Common-mode transient immunity circuit and modulation-demodulation circuit, common-mode transient immunity circuit is applied to connecting with modulation circuit or demodulation circuit, comprising first isolation circuit, common-mode bias circuit, reference circuit and comparison circuit. Common-mode bias circuit provides common-mode bias voltage for first isolation circuit; first isolation circuit transmits common-mode bias voltage to comparison circuit; reference circuit provides reference voltage for comparison circuit; comparison circuit compares common-mode bias voltage with reference voltage, when common-mode bias voltage is larger than reference voltage, comparison circuit outputs enable signal to modulation circuit or demodulation circuit, and modulation circuit is driven to stop outputting modulation signal or demodulation circuit is driven to stop receiving modulation signal. According to invention, when common-mode transient occurs, enable signal is output to drive modulation circuit or demodulation circuit to stop working, so that influence of common-mode transient on output signal is avoided.

The present disclosure provides a DC mechanical circuit breaker that can utilize two switches, one of which can generate zero-crossing with an alternate oscillatory circuit for the other one, which can be a conventional zero-crossing-based AC breaker and can be used in the main circuit. This is different from the conventional single-switch commute-and-absorb method currently used. The present disclosure shows that disclosed circuit breaker improves the fault current extinction and significantly reduces the voltage rate-of-change while creating the current zero-crossing faster compared to the available technology. Thus, disclosed circuit breaker is capable of interrupting high DC currents with minimal arc through a less expensive AC circuit breaker. Simulation and hardware results are provided to show the efficiency of the disclosed circuit breaker.

A drive circuit includes a second drive circuit that drives a semiconductor switching element in a case where a pulse width of a corresponding signal is determined to be larger than a second threshold, and a timing adjustment circuit that adjusts a timing at which the second drive circuit cooperates with a first drive circuit to drive the semiconductor switching element during a turn-off period of the semiconductor switching element due to drive of the first drive circuit.

Disclosed herein are switching or other active FET configurations that implement a branch design with one or more interior FETs of a main path coupled in parallel with one or more auxiliary FETs of an auxiliary path. Such designs include a circuit assembly for performing a switching function that includes a branch with a plurality of auxiliary FETs coupled in series and a main FET coupled in parallel with an interior FET of the plurality of auxiliary FETs. The body nodes of the FETs can be interconnected and/or connected to a body bias network. The body nodes of the FETs can be connected to body bias networks to enable individual body bias voltages to be used for individual or groups of FETs.

A digital step attenuator (DSA) cell and related method are provided. The DSA cell includes a first branch comprising a first resistor connected, at a first side, to an input port and, at a second side, to an output port; a second resistor connected, at a first side, to the first resistor and, at a second side, to a first transistor and a third resistor connected, at a first side, to the first resistor and, at a second side, to a second transistor. Also included in the DSA cell is a second branch, in a parallel configuration with the first resistor, that includes a fourth resistor and a third transistor. Also included is a third branch, in a parallel configuration with the first resistor, that includes a fourth transistor. The first transistor, the second transistor, the third transistor, and the fourth transistor are configured to be operated independently.

A radio frequency (RF) switching circuit is provided. The RF switching circuit includes a low-figure-of-merit (FOM) switching path that requires a longer duration to be switched on and off and a high-FOM switching path having a higher FOM than the low-FOM switching path but that can be switched on and off faster than the low-FOM switching path. In one aspect, the RF switching circuit passes an RF signal via the high-FOM switching path while toggling the low-FOM switching path to help reduce overall switching time of the RF switching circuit. In another aspect, the RF switching circuit passes the RF signal via the low-FOM switching path whenever the low-FOM switching path is switched on to help improve overall FOM of the RF switching circuit. As a result, the RF switching circuit may achieve a good overall response time and a reasonable overall FOM.

Methods and apparatuses for use in tuning reactance are described. Open loop and closed loop control for tuning of reactances are also described. Tunable inductors and/or tunable capacitors may be used in filters, resonant circuits, matching networks, and phase shifters. Ability to control inductance and/or capacitance in a circuit leads to flexibility in operation of the circuit, since the circuit may be tuned to operate under a range of different operating frequencies.

A control circuit includes a detection module configured to detect an operating condition of a semiconductor switching device; a determining module configured to determine a gate allowable voltage of the semiconductor switching device based on the operating condition; and an output module configured to output a control signal to a driving power supply circuit of the semiconductor switching device based on the gate allowable voltage, to control the driving power supply circuit to provide a gate on voltage that is not higher than the gate allowable voltage and that is positively correlated with the gate allowable voltage for the semiconductor switching device. When the operating condition of the semiconductor switching device becomes better, the gate allowable voltage of the semiconductor switching device is increased.

A control circuit includes a detection module configured to detect an operating condition of a semiconductor switching device; a determining module configured to determine a gate allowable voltage of the semiconductor switching device based on the operating condition; and an output module configured to output a control signal to a driving power supply circuit of the semiconductor switching device based on the gate allowable voltage, to control the driving power supply circuit to provide a gate on voltage that is not higher than the gate allowable voltage and that is positively correlated with the gate allowable voltage for the semiconductor switching device. When the operating condition of the semiconductor switching device becomes better, the gate allowable voltage of the semiconductor switching device is increased.

Various embodiments provide a laser power beaming system that delivers power via high intensity light, such as from a laser, using either power over fiber or free space power to isolate (or eliminate) high frequency noise and electromagnetic interference (EMI) due to, for example, switching. Damage or other harms from the EMI may be prevented. The opto-isolated power may be delivered from a remote source, or within a switched device, such as a variable frequency drive (VFD), itself.