In one example, an arc fault circuit interrupter (AFCI) is provided. The AFCI may include a plurality of current arc signature detection blocks configured to output a plurality of corresponding current arc signatures, and a processor. The processor may be configured to receive each of the plurality of current arc signature from each of plurality of current arc signature detection blocks, respectively, and generate a first trigger signal. The processor may be further configured to assess each of the current arc signatures, determine whether an arc fault exists based on the assessment, and generate the first trigger signal if an arc fault is determined to exist. A method for detecting an arc fault is also provided.

A sensor device includes a first and second Micro-Electro-Mechanical (MEM) structures. The first MEM structure includes a first heating element on a first layer of the first MEM structure. The first heating element includes an input adapted to receive an input signal. The first MEM structure also includes a first temperature sensing element on a second layer of the first MEM structure. The second MEM structure includes a second heating element on a first layer of the second MEM structure and a second temperature sensing element on a second layer of the second MEM structure. An output circuit has a first input coupled to the first temperature sensing element and a second input coupled to the second temperature sensing element.

A device that includes an adaptive acoustic detection circuit and an acoustic sensor device such as a microphone is described. The device includes in addition to the sensor a circuit configured to detect when an input stimulus to the sensor satisfies an adaptive threshold, and further configured to produce a signal upon detection that causes adjustment of performance of the device, wherein the adaptive threshold is a threshold value that varies over time in accordance with detected changes to sound of an environment in which the device is located.

A device that includes an adaptive acoustic detection circuit and an acoustic sensor device such as a microphone is described. The device includes in addition to the sensor a circuit configured to detect when an input stimulus to the sensor satisfies an adaptive threshold, and further configured to produce a signal upon detection that causes adjustment of performance of the device, wherein the adaptive threshold is a threshold value that varies over time in accordance with detected changes to sound of an environment in which the device is located.

Permanent magnet (PM) flux strength in a permanent magnet synchronous machine (PMSM) can be affected by operating conditions including thermal, mechanical, environmental and electrical stresses. Reduced flux strength, also called demagnetization, can lead to the degradation of the efficiency, performance and reliability of the machine and the drive system. A reliable PM strength, PM flux linkage, PM SOH, PM demagnetization detection method using the same inverter (i.e. motor drive) used to operate the PMSM is provided. The method comprises applying phase voltages to each of a plurality of motor leads of the PMSM with the PMSM at a stand-still condition; measuring current in each of the plurality of motor leads of the PMSM while applying the phase voltages thereto; and determining at least one of flux linkage, PM strength, PM SoH, or PM demagnetization based on a value of the current in at least one of the motor leads.

Permanent magnet (PM) flux strength in a permanent magnet synchronous machine (PMSM) can be affected by operating conditions including thermal, mechanical, environmental and electrical stresses. Reduced flux strength, also called demagnetization, can lead to the degradation of the efficiency, performance and reliability of the machine and the drive system. A reliable PM strength, PM flux linkage, PM SOH, PM demagnetization detection method using the same inverter (i.e. motor drive) used to operate the PMSM is provided. The method comprises applying phase voltages to each of a plurality of motor leads of the PMSM with the PMSM at a stand-still condition; measuring current in each of the plurality of motor leads of the PMSM while applying the phase voltages thereto; and determining at least one of flux linkage, PM strength, PM SoH, or PM demagnetization based on a value of the current in at least one of the motor leads.

A control circuit for a power factor correction (PFC) circuit, the control circuit includes a multiplier having first, second, and third multiplier inputs and a multiplier output. The control circuit has an adder having first and second inputs and an output. The first input of the adder is coupled to the multiplier output. The control circuit further includes a root mean square (RMS) calculation circuit configured to determine a square of a root mean square of an input sinusoidal voltage. The RMS calculation circuit has an output coupled to the second multiplier input. An input voltage square calculation circuit is configured to determine a square of the input sinusoidal voltage. The input voltage square calculation circuit has an output coupled to the third multiplier input.

A control circuit for a power factor correction (PFC) circuit, the control circuit includes a multiplier having first, second, and third multiplier inputs and a multiplier output. The control circuit has an adder having first and second inputs and an output. The first input of the adder is coupled to the multiplier output. The control circuit further includes a root mean square (RMS) calculation circuit configured to determine a square of a root mean square of an input sinusoidal voltage. The RMS calculation circuit has an output coupled to the second multiplier input. An input voltage square calculation circuit is configured to determine a square of the input sinusoidal voltage. The input voltage square calculation circuit has an output coupled to the third multiplier input.

A method and system measure a characteristic of a signal under test (SUT) using a signal measurement device. The method includes receiving the SUT through first and second input channels; digitizing first and second copies of the SUT to obtain first and second digitized waveforms; repeatedly determining first and second measurement trends to obtain measurement trend pairs; cross-correlating the first and second measurement trends in each measurement trend pair to obtain cross-correlation vectors; extracting zero-displacement values from the cross-correlation vectors, respectively; summing the zero-displacement values to obtain a sum of measurement products for the measurement trend pairs; divide the sum of zero-displacement values by a total number of measurement products to obtain an average value of the measurement products, corresponding to MSV of the measured SUT characteristic; and determining a square root of the average value of the MSV to obtain an RMS value of the measured SUT characteristic.

An apparatus comprises a switch, a current monitor, and a controller. During operation, the switch controls an amount of current through the load. The current monitor samples a magnitude of the current through the load, a magnitude of which varies over time during a time duration. Based on integrating the sample magnitudes of the current through the load over the time duration, the current monitor produces a current sense value. The current sense value is representative of an amount of current through the load. The controller controls an operational state of the switch based upon a comparison of the current sense value with respect to an over-current threshold value. For example, in response to detecting a condition in which the current sense value is greater than the overcurrent threshold value, the controller turns OFF (deactivates) the switch, reducing or eliminating delivery of current through the load.