Surgical generator for ultrasonic and electrosurgical devices

Abstract

A control circuit of a surgical device is disclosed. The control circuit includes a first circuit portion coupled to at least one switch operable between an open state and a closed state. The first circuit portion communicates with a surgical generator over a conductor pair to receive a control signal to determine a state of the at least one switch.

We claim: 
     
       1. A surgical device, the surgical device comprising:
 an end effector to act on tissue; and 
 a control circuit configured for communication with a surgical generator, the control circuit comprising:
 a conductor pair to communicate with the surgical generator; 
 a first circuit portion comprising:
 a first switch configured to switch between an open state and a closed state; 
 a first resistor coupled in parallel with the first switch; 
 a second switch configured to switch between an open state and a closed state; and 
 a second resistor coupled in parallel with the second switch, wherein a combination of the first switch and the first resistor is coupled in series with a combination of the second switch and the second resistor; 
 a voltage reference coupled in parallel with the first circuit portion, 
 wherein the control circuit is configured to receive from the generator and over the conductor pair an interrogation signal, wherein a state of at least one of the first switch or the second switch is determined from at least one characteristic of the interrogation signal; 
 
 a capacitor coupled in parallel with the first circuit portion; 
 a resistor coupled in series parallel with the first circuit portion; and 
 a memory device coupled to the first circuit portion. 
 
 
     
     
       2. The surgical device of  claim 1 , wherein the state of the first switch is determinable based on a slope of a voltage on the capacitor. 
     
     
       3. The surgical device of  claim 1 , comprising an oscillator in communication with the at least one switch, wherein the state of the at least one switch is determinable based on a frequency of the oscillator. 
     
     
       4. The surgical device of  claim 1 , comprising a one-wire multi-switch input device coupled to the at least one switch, wherein the state of the at least one switch is communicated to the generator over a one-wire communication protocol. 
     
     
       5. The surgical device of  claim 1 , wherein the interrogation signal is a differential constant current pulse having a positive phase and a negative phase. 
     
     
       6. The surgical device of  claim 1 , wherein the memory device comprises at least one one-wire electrically erasable programmable read only memory (EEPROM). 
     
     
       7. The surgical device of  claim 5 , wherein the positive phase of the interrogation signal is a positive transition of the differential constant current pulse and the negative phase of the differential constant current pulse is a negative transition of the differential constant current pulse. 
     
     
       8. The surgical device of claim 1, further comprising an end effector to act on tissue. 
     
     
       9. The surgical device of claim 1, wherein the first resistor is coupled in series with a combination of the second switch and the second resistor. 
     
     
       10. The surgical device of claim 1, further comprising a rectifier coupled in parallel with the first circuit portion. 
     
     
       11. The surgical device of claim 1, further comprising a voltage reference. 
     
     
       12. The surgical device of claim 1, further comprising a resister coupled in series with the first circuit portion. 
     
     
       13. A surgical device, the surgical device comprising:
 a control circuit configured for communication with a surgical generator, the control circuit comprising:
 a conductor pair to communicate with the surgical generator; 
 a first circuit portion comprising:
 a first switch configured to switch between an open state and a closed state; 
 a first resistor coupled with the first switch; 
 a second switch configured to switch between an open state and a closed state; and a second resistor coupled with the second switch, wherein a combination of the first switch and the first resistor is coupled with a combination of the second switch and the second resistor; 
 
   wherein the control circuit is configured to receive from the generator and over the conductor pair an interrogation signal, wherein a state of at least one of the first switch or the second switch is determined from at least one characteristic of the interrogation signal;   a capacitor coupled in parallel with the first circuit portion;   a resistor coupled in parallel with the first circuit portion; and   a memory device coupled to the first circuit portion.   
     
     
       14. The surgical device of claim 13, further comprising a rectifier coupled in parallel with the first circuit portion. 
     
     
       15. The surgical device of claim 13, wherein the state of the first switch is determinable based on a slope of a voltage on the capacitor. 
     
     
       16. The surgical device of claim 13, comprising an oscillator in communication with the at least one switch, wherein the state of the at least one switch is determinable based on a frequency of the oscillator. 
     
     
       17. The surgical device of claim 13, comprising a one-wire multi-switch input device coupled to the at least one switch, wherein the state of the at least one switch is communicated to the generator over a one-wire communication protocol. 
     
     
       18. The surgical device of claim 13, wherein the interrogation signal is a differential constant current pulse having a positive phase and a negative phase. 
     
     
       19. The surgical device of claim 13, wherein the memory device comprises at least one one-wire electrically erasable programmable read only memory (EEPROM). 
     
     
       20. The surgical device of claim 18, wherein the positive phase of the interrogation signal is a positive transition of the differential constant current pulse and the negative phase of the differential constant current pulse is a negative transition of the differential constant current pulse. 
     
     
       21. A surgical device, the surgical device comprising:
 a control circuit configured for communication with a surgical generator, the control circuit comprising:
 a conductor pair to communicate with the surgical generator; 
 a first circuit portion comprising: 
 a first switch configured to switch between an open state and a closed state; 
 a first resistor coupled in parallel with the first switch; 
 a second switch configured to switch between an open state and a closed state; and 
 a second resistor coupled in parallel with the second switch, wherein at least one of the first switch or the first resistor is coupled in series with at least one of the second switch or the second resistor; 
   wherein the control circuit is configured to receive from the generator and over the conductor pair an interrogation signal, wherein a state of at least one of the first switch or the second switch is determined from at least one characteristic of the interrogation signal;   a capacitor coupled in parallel with the first circuit portion;   a resistor coupled in parallel with the first circuit portion; and   a memory device coupled to the first circuit portion.   
     
     
       22. The surgical device of claim 21, further comprising a rectifier coupled in parallel with the first circuit portion. 
     
     
       23. The surgical device of claim 21, wherein the state of the first switch is determinable based on a slope of a voltage on the capacitor. 
     
     
       24. The surgical device of claim 21, comprising an oscillator in communication with the at least one switch, wherein the state of the at least one switch is determinable based on a frequency of the oscillator. 
     
     
       25. The surgical device of claim 21, comprising a one-wire multi-switch input device coupled to the at least one switch, wherein the state of the at least one switch is communicated to the generator over a one-wire communication protocol. 
     
     
       26. The surgical device of claim 21, wherein the interrogation signal is a differential constant current pulse having a positive phase and a negative phase. 
     
     
       27. The surgical device of claim 21, wherein the memory device comprises at least one one-wire electrically erasable programmable read only memory (EEPROM). 
     
     
       28. The surgical device of claim 27, wherein the positive phase of the interrogation signal is a positive transition of the differential constant current pulse and the negative phase of the differential constant current pulse is a negative transition of the differential constant current pulse.