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 hybrid metal-oxide semiconductor field-effect transistor with variable gate impedance and an implementation method thereof, wherein the hybrid metal-oxide semiconductor field-effect transistor has the characteristic of changing the on-resistance according to different drive voltages. By use of a feedback loop and a variable gate drive voltage generator which can vary the generated gate drive voltage based on different loads, the present disclosure can still adjust the gate drive voltage under different load conditions without requiring a plurality of metal-oxide semiconductor field-effect transistors in series/parallel to achieve the lowest power loss.

A hybrid metal-oxide semiconductor field-effect transistor with variable gate impedance and an implementation method thereof, wherein the hybrid metal-oxide semiconductor field-effect transistor has the characteristic of changing the on-resistance according to different drive voltages. By use of a feedback loop and a variable gate drive voltage generator which can vary the generated gate drive voltage based on different loads, the present disclosure can still adjust the gate drive voltage under different load conditions without requiring a plurality of metal-oxide semiconductor field-effect transistors in series/parallel to achieve the lowest power loss.

A driver device includes: a voltage terminal; a ground terminal; an output terminal; a first nMOS power transistor having a drain electrically connected to the voltage terminal, a source electrically connected to the output terminal, and a gate; an overvoltage protection circuit configured to limit a gate-to-source voltage of the first nMOS power transistor in a normal operating mode for the driver device; a pulldown circuit configured to force the first nMOS power transistor off in a stress test mode for the driver device; and a blocking circuit configured to block current flow from the output terminal to the ground terminal through the overvoltage protection circuit and the pulldown circuit in the stress test mode. A method of stress testing the driver device is also described.

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.

A control circuit regulates the propagation delay of a field effect transistor (FET) before the FET transitions to the Miller region by applying a pre-charge current for a fixed duration to the gates of the FET. After the fixed duration, the current is reduced to a lower drive current level which is based on a desired output voltage slew rate. After the FET transitions to the Miller region, the output voltage slews down in accordance with the output voltage slew rate. By regulating the slew-rate of the output voltage in the Miller region and regulating the propagation delay of the FET prior to the Miller region, the control circuit reduces electromagnetic interference (EMI) caused by the switching of the FET, thereby improving electromagnetic compatibility (EMC) of switch mode driver systems without increasing the propagation delay of the FET.

A control circuit regulates the propagation delay of a field effect transistor (FET) before the FET transitions to the Miller region by applying a pre-charge current for a fixed duration to the gates of the FET. After the fixed duration, the current is reduced to a lower drive current level which is based on a desired output voltage slew rate. After the FET transitions to the Miller region, the output voltage slews down in accordance with the output voltage slew rate. By regulating the slew-rate of the output voltage in the Miller region and regulating the propagation delay of the FET prior to the Miller region, the control circuit reduces electromagnetic interference (EMI) caused by the switching of the FET, thereby improving electromagnetic compatibility (EMC) of switch mode driver systems without increasing the propagation delay of the FET.

There is provided an apparatus and method, the apparatus comprising a power input and a switch isolation circuit to provide isolation between the power input and a protected switch responsive to a timing signal. The switch isolation circuit comprises a switch isolation charge store, and a buffer circuit to receive power from the switch isolation charge store and coupled between the timing signal and the protected switch. The switch isolation circuit is configured to, in response to the timing signal having the first value, operate in a powered mode in which the switch isolation charge store receives power from the power input; and, in response to the timing signal having the second value, operate in an isolation mode in which the switch isolation charge store is isolated from the power input.