Apparatuses and methods for limiting load current in nanosecond pulsed power sources
AssigneePulse Biosciences, Inc.
InventorsChaofeng Huang, Gregory P. Schaadt, Kenneth R. Krieg
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Abstract
Described herein are apparatuses and methods for applying high voltage, high current, sub-microsecond (e.g., nanosecond range) pulsed output to a biological material, e.g., tissues, cells, etc., while preventing damage from load arcing. Some of the apparatuses and methods described herein may limit the load and pulsed power source current in case of load arcing significantly by using a transmission line (e.g., coaxial cable, twisted pair or parallel pair cables) between the pulsed power source and the load having a length configured to achieve this goal.
Claims25
An apparatus for delivering nanosecond pulsed electrical energy comprising:
- a nanosecond pulse generator configured to provide at least a high voltage pulsed output having a maximum pulse duration of up to 1000 ns;
- a transmission cable coupled to the nanosecond pulse generator at a first end, the transmission cable having a characteristic impedance (Z0) and a characteristic pulse speed (v), wherein the transmission cable has a length between the first end and a second end that is greater than or equal to F times of the maximum pulse duration (in ns) divided by the characteristic pulse speed on the transmission cable (in ns/ft), wherein F is between 0.1 and 0.5;
- and
- a pulse delivery output, wherein the pulse delivery output couples to the second end of the transmission cable.
A method of delivering nanosecond pulsed electrical energy to a biological material, the method comprising:
- generating a high voltage pulsed output having a maximum pulse duration of up to 1000 ns;
- and
- transmitting the pulsed output from a first end of a transmission cable coupled to a nanosecond pulse generator to a pulse delivery output at a second end of the transmission cable at a characteristic pulse speed on the transmission cable;
- wherein the transmission cable has a length between the first end and the second end that is greater than or equal to F times of the maximum pulse duration divided by the characteristic pulse speed on the transmission cable wherein F is between 0.1 and 0.5, so that any electrical reflection from the second end of the transmission cable do not reach the nanosecond pulse generator before the nanosecond pulse generator has switched off the high voltage pulsed output.
An apparatus for delivering nanosecond pulsed electrical energy comprising:
- a nanosecond pulse generator configured to provide at least a high voltage pulsed output having a maximum pulse duration of up to 1000 ns;
- a housing at least partially enclosing the nanosecond pulse generator;
- a transmission cable coupled to the nanosecond pulse generator at a first end, the transmission cable having a characteristic impedance (Z0) and a characteristic pulse speed (v), wherein the transmission cable has a transmission cable length comprising an internal cable length that is housed within the housing and an external cable length that is extended or extendable from the housing, wherein a majority of the transmission cable length is the internal cable length, such that a distributed inductance of the transmission cable decreases currents of 300 A or more that are reflected back to the pulse generator to prevent damage to the nanosecond pulse generator;
- and
- a pulse delivery output, wherein the pulse delivery output couples to the external cable length of the transmission cable.
Dependencies are inferred from the claim text.