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Re: [TCML] A Question about Solid State Drivers

Greg Morris wrote:
Hi Steve,

Thanks for the advice!

The reason I mentioned such a high "bandwidth" is because I intend to music
modulate the coil. The coil will be nominally operating at around 200kHz,
but I want to be able to modulate it down to a 10% duty cycle, and up to a
90% duty cycle (as well as 0% and 100%, of course, but not 95%, for
example). And so for a 10% duty cycle (or 90%) at 200kHz, the system needs
to be able to operate at a switching frequency of 10*200kHz = 2MHz.

Are you modulating the duty cycle to change the "loudness"? Your waveform is basically going to be a pulse train amplitude modulating a 200kHz carrier at, say, 440 Hz (for the note A). The duty cycle you need to worry about is the audio modulation (e.g. say you use 1 millisecond bursts as "full power", you want to go down to say, 100 microseconds, which would give you a 10:1 variation (comparable to your 10% to 100%). Even at 100 microseconds, you've got 20 cycles of the 200 kHz carrier, which is plenty.
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