CN-116113377-B - Signal generator for tissue modification system

Abstract

The present invention relates to signal generators, systems including the same, and related methods. The signal generator includes a capacitor that stores energy for generating the processed signal. The signal generator further includes a waveform shaping circuit, a controller, a voltage sensing circuit, and a current sensing circuit. The waveform shaping circuit is coupled to the capacitor and includes a first switch, a second switch, a third switch, and a fourth switch, each switch configured to be selectively turned on and off to allow current to pass through the switch when the switch is on and to prevent current from passing through the switch when the switch is off. The controller selectively controls the switch to generate the processing signal. The controller also selectively controls the switches to perform certain fault tests that depend on the voltage sensed by the voltage sensing circuit and the current sensed by the current sensing circuit.

Inventors

• T. J. Gunder
• P. B. Friedrich

Assignees

• 镀锌医疗公司

Dates

Publication Date

20260505

Application Date

20210505

Priority Date

20210409

Claims (20)

1. 1. A signal generator, comprising: one or more capacitors coupled between the high voltage rail and the low voltage rail and configured to store energy that can be used to selectively generate the processing signal; A waveform shaping circuit coupled to the one or more capacitors and comprising a first switch, a second switch, a third switch, and a fourth switch, each of the switches configured to selectively turn on and off, and each of the switches configured to allow current to pass through the switch when the switch is on and to block current from passing through the switch when the switch is off, wherein the first switch and the second switch are connected in series within a first leg of the waveform shaping circuit, the third switch and the fourth switch are connected in series within a second leg of the waveform shaping circuit, the first leg and the second leg being connected in parallel with each other; A controller configured to selectively control the switches so as to selectively turn on a first pair of the switches and turn off a second pair of the switches during a first period of time, and to selectively turn off the first pair of the switches and turn on a second pair of the switches during a second period of time, so as to generate the processing signal, wherein the first pair of switches includes the first switch and the fourth switch, and the second pair of switches includes the second switch and the third switch; a voltage sensing circuit configured to sense a voltage stored on the one or more capacitors, and A current sensing circuit configured to sense a current having a magnitude that characterizes a magnitude of the current flowing through a pair of switches turned on by the controller; The controller is further configured to: Selectively performing a first fault test on the signal generator, wherein during the first fault test, the first pair of switches is turned on and the second pair of switches is turned off, comparing the voltage stored on the one or more capacitors sensed by the voltage sensing circuit with a specified voltage threshold, and comparing the current magnitude sensed by the current sensing circuit with a specified current threshold; Determining that the signal generator passes the first fault test in response to the voltage stored on the one or more capacitors sensed by the voltage sensing circuit being below a specified voltage threshold and the current magnitude sensed by the current sensing circuit being above a specified current threshold, and In response to the current magnitude sensed by the current sensing circuit being below the specified current threshold, it is determined that the signal generator failed the first fault test.
2. 2. The signal generator of claim 1, wherein, as part of the first fault test, the controller is configured to: Determining that at least one switch of the first pair of switches is stuck in an open state in response to the current magnitude sensed by the current sensing circuit being below the specified current threshold and the voltage sensed by the voltage sensing circuit being above the specified voltage threshold, and In response to the current magnitude sensed by the current sensing circuit being below the specified current threshold and the voltage sensed by the voltage sensing circuit being below the specified voltage threshold, it is determined that at least one switch of the second pair of switches is stuck in an on state.
3. 3. The signal generator of claim 1, wherein the controller is further configured to: Selectively performing a second fault test on the signal generator, wherein during the second fault test the first pair of switches is turned off and the second pair of switches is turned on, and Determining that the signal generator passes the second fault test in response to the voltage sensed by the voltage sensing circuit being below the specified voltage threshold and the current magnitude sensed by the current sensing circuit being above the specified current threshold, and In response to the current magnitude sensed by the current sensing circuit being below the specified current threshold, determining that the signal generator failed the second fault test.
4. 4. A signal generator according to claim 3, wherein, as part of the second fault test, the controller is configured to: Determining that at least one switch of the second pair of switches is stuck in an open state in response to the current magnitude sensed by the current sensing circuit being below the specified current threshold and the voltage sensed by the voltage sensing circuit being above the specified voltage threshold, and In response to the current magnitude sensed by the current sensing circuit being below the specified current threshold and the voltage sensed by the voltage sensing circuit being below the specified voltage threshold, it is determined that at least one switch of the first pair of switches is stuck in an on state.
5. 5. The signal generator of claim 4, wherein the controller is configured to perform at least one of the first fault test and the second fault test in response to the signal generator being powered on.
6. 6. The signal generator of any one of claims 1 to 5, wherein the controller is implemented by at least one of a processor or a Field Programmable Gate Array (FPGA).
7. 7. The signal generator of any one of claims 1 to 5, wherein: a first output node of the waveform shaping circuit is located between the first switch and the second switch; the second output node of the waveform shaping circuit is located between the third switch and the fourth switch.
8. 8. The signal generator of claim 7, wherein: The first switch is connected between the high voltage rail and the first output node; the second switch is connected between the first output node and the low voltage rail; the third switch is connected between the high voltage rail and the second output node, and The fourth switch is connected between the second output node and the low voltage rail.
9. 9. The signal generator of claim 8, further comprising: a transformer comprising a first primary winding, a second primary winding, and a secondary winding; Wherein the first primary winding and the second primary winding are connected in parallel with each other and coupled between the first output node and the second output node of the waveform shaping circuit, and Wherein the current sensed by the current sensing circuit is generated in response to a voltage induced in the secondary winding and is used to generate a treatment signal applied to patient tissue.
10. 10. The signal generator of any one of claims 1 to 5, further comprising: a transformer comprising a first primary winding, a second primary winding, and a secondary winding; wherein the first primary winding and the second primary winding are connected in parallel with each other and coupled to the waveform shaping circuit, and Wherein the current sensed by the current sensing circuit is generated in response to a voltage induced in the secondary winding and is used to generate a treatment signal applied to patient tissue.
11. 11. A method for use by a signal generator, the signal generator comprising: one or more capacitors configured to store energy that can be used to selectively generate a processed signal, and A waveform shaping circuit coupled to the one or more capacitors and comprising a first switch, a second switch, a third switch, and a fourth switch, each of the switches configured to selectively turn on and off, and each of the switches configured to allow current to pass through the switch when the switch is on and to block current from passing through the switch when the switch is off, wherein the first switch and the second switch are connected in series within a first leg of the waveform shaping circuit, the third switch and the fourth switch are connected in series within a second leg of the waveform shaping circuit, the first leg and the second leg being connected in parallel with each other; The method comprises the following steps: Performing a first fault test on the signal generator, wherein during the first fault test a first pair of the switches is turned on and a second pair of the switches is turned off, wherein the first pair of switches comprises the first switch and the fourth switch and the second pair of switches comprises the second switch and the third switch; Sensing a first voltage stored on the one or more capacitors as part of the first fault test and comparing the first voltage to a specified voltage threshold; Sensing a first current as part of the first fault test, the first current having a magnitude that characterizes a magnitude of current flowing through the first pair of switches that are turned on and comparing the magnitude of the first current to a specified current threshold, and Based on a comparison of the first voltage stored on the one or more capacitors to the specified voltage threshold and based on a comparison of the first current to the specified current threshold, determining whether the signal generator passes the first fault test.
12. 12. The method of claim 11, wherein determining whether the signal generator passes the first fault test comprises: the signal generator is determined to pass the first fault test in response to the first voltage sensed as part of the first fault test being below a specified voltage threshold and the magnitude of the first current sensed as part of the first fault test being above a specified current threshold.
13. 13. The method of claim 12, wherein determining whether the signal generator passes the first fault test comprises: In response to the magnitude of the first current being below the specified current threshold, it is determined that the signal generator failed the first fault test.
14. 14. The method of claim 13, wherein determining that the signal generator fails the first fault test further comprises: Determining that at least one switch of the first pair of switches is in an open state in response to the magnitude of the first current sensed as part of the first fault test being below the specified current threshold and the first voltage sensed as part of the first fault test being above the specified voltage threshold, and In response to the magnitude of the first current sensed as part of the first fault test being below the specified current threshold and the first voltage sensed as part of the first fault test being below the specified voltage threshold, it is determined that at least one switch of the second pair of switches is stuck in an on state.
15. 15. The method of claim 14, wherein A first output node of the waveform shaping circuit is located between the first switch and the second switch; the second output node of the waveform shaping circuit is located between the third switch and the fourth switch.
16. 16. The method of any of claims 11 to 15, further comprising: Performing a second fault test on the signal generator, wherein during the second fault test, the first pair of switches is turned off and the second pair of switches is turned on; Sensing a second voltage stored on the one or more capacitors as part of the second fault test; sensing a second current as part of the second fault test, the second current having a magnitude that is indicative of a magnitude of current flowing through the second pair of switches that are turned on, and Determining whether the signal generator passes the second fault test based on the second voltage stored on the one or more capacitors and based on the second current, wherein the second current has a magnitude that characterizes a magnitude of current flowing through the second pair of switches that are turned on, the second voltage and the second current being sensed as part of the second fault test.
17. 17. The method of claim 16, wherein determining whether the signal generator passes the second fault test comprises: in response to the second voltage sensed as part of the second fault test being below a specified voltage threshold and the magnitude of the second current sensed as part of the second fault test being above a specified current threshold, determining that the signal generator passed the second fault test.
18. 18. The method of claim 17, wherein determining whether the signal generator passes the second fault test comprises: In response to the magnitude of the second current sensed as part of the second fault test being below the specified current threshold, it is determined that the signal generator failed the second fault test.
19. 19. The method of claim 18, wherein determining that the signal generator fails the second fault test further comprises: determining that at least one switch of the second pair of switches is in an open state in response to the magnitude of the second current sensed as part of the second fault test being below the specified current threshold and the second voltage sensed as part of the second fault test being above the specified voltage threshold, or In response to the magnitude of the second current sensed as part of the second fault test being below the specified current threshold and the second voltage sensed as part of the second fault test being below the specified voltage threshold, it is determined that at least one switch of the first pair of switches is stuck in an on state.
20. 20. A signal generator, comprising: One or more capacitors configured to store energy capable of selectively generating a processed signal; A switching network comprising a first switch, a second switch, a third switch, and a fourth switch, the first switch and the second switch being connected in series with each other and in parallel with the one or more capacitors, and the third switch and the fourth switch being connected in series with each other and in parallel with the one or more capacitors; Each of the first switch, the second switch, the third switch, and the fourth switch is configured to be selectively turned on and off, configured to allow current to pass through the switch when the switch is turned on, and configured to prevent current from passing through the switch when the switch is turned off; A controller configured to selectively control the switches so as to selectively turn on the first switch and the fourth switch and turn off the second switch and the third switch during a first period of time, and to selectively turn off the first switch and the fourth switch and turn on the second switch and the third switch during a second period of time, so as to generate the processing signal; a voltage sensing circuit configured to sense a voltage stored on the one or more capacitors, and A current sensing circuit configured to sense a current having a magnitude that characterizes a magnitude of the current flowing through a switch turned on by the controller; The controller is further configured to: selectively performing a first fault test on the signal generator, wherein during the first fault test, the first switch and the fourth switch are turned on, the second switch and the third switch are turned off, comparing a voltage stored on the one or more capacitors sensed by a voltage sensing circuit with a specified voltage threshold, and comparing a current magnitude sensed by a current sensing circuit with a specified current threshold; determining that the signal generator passes the first fault test in response to the voltage sensed by the voltage sensing circuit being below a specified voltage threshold and the current magnitude sensed by the current sensing circuit being above a specified current threshold, and In response to the magnitude of the current stored on the one or more capacitors sensed by the current sensing circuit being below the specified current threshold, determining that the signal generator fails the first fault test.

Description

Signal generator for tissue modification system Technical Field Certain embodiments of the present technology relate to signal generators for use in processing systems, such as tissue modification systems, and to processing systems that include signal generators. Certain embodiments of the present technology also relate to methods used by a signal generator and/or by a processing system that includes a signal generator. Priority claim The present application claims priority from U.S. provisional patent application No.63/077,022, filed on day 9 and 11, and U.S. non-provisional patent application No.17/227,232, filed on day 4 and 9, 2021, which are incorporated herein by reference. Background Pulsed electric field therapy can be used to deliver high voltage and short duration pulses to affect various luminal structures (airways and gastrointestinal tract), unresectable tissue targets (liver, pancreas, lung and kidney), or diseased tissue in cancerous solid tumors. Signal generators are commonly used to generate pulsed electric field signals for such tissue treatment therapies. Because of the short duration of the pulses used to deliver the therapy, the signal generator typically includes a switching network containing solid state electronics. The signal generator may use its switching network to generate a biphasic processed signal comprising positive and negative going pulses. Alternatively, the signal generator may use its switching network to generate monophasic pulses. Solid state switches of signal generators can sometimes fail and present reliability problems due to the high voltages and currents that may be present under low impedance conditions. Disclosure of Invention In accordance with embodiments of the present technique, the signal generator includes one or more capacitors coupled between the high voltage rail and the low voltage rail and configured to store energy that may be used to selectively generate the processed signal. The signal generator further includes a waveform shaping circuit, a controller, a voltage sensing circuit, and a current sensing circuit and controller. The waveform shaping circuit is coupled to the one or more capacitors and includes a first switch, a second switch, a third switch, and a fourth switch, each configured to be selectively turned on and off, and each configured to allow current to pass through the switch when the switch is on and to prevent current from passing through the switch when the switch is off. The controller is configured to selectively control the switches to selectively turn on the first pair of switches and turn off the second pair of switches during a first time period and to selectively turn off the first pair of switches and turn on the second pair of switches during a second time period to generate the processing signal. The voltage sensing circuit is configured to sense a voltage stored in the one or more capacitors. The current sensing circuit is configured to sense a current having a magnitude that is characteristic of a magnitude of the current flowing through a pair of switches that are turned on by the controller. According to some embodiments, the controller is further configured to selectively perform a first fault test on the signal generator, wherein during the first fault test, the first pair of switches is on and the second pair of switches is off, determine that the signal generator passes the first fault test in response to the voltage sensed by the voltage sensing circuit being below a specified voltage threshold and the current magnitude sensed by the current sensing circuit being above a specified current threshold, and determine that the signal generator fails the first fault test in response to the current magnitude sensed by the current sensing circuit being below the specified current threshold. According to some embodiments, as part of the first fault test, the controller is configured to determine that at least one switch of the first pair of switches is stuck in an off state in response to a current magnitude sensed by the current sensing circuit being below a specified current threshold and a voltage sensed by the voltage sensing circuit being above a specified voltage threshold, and to determine that at least one switch of the second pair of switches is stuck in an on state in response to a current magnitude sensed by the current sensing circuit being below a specified current threshold and a voltage sensed by the voltage sensing circuit being below a specified voltage threshold. According to some embodiments, the controller is further configured to selectively perform a second fault test on the signal generator, wherein during the second fault test, the first pair of switches is open and the second pair of switches is closed, determine that the signal generator passes the second fault test in response to the voltage sensed by the voltage sensing circuit being below a specified voltage threshold and the current magnit