According to one embodiment, a semiconductor device includes a first switch element including a first end to which a first voltage is applied, and a second end and a gate electrically coupled to a first node, a second switch element including a first end to which a second voltage is applied, and a second end and a gate electrically coupled to the first node, a third switch element including a first end to which the second voltage is applied, a second end electrically coupled to a second node, and a gate coupled to the first node, a fourth switch element including a gate coupled to the second node, and a first terminal electrically coupled to a first end of the fourth switch element and outputting a signal based on a voltage of the second node.

We disclose a III-nitride semiconductor based heterojunction power device comprising: a first heterojunction transistor formed on a substrate, the first heterojunction transistor comprising: a first III-nitride semiconductor region formed over the substrate, wherein the first III-nitride semiconductor region comprises a first heterojunction comprising at least one two dimensional carrier gas; a first terminal operatively connected to the first III-nitride semiconductor region; a second terminal laterally spaced from the first terminal and operatively connected to the first III-nitride semiconductor region; a first plurality of highly doped semiconductor regions of a first polarity formed over the first III-nitride semiconductor region, the first plurality of highly doped semiconductor regions being formed between the first terminal and the second terminal; a first gate region operatively connected to the first plurality of highly doped semiconductor regions; and a second heterojunction transistor formed on the substrate. The second heterojunction transistor comprises: a second III-nitride semiconductor region formed over the substrate, wherein the second III-nitride semiconductor region comprises a second heterojunction comprising at least one two dimensional carrier gas; a third terminal operatively connected to the second III-nitride semiconductor region; a fourth terminal laterally spaced from the third terminal in the first dimension and operatively connected to the second III-nitride semiconductor region; a second gate region being formed over the second III-nitride semiconductor region, and between the third terminal and the fourth terminal. One of the first and second heterojunction transistors is an enhancement mode field effect transistor and the other of the first and second heterojunction transistors is a depletion mode field effect transistor.

Apparatus and circuits including transistors with different threshold voltages and methods of fabricating the same are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a substrate; an active layer that is formed over the substrate and comprises a plurality of active portions; a polarization modulation layer comprising a plurality of polarization modulation portions each of which is disposed on a corresponding one of the plurality of active portions; and a plurality of transistors each of which comprises a source region, a drain region, and a gate structure formed on a corresponding one of the plurality of polarization modulation portions. The transistors have at least three different threshold voltages.

The disclosure relates to a pulsed laser driver that utilizes a high-voltage switch transistor to support a high output voltage for a laser, and a low-voltage switch transistor that switches between an ON state and an OFF state to generate a pulsed current that is supplied to the laser to generate an output pulsed laser signal. The pulsed laser driver switches the low-voltage switch transistor between the ON state and the OFF state according to an input pulsed signal such that the output pulsed laser signal is modulated according to the input pulsed signal. The pulsed laser driver also utilizes a feedback control module to control the gate terminal voltage of the high-voltage switch transistor to improve the precision of the output pulsed laser signal.

A semiconductor circuit includes: a first inductor part configured to connect in series with a source electrode of a first semiconductor element; and a second inductor part configured to connect in series with a source electrode in a second semiconductor element that is configured to connect in parallel with the first semiconductor element; the first inductor part and the second inductor part are arranged to generate an induced electromotive force in the first inductor part and the second inductor part by way of a magnetic interaction so that the currents flowing in the first inductor part and the second inductor part are reinforced in the same direction.

A semiconductor device includes a junction field effect transistor (JFET) including a source electrode, a drain electrode, and a gate electrode, and a metal oxide semiconductor field effect transistor (MOSFET) including a source electrode, a drain electrode, and a gate electrode. The JFET and the MOSFET are cascode-connected such that the source electrode of the JFET and the drain electrode of the MOSFET are electrically connected. A gate voltage dependency of the JFET or a capacitance ratio of a mirror capacitance of the MOSFET to an input capacitance of the MOSFET is adjusted in a predetermined range.

A semiconductor device includes a MOSFET including a drift layer, a channel layer, a trench gate structure, a source layer, a drain layer, a source electrode, and a drain electrode. The trench gate structure includes a trench penetrating the channel layer and protruding into the drift layer, a gate insulating film disposed on a wall surface of the trench, and a gate electrode disposed on the gate insulating film. A portion of the trench protruding into the drift layer is entirely covered with a well layer, and the well layer is connected to the channel layer.

A level shift transistor of a first conductivity type configured to level shift a signal from a primary side circuit to a secondary side circuit between the primary side circuit having a primary side reference potential as reference and the secondary side circuit having a secondary side reference potential independent from the primary side reference potential as reference, a diode connected in a forward direction between a first main electrode of the level shift transistor and the secondary side circuit, a capacitor connected in parallel to the diode, and an inverter configured to invert the signal are provided. A control electrode of the level shift transistor is connected to a primary side power supply of the primary side circuit, and a second main electrode thereof is connected to an output of the inverter. The inverter operates between the primary side reference potential and the primary side power supply.

A power source switch circuit and an operation method thereof are provided. The power source switch circuit may include a switch circuit that includes a first switch configured switch a supply of a voltage from a first power supply circuit to a power supply terminal of a power amplifier, and a second switch configured to switch a supply of a voltage from a second power supply circuit to the power supply terminal of the power amplifier; and a switch controller configured to control the switch circuit to set the first switch and the second switch in a turned-on state during a first period when the first switch is turned off and the second switch is turned on.

A multiplexing circuit includes an output terminal, a first type transistor, a second type transistor and an impedance circuit. The output terminal is arranged to output a serial output signal. The first type transistor is coupled between a first reference voltage and the output terminal. The second type transistor is coupled between a second reference voltage and the output terminal, wherein the first type is different from the second type. The impedance circuit is arranged to provide an impedance between a gate terminal of the first type transistor and the output terminal.