Firing circuit for surgical stapler

A surgical stapling instrument comprising:

• (a) a body;
• (b) a shaft assembly extending distally from the body;
• (c) a stapling head assembly at a distal end of the shaft assembly, wherein the stapling head assembly includes:
• (i) a plurality of staples,
• (ii) a plurality of staple drivers configured to translate to drive the staples through tissue, and
• (iii) a knife configured to translate to cut the tissue;
• (d) a rotary member housed within the body and operatively coupled with the stapling head assembly, wherein the rotary member is rotatable through a rotary stroke to actuate the staple drivers through a driver translation stroke and the knife through a knife translation stroke such that the stapling head assembly staples and cuts the tissue;
• (e) a motor housed within the body, wherein the motor is operable to actuate the rotary member through the rotary stroke;
• (f) a user input feature coupled with the body, wherein the user input feature is selectively actuatable by a user;
• and
• (g) an electrical circuit in communication with the motor and the user input feature, wherein the electrical circuit is configured to activate and deactivate the motor and thereby control rotation of the rotary member,
• wherein the electrical circuit is configured to activate the motor in response to an initial actuation of the user input feature to an actuated state,
• wherein the electrical circuit includes an electrical feature that is configured to maintain activation of the motor without deactivating the motor following the initial actuation of the user input feature, until the rotary member completes the rotary stroke, the staple drivers complete the driver translation stroke, and the knife completes the knife translation stroke, and thereby render the user input feature inactive in the presence of a subsequent movement of the user input feature in a direction away from the actuated state during the rotary stroke.

A method of operating a surgical stapling instrument, wherein the instrument comprises a body, a shaft assembly extending distally from the body, a stapling head assembly at a distal end of the shaft assembly, a rotary member housed within the body, a motor, and a user input feature, the method comprising:

• (a) in response to an initial actuation of the user input feature from a non-actuated state to an actuated state, activating the motor to rotate the rotary member in a first direction through a first portion of a rotary stroke;
• (b) in response to the rotation of the rotary member through the first portion of the rotary stroke, actuating a staple driver and a knife of the stapling head assembly distally from respective proximal positions to respective distal positions to thereby staple and cut tissue engaged by the stapling head assembly;
• (c) upon completion of the first portion of the rotary stroke by the rotary member, maintaining activation of the motor to continue rotating the rotary member in the first direction through a second portion of the rotary stroke;
• (d) in response to the rotation of the rotary member through the second portion of the rotary stroke, retracting the staple driver and the knife proximally to their respective proximal positions;
• and
• (e) in response to completion of the second portion of the rotary stroke by the rotary member, deactivating the motor such that the staple driver and the knife remain in their respective proximal positions,
• wherein the rotary member rotates continuously through the first and second portions of the rotary stroke regardless of a state of the user input feature subsequent to the initial actuation thereof.