Abstract: A noninvasive method of sensing an arterial pulse on a paw pad includes providing an instrument having a probe; placing the probe housing a tactile transducer and a reflective optical coupler comprising an infrared emitter and an infrared detector on a subject's metatarsal or metacarpal pad; emitting infrared light from the emitter; detecting infrared light with the detector; maintaining a linear direct current bias of the detector; converting a signal emitted by the infrared detector into a digital pulse that drives the tactile transducer to emit tactile pulses; and counting the tactile pulses over a predetermined time. An arterial pulse detection system includes a probe. The probe contains an optical sensor and a tactile transducer to which instrumentation is electrically connected. The optical sensor includes an infrared emitter and an infrared detector.

Abstract: A noninvasive method of sensing an arterial pulse on a paw pad includes providing an instrument having a probe; placing the probe housing a tactile transducer and a reflective optical coupler comprising an infrared emitter and an infrared detector on a subject's metatarsal or metacarpal pad; emitting infrared light from the emitter; detecting infrared light with the detector; maintaining a linear direct current bias of the detector; converting a signal emitted by the infrared detector into a digital pulse that drives the tactile transducer to emit tactile pulses; and counting the tactile pulses over a predetermined time. An arterial pulse detection system includes a probe. The probe contains an optical sensor and a tactile transducer to which instrumentation is electrically connected. The optical sensor includes an infrared emitter and an infrared detector.

Abstract: A circuit for providing thermal compensation for a driver circuit used to drive light emitting diodes (LEDs) is provided. The driver circuit can include a rectifier circuit configured to rectify an AC power source into a DC power source providing a DC source voltage. The driver circuit can further include a boost circuit configured to boost the DC source voltage to provide a drive voltage for driving the light emitting diodes. The boost circuit can include a switching element that is controlled based at least in part on a current sense circuit having a sense transistor. A thermal tracking transistor is provided as part of the reference to the sense circuit.

Abstract: An LED driver is presented with a sensing circuit and attenuator circuits to provide three-way switched dimming as well as phase-cut dimming to control the output power driving an LED load allowing installation into conventional three-way switched lamp sockets or in sockets wired to a wall or table mounted phase-cutting dimmer control. When installed in a three way socket, the circuit senses the position of the three way switch and changes the lamp current accordingly. The lamp can also be dimmed by a table-top dimmer or a wall dimmer (in a three-way socket or in a conventional dual contact socket) by applying a phase-cut power input, with the driver circuit including circuitry to sense the average value of a phase-cut power line to adjust lamp current.

Abstract: Light sources are presented in which lamp ballast or LED driver circuitry is disposed within a base assembly using integrated boards with components embedded between board layers and/or circular flex boards with pot core magnetic components and/or ASICs and thermally conductive board core materials with thermal vias, reflective mirrors, and/or potting materials to conduct heat out through the base to facilitate reduced form factors for lamps and/or LED light sources.

Abstract: Fluorescent lamp ballasts and methods are disclosed in which a resonant impedance of a self-oscillating inverter is modified to control the inverter frequency to selectively preheat lamp cathodes using power from the inverter output during a preheating period after power is applied and to change the inverter frequency to a different range following ignition of the lamp.

Abstract: A pre-programmed energy saving ballast or driver is presented, having a pre-defined energy profile to which the output power is controlled in accordance with the current time ascertained from the input power connection via simplex clock information or from received broadcast time signals, and which allows a user to select from a number of pre-programmed profiles and/or to modify and store user-defined energy profiles.

Abstract: A driver circuit includes an inverter having a controlled switch with an input for controlling switching operations. A tuned circuit has a resonant frequency when connected to a resonant load. The tuned circuit receives inverter output and generates a driving signal. Frequency of the inverter output and frequency of the driving signal substantially equal the resonant frequency of the tuned circuit. The tuned circuit boosts the inverter output to generate the driving signal such that a voltage of the driving signal is greater than a voltage of the inverter output. A feedback portion receives the inverter output and phase-shifts it to generate an inverter control signal. The feedback portion provides the inverter control signal to the input of the controlled switch to control switching operations of controlled switch. The driver self-oscillates at the resonant frequency due to the feedback portion phase-shifting the inverter output to generate the inverter control signal.

Abstract: Drivers and ballast circuits are presented having a boost converter with a triac compatibility circuit providing regulated current load to accommodate phase-cutting triac circuit holding current requirements, including auto switching driver circuit with overvoltage protection and an auto leveling circuit to regulate against thermal and load fluctuations.

Abstract: Light source power circuits and EMI filters therefor are presented in which a depletion mode field effect transistor is connected in series with an EMI filter capacitor following an input rectifier to allow filtering of EMI and to limit capacitive currents during triac switching when powered through a phase-cutting dimmer circuit.

Abstract: An LED driver circuit and an isolated DC-DC converter therefor are presented, in which a primary side state estimator circuit is provided for inferred output current sensing for closed loop control of pulse width modulated flyback or buck converters. Specifically, the estimator circuit includes a capacitance having a first terminal coupled to a comparator input of a pulse width modulation controller, and a second terminal coupled to an error input of an error amplifier, and a switching device having a first power terminal coupled to the second terminal of the capacitance, a second power terminal coupled to the circuit ground, and a control input terminal coupled to a drive output of the pulse width modulation controller.

Abstract: A ballast and method are presented for detecting end-of-life conditions of fluorescent lamps in which a ballast output is controlled according to a dimming input when a DC voltage or current of the lamp is in a predefined range or when the AC lamp current is below a predefined threshold, and the output is reduced to an EOL protection level when the lamp DC voltage or current is outside the predefined range and the AC lamp current is above the predefined threshold.

Abstract: A circuit for protecting an electronic ballast for use with a remote controller for gas discharge lamps against miswiring to a power source. Depletion mode MOSFETS are employed in both sides of the circuit to the controller and the MOSFETS respond to overvoltage, including polarity reversal to create an open circuit condition in the circuit to the controller.

Abstract: A communications apparatus and techniques are presented for communicating with ballasts or drivers through lighting system power connections in which the power connections are energized with low levels of power to power communications components in the ballast/drivers while the light sources are off and low frequency AC communications signals are transmitted through the power connections.

Abstract: Light e power circuits and EMI filters therefor are presented in which a depletion mode field effect transistor is connected in series with an EMI filter capacitor following an input rectifier to allow filtering of EMI and to limit capacitive currents during triac switching when powered through a phase-cutting dimmer circuit.

Abstract: Drivers and ballast circuits are presented having a boost converter with a triac compatibility circuit providing regulated current load to accommodate phase-cutting triac circuit holding current requirements, including auto switching driver circuit with overvoltage protection and an auto leveling circuit to regulate against thermal and load fluctuations.

Abstract: An LED driver is presented with a sensing circuit and attenuator circuits to provide three-way switched dimming as well as phase-cut dimming to control the output power driving an LED load.

Abstract: A LED driver circuit and an isolated DC-DC converter therefor are presented, in which a primary side state estimator circuit is provided for inferred output current sensing for closed loop control of pulse width modulated flyback or buck converters.

Abstract: Light sources are presented in which lamp ballast or LED driver circuitry is disposed within a base assembly using integrated boards with components embedded between board layers and or circular flex boards with pot core magnetic components and/or ASICs and thermally conductive board core materials with thermal vias, reflective mirrors, and/or potting materials to conduct heat out through the base to facilitate reduced form factors for lamps and/or LED light sources.

Abstract: A ballast and method are presented for detecting end-of-life conditions of fluorescent lamps in which a ballast output is controlled according to a dimming input when a DC voltage or current of the lamp is in a predefined range or when the AC lamp current is below a predefined threshold, and the output is reduced to an EOL protection level when the lamp DC voltage or current is outside the predefined range and the AC lamp current is above the predefined threshold.