A gate drive circuit includes: an input terminal; a first circuit path inserted into a line connecting the input terminal and a gate of a power transistor; a second circuit path connected in parallel to the first circuit path; and a third circuit path connected in parallel to the second circuit path. The first circuit path includes a gate resistor (Rgon). The second circuit path includes a first capacitor and a first resistor connected in series. The third circuit path includes a second capacitor and a second resistor connected in series. The second capacitor has a capacitance value greater than a capacitance value of the first capacitor. The second resistor has a resistance value greater than a resistance value of the first resistor. The gate resistor (Rgon) has a resistance value greater than the resistance value of the second resistor.

Universal Serial Bus (USB) protection circuits are provided. A circuit includes a plurality of first transistors connected in series between a pad and ground. The circuit also includes a plurality of second transistors connected in series between the pad and a supply voltage. The circuit further includes a control circuit that applies respective bias voltages to each one of the plurality of first transistors and to each one of the plurality of second transistors. The bias voltages are configured to: turn off the plurality of first transistors and turn off the plurality of second transistors when a pad voltage of the pad is within a nominal voltage range; sequentially turn on the plurality of first transistors when the pad voltage increases above the nominal voltage range; and sequentially turn on the plurality of second transistors when the pad voltage decreases below the nominal voltage range.

Universal Serial Bus (USB) protection circuits are provided. A circuit includes a plurality of first transistors connected in series between a pad and ground. The circuit also includes a plurality of second transistors connected in series between the pad and a supply voltage. The circuit further includes a control circuit that applies respective bias voltages to each one of the plurality of first transistors and to each one of the plurality of second transistors. The bias voltages are configured to: turn off the plurality of first transistors and turn off the plurality of second transistors when a pad voltage of the pad is within a nominal voltage range; sequentially turn on the plurality of first transistors when the pad voltage increases above the nominal voltage range; and sequentially turn on the plurality of second transistors when the pad voltage decreases below the nominal voltage range.

A gate drive circuit has a capacitor and a gate drive voltage source connected in series with a gate terminal of a voltage-driven switching device. The gate drive source voltage feeds, as a gate drive voltage, a voltage higher than the sum of the voltage applied to a gate-source parasitic capacitance of the switching device when the switching device is in a steady ON state and the voltage applied to, of any circuit component interposed between the gate drive voltage source and the gate terminal of the switching device, a circuit component other than the capacitor (such as an upper transistor forming the output stage of the driver). No other circuit component (such as a resistor connected in parallel with the capacitor) is essential but the capacitor as the sole circuit component to be directly connected to the gate terminal of the switching device.

A gate drive circuit has a capacitor and a gate drive voltage source connected in series with a gate terminal of a voltage-driven switching device. The gate drive source voltage feeds, as a gate drive voltage, a voltage higher than the sum of the voltage applied to a gate-source parasitic capacitance of the switching device when the switching device is in a steady ON state and the voltage applied to, of any circuit component interposed between the gate drive voltage source and the gate terminal of the switching device, a circuit component other than the capacitor (such as an upper transistor forming the output stage of the driver). No other circuit component (such as a resistor connected in parallel with the capacitor) is essential but the capacitor as the sole circuit component to be directly connected to the gate terminal of the switching device.

Driver unit for a voltage-controlled switching element, includes a first output terminal for connecting a control terminal of the switching element, a second output terminal for connecting a further terminal of the switching element, an output stage section having a high-side terminal and a low-side terminal and being controllable to connect one of its terminals to the first output terminal of the driver unit based on a control signal representative switching the switching element, and a DC conversion section configured to supply the output stage section and to convert an input voltage into a positive first voltage between the high-side terminal and the second output terminal of the driver unit and into a positive second voltage between the second output terminal of the driver unit and the low-side terminal.

A voltage supply circuit includes a level shifter that switches between voltages of two voltage input units and that outputs one of the voltages, a charge pump that transforms a voltage of an input power supply and that applies the transformed voltage to the level shifter, and a charge pump control circuit. The voltage supply circuit controls supply and interruption of a predetermined voltage to a voltage-supplied circuit (RF switch 20). The charge pump control circuit causes the charge pump to perform a continuous operation in an on-mode and to perform an intermittent operation in an off-mode, the off-mode representing a state in which the voltage supply to the voltage-supplied circuit (RF switch 20) is stopped, the on-mode representing a state in which the predetermined voltage is supplied.

A voltage supply circuit includes a level shifter that switches between voltages of two voltage input units and that outputs one of the voltages, a charge pump that transforms a voltage of an input power supply and that applies the transformed voltage to the level shifter, and a charge pump control circuit. The voltage supply circuit controls supply and interruption of a predetermined voltage to a voltage-supplied circuit (RF switch 20). The charge pump control circuit causes the charge pump to perform a continuous operation in an on-mode and to perform an intermittent operation in an off-mode, the off-mode representing a state in which the voltage supply to the voltage-supplied circuit (RF switch 20) is stopped, the on-mode representing a state in which the predetermined voltage is supplied.

A radio frequency signal transmission circuit includes a direct current blocking unit, a biasing impedance circuit, and a radio frequency element. The direct current blocking unit has a first terminal for receiving an input signal, and a second terminal coupled to a first bias voltage terminal. The biasing impedance circuit has a first terminal coupled to the first bias voltage terminal for providing a first bias voltage, and a second terminal coupled to a second bias voltage terminal for receiving a second bias voltage. The radio frequency element is coupled to the first bias voltage terminal, and receives and processes the input signal. When the biasing impedance circuit operates in a first mode, the biasing impedance circuit provides a first impedance. When the biasing impedance circuit operates in a second mode, the biasing impedance circuit provides a second impedance greater than the first impedance.

A radio frequency signal transmission circuit includes a direct current blocking unit, a biasing impedance circuit, and a radio frequency element. The direct current blocking unit has a first terminal for receiving an input signal, and a second terminal coupled to a first bias voltage terminal. The biasing impedance circuit has a first terminal coupled to the first bias voltage terminal for providing a first bias voltage, and a second terminal coupled to a second bias voltage terminal for receiving a second bias voltage. The radio frequency element is coupled to the first bias voltage terminal, and receives and processes the input signal. When the biasing impedance circuit operates in a first mode, the biasing impedance circuit provides a first impedance. When the biasing impedance circuit operates in a second mode, the biasing impedance circuit provides a second impedance greater than the first impedance.