Abstract: Filters are monitored. Color data is determined for a filter. A filter status for the filter is derived from the color data. An action is taken based on the filter status. The filter status may include a dirty status or an empty status for the filter. The action may include alerting a user based on the filter status. The filter may be illuminated prior to the determining of the color data for the filter.

Abstract: An adaptive pre-charge control circuit includes include a high-voltage switch and a control circuit. The high-voltage switch controls the flow of current between an electric battery and a DC link capacitor, the electric battery to supply power to an electric vehicle. The DC link capacitor is made up of a sum of individual input capacitors of multiple subunits within an electric vehicle. The control circuit sends a PWM signal to the high-voltage switch based on a difference between an electric battery voltage and a DC link capacitor voltage.

Abstract: An adaptive pre-charge control circuit includes include a high-voltage switch and a control circuit. The high-voltage switch controls the flow of current between an electric battery and a DC link capacitor, the electric battery to supply power to an electric vehicle. The DC link capacitor is made up of a sum of individual input capacitors of multiple subunits within an electric vehicle. The control circuit sends a PWM signal to the high-voltage switch based on a difference between an electric battery voltage and a DC link capacitor voltage.

Abstract: A latching relay includes a supply terminal, a load terminal, first and second coupling circuits, a latch circuit, first and second transistors, and a local supply node coupled to a capacitor. In one example, the supply terminal is coupled to a supply node and the load terminal is coupled to the load. The first and second transistors control the conductivity of a drive transistor coupled to the load. A microcontroller controls the latching relay to switch the load on and off. To enable the load, the microcontroller sinks current from the supply terminal and through the first coupling circuit. While the load is enabled, the capacitor is discharged. The latching relay is operable in a refresh mode in which current is pulsed through the first coupling circuit causing capacitor to be re-charged from the supply terminal. To disable the load, the microcontroller sinks current through the second coupling circuit.

Abstract: A latching relay includes a supply terminal, a load terminal, first and second coupling circuits, a latch circuit, first and second transistors, and a local supply node coupled to a capacitor. In one example, the supply terminal is coupled to a supply node and the load terminal is coupled to the load. The first and second transistors control the conductivity of a drive transistor coupled to the load. A microcontroller controls the latching relay to switch the load on and off. To enable the load, the microcontroller sinks current from the supply terminal and through the first coupling circuit. While the load is enabled, the capacitor is discharged. The latching relay is operable in a refresh mode in which current is pulsed through the first coupling circuit causing capacitor to be re-charged from the supply terminal. To disable the load, the microcontroller sinks current through the second coupling circuit.

Abstract: A latching relay includes a supply terminal, a load terminal, first and second coupling circuits, a latch circuit, first and second transistors, and a local supply node coupled to a capacitor. In one example, the supply terminal is coupled to a supply node and the load terminal is coupled to the load. The first and second transistors control the conductivity of a drive transistor coupled to the load. A microcontroller controls the latching relay to switch the load on and off. To enable the load, the microcontroller sinks current from the supply terminal and through the first coupling circuit. While the load is enabled, the capacitor is discharged. The latching relay is operable in a refresh mode in which current is pulsed through the first coupling circuit causing capacitor to be re-charged from the supply terminal. To disable the load, the microcontroller sinks current through the second coupling circuit.

Abstract: In one embodiment of the spectroscopy method, the method comprises the steps of modulating the wavelength of a monochromatic radiation at a modulation amplitude and a modulation frequency; determining a first variable representative of an absorbance of an analyte in a sample; and demodulating by phase-sensitive detection the first variable at a harmonic of the modulation frequency to produce a harmonic spectrum of the analyte. In one embodiment of the spectroscopy apparatus, the apparatus comprises a laser diode integrated with a first photodetector configured to detect an intensity of a backward emission from the laser diode and act as a reference detector; a second photodetector configured to detect an intensity of laser radiation exiting a sample; and electronic circuitry coupled to the laser diode and the photodetectors, configured to acquire and process spectra of the sample.

Abstract: In one embodiment of the spectroscopy method, the method comprises the steps of modulating the wavelength of a monochromatic radiation at a modulation amplitude and a modulation frequency; determining a first variable representative of an absorbance of an analyte in a sample; and demodulating by phase-sensitive detection the first variable at a harmonic of the modulation frequency to produce a harmonic spectrum of the analyte. In one embodiment of the spectroscopy apparatus, the apparatus comprises a laser diode integrated with a first photodetector configured to detect an intensity of a backward emission from the laser diode and act as a reference detector; a second photodetector configured to detect an intensity of laser radiation exiting a sample; and electronic circuitry coupled to the laser diode and the photodetectors, configured to acquire and process spectra of the sample.

Abstract: A data access arrangement (DAA) circuit for an item of customer premise equipment (CPE, i.e., telephone terminal equipment) utilizes RF coupling across an isolation barrier between two sides of the DAA circuit.

Abstract: A data access arrangement (DAA) circuit for an item of customer premise equipment (CPE, i.e., telephone terminal equipment) utilizes RF coupling across an isolation barrier between two sides of the DAA circuit.

Abstract: An improved line interface device and an improved xDSL modem for use in connecting data communications equipment to a xDSL line is disclosed. The line interface device provides the required isolation between the xDSL line and the communications equipment using optical isolation or capacitive techniques, as well as provides the power necessary to produce the transmit signal levels required by the communications services by utilizing a switching power supply deriving its power from a source isolated from the line, and including a transformer for isolating the source from the xDSL line. By switching at high frequencies the size of the transformer can be sufficiently small so that the interface device and supply can be provided in accordance with small form factor requirements.

Abstract: An isolation amplifier circuit with hook switch control includes first and second amplifier stages optically isolated from and coupled to each other. A biasing circuit is optically coupled to the amplifier to provide a switchable prebias to the amplifier to allow the amplifier to process bipolar voltage input signals. A hook switch circuit is coupled to the biasing circuit such that as the bias condition is switched, the hook switch is opened or closed. The same optical coupling circuitry can be used to couple the first and second amplifier stages and to couple the biasing circuit to the hook switch circuit such that savings in circuit space and cost are realized.