Abstract: There is a need to monitor and control the state of relays and circuit breakers within power distribution systems. The monitoring of a relay state, i.e. open or closed, is often performed by applying a monitoring signal to sensing contacts added to the relay. Manufactures of such systems have chosen many different voltages for their own monitoring systems making it difficult to interconnect dissimilar monitoring systems. A signal conditioning circuit is provided that can cope with a large input voltage range and can be configured to allow may items of equipment (which may be new item or legacy items) to be connected to a controller.

Abstract: There is a need to monitor and control the state of relays and circuit breakers within power distribution systems. The monitoring of a relay state, i.e. open or closed, is often performed by applying a monitoring signal to sensing contacts added to the relay. Manufactures of such systems have chosen many different voltages for their own. monitoring systems making it difficult to interconnect dissimilar monitoring systems. A signal conditioning circuit is provided that can cope with a large input voltage range and can be configured to allow may items of equipment(which may be new item or legacy items) to be connected to a controller.

Abstract: A signal level crossing detector circuit includes a DC isolator and a detector circuit. The DC isolator has at least a first input, which is operable to receive a high voltage AC signal, and at least a first capacitor, a first plate of the first capacitor being electrically connected to the first input. The detector circuit is operable at a low voltage and has at least a first detector input, the first detector input being electrically connected to a second plate of the first capacitor, the low voltage detector circuit being operable to provide a change in output signal in dependence on a high voltage AC signal on the first input crossing a predetermined signal level. The signal level crossing detector may be single ended or differential.

Abstract: A signal level crossing detector circuit includes a DC isolator and a detector circuit. The DC isolator has at least a first input, which is operable to receive a high voltage AC signal, and at least a first capacitor, a first plate of the first capacitor being electrically connected to the first input. The detector circuit is operable at a low voltage and has at least a first detector input, the first detector input being electrically connected to a second plate of the first capacitor, the low voltage detector circuit being operable to provide a change in output signal in dependence on a high voltage AC signal on the first input crossing a predetermined signal level. The signal level crossing detector may be single ended or differential.

Abstract: A powerline communication (PLC) transmission module transmits a signal over a three-line electrical mains supply. The PLC transmission module includes at least two coupling transformers, each transformer coupling the signal to first and second line-pairs of a three-line electrical mains supply, the first and second line-pairs different from one another. Driving circuitry drives a first version of the signal over the first line-pair and a second version of the signal over the second line-pair. Inversion circuitry selectively inverts one version of the signal relative to the other version of the signal, dependent upon an enacted transmission mode. The inversion circuitry may invert neither/both of the versions of the signal so that the signal is transmitted as a differential-mode signal on the line-pairs or invert one of the first and second versions of the signal relative to the other so that the signal is a common-mode signal.

Abstract: The invention discloses an electrical isolator circuit comprising: an input stage comprising a transmitter of an opto-isolator; and an output stage comprising: a receiver of the opto-isolator; an active circuit in series with the receiver between the receiver and a power rail of the output stage; a first resistor connected to an output of the active circuit, and an input for the application of a predetermined voltage to the active circuit, the output stage being configured such that a varying output voltage is developed across the first resistor in response to input of a high voltage AC signal to the input stage. Ideally the output stage is operable to clamp the voltage across the receiver at the level of the predetermined voltage, thereby allowing for an increase in the load resistor and variable output resistor without increasing the time constant to unacceptably having regards to switching requirements.

Abstract: Disclosed is an electrical isolator circuit comprising an input stage comprising first and second inputs, the input stage being configured to receive an input voltage signal; an output stage comprising first and second outputs electrically connected across a load capacitor; and a DC isolator comprising a first capacitor between said first input and said first output and second capacitor between said second input and said second output. The first and second plates of each of the first, second and load capacitors are defined by conductive layers of a printed circuit board and the dielectric of each of the first, second and load capacitors are defined by a non-conducting part of the printed circuit board.

Abstract: A voltage measurement circuit is operative to measure a high voltage AC signal and includes a capacitive divider circuit and a compensator circuit. The capacitive divider circuit includes first and second inputs, across which, in use, is received a high voltage AC signal and also includes second and third capacitors. First and second plates of each of the first, second and third capacitors are defined by conductive layers of a printed circuit board and the dielectric of each of the first, second and third capacitors being defined by a non-conducting part of the printed circuit board. A compensator circuit has a configurable transfer function and includes an input connected across the first and second plates of the third capacitor and an output. The compensator circuit is operative to change a voltage received at its input in accordance with the transfer function and to provide the changed voltage at its output.

Abstract: A voltage measurement circuit is operative to measure a high voltage AC signal and includes a capacitive divider circuit and a compensator circuit. The capacitive divider circuit includes first and second inputs, across which, in use, is received a high voltage AC signal and also includes second and third capacitors. First and second plates of each of the first, second and third capacitors are defined by conductive layers of a printed circuit board and the dielectric of each of the first, second and third capacitors being defined by a non-conducting part of the printed circuit board. A compensator circuit has a configurable transfer function and includes an input connected across the first and second plates of the third capacitor and an output. The compensator circuit is operative to change a voltage received at its input in accordance with the transfer function and to provide the changed voltage at its output.

Abstract: A voltage measurement circuit is operative to measure a high voltage AC signal and includes a capacitive divider circuit and a compensator circuit. The capacitive divider circuit includes first and second inputs, across which, in use, is received a high voltage AC signal and also includes second and third capacitors. First and second plates of each of the first, second and third capacitors are defined by conductive layers of a printed circuit board and the dielectric of each of the first, second and third capacitors being defined by a non-conducting part of the printed circuit board. A compensator circuit has a configurable transfer function and includes an input connected across the first and second plates of the third capacitor and an output. The compensator circuit is operative to change a voltage received at its input in accordance with the transfer function and to provide the changed voltage at its output.

Abstract: What is disclosed is a current measuring apparatus comprising: a mains connector, such as a plug, for connecting to a wire of a mains supply; an apparatus connector, such as a socket, to provide for electrical conduction to an electrical apparatus; a coil in series between the mains connector and the apparatus connector; and a measurement circuit that is operative to measure a voltage drop across the coil. In particular the coil is one present to also filter the mains signal. Also disclosed is a mains voltage powered consumer product, a network and an adaptor utilising the current measuring apparatus.

Abstract: Disclosed is an electrical isolator circuit comprising an input stage comprising first and second inputs, the input stage being configured to receive an input voltage signal; an output stage comprising first and second outputs electrically connected across a load capacitor; and a DC isolator comprising a first capacitor between said first input and said first output and second capacitor between said second input and said second output. The first and second plates of each of the first, second and load capacitors are defined by conductive layers of a printed circuit board and the dielectric of each of the first, second and load capacitors are defined by a non-conducting part of the printed circuit board.

Abstract: A powerline communication (PLC) transmission module transmits a signal over a three-line electrical mains supply. The PLC transmission module includes at least two coupling transformers, each transformer coupling the signal to first and second line-pairs of a three-line electrical mains supply, the first and second line-pairs different from one another. Driving circuitry drives a first version of the signal over the first line-pair and a second version of the signal over the second line-pair. Inversion circuitry selectively inverts one version of the signal relative to the other version of the signal, dependent upon an enacted transmission mode. The inversion circuitry may invert neither/both of the versions of the signal so that the signal is transmitted as a differential-mode signal on the line-pairs or invert one of the first and second versions of the signal relative to the other so that the signal is a common-mode signal.

Abstract: The invention discloses an electrical isolator circuit comprising: an input stage comprising a transmitter of an opto-isolator; and an output stage comprising: a receiver of the opto-isolator; an active circuit in series with the receiver between the receiver and a power rail of the output stage; a first resistor connected to an output of the active circuit, and an input for the application of a predetermined voltage to the active circuit, the output stage being configured such that a varying output voltage is developed across the first resistor in response to input of a high voltage AC signal to the input stage. Ideally the output stage is operable to clamp the voltage across the receiver at the level of the predetermined voltage, thereby allowing for an increase in the load resistor and variable output resistor without increasing the time constant to unacceptably having regards to switching requirements.

Abstract: An external power supply unit (PSU) for an appliance includes rectification circuitry operable to convert an AC voltage from mains power lines to a DC voltage output, decoupling circuitry operable to decouple a broadband data signal from the mains power lines, timing circuitry operable to provide a signal representative of the mains AC voltage timing, and conveyance circuitry operable to convey the DC voltage output, a ground reference signal, the signal representative of the mains AC voltage timing, and the broadband data signal to the appliance, wherein the conveyance circuitry has no more than four conductors. The timing circuitry may be further operable to modulate the signal representative of the mains AC voltage timing onto either the DC voltage output or the broadband data signal. The timing circuitry may be a zero-crossing detector.

Abstract: A signal level crossing detector circuit includes a DC isolator and a detector circuit. The DC isolator has at least a first input, which is operable to receive a high voltage AC signal, and at least a first capacitor, a first plate of the first capacitor being electrically connected to the first input. The detector circuit is operable at a low voltage and has at least a first detector input, the first detector input being electrically connected to a second plate of the first capacitor, the low voltage detector circuit being operable to provide a change in output signal in dependence on a high voltage AC signal on the first input crossing a predetermined signal level. The signal level crossing detector may be single ended or differential.

Abstract: A voltage measurement circuit is operative to measure a high voltage AC signal and includes a capacitive divider circuit and a compensator circuit. The capacitive divider circuit includes first and second inputs, across which, in use, is received a high voltage AC signal and also includes second and third capacitors. First and second plates of each of the first, second and third capacitors are defined by conductive layers of a printed circuit board and the dielectric of each of the first, second and third capacitors being defined by a non-conducting part of the printed circuit board. A compensator circuit has a configurable transfer function and includes an input connected across the first and second plates of the third capacitor and an output. The compensator circuit is operative to change a voltage received at its input in accordance with the transfer function and to provide the changed voltage at its output.