Abstract: The present invention relates to a power conversion apparatus or system configured to receive a high voltage alternating current (AC) signal at an input and to provide in dependence thereon a low voltage direct current (DC) signal from an output stage. The power conversion apparatus comprises a main path comprising a high voltage capacitor in series with the input. In an example, the capacitor comprises a portion of an electric field energy harvesting system.

Abstract: A power conversion apparatus can receive an alternating current (AC) signal at an input and provide in dependence thereon a low voltage direct current (DC) signal from an output stage. The apparatus comprises a main path comprising a capacitor in series with the input. The apparatus comprises a first path to carry current carried by the main path in at least one of a positive going part and a negative going part of the AC signal and a second path to carry current carried by the main path in a positive going part and a negative going part of the AC signal. The apparatus further comprises switches operative to determine when one of the first and second paths carries current. The output stage receives current flowing in the first path and at least one of the switches operates based on a control signal derived from the DC signal.

Abstract: An apparatus is provided that can estimate a transfer function, for example of current measurement systems, voltage measurement systems and power measurement systems, and also provide an estimate of certainty about the transfer function. This enables customers to have confidence that they are not being overcharged for electricity.

Abstract: Current transducers are widely used in current measuring systems. They provide good isolation between the supply voltage and the measurement equipment. However they can introduce small phase errors which can become significant sources of error if the current to a load is out of phase with the supply voltage for the load. This disclosure discusses a robust measurement apparatus and method that can be used in situ to monitor for and correct phase errors.

Abstract: The present invention relates to electrical measurement apparatus (10). The electrical measurement apparatus (10) comprises a measurement arrangement (20,24) configured to be disposed in relation to an electrical circuit (12,14,16,18) which bears an electrical signal, the measurement arrangement (20,24) being operative when so disposed to measure the electrical signal. The electrical measurement apparatus (10) further comprises a signal source (22) operative to apply a reference input signal to the measurement arrangement (20,24) whereby an output signal from the measurement arrangement comprises an electrical output signal corresponding to the electrical signal and a reference output signal corresponding to the reference input signal, the reference input signal having a substantially piecewise constant form which is repeated over each of plural cycles.

Abstract: Current measurement apparatus comprises a measurement arrangement and a signal source. The measurement arrangement is configured to measure a current signal drawn by a load. The signal source is operative to apply a reference input signal to the measurement arrangement whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input signal.

Abstract: Current measurement apparatus comprises a measurement arrangement and a signal source. The measurement arrangement is configured to measure a current signal drawn by a load. The signal source is operative to apply a reference input signal to the measurement arrangement whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input signal.

Abstract: The present invention relates to power conversion apparatus (40) configured to receive a high voltage alternating current (AC) signal at an input (42, 44) and to provide in dependence thereon a low voltage direct current (DC) signal from an output stage (58, 60). The power conversion apparatus (40) comprises a main path comprising a high voltage capacitor (46) in series with the input. The power conversion apparatus (40) also comprises a first path operative to carry current carried by the main path in at least one of a positive going part and a negative going part of the high voltage alternating current signal and a second path operative to carry current carried by the main path in a positive going part and a negative going part of the high voltage alternating current signal. The power conversion apparatus further comprises first and second switches (52, 54) which are operative to determine when a respective one of the first and second paths carries current.

Abstract: The present invention relates to electrical measurement apparatus (10). The electrical measurement apparatus (10) comprises a measurement arrangement (20,24) configured to be disposed in relation to an electrical circuit (12,14,16,18) which bears an electrical signal, the measurement arrangement (20,24) being operative when so disposed to measure the electrical signal. The electrical measurement apparatus (10) further comprises a signal source (22) operative to apply a reference input signal to the measurement arrangement (20,24) whereby an output signal from the measurement arrangement comprises an electrical output signal corresponding to the electrical signal and a reference output signal corresponding to the reference input signal, the reference input signal having a substantially piecewise constant form which is repeated over each of plural cycles.

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: Current measurement apparatus comprises a measurement arrangement and a signal source. The measurement arrangement is configured to measure a current signal drawn by a load. The signal source is operative to apply a reference input signal to the measurement arrangement whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input 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: 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.