A resonant power converter controller comprising a control circuit configured to turn on a synchronous rectifier (SR) in response to a count of a number of times a drain voltage of the SR crosses below a turn on threshold based on a stored count and turns off the SR when the drain voltage crosses above a turn off threshold. The control circuit comprises a first comparator configured to generate a first detection signal in response to the drain voltage being less than the turn on threshold. A first turn on detection circuit generates a first turn on signal when the count reaches the stored count. A first turn off signal is generated in response to the drain voltage being greater than the turn off threshold. A drive circuit turns on and off the SR in response to the first turn on signal and the first turn off signal.

The Robust Safe Switch and Control Device is an “Internet of Things” end effecter that provides a minimally dissipating, robust switch tightly integrated with circuit, life and property automated safety features. The device enables extended sensing and monitoring capabilities that enable the effective management of the “Internet of Things.”

A color temperature switching scheme for an LED lighting device is disclosed. The color temperature switching scheme comprises a plurality of different color temperature performances correspondingly generated by a plurality of different paired combinations of a first electric power allocated to a first LED load emitting a light with a first color temperature and a second electric power allocated to a second LED load emitting a light with a second color temperature such that a mingled color temperature between the first color temperature and the second color temperature can be generated thru a light diffuser. For tuning the mingled color temperature of the LED lighting device a reverse yet complementary power adjustment process for distributing a total electric power T between the first LED circuit and the second LED circuit is required such that a total light intensity remains essentially unchanged while the mingled color temperature is being adjusted.

A relay circuit, including a solid state relay switch, connected to a first relay line and to a charging capacitor, and connected to a second relay line. The relay circuit may also include a solid state relay control circuit, coupled between the charging capacitor and the solid state relay switch. The solid state relay control circuit may include a voltage detection circuit, having an input coupled to an output of the charging capacitor, and having an output arranged to generate a LOW voltage signal when a voltage level of the charging capacitor is below a low threshold value. The solid state relay control circuit may also include a zero crossing circuit, coupled to the first relay line and the second relay line, and having an output to generate a clock signal when a zero crossing event takes place between the first relay line and the second relay line.

A relay circuit, including a solid state relay switch, connected to a first relay line and to a charging capacitor, and connected to a second relay line. The relay circuit may also include a solid state relay control circuit, coupled between the charging capacitor and the solid state relay switch. The solid state relay control circuit may include a voltage detection circuit, having an input coupled to an output of the charging capacitor, and having an output arranged to generate a LOW voltage signal when a voltage level of the charging capacitor is below a low threshold value. The solid state relay control circuit may also include a zero crossing circuit, coupled to the first relay line and the second relay line, and having an output to generate a clock signal when a zero crossing event takes place between the first relay line and the second relay line.

The present invention provides a method of determining an electrical operating time of a circuit breaker (140) in a multiphase electrical system having a subsystem (160) at an electric potential resulting from electrical characteristics of electrical components within the subsystem. The method comprises monitoring (145) the voltage of the subsystem in the first phase, determining a first rate of change from the monitored voltage in the first phase, detecting at least one instance of switching based on the first rate of change, determining an electrical operating time of the circuit breaker based on the detected at least one instance of switching and an instance at which a command for switching was provided to the circuit breaker.

A controller protection circuit for a voltage power optimiser. The circuit having: a first terminal for connecting to a first end of a winding in the voltage power optimiser; a second terminal for connecting to a second end of the winding in the voltage power optimiser; and a thyristor. The controller protection circuit also includes a thyristor gate control circuit. The thyristor gate control circuit is configured to: set the gate control signal such that the thyristor is configured to conduct in response to a potential difference between the anode terminal and the cathode terminal of the thyristor; and set the gate control signal such that the thyristor is configured not to conduct in response to a signal received from a voltage controller. The thyristor gate control circuit includes a normally-on switch having a conduction channel and a control terminal, and a photovoltaic isolator configured to set the gate control signal such that the thyristor is configured not to conduct in response to a signal received from a voltage controller.

A thyristor switch is constituted of a pair of arms connected in anti-parallel, each of the anus including a plurality of thyristors connected in series. A controller includes a phase detecting unit configured to detect a phase of a power supply voltage supplied from an alternating-current power supply, and a gate signal generating unit configured to interrupt a gate signal when an open command is provided to the static switch and the phase of the power supply voltage detected by the phase detecting unit matches a target phase. The target phase is set outside of a phase range where interruption of the gate signal is prohibited, the phase range being set so as to include a zero crossing point at which a load current is switched in polarity.

A thyristor switch is constituted of a pair of arms connected in anti-parallel, each of the anus including a plurality of thyristors connected in series. A controller includes a phase detecting unit configured to detect a phase of a power supply voltage supplied from an alternating-current power supply, and a gate signal generating unit configured to interrupt a gate signal when an open command is provided to the static switch and the phase of the power supply voltage detected by the phase detecting unit matches a target phase. The target phase is set outside of a phase range where interruption of the gate signal is prohibited, the phase range being set so as to include a zero crossing point at which a load current is switched in polarity.

In one aspect, a solid-state switching apparatus is provided that includes a pair of anti-parallel thyristors, a quasi-resonant turn-off circuit, a sensor, and a control circuit. The turn-off circuit is coupled in parallel with the pair of anti-parallel thyristors and includes a first selectively conductive path and a second selectively conductive path. The sensor is configured to sense a thyristor current conducted by at least one of the pair of anti-parallel thyristors. The control circuit is configured to receive the sensed thyristor current from the sensor and determine a magnitude of the sensed thyristor current and a polarity of the sensed thyristor current. The control circuit is further configured to activate, in response to determining that the magnitude is greater than a threshold value, one of the first selectively conductive path and the second selectively conductive path based on the polarity to commutate and interrupt the thyristor current.