Abstract: The present invention discloses a negative pressure wave monitoring based leak detection method of a multipath pipeline network, including: analyzing a propagation process of a negative pressure wave in a single straight pipeline to obtain a calculated result of a sound velocity in a thin-walled pipe marking the pressure sensors at known disposing positions on a pipeline network map; linearly interpolating position coordinates of key nodes in the pipeline network to extend pipeline network information; resolving the time that a negative pressure wave signal generated by a leak propagates to each disposed RTUs to form a data column; and simulating a leak situation, detecting a pipeline pressure waveform by using the RTUs in a current network, and determining a point corresponding to the data column closest to a measured propagation time delay in the time delay standard library as a leak point, and outputting the position of the leak point.

Abstract: A fiber optic distribution box includes a box unit, a protective shield unit pivotally mounted on the box unit, and a plurality of mounting units detachably installed to the box unit for accommodating a plurality of adapters. The box unit includes a box body defining an interior space and a plurality of base brackets disposed on the box body and accommodated in the interior space. Each mounting unit includes a flanged seat and a tubular portion extending obliquely upwardly from the flanged seat.

Abstract: Various examples are directed to a frequency-compensated amplifier circuit comprising a first multi-stage amplifier comprising a first amplifier input node, a first amplifier output node, and a first amplifier intermediate node. A first feedback path between the first amplifier input node and the first amplifier output node comprises a feedback resistance. A second feedback path between the first amplifier output node and the first amplifier intermediate node comprises a first capacitor and a portion of the feedback resistance. A first switch circuit may be electrically coupled to the first capacitor and to the feedback resistance. The first switch circuit may have a first state in which the first capacitor is coupled to a first tap point of the feedback resistance and the portion of the feedback resistance has a first value.

Abstract: A system for processing a signal in a signal chain having decentralized embedded power management of components of the signal chain includes an input circuit to generate a measurement signal responsive to a stimulus, where the measurement signal is indicative of a characteristic of the stimulus. The system additionally includes a signal converter circuit coupled to the input circuit to convert the measurement signal to a digital signal according to a timing condition for capturing a sample of the measurement signal. The signal converter includes a control circuit to provide electrical power to the input circuit based on the timing condition and a sampling circuit to capture the sample of the measurement signal responsive to an indicator signal generated by the sensor circuit.

Abstract: A system for processing a signal in a signal chain having decentralized embedded power management of components of the signal chain includes an input circuit to generate a measurement signal responsive to a stimulus, where the measurement signal is indicative of a characteristic of the stimulus. The system additionally includes a signal converter circuit coupled to the input circuit to convert the measurement signal to a digital signal according to a timing condition for capturing a sample of the measurement signal. The signal converter includes a control circuit to provide electrical power to the input circuit based on the timing condition and a sampling circuit to capture the sample of the measurement signal responsive to an indicator signal generated by the sensor circuit.

Abstract: Various examples are directed to a frequency-compensated amplifier circuit comprising a first multi-stage amplifier comprising a first amplifier input node, a first amplifier output node, and a first amplifier intermediate node. A first feedback path between the first amplifier input node and the first amplifier output node comprises a feedback resistance. A second feedback path between the first amplifier output node and the first amplifier intermediate node comprises a first capacitor and a portion of the feedback resistance. A first switch circuit may be electrically coupled to the first capacitor and to the feedback resistance. The first switch circuit may have a first state in which the first capacitor is coupled to a first tap point of the feedback resistance and the portion of the feedback resistance has a first value.

Abstract: A difference amplifier can be used for providing an amplified representation of a sensed current through a load device. A separate signal path can be used to provide fast fault detection, without requiring use of the difference amplifier. For example, a voltage scaling circuit can be used to scale a differential input signal indicative of the load current. The scaled representation can then be compared against a specified threshold corresponding to a fault current value. In this manner, a high-speed low-voltage comparator can be used to provide detection of a fault current that otherwise exceeds an input range of the difference amplifier, where the difference amplifier is used separately for precision current monitoring. As an illustrative example, such a scheme can provide fault detection even when an input of the difference amplifier is saturated.

Abstract: A fan includes a metal plate, multiple cylindrical coils, a frame and an impeller. Multiple teeth annularly arranged and connected with each other are formed on the metal plate. Each cylindrical coil is arranged between adjacent teeth, and each end of the cylindrical coil is arranged toward corresponding tooth. The frame is arranged on a surface of the metal plate and extended along an edge of the metal plate. A flow channel and an air outlet connected to the flow channel are formed by the frame. The impeller is arranged in the flow channel. A stator structure of the fan is simplified by forming the teeth on the metal plate.

Abstract: An amplifier circuit comprises a differential input stage configured to receive a differential input signal, wherein the differential input stage is susceptible to an offset error that includes a linear offset error portion and a nonlinear offset error portion; and an offset error correction circuit coupled to the differential input stage and configured to apply a second order error correction signal to the differential input stage to reduce the nonlinear portion of the offset error.

Abstract: An amplifier circuit comprises a differential input stage configured to receive a differential input signal, wherein the differential input stage is susceptible to an offset error that includes a linear offset error portion and a nonlinear offset error portion; and an offset error correction circuit coupled to the differential input stage and configured to apply a second order error correction signal to the differential input stage to reduce the nonlinear portion of the offset error.

Abstract: A difference amplifier can he used for providing an amplified representation of a sensed current through a load device. A separate signal path can be used to provide fast fault detection, without requiring use of the difference amplifier. For example, a voltage scaling circuit can be used to scale a differential input signal indicative of the load current. The scaled representation can then be compared against a specified threshold corresponding to a fault current value. In this manner, a high-speed low-voltage comparator can be used to provide detection of a fault current that otherwise exceeds an input range of the difference amplifier, where the difference amplifier is used separately for precision current monitoring. As an illustrative example, such a scheme can provide fault detection even when an input of the difference amplifier is saturated.

Abstract: An amplifier circuit can have a differential input. A common-mode signal present at the differential input can induce an offset voltage at an output of the amplifier circuit. A compensation can be performed to reduce or eliminate such an offset, such as at a first temperature. Circuits and techniques for drift correction can be performed, such as to correct for residual offset error across an entirety of a specified operation temperature range. In an example, first and second drift correction signal generator circuits can be used, such as to provide signals proportional to a common mode voltage, but having different temperature coefficients.

Abstract: An amplifier circuit can have a differential input. A common-mode signal present at the differential input can induce an offset voltage at an output of the amplifier circuit. A compensation can be performed to reduce or eliminate such an offset, such as at a first temperature. Circuits and techniques for drift correction can be performed, such as to correct for residual offset error across an entirety of a specified operation temperature range. In an example, first and second drift correction signal generator circuits can be used, such as to provide signals proportional to a common mode voltage, but having different temperature coefficients.

Abstract: A low-noise, low-power reference voltage circuit can include an operational transconductance amplifier (OTA) with inputs coupled to a temperature-compensated voltage, such as can be provided by source-coupled first and second field-effect transistors (FETs) having different threshold voltages. A capacitive voltage divider can feed back a portion of a reference voltage output by the OTA to the inputs of the OTA to help establish or maintain the temperature-compensated voltage across the inputs of the OTA. A switching network can be used, such as initialize the capacitive voltage divider or other capacitive feedback circuit, such as during power-down cycles, or when resuming powered-on cycles. A switch can interrupt current to the OTA during the power-down cycles to save power. The cycled voltage reference circuit can provide a reference voltage to an ADC reservoir capacitor. Powering down can occur during analog input signal sampling, during successive approximation routine (SAR) conversion, or both.

Abstract: A low-noise, low-power reference voltage circuit can include an operational transconductance amplifier (OTA) with inputs coupled to a temperature-compensated voltage, such as can be provided by source-coupled first and second field-effect transistors (FETs) having different threshold voltages. A capacitive voltage divider can teed back a portion of a reference voltage output by the OTA to the inputs of the OTA to help establish or maintain the temperature-compensated voltage across the inputs of the OTA. A switching network can be used, such as initialize the capacitive voltage divider or other capacitive feedback circuit, such as during power-down cycles, or when resuming powered-on cycles. A switch can interrupt current to the OTA during the power-down cycles to save power. The cycled voltage reference circuit can provide a reference voltage to an ADC reservoir capacitor. Powering down can occur during analog input signal sampling, during successive approximation routine (SAR) conversion, or both.

Abstract: A difference amplifier circuit can be used to amplify a differential input signal representative of a current flowing through a current sensing element, such as a resistor. In certain applications, a common mode voltage established at an input of the difference amplifier circuit can be greater in magnitude than a supply voltage provided to the difference amplifier circuit. A component of the differential input signal, such as one polarity of the differential signal, can be used to power the difference amplifier circuit. Such powering of the difference amplifier by the component of the differential input signal can be performed selectively, such as when a magnitude of the common mode voltage exceeds the supply voltage or another specified threshold. In this manner, a common mode input voltage capability can be greater in magnitude than a magnitude of a supply input voltage provided to an integrated circuit including the difference amplifier circuit.

Abstract: A difference amplifier circuit can be used to amplify a differential input signal representative of a current flowing through a current sensing element, such as a resistor. In certain applications, a common mode voltage established at an input of the difference amplifier circuit can be greater in magnitude than a supply voltage provided to the difference amplifier circuit. A component of the differential input signal, such as one polarity of the differential signal, can be used to power the difference amplifier circuit. Such powering of the difference amplifier by the component of the differential input signal can be performed selectively, such as when a magnitude of the common mode voltage exceeds the supply voltage or another specified threshold. In this manner, a common mode input voltage capability can be greater in magnitude than a magnitude of a supply input voltage provided to an integrated circuit including the difference amplifier circuit.

Abstract: An amplifier circuit can include an amplifier and a resistor network coupled to the amplifier. The resistor network can include a range resistor coupled in parallel to a resistor string, and one or more switches coupled to the resistor string. The resistor network can be used to calibrate gain and common mode rejection ratio (CMRR) of the amplifier circuit.

Abstract: A fan includes a metal plate, multiple cylindrical coils, a frame and an impeller. Multiple teeth annularly arranged and connected with each other are formed on the metal plate. Each cylindrical coil is arranged between adjacent teeth, and each end of the cylindrical coil is arranged toward corresponding tooth. The frame is arranged on a surface of the metal plate and extended along an edge of the metal plate. A flow channel and an air outlet connected to the flow channel are formed by the frame. The impeller is arranged in the flow channel. A stator structure of the fan is simplified by forming the teeth on the metal plate.

Abstract: A fan includes a metal plate (100), multiple cylindrical coils (300), a frame (130) and an impeller (400). Multiple teeth (110) annularly arranged and connected with each other are formed on the metal plate (100). Each cylindrical coil (300) is arranged between adjacent teeth (110), and each end of the cylindrical coil (300) is arranged toward corresponding tooth (110). The frame (130) is arranged on a surface of the metal plate (100) and extended along an edge of the metal plate (100). A flow channel (131) and an air outlet (132) connected to the flow channel (131) are formed by the frame (130). The impeller (400) is arranged in the flow channel (131). A stator structure of the fan is simplified by forming the teeth (11) on the metal plate (100).