JPWO2021110605A5 - - Google Patents

Claims (15)

A bipolar pulse generation circuit for an electrosurgical generator, the circuit comprising:
a voltage source connectable to a load via a switching element;
A coaxial transmission line having an inner conductor separated from an outer conductor by a dielectric material, the inner conductor having a first end connected between an input of the switching element and the voltage source and an open circuit condition. and a second end located at the voltage source, the coaxial transmission line being charged by the voltage source when the switching element is in an off state, and the coaxial transmission line being discharged when the switching element is in an on state. said coaxial transmission line,
a first output connectable to the load, the first output located between the output of the switching element and ground to support positive pulses when the coaxial transmission line discharges; , the first output;
a second output connectable to the load, the second output between the external conductor of the coaxial transmission line and ground to support negative pulses when the coaxial transmission line discharges; the second output located at;
The impedance of the coaxial transmission line is configured to match the sum of (i) the impedance of the switching element, (ii) the impedance of the load at the first output, and (iii) the impedance of the load at the second output. consists of
a delay line is connected to either the first output or the second output, and the provision of the positive pulse and the negative pulse at the first output and the second output occurs sequentially;
The bipolar pulse generation circuit. The bipolar pulse generation circuit of claim 1, wherein the delay line is adjustable in length. 3. A bipolar pulse generation circuit according to claim 1 or 2, wherein the delay line is another length of coaxial transmission line. The switching element is
a plurality of series-connected avalanche transistors;
a trigger pulse generator configured to generate a trigger pulse that activates the plurality of series-connected avalanche transistors;
The bipolar pulse generation circuit according to any one of claims 1 to 3, comprising: 5. The bipolar pulse generation circuit of claim 4, wherein the trigger pulse generator includes a TTL device. 6. The bipolar pulse generation circuit according to claim 4, wherein the trigger pulse has a voltage less than the emitter-base breakdown voltage of each of the plurality of avalanche transistors. The bipolar pulse generation circuit according to any one of claims 4 to 6, wherein the trigger pulse generator is connected to the plurality of series-connected avalanche transistors via a transformer. 8. The bipolar pulse generation circuit according to claim 4, wherein the trigger pulse is applied between a collector and an emitter of a first transistor of the plurality of series-connected avalanche transistors. 9. The bipolar pulse generation circuit of claim 8, wherein the first transistor is furthest from the coaxial transmission line. A diode is connected in parallel with each of the plurality of series connected avalanche transistors to clamp the voltage across each transistor below its collector-base breakdown voltage. The bipolar pulse generation circuit described in . The bipolar pulse generation circuit according to any one of claims 4 to 10, wherein each transistor in the plurality of series-connected avalanche transistors is the same. A bipolar pulse generation circuit according to any preceding claim , wherein the coaxial transmission line has a length selected to provide a line delay of 5 nanoseconds or less. A bipolar pulse generation circuit according to any one of claims 1 to 12, wherein the coaxial transmission line is charged by the voltage source through a resistor. A bipolar pulse generation circuit according to any one of claims 1 to 13 , wherein the load is an electrosurgical instrument. An electrosurgical generator comprising a bipolar pulse generation circuit according to any one of claims 1 to 14 .