Abstract: Physical Unclonable Functions, PUFs, are hardware devices designed to generate a number that is random (i.e., two identical PUFs should produce randomly different numbers from each other) and persistent (i.e., a PUF should consistently generate the same number over time). Over time, aspects of the PUF hardware may change or drift, which may ultimately cause the generated number to change, and therefore no longer be persistent. Failure to generate a persistent number may cause difficulties for other devices that rely on the persistence of the number generated by the PUF, for example as part of a cryptographic process. The present disclosure relates to monitoring over time the physical characteristics of the PUF that are used to generate its number, and thereby keep track of its reliability to generate a random number that is persistent.

Abstract: The disclosure relates to accurately determining a DC energy signal, such as a DC current or DC voltage, which may be particularly useful when controlling a formation/testing current of a battery cell during formation and/or testing. In the battery formation/testing context, a current sensor is used to measure the current of the battery cell, which is used as a feedback signal for controlling the current to achieve a target current. The transfer function of the current sensor is used to improve the accuracy of the current measurement. Because the transfer function can be regularly determined during formation/testing, a lower-cost current sensor with relatively poor temperature coefficient may be used. Any change in the gain of the current sensor may be detected by the transfer function determination and corrected for. Therefore, high current control accuracy may be achieved at lower cost.

Abstract: This disclosure relates to monitoring the condition of electrical/electronic switches over time by monitoring the impedance of the switch. The condition of switches can degrade as they age, which can reduce their performance and may ultimately lead to failure. In many applications, particularly high-voltage applications, the reliable operation of switches may be very important and failures can present a safety risk and cause costly unscheduled system downtime for repairs. It has been realised that as the condition of switches change, their impedance changes, so monitoring the impedance can give a good indication of the condition of the switch, enabling potential faults/failures to be identified early and acted upon pre-emptively.

Abstract: The present disclosure relates to configuring at least one pair of devices in a physical unclonable function (PUF) apparatus and reading out at least one pair of devices for determining a persistent random PUF output. The pair of devices may be readout by measuring a physical difference between the devices/components caused by random manufacturing differences, which may then be used to determine a persistence random PUF output. Configuring the pair of devices includes measuring the random manufacturing difference and, based on that measurement, setting a readout condition for the pair of devices, which dictates aspects of the readout process that should be used for that pair of devices. Each time the pair of devices is readout in the future, it may be readout in accordance with the condition that was set at configuration.

Abstract: An apparatus is provided which substantially removes a perturbation signal from a pulse density modulated signal representing a combination of a signal to be measured and a perturbation applied to the signal to be measured. The removal of the perturbation is done by subtracting a correcting signal from the pulse density modulated signal. This approach introduces very little delay as it can be implemented by simple logic gates. It also provided enhanced immunity from the effects of bit errors.

Abstract: Techniques for controlling a current of a battery cell during formation and/or testing are described. A current sensor is used to measure the current of the battery cell, which is used as a feedback signal for controlling the current to achieve a target current. The transfer function of the current sensor is used to improve the accuracy of the current measurement. Because the transfer function can be regularly determined during formation/testing, a lower-cost current sensor with relatively poor temperature coefficient may be used. Any change in the gain of the current sensor may be detected by the transfer function determination and corrected for. Therefore, high current control accuracy may be achieved at lower cost.

Abstract: The present disclosure relates to configuring at least one pair of devices in a physical unclonable function (PUF) apparatus and reading out at least one pair of devices for determining a persistent random PUF output. The pair of devices may be readout by measuring a physical difference between the devices/components caused by random manufacturing differences, which may then be used to determine a persistence random PUF output. Configuring the pair of devices includes measuring the random manufacturing difference and, based on that measurement, setting a readout condition for the pair of devices, which dictates aspects of the readout process that should be used for that pair of devices. Each time the pair of devices is readout in the future, it may be readout in accordance with the condition that was set at configuration.

Abstract: Techniques for controlling a current of a battery cell during formation and/or testing are described. A current sensor is used to measure the current of the battery cell, which is used as a feedback signal for controlling the current to achieve a target current. The transfer function of the current sensor is used to improve the accuracy of the current measurement. Because the transfer function can be regularly determined during formation/testing, a lower-cost current sensor with relatively poor temperature coefficient may be used. Any change in the gain of the current sensor may be detected by the transfer function determination and corrected for. Therefore, high current control accuracy may be achieved at lower cost.

Abstract: Physical Unclonable Functions, PUFs, are hardware devices designed to generate a number that is random (i.e., two identical PUFs should produce randomly different numbers from each other) and persistent (i.e., a PUF should consistently generate the same number over time). Over time, aspects of the PUF hardware may change or drift, which may ultimately cause the generated number to change, and therefore no longer be persistent. Failure to generate a persistent number may cause difficulties for other devices that rely on the persistence of the number generated by the PUF, for example as part of a cryptographic process. The present disclosure relates to monitoring over time the physical characteristics of the PUF that are used to generate its number, and thereby keep track of its reliability to generate a random number that is persistent.

Abstract: The present disclosure relates to configuring at least one pair of devices in a physical unclonable function (PUF) apparatus and reading out at least one pair of devices for determining a persistent random PUF output. The pair of devices may be readout by measuring a physical difference between the devices/components caused by random manufacturing differences, which may then be used to determine a persistence random PUF output. Configuring the pair of devices includes measuring the random manufacturing difference and, based on that measurement, setting a readout condition for the pair of devices, which dictates aspects of the readout process that should be used for that pair of devices. Each time the pair of devices is readout in the future, it may be readout in accordance with the condition that was set at configuration.

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: This disclosure relates to monitoring the condition of electrical/electronic switches over time by monitoring the impedance of the switch. The condition of switches can degrade as they age, which can reduce their performance and may ultimately lead to failure. In many applications, particularly high-voltage applications, the reliable operation of switches may be very important and failures can present a safety risk and cause costly unscheduled system downtime for repairs. It has been realised that as the condition of switches change, their impedance changes, so monitoring the impedance can give a good indication of the condition of the switch, enabling potential faults/failures to be identified early and acted upon pre-emptively.

Abstract: A measurement circuit is arranged to make several measurements, either at different times or in respect of different frequency components of currents measured by current sensors in respective phases of a multiphase supply system. The measurements are then used to correct for discrepancies in the transfer function of the sensors.

Abstract: An apparatus is provided which substantially removes a perturbation signal from a pulse density modulated signal representing a combination of a signal to be measured and a perturbation applied to the signal to be measured. The removal of the perturbation is done by subtracting a correcting signal from the pulse density modulated signal. This approach introduces very little delay as it can be implemented by simple logic gates. It also provided enhanced immunity from the effects of bit errors.

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: A power conversion apparatus or system can be 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 can include 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 measurement circuit is arranged to make several measurements, either at different times or in respect of different frequency components of currents measured by current sensors in respective phases of a multiphase supply system. The measurements are then used to correct for discrepancies in the transfer function of the sensors.

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 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.