GENERATOR AND METHOD FOR PRODUCING A TREATMENT VOLTAGE

Abstract

A generator includes a number of impulse generators that are individually controlled by means of a control device in a timely flexible manner. The RF voltage required for supply of a surgical instrument is thus composed of individual impulses. The same applies for the current flowing at the electrode of the instrument. Due to omitting resonance effects in the impulse generators and omitting of energy storage in a system that is able to oscillate (system of second order), the user has an increased degree of control of the wave forms of the voltage supplied to the instrument and the current flowing to the instrument.

Claims

1. A generator comprising: an output configured to be connected to a medical instrument; a plurality of impulse generators, individual ones of which comprise a control input and an impulse generator output; and a control device that is connected with the control inputs to provide a control impulse to a respective impulse generator of the plurality of impulse generators to cause the respective impulse generator to output an output impulse, wherein the impulse generator outputs of each of the plurality of impulse generators are connected with the output of the generator.

2. The generator according to claim 1, wherein each of the plurality of impulse generators are identically configured compared with one another.

3. The generator according to claim 1, wherein each of the plurality of impulse generators is configured to output an output impulse at its impulse generator output in reaction to receipt of a control impulse at its control input.

4. The generator according to claim 1, wherein the control device is configured to output control impulses to at least two of the plurality of impulse generators sequentially.

5. The generator according to claim 1, wherein the control device is configured to output control impulses to at least two of the plurality of impulse generators concurrently.

6. The generator according to claim 1, wherein the control device is configured to output control impulses according to different time patterns.

7. The generator according to claim 1, wherein the impulse generator outputs are electrically connected in series.

8. The generator according to claim 1, wherein each of the plurality of impulse generators comprises an energy storage.

9. The generator according to claim 8, wherein the energy storage is an inductor.

10. The generator according to claim 9, wherein the impulse generator output is a coil coupling with the inductor in a transformer-type manner.

11. The generator according to claim 1, wherein individual ones of the plurality of impulse generators are flyback converters.

12. A method for producing an electrical voltage for supply of an electrosurgical instrument with a sequence of current impulses, the method comprising: producing a sequence of current impulses by a plurality of impulse generators that are connected with one another on their output sides.

13. The method according to claim 12, further comprising causing at least two of the plurality of impulse generators to output current impulses concurrently.

14. The method according to claim 12, further comprising causing at least two of the plurality of impulse generators to output current impulses sequentially.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 an overview block diagram of a generator according to the invention,

[0021] FIGS. 2 and 3 embodiments of impulse generators for the generator according to FIG. 1,

[0022] FIG. 4 a simplified circuit diagram of the generator according to FIG. 1 and

[0023] FIGS. 5 to 10 control signal diagrams and output voltage diagrams of the generator according to FIGS. 1 and 4 in different operating modes.

DETAILED DESCRIPTION

[0024] FIG. 1 illustrates a generator 11 that serves for supply of a surgical instrument 12. As an example a surgical instrument 12 for the open surgical use is illustrated in FIG. 1 having a handle 13 and an electrode 14. In this case it is a monopolar instrument. For discharging the current flowing from the instrument 12 to the patient, a neutral electrode 15 is provided that is connected via a suitable line with an output 16 of generator 11, just as the instrument 12. A monopolar instrument 12 is illustrated in FIG. 1 by way of example. Generator 11 is, however, also suitable for supply of bipolar instruments. In addition, it can also be provided for supply of instruments (probes) for laparoscopic or endoscopic use independent from whether they are monopolar or bipolar instruments. The generator 11 comprises a number of impulse generators G.sub.1, G.sub.2, G.sub.3, G.sub.4 . . . G.sub.n in a suitable number, e.g. 4, 6, 12 or also in a number different therefrom. The impulse generators G.sub.1 to G.sub.n are identically configured compared with one another and are connected in parallel to each other to an operating voltage U.sub.b as well as to ground 17. Basically this is not necessary; the impulse generators G.sub.1 to G.sub.n can also be configured differently in terms of their structure and/or dimensioning, e.g. in order to deliver output impulses having different amounts.

[0025] Each impulse generator G.sub.1 to G.sub.n comprises an impulse generator output A.sub.1 to A.sub.n that is respectively connected with the output 16 of generator 11. For this purpose the impulse generator outputs A.sub.1 to A.sub.n are, for example, connected in series with each other as shown in FIG. 1. This is particularly possible, because the impulse generator outputs A.sub.1 to A.sub.n are low-ohmic, i.e. they are able to forward output impulses of other impulse generators within the series connection. If the impulse generator outputs A.sub.1 to A.sub.n are high-ohmic, they can be connected in parallel to one another and can be connected with the output 16.

[0026] In addition, generator 11 comprises a control device 18 having control signal outputs that are connected with control signal inputs E.sub.1 to E.sub.n of the impulse generators G.sub.1 to G.sub.n. The control device 18 in turn comprises a control input S via which the control device 18 can receive an activation signal that can be created by means of an operating element, e.g. a foot switch, a hand switch or the like.

[0027] In figure the impulse generator G.sub.1 is described as representative for all other impulse generators G.sub.2 to G.sub.n. The following description of impulse generator G.sub.1 applies to all other impulse generators G.sub.2 to G.sub.n with regard to the structure of its configuration and its function accordingly.

[0028] The impulse generator G.sub.1 is preferably configured as flyback converter. It comprises an inductor L.sub.1, i.e., for example, a coil wound on a core having only a few windings or an air coil that is connected to the operating voltage U.sub.b with one end and to an electronic switch T.sub.1 with its other end that connects the inductor L.sub.1 selectively with ground 17 or interrupts this connection. A protection capacitor C.sub.1 can be assigned to the electronic switch T.sub.1 that is connected parallel to the switchable path of the electronic switch. If the electronic switch T.sub.1 is a transistor, e.g. a field effect transistor, the switchable path is the drain-source-path.

[0029] A control circuit V.sub.1 is assigned to the electronic switch T.sub.1, the control circuit V.sub.1 being preferably effective between ground 17 and a control electrode 21 of electronic switch T.sub.1. The control circuit V.sub.1 can be an active or passive control circuit. It serves to open or block the controlled path of the electronic switch T.sub.1 by means of a respective provision of signals at the control electrode 21. The control circuit V.sub.1 comprises an input E.sub.1 that is connected with control device 18.

[0030] The operating voltage U.sub.b is provided by a DC voltage source 22, preferably via a decoupling diode 23. Diodes 23 of the individual generators G.sub.1 to G.sub.n decouple them from one another. The operating voltage U.sub.b is stored in each impulse generator G.sub.1 to G.sub.n preferably on a buffer capacitor 24.

[0031] The impulse generator G.sub.1 comprises an output A.sub.1 that is realized by the ends of a coil 26-1 that is coupled with the inductor L.sub.1 in a transformer-type manner. In the present embodiment inductor L.sub.1 and coil 26-1 have equidirectional polarities. However, they could also have reverse polarities.

[0032] The impulse generator G.sub.1 according to FIG. 3 is basically identical with the impulse generator G.sub.1 according to FIG. 2. The description provided for this applies based on identical reference numerals accordingly. The particularity of impulse generator G.sub.1 according to FIG. 3 is in the parallel connection of a diode D to the switchable path of the electronic switch T.sub.1 in blocking direction. It protects the switch T.sub.1 and lowers the internal resistance of impulse generator output A.sub.1.

[0033] As apparent from FIG. 4, the impulse generators G.sub.1 to G.sub.n are connected in parallel with regard to the DC voltage. The switches T.sub.1 . . . T.sub.n, the inductors L.sub.1 . . . L.sub.n, the control circuits V.sub.1 . . . V.sub.n, the capacitors C.sub.1 . . . C.sub.n and the coils 26-1 to 26-n have respective letter indices that correspond to the respective impulse generators G.sub.1 . . . G.sub.n. Their impulse generator outputs A.sub.1 . . . A.sub.n, i.e. the coils 26-1 to 26-n, are, however, connected equidirectionally in series. The coil beginnings of inductors L.sub.1 to L.sub.n and of coils 26-1 to 26-n in FIG. 4 are respectively marked with a dot. The equidirectional series connection of coils 26-1 to 26-n means that a coil beginning is respectively connected with a coil end of the adjacent coil. This applies particularly, if all coil beginnings of the inductors L.sub.1 to L.sub.n are connected with identical senses, i.e. all coil beginnings are respectively connected with the electronic switch T.sub.1 to T.sub.n and all coil ends are respectively connected with the operating voltage U.sub.b (or vice versa).

[0034] The series connection of impulse generator outputs A.sub.1 . . . A.sub.n can be connected with a generator output 16 via one or more coupling capacitors 27, 28. The coupling capacitors 27, 28 can also be arranged at another position of the series connection or can also be omitted alternatively. If they are provided, they eliminate the direct current component of the current output from the generator 11. If such a direct current component of the current shall be allowed, they can be omitted or can be provided with a controlled or non-controlled bridging circuit.

[0035] The generator 11 described so far operates as follows:

[0036] The control device 18 produces control impulses for the impulse generators G.sub.1 to G.sub.n in a timely coordinated manner. FIG. 5 illustrates such control impulses I.sub.1 to I.sub.6 for a generator 11 having six impulse generators G.sub.1 to G.sub.6 by way of example of an operating mode (first mode) having regular time intervals. As shown in FIG. 5, the control impulse I.sub.2 for the impulse generator G.sub.2 can be output after a predefined time period, e.g. 5 μs, after the control impulse I.sub.1 for impulse generator G.sub.1 has been output. This applies accordingly for the other control impulses I.sub.3, I.sub.4, I.sub.5 and I.sub.6. I.sub.3 can be output by a time delay, e.g. 5 μs, later than I.sub.2, I.sub.4 later than I.sub.3, etc. In the example according to FIG. 5, always a time interval of 5 μs is provided. The impulse generators G.sub.1 to G.sub.n thus obtain their control impulses I.sub.1 to I.sub.n in time intervals of 30 μs respectively (six impulse generators G.sub.1 to G.sub.6 multiplied with 5 μs). Within this period all other impulse generators G.sub.1 to G.sub.6 receive their control impulses I.sub.1 . . . I.sub.n in a non-varying time interval, e.g. 5 μs in the present case. Accordingly, the individual impulse generators G.sub.1 to G.sub.6 output their output impulses sequentially in a 5 μs-interval. The output impulse sequence schematically illustrated in FIG. 6 results at the output 16 of generator 11. The individual impulses of impulse generators G.sub.1 to G.sub.n are to a great extent of identical magnitude and together form an impulse sequence having a basic frequency of 333 kHz. The voltage provided at the output 16 is an asymmetric high frequency voltage. With other time intervals between the control impulses I.sub.1 . . . I.sub.n, also other basic frequencies can be obtained.

[0037] The control impulses I.sub.1 . . . I.sub.n are blocking impulses for the electronic switches T.sub.1 . . . T.sub.n. As control impulses, however, also all other signal shapes can be used that are suitable to cause the impulse generators G.sub.1 . . . G.sub.n to output an output impulse or also a sequence of output impulses.

[0038] FIG. 7 illustrates another control pattern in which the control signals, i.e. the control impulses I.sub.1, I.sub.2, I.sub.3, for the impulse generators G.sub.1, G.sub.2, G.sub.3 are supplied to the respective impulse generators concurrently for a second operating mode (second mode), while the control impulses I.sub.4, I.sub.5 and I.sub.6 are provided to the impulse generators G.sub.4, G.sub.5, G.sub.6 timely sequentially. At the output 16 of generator 11 the impulse sequence, according to FIG. 8, is produced having a high first output impulse 29 that has been created by means of superimposition of output impulses of the three concurrently operating generators G.sub.1, G.sub.2 and G.sub.3. The further output impulses 30, 31 and 32 are single output impulses of individual impulse generators respectively. After output of the final output impulse 32 a pause of arbitrary duration, e.g. 15 μs in the present case, can follow.

[0039] Another example for explanation of the flexibility of the signal configuration results from FIGS. 9 and 10 that illustrate a third operating mode (third mode). According to FIG. 9, generators G.sub.1 and G.sub.2 are synchronously provided with control impulses I.sub.1 and I.sub.2 and thus create doubled output impulse 33. It follows the control impulse I.sub.3 for generator G.sub.3 that creates a single (one fold) output impulse 34. The impulse generators G.sub.4, G.sub.5 and G.sub.6 receive their control impulses I.sub.4, I.sub.5, I.sub.6 in turn concurrently and thus create a triple output impulse 35.

[0040] As apparent due to the timing of control impulses I.sub.1 to I.sub.6, different output voltage shapes can be created that could not have been produced with a resonance generator. In doing so, the presented circuit principle provides the possibility of production of voltage shapes with physiological effects that could not have been created with previous generators. Apart from the modes illustrated explicitly here, additional modes can be produced, in that the timing of the control impulses I.sub.1 . . . I.sub.n and thus of the output impulses A.sub.1 . . . A.sub.n of impulse generators G.sub.1 . . . G.sub.n and/or the number of impulse generators G.sub.1 . . . G.sub.n and/or the plurality of the coils 26-1 . . . 26-n is varied.

[0041] A generator 11, according to the invention, comprises a number of impulse generators G.sub.1 to G.sub.n that are individually controlled by means of a control device 18 in a timely flexible manner. The RF voltage required for supply of a surgical instrument 12 is thus composed of individual impulses. The same applies for the current flowing at the electrode 14 of the instrument 12. Due to omitting resonance effects in the impulse generators G.sub.1 to G.sub.n and omitting of energy storage in a system that is able to oscillate (system of second order), the user has an increased degree of control of the wave forms of the voltage supplied to the instrument 12 and the current flowing to the instrument 12.

LIST OF REFERENCE SIGNS

[0042] 11 generator [0043] 12 instrument [0044] 13 handle [0045] 14 electrode [0046] 15 neutral electrode [0047] 16 output [0048] G.sub.1 . . . G.sub.n impulse generators [0049] U.sub.b operating voltage [0050] 17 ground [0051] A.sub.1 . . . A.sub.n impulse generator outputs [0052] 18 control device [0053] L.sub.1 . . . L.sub.n inductors [0054] E.sub.1 . . . E.sub.2 control signal inputs of impulse generators G.sub.1 . . . G.sub.n [0055] I.sub.1 . . . I.sub.n control impulses for impulse generators G.sub.1 . . . G.sub.n [0056] S control input [0057] T.sub.1 . . . T.sub.n electronic switch [0058] C.sub.1 . . . C.sub.n protection capacitors [0059] V.sub.1 . . . V.sub.n control circuits [0060] 21 control electrode [0061] 22 DC voltage source [0062] 23 decoupling diode [0063] 24 buffer capacitor [0064] 26-1 . . . 26-n coils [0065] 27, 28 coupling capacitors [0066] 29 . . . 35 output impulses