A power control system for controlling the delivery of power to a vessel fusing surgical instrument including an end effector, the power control system comprising: an impedance sensing circuit for detecting impedance from an alternating output voltage and an alternating output current delivered by a power supply to the vessel fusing surgical instrument ; a power sequencing module configured to automatically sequence the power delivered by the power supply; wherein the power sequencing module is configured to apply power at a constant power, Pmax, of no less than 7 watts and no more than 35 watts during a period of time of 3 seconds or less, wherein: applying a constant power comprises allowing the current to float between 0.5 and 2 Amperes RMS and the voltage to float below 100 Volts RMS; and the period of time is measured from the beginning of the application of power; monitor the impedance through the impedance sensing circuit during the period of time; and reduce the power when the impedance reaches a set impedance threshold within the period of time; and switch off the power when the period of time has elapsed, wherein the impedance threshold is indicative of the beginning of desiccation of a blood vessel and the step of reducing the power further comprises reducing the power by 60% to 80% to a reduced power, Pmin, for a length of time prior to terminating the flow of power. an impedance sensing circuit for detecting impedance from an alternating output voltage and an alternating output current delivered by a power supply to the vessel fusing surgical instrument ; a power sequencing module configured to automatically sequence the power delivered by the power supply; wherein the power sequencing module is configured to apply power at a constant power, Pmax, of no less than 7 watts and no more than 35 watts during a period of time of 3 seconds or less, wherein: applying a constant power comprises allowing the current to float between 0.5 and 2 Amperes RMS and the voltage to float below 100 Volts RMS; and the period of time is measured from the beginning of the application of power; monitor the impedance through the impedance sensing circuit during the period of time; and reduce the power when the impedance reaches a set impedance threshold within the period of time; and switch off the power when the period of time has elapsed, wherein the impedance threshold is indicative of the beginning of desiccation of a blood vessel and the step of reducing the power further comprises reducing the power by 60% to 80% to a reduced power, Pmin, for a length of time prior to terminating the flow of power. applying a constant power comprises allowing the current to float between 0.5 and 2 Amperes RMS and the voltage to float below 100 Volts RMS; and the period of time is measured from the beginning of the application of power; monitor the impedance through the impedance sensing circuit during the period of time; and reduce the power when the impedance reaches a set impedance threshold within the period of time; and switch off the power when the period of time has elapsed, wherein the impedance threshold is indicative of the beginning of desiccation of a blood vessel and the step of reducing the power further comprises reducing the power by 60% to 80% to a reduced power, Pmin, for a length of time prior to terminating the flow of power. <EOS>