Abstract: A system to completely measure multiple densities in varying levels in tanks or vessels. The present invention provides a multiplicity of aligned sources and separate aligned detectors, the combination aligned sources and separate detectors are positioned horizontally relative to each other at varying vertical tank levels, each combination separate source and aligned detector at each measuring level in the tank provide continuous density data at each level. The sources and separate detectors are placed in a vertically aligned array in the separation tank near the weir, with each individual source and separate detector aligned with a given level.

Abstract: An apparatus and method for igniting a lamp during a strike mode of an inverter comprising: sequentially controlling a duty cycle sweep and a frequency sweep of driving signals in the inverter to provide an increasing output voltage to the lamp. One embodiment advantageously includes a closed feedback loop to implement the duty cycle sweep and the frequency sweep such that an open lamp voltage is reliably regulated during the strike mode. For example, the closed feedback loop stops the duty cycle sweep or the frequency sweep when the output voltage to the lamp reaches a predetermined threshold and makes adjustments to the duty cycle or frequency the driving signals as needed to keep the output voltage at approximately the predetermined threshold if the lamp has not ignited.

Abstract: A feed-forward correction circuit in a PWM controller adjusts an error signal inversely with respect to a supply voltage for a switching voltage regulator to quickly compensate for changes or transients in the supply voltage. The adjusted error signal is provided to a PWM comparator to control a duty cycle of an output signal. The switching voltage regulator can be a DC-to-DC converter or a DC-to-AC converter, and the output signal is used to generate one or more driving signals to control semiconductor switches in the switching voltage regulator. The feed-forward correction circuit uses an offset compensation technique or a translinear circuit to maintain a substantially inverse product relationship between the supply voltage and the duty cycle of the output signal, thereby reducing overshoots and undershoots in a regulated output voltage of the switching voltage regulator.

Abstract: An apparatus and method for igniting a lamp during a strike mode of an inverter comprising: sequentially controlling a duty cycle sweep and a frequency sweep of driving signals in the inverter to provide an increasing output voltage to the lamp. One embodiment advantageously includes a closed feedback loop to implement the duty cycle sweep and the frequency sweep such that an open lamp voltage is reliably regulated during the strike mode. For example, the closed feedback loop stops the duty cycle sweep or the frequency sweep when the output voltage to the lamp reaches a predetermined threshold and makes adjustments to the duty cycle or frequency the driving signals as needed to keep the output voltage at approximately the predetermined threshold if the lamp has not ignited.

Abstract: An apparatus and method for igniting a lamp during a strike mode of an inverter comprising: sequentially controlling a duty cycle sweep and a frequency sweep of driving signals in the inverter to provide an increasing output voltage to the lamp. One embodiment advantageously includes a closed feedback loop to implement the duty cycle sweep and the frequency sweep such that an open lamp voltage is reliably regulated during the strike mode. For example, the closed feedback loop stops the duty cycle sweep or the frequency sweep when the output voltage to the lamp reaches a predetermined threshold and makes adjustments to the duty cycle or frequency the driving signals as needed to keep the output voltage at approximately the predetermined threshold if the lamp has not ignited.

Abstract: A lamp inverter with continuous strike voltage facilitates faster striking of a fluorescent lamp, especially at cold temperatures. A frequency sweep generator sweeps the frequency of the lamp inverter to a striking frequency corresponding to a striking lamp voltage and then maintains the striking frequency until the lamp strikes.

Abstract: An illumination control circuit allows a user to set a desired brightness level and maintains the desired brightness level over temperature and life of a light source. The illumination control circuit uses a dual feedback loop with both optical and thermal feedbacks. The optical feedback loop controls power to the light source during normal operations. The thermal feedback loop overrides the optical feedback loop when the temperature of the light source becomes excessive.

Abstract: An apparatus and method for igniting a lamp during a strike mode of an inverter comprising: sequentially controlling a duty cycle sweep and a frequency sweep of driving signals in the inverter to provide an increasing output voltage to the lamp. One embodiment advantageously includes a closed feedback loop to implement the duty cycle sweep and the frequency sweep such that an open lamp voltage is reliably regulated during the strike mode. For example, the closed feedback loop stops the duty cycle sweep or the frequency sweep when the output voltage to the lamp reaches a predetermined threshold and makes adjustments to the duty cycle or frequency the driving signals as needed to keep the output voltage at approximately the predetermined threshold if the lamp has not ignited.

Abstract: A feed-forward correction circuit in a PWM controller adjusts an error signal inversely with respect to a supply voltage for a switching voltage regulator to quickly compensate for changes or transients in the supply voltage. The adjusted error signal is provided to a PWM comparator to control a duty cycle of an output signal. The switching voltage regulator can be a DC-to-DC converter or a DC-to-AC converter, and the output signal is used to generate one or more driving signals to control semiconductor switches in the switching voltage regulator. The feed-forward correction circuit uses an offset compensation technique or a translinear circuit to maintain a substantially inverse product relationship between the supply voltage and the duty cycle of the output signal, thereby reducing overshoots and undershoots in a regulated output voltage of the switching voltage regulator.

Abstract: A power conversion circuit improves lamp operating life and lamp efficiency by driving a fluorescent lamp with a square wave signal. The square wave signal is an alternating current signal with relatively fast transition times. The square wave signal advantageously reduces lamp current crest factor for more efficient operation of the fluorescent lamp.

Abstract: A lamp inverter with continuous strike voltage facilitates faster striking of a fluorescent lamp, especially at cold temperatures. A frequency sweep generator sweeps the frequency of the lamp inverter to a striking frequency corresponding to a striking lamp voltage and then maintains the striking frequency until the lamp strikes.

Abstract: An illumination control circuit allows a user to set a desired brightness level and maintains the desired brightness level over temperature and life of a light source. The illumination control circuit uses a dual feedback loop with both optical and thermal feedbacks. The optical feedback loop controls power to the light source during normal operations. The thermal feedback loop overrides the optical feedback loop when the temperature of the light source becomes excessive.

Abstract: A lamp inverter with continuous strike voltage facilitates faster striking of a fluorescent lamp, especially at cold temperatures. A frequency sweep generator sweeps the frequency of the lamp inverter to a striking frequency corresponding to a striking lamp voltage and then maintains the striking frequency until the lamp strikes.

Abstract: A power conversion circuit improves lamp operating life and lamp efficiency by driving a fluorescent lamp with a square wave signal. The square wave signal is an alternating current signal with relatively fast transition times. The square wave signal advantageously reduces lamp current crest factor for more efficient operation of the fluorescent lamp.

Abstract: A multiple output regulating charge pump includes a load current regulator to balance currents in multiple branches of at least one load, such as light emitting diodes in a parallel configuration. The load current regulator includes current mirror circuits to provide substantially identical currents to the respective light emitting diodes, thereby producing uniform light from each of the light emitting diodes. The multiple output charge pump includes a charge storage component that is alternately charged during a charge cycle and discharged during a discharge cycle. The charge pump provides current to a second load during the charge cycle and to a first load during a discharge cycle.

Abstract: An efficient power conversion circuit for driving a fluorescent lamp uses a pre-regulator to generate a regulated voltage with a relatively high level of ripple voltage. The regulated voltage can be varied to provide dimming of the fluorescent lamp. The regulated voltage is provided to a direct drive inverter. The direct drive inverter uses driving signals of fixed pulse widths to generate an output voltage to drive the fluorescent lamp. The output voltage has relatively long on-time durations so that the difference between the peak lamp current and the average lamp current is reduced, thus reducing a lamp current crest factor for improved lamp lighting efficiency.

Abstract: A single mode buck/boost charge pump has multiple outputs and is adapted to power a plurality of separate loads, such as light emitting diodes, in a highly efficient manner. The multiple outputs have different voltages. The output current or voltage of at least one of the multiple outputs is regulated by a feedback circuit. The feedback circuit provides a control signal based on a comparison of a reference voltage with a feedback voltage. The feedback voltage is proportional to an output voltage when the charge pump is configured to regulate the output voltage. Alternately, the feedback voltage is a sense voltage across a sense resistor connected in series with a load when the charge pump is configured to regulate output current provided to the load.

Abstract: A lamp inverter with continuous strike voltage facilitates faster striking of a fluorescent lamp, especially at cold temperatures. A frequency sweep generator sweeps the frequency of the lamp inverter to a striking frequency corresponding to a striking lamp voltage and then maintains the striking frequency until the lamp strikes.

Abstract: A single mode buck/boost charge pump has multiple outputs and is adapted to power a plurality of separate loads, such as light emitting diodes, in a highly efficient manner. The multiple outputs have different voltages. The output current or voltage of at least one of the multiple outputs is regulated by a feedback circuit. The feedback circuit provides a control signal based on a comparison of a reference voltage with a feedback voltage. The feedback voltage is proportional to an output voltage when the charge pump is configured to regulate the output voltage. Alternately, the feedback voltage is a sense voltage across a sense resistor connected in series with a load when the charge pump is configured to regulate output current provided to the load.

Abstract: An efficient power conversion circuit for driving a fluorescent lamp uses a pre-regulator to generate a regulated voltage with a relatively high level of ripple voltage. The regulated voltage can be varied to provide dimming of the fluorescent lamp. The regulated voltage is provided to a direct drive inverter. The direct drive inverter uses driving signals of fixed pulse widths to generate an output voltage to drive the fluorescent lamp. The output voltage has relatively long on-time durations so that the difference between the peak lamp current and the average lamp current is reduced, thus reducing a lamp current crest factor for improved lamp lighting efficiency.