps the PIC devices have? The AS1101 is only $1.16, so the issue is not really one of cost, but rather the simplicity of using just one chip.
Regards, John
Comment to moderators: I have a separate thread in Projects that also deals with this lightning detector, but I would like to keep that thread focused on the waveforms needed for emulation, rather than a sub-component of how to get them.
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