Abstract: A mixed signal integrated circuit includes a signal source to inject a test signal into the signal path of the mixed signal integrated circuit, a feedback loop and a signal comparator for determining characteristics of a resulting signal. Conveniently, the test signal may be a digital signal injected upstream of a digital to analog converter (DAC). By connecting the output to the input, the entirety of the signal path and the majority of the integrated circuit may be tested. The signal may be condition or manipulated in the feedback loop. By incorporating test signal generation and measurement into the mixed signal integrated circuit, the cost of test equipment and the test duration for each device under test may be reduced.

Abstract: A high current drive bandgap based voltage regulator for providing a reference voltage at a an output voltage at a designed output voltage value. The high current drive bandgap based voltage regulator includes a high current drive output transistor, a feedback network, an output terminal and an operational amplifier. The feedback network is coupled between the output of the transistor and the input of the transistor. The operational amplifier is in the feedback network and has at least two operational amplifier input terminals and an operational amplifier output terminal. The operational amplifier output terminal is coupled to the transistor input terminal, and the operational input terminals are coupled to the transistor output terminal. The output terminal of the high current drive bandgap based voltage regulator is coupled to the output of the high current drive transistor.

Abstract: An oxygen concentrator system that includes or can be expanded to include more than one compressor is provided. The system utilizes a controller that is adapted to selectively activate or deactivate one or more of the compressors to optimize system performance and efficiency. Multiple compressors can be selected to operate at the same time, thereby enabling the system to operate at a higher peak pressure, increase the recovery of the PSA cycle, and expand the product rate. The additional compressors can also be removed when not in use so as to reduce weight of the system. In some implementations, the system housing reserves a certain amount of space for accommodating additional compressors and related components, which can be added to the system as after market parts. In other implementations, the additional compressor can be located external to the system.

Abstract: A rotary engine with multiple pivotally mounted lobes desmodromically extendible and retractable from a rotor to trace asymmetric volumes for inlet and compression and expansion and exhaust based on the contour of the engine case which the lobes sealingly engage.

Abstract: A high current drive bandgap based voltage regulator for providing a reference voltage at a an output voltage at a designed output voltage value. The high current drive bandgap based voltage regulator includes a high current drive output transistor, a feedback network, an output terminal and an operational amplifier. The feedback network is coupled between the output of the transistor and the input of the transistor. The operational amplifier is in the feedback network and has at least two operational amplifier input terminals and an operational amplifier output terminal. The operational amplifier output terminal is coupled to the transistor input terminal, and the operational input terminals are coupled to the transistor output terminal. The output terminal of the high current drive bandgap based voltage regulator is coupled to the output of the high current drive transistor.

Abstract: A rotary engine with multiple pivotally mounted lobes desmodromically extendible and retractable from a rotor to trace asymmetric volumes for inlet and compression and expansion and exhaust based on the contour of the engine case which the lobes sealingly engage.

Abstract: In an embodiment, the invention is an improved interface to a conserver for therapeutic gas delivery. The improved circuit allows for fine control of the frequency response of a feedback element, which permits a high gain interface. The result is excellent compensation of transducer drift with little distortion of the frequencies of interest for breath detection, even for low breath pressure scenarios.

Abstract: A variable speed wind turbine employing a rotor connected to a multiplicity of synchronous generators with wound field or permanent magnet rotors. A passive rectifier and an inverter are used for power transfer back to the grid. A Turbine Control Unit (TCU) commands a required generator torque based on rotor speed and power output of the turbine inverters. Torque is controlled by regulating the DC current by control of the inverter. A main-shaft-damping filter is provided by measurement of the DC bus voltage. In high winds the turbine remains at a constant average output power through a constant torque command and a varying pitch command to a rotor pitch servo system. A set point is fixed at the inverter output such that output VAR load is minimized running the turbine at very nearly unity power factor. Dynamic VAR and power factor control is provided by a separate VAR apparatus.

Abstract: A process and apparatus for absorption heat pumping include supplying heat to a first generator, desorbing vapor from a solution of absorbent and refrigerant in the first generator; in a first absorber, partially absorbing into an absorbent solution the vapor desorbed in the first generator to produce a mixture of vapor and liquid; further absorbing the vapor from the mixture in a second absorber, thereby producing a strong solution and evolving a heat of absorption; vaporizing some of the strong solution by reducing the ambient pressure, thereby extracting heat from a load, supplying absorbent vapor and liquid from the second generator to a third generator to produce more vapor, the third generator receiving the heat of absorption evolved by the second absorber, and leaving a remaining liquid that is pumped to the first absorber; supplying vapor from the third generator to a third absorber in which the vapor is absorbed into an absorbent solution, pumping absorbent solution from the third absorber to the fir