Patent ID: 7660094

Claim:
An inverter circuit comprising: at least one main circuit switch having a control terminal, and first and second main terminals through which the main current flows; a driving circuit for each main circuit switch, for applying a driving voltage to the control terminal thereof, and controlling the main current in accordance with the voltage between the control terminal and the first main terminal, to switch each main circuit switch; and a noise-suppression circuit for each main circuit switch, between each main circuit switch and each driving circuit, that is configured to detect fluctuations in the voltage between the first and the second main terminals of each main circuit switch, and, in accordance with the amplitude and the frequency of the detected voltage fluctuations, to bring to substantially zero the impedance across the control terminal of each main circuit switch and the first main terminal of each main circuit switch, wherein: the driving circuit is series connected to the noise-suppression circuit, which is connected to control terminal of the main circuit switch, by a component comprising a resistor connected in parallel to a diode and wherein the noise-suppression circuit is series connected to the control terminal of the main circuit switch, a cathode of the diode is connected to the control terminal of the main circuit switch, the noise-suppression circuit comprises a first capacitor, a first resistor, and a first semiconductor switch that has a control terminal and two main terminals through which the main current flows, the first capacitor and the first resistor are connected in series, the first capacitor and the first resistor in series as a component are connected between the first main terminal and the second main terminal of the main circuit switch, the control terminal of the first semiconductor switch is connected to a point where the first capacitor and the first resistor connect, one of the main terminals of the first semiconductor switch is connected to the control terminal of the main circuit switch, the other of the main terminals of the first semiconductor switch is connected to the first main terminal of the main circuit switch, the noise-suppression circuit further comprises a second resistor, a second capacitor, and a second semiconductor switch, the second resistor and the second capacitor in series as a component are connected in parallel between the two main terminals of the first semiconductor switch, the control terminal of the second semiconductor switch is connected to a point where the second resistor and the second capacitor connect, one of the two main terminals of the second semiconductor switch is connected to the control terminal of the first semiconductor switch, and the other of the two main terminals of the second semiconductor switch is connected to the one main terminal, out of the two main terminals of the first semiconductor switch, that is connected to the first main terminal of the main circuit switch.