# US 12,119,759 B2 · High voltage, high efficiency sine wave generator that prevents spikes during amplitude adjustments and switching of channels > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,119,759 B2 - Document ID: US12119759B2 - Status: Granted - Kind: B2 - Application number: 18/105,069 - Filed: 2023-02-02 - Published: 2023-06-15 - Granted: 2024-10-15 - Earliest claimed: 2019-12-31 - Assignees: Novocure GmbH - Applicants: Novocure GmbH - Inventors: Yoram Wasserman - Web page: https://patentgrep.com/patent/US12119759B2 ## CPC - A61N 1/36002: {Cancer treatment, e.g. tumour} - H02M 7/53871: {with automatic control of output voltage or current} - A61N 1/326: {for promoting growth of cells, e.g. bone cells} - A61N 1/36034: {specified by the stimulation parameters} - A61N 1/40: Applying electric fields by inductive or capacitive coupling (microwave apparatus A61N5/00); {Applying radio-frequency signals} - G06F 1/022: {Waveform generators, i.e. devices for generating periodical functions of time, e.g. direct digital synthesizers (G06F1/025, G06F1/03 take precedence)} - H02M 1/0012: {Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873)} - H02M 1/007: {Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826)} - A61N 1/0476: {Array electrodes (including any electrode arrangement with more than one electrode for at least one of the polarities)} - H02M 7/53878: {by time shifting switching signals of one diagonal pair of the bridge with respect to the other diagonal pair} - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## 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. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the electronic switch is further configured to (c) operate in a third mode in which the output of the AC voltage generator is not routed to either the first power output or the second power output, and (d) cycle through the first mode, the second mode, and the third mode in the following repeating sequence (1) first mode, (2) third mode, (3) second mode, and (4) third mode. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the controller is 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 1.1°, the middle 2.2°, and the last 1.1° of each 360° cycle of the AC voltage generator. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the AC voltage generator continues to operate at its full steady-state AC output voltage during transitions of the electronic switch to either the first mode or the second mode. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the controller synchronizes the operation of the AC voltage generator and the electronic switch by controlling the AC voltage generator so that the output of the AC voltage generator is turned off whenever a transition of the electronic switch occurs. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the controller synchronizes the operation of the AC voltage generator and the electronic switch by both (a) controlling timing of transitions of the electronic switch so that the transitions coincide with 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 and (b) controlling the AC voltage generator so that the output of the AC voltage generator is turned off whenever a transition of the electronic switch occurs. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the electronic switch is configured to cycle through the first mode and the second mode in the following repeating sequence (1) first mode, (2) second mode, and wherein the electronic switch is configured to switch directly from the first mode to the second mode and to switch directly from the second mode to the first mode. ### Claim 8 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 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. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the electronic switch is further configured to (c) operate in a third mode in which the output of the AC voltage generator is not routed to either the first power output or the second power output, and (d) cycle through the first mode, the second mode, and the third mode in the following repeating sequence (1) first mode, (2) third mode, (3) second mode, and (4) third mode. ### Claim 10 (depends on 8) The apparatus of claim 8, wherein the controller is configured to synchronize the operation of the AC voltage generator and the electronic switch such that the instantaneous output of the AC voltage generator is less than 1 V in magnitude whenever the electronic switch switches to either the first mode or the second mode. ### Claim 11 (depends on 8) The apparatus of claim 8, wherein the AC voltage generator continues to operate at its full steady-state AC output voltage during transitions of the electronic switch to either the first mode or the second mode. ### Claim 12 (depends on 8) The apparatus of claim 8, wherein the controller synchronizes the operation of the AC voltage generator and the electronic switch by controlling timing of transitions of the electronic switch so that the transitions coincide with windows of time during which the instantaneous output of the AC voltage generator has a magnitude that is below the magnitude at which a subject to be treated is expected to begin to experience perceptible sensation. ### Claim 13 (depends on 8) The apparatus of claim 8, wherein the controller synchronizes the operation of the AC voltage generator and the electronic switch by controlling the AC voltage generator so that the output of the AC voltage generator is turned off whenever a transition of the electronic switch occurs. ### Claim 14 (depends on 8) The apparatus of claim 8, wherein the controller synchronizes the operation of the AC voltage generator and the electronic switch by both (a) controlling timing of transitions of the electronic switch so that the transitions coincide with windows of time during which the instantaneous output of the AC voltage generator has a magnitude that is below the threshold and (b) controlling the AC voltage generator so that the output of the AC voltage generator is turned off whenever a transition of the electronic switch occurs. ### Claim 15 (depends on 8) The apparatus of claim 8, wherein the electronic switch is configured to cycle through the first mode and the second mode in the following repeating sequence (1) first mode, (2) second mode, and wherein the electronic switch is configured to switch directly from the first mode to the second mode and to switch directly from the second mode to the first mode. ### Claim 16 A method for generating AC electrical signals using an AC voltage generator and an electronic switch, the method comprising: switching the electronic switch to a first state that routes the output of the AC voltage generator to a first output; switching the electronic switch to a second state that routes the output of the AC voltage generator to a second output; and cycling through a repeating sequence that includes switching the electronic switch to the first state and switching the electronic switch to the second state, wherein the switching of the electronic switch to either the first state or the second state 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's output. ### Claim 17 (depends on 16) The method of claim 16, wherein the switching of the electronic switch to either the first state or the second state is restricted to windows of time that correspond to the first 1.1°, the middle 2.2°, and the last 1.1° of each 360° cycle of the AC voltage generator. ### Claim 18 (depends on 16) The method of claim 16, wherein the AC voltage generator continues to operate at its full steady-state AC output voltage during switching of the electronic switch to either the first state or the second state. ### Claim 19 (depends on 16) The method of claim 16, wherein the electronic switch is configured to switch directly from the first state to the second state and to switch directly from the second state to the first state.