Power supply device for high frequency treatment instrument, and treatment system including the same

A power supply device for a treatment system to supply a high frequency electric current between an end electrode of a treatment instrument that uses high frequency power and a return electrode that is configured to be affixed to a surface of a human body, the power supply device comprising:

• a power source which generates alternating-current power;
• a treatment instrument-connecting terminal for electrically connecting the treatment instrument;
• a return electrode-connecting terminal for electrically connecting the return electrode;
• an active side detection circuit which acquires a first signal for the alternating-current power output from the power source to the treatment instrument via the treatment instrument-connecting terminal, and a second signal for a power output from the power source to the treatment instrument via the treatment instrument-connecting terminal and returned from the treatment instrument to the treatment instrument-connecting terminal;
• a passive side detection circuit which acquires a third signal for a power output from the power source to the treatment instrument via the treatment instrument-connecting terminal and passing through the return electrode to the return electrode-connecting terminal;
• and
• a processor which calculates a return loss as the second signal to the first signal and a first insertion loss as the third signal to the first signal, and specifies an occurrence location of an abnormality based on the return loss and the first insertion loss upon occurrence of the abnormality in the treatment system,
• wherein the processor determines that an error has occurred if a variation of the return loss or a variation of the first insertion loss per unit of time exceeds a predetermined threshold while the calculated return loss is increasing or while the calculated first insertion loss is decreasing.