High voltage, high efficiency sine wave generator that prevents spikes during amplitude adjustments and switching of channels
AssigneeNovocure GmbH
InventorYoram Wasserman
Life of this patent
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Abstract
This application describes a variety of approaches for generating high voltage sinusoidal signals whose output voltage can be adjusted rapidly, without introducing high-frequency artifacts on the output. When these approaches are used, stronger electric fields can be applied to the tumor for a higher percentage of time, which can increase the efficacy of TTFields therapy. In some embodiments, this is accomplished by preventing adjustments to a DC power source during times when the output of that DC power source is powering the output signal. In some embodiments, this is accomplished by synchronizing the operation of an AC voltage generator and an electronic switch that is connected to the output of the AC voltage generator.
Claims20
An apparatus for generating AC electrical signals for application to a first pair of electrodes and a second pair of electrodes, the apparatus comprising:
- an AC voltage generator having an output;
- an electronic switch having an input that receives the output of the AC voltage generator, a first power output, and a second power output, wherein the electronic switch is configured to (a) operate in a first mode that routes the output of the AC voltage generator to the first power output, and (b) operate in a second mode that routes the output of the AC voltage generator to the second power output, and wherein the electronic switch is further configured to cycle through a repeating sequence that includes the first mode and the second mode;
- and
- a controller configured to synchronize the operation of the AC voltage generator and the electronic switch such that switching of the electronic switch to either the first mode or the second mode is restricted to windows of time that correspond to the first 5.7°, the middle 11.4°, and the last 5.7° of each 360° cycle of the AC voltage generator,
- wherein, within 20 ms after the electronic switch switches to either the first mode or the second mode, the AC voltage generator's output voltage is at least 80% of the AC voltage generator's steady-state output voltage.
An apparatus for generating AC electrical signals for application to a first pair of electrodes and a second pair of electrodes, the apparatus comprising:
- an AC voltage generator having an output;
- an electronic switch having an input that receives the output of the AC voltage generator, a first power output, and a second power output, wherein the electronic switch is configured to (a) operate in a first mode that routes the output of the AC voltage generator to the first power output, and (b) operate in a second mode that routes the output of the AC voltage generator to the second power output, and wherein the electronic switch is further configured to cycle through a repeating sequence that includes the first mode and the second mode;
- and
- a controller configured to synchronize the operation of the AC voltage generator and the electronic switch such that switching of the electronic switch to either the first mode or the second mode occurs only during portions of a 360° cycle of the output of the AC voltage generator has-that have a magnitude that is below a magnitude at which a subject to be treated is expected to begin to experience a perceptible sensation, wherein, within 20 ms after the electronic switch switches to either the first mode or the second mode, the AC voltage generator's output voltage is at least 80% of the AC voltage generator's steady-state output voltage.
Dependencies are inferred from the claim text.