Patent ID: 8243008

Claim:
A separately excited inverter circuit, comprising: a step-up transformer having a primary winding and a secondary winding; a full bridge circuit that is coupled with the primary winding of the step-up transformer, converts a direct current (DC) input voltage into an alternate current (AC) output voltage, and applies the AC output voltage to the primary winding of the step-up transformer; a control circuit that is coupled with a command signal transmission line, and performs switching control of the full bridge circuit when receiving a command signal from the command signal transmission line; a terminal voltage monitoring circuit that monitors a terminal voltage of a gate of a first switching element forming the full bridge circuit; and a thyristor that is coupled with the command signal transmission line; wherein the full bridge circuit has a half bridge connection; the half bridge connection has the first switching element and a second switching element; a source of the first switching element is connected to a switching output point; a gate of the first switching element is connected to the control circuit; a drain of the second switching element is connected to the switching output point; a gate of the second switching element is connected to the control circuit; the switching output point is connected to the primary winding of the step-up transformer; the terminal voltage monitoring circuit is connected to the gate of the first switching element; the terminal voltage monitoring circuit outputs a reference voltage to a gate of the thyristor when the terminal voltage of the gate of the first switching element is not greater than a predetermined voltage; when the reference voltage from the terminal voltage monitoring circuit is input to the gate of the thyristor, a gate current flows through the thyristor, and the thyristor turns on and impedes the command signal on the command signal transmission line to thereby stop the oscillation of the control circuit.