Abstract: Systems and methods to generate drive current in a power supply, independent of the input voltage, are provided. The power supply includes front end circuitry, control circuitry, and drive circuitry. The front end circuitry includes protection circuitry to defend against damage from EMI, voltage spikes, and the like. The control circuitry includes startup circuitry, power factor correction (PFC) circuitry, and output power configuration circuitry. The startup circuitry provides operational voltage to the PFC circuitry, derived from an input voltage, until an internally generated operational voltage becomes available. The PFC circuitry uses the operational voltage to generate output power for the drive circuitry based on the output power configuration circuitry. The drive circuitry includes drive current configuration circuitry to generate a drive current to drive a load, coupled to the power supply, independent of the input voltage.

Abstract: Systems and methods to generate drive current in a power supply, independent of the input voltage, are provided. The power supply includes front end circuitry, control circuitry, and drive circuitry. The front end circuitry includes protection circuitry to defend against damage from EMI, voltage spikes, and the like. The control circuitry includes startup circuitry, power factor correction (PFC) circuitry, and output power configuration circuitry. The startup circuitry provides operational voltage to the PFC circuitry, derived from an input voltage, until an internally generated operational voltage becomes available. The PFC circuitry uses the operational voltage to generate output power for the drive circuitry based on the output power configuration circuitry. The drive circuitry includes drive current configuration circuitry to generate a drive current to drive a load, coupled to the power supply, independent of the input voltage.

Abstract: A power supply circuit and method for supplying power are provided. The power supply circuit includes a front end circuit, a power factor correction circuit, and a drive circuit. The front end circuit is configured to generate a direct current voltage based on an input voltage. The front end circuit includes a first surge protection circuit. The power factor correction circuit is configured to generate a driving voltage based on the generated direct current voltage. The power factor correction circuit includes a second surge protection circuit and an over-temperature protection circuit. The drive circuit is configured to generate an output voltage for a load based on the driving voltage. The drive circuit includes a third surge protection circuit, a startup circuit, and an open-circuit protection circuit.

Abstract: A power supply circuit and method for supplying power are provided. The power supply circuit includes a front end circuit, a power factor correction circuit, and a drive circuit. The front end circuit is configured to generate a direct current voltage based on an input voltage. The front end circuit includes a first surge protection circuit. The power factor correction circuit is configured to generate a driving voltage based on the generated direct current voltage. The power factor correction circuit includes a second surge protection circuit and an over-temperature protection circuit. The drive circuit is configured to generate an output voltage for a load based on the driving voltage. The drive circuit includes a third surge protection circuit, a startup circuit, and an open-circuit protection circuit.

Abstract: A driver circuit for a dimmable solid state light source, and devices such as lamps and fixtures incorporating the same, and methods of driving such sources, are provided. A supply voltage circuit provides a supply voltage to a power factor controller circuit, such that the supply voltage is maintained within the high end of a nominal supply voltage operating range of the power factor controller circuit. The driver may also include an open circuit protection circuit for disabling the power factor controller circuit when an open circuit occurs in the load, and/or protection against electromagnetic interference (EMI).

Abstract: A driver circuit for a lamp assembly including one or more solid state light sources is provided. The driver circuit includes filtering and power factor correction with protective isolation. The driver circuit includes a transformer with electrically isolated windings and a power factor correction circuit that receives no feedback from a secondary winding of the transformer.

Abstract: A driver circuit, solid state light (SSL) source assembly including same, and a method of driving an SSL source are provided. The driver circuit includes a rectifier, an inverter, a transformer, a PFC circuit, and a frequency control. The rectifier receives an AC voltage and provides an unregulated DC voltage. The inverter includes two switches, and receives respective control signals to operate these, to generate a resonate AC signal from the unregulated DC voltage. The transformer includes a primary winding coupled to the inverter, a secondary winding to be coupled to an SSL source through an output stage, and a feedback winding. The PFC circuit controls the inverter in response to signals representative of the unregulated DC voltage and the inverter's current. The frequency control generates the control signals to control the inverter's switching frequency in response to signals representative of the output stage's current and the feedback winding's current.

Abstract: A ballast circuit for a light emitting diode (LED) based lamp including power factor correction with protective isolation. The circuit includes a transformer with electrically isolated windings and a power factor correction circuit that receives no feedback from a secondary winding side of the transformer. An LED-based lamp assembly and a method of driving an LED-based light source are also provided.

Abstract: A driver circuit for a dimmable solid state light source, and devices such as lamps and fixtures incorporating the same, and methods of driving such sources, are provided. A supply voltage circuit provides a supply voltage to a power factor controller circuit, such that the supply voltage is maintained within the high end of a nominal supply voltage operating range of the power factor controller circuit. The driver may also include an open circuit protection circuit for disabling the power factor controller circuit when an open circuit occurs in the load, and/or protection against electromagnetic interference (EMI).

Abstract: A ballast circuit for a light emitting diode (LED) based lamp including power factor correction with protective isolation. The circuit includes a transformer with electrically isolated windings and a power factor correction circuit that receives no feedback from a secondary winding side of the transformer. An LED-based lamp assembly and a method of driving an LED-based light source are also provided.

Abstract: A driver circuit, solid state light (SSL) source assembly including same, and a method of driving an SSL source are provided. The driver circuit includes a rectifier, an inverter, a transformer, a PFC circuit, and a frequency control. The rectifier receives an AC voltage and provides an unregulated DC voltage. The inverter includes two switches, and receives respective control signals to operate these, to generate a resonate AC signal from the unregulated DC voltage. The transformer includes a primary winding coupled to the inverter, a secondary winding to be coupled to an SSL source through an output stage, and a feedback winding. The PFC circuit controls the inverter in response to signals representative of the unregulated DC voltage and the inverter's current. The frequency control generates the control signals to control the inverter's switching frequency in response to signals representative of the output stage's current and the feedback winding's current.

Abstract: A transient voltage protection circuit that protects a load from transient voltages is disclosed. The circuit includes a series combination of a thyristor surge protection device (TSPD), a resistor and a transorb coupled for coupling in parallel with the load, and a fuse coupled between an AC input and the series combination. The TSPD and the transorb are configured to enter a transient mode upon application of a transient voltage to the circuit to shunt current from the load and provide an AC output voltage to the load less than the transient voltage without opening the fuse.

Abstract: A power converter and power conversion method converts an input AC signal to a voltage usable by a load while reducing power consumption, thereby making the converter and method suitable for a wider range of applications. A rectifier receives the AC input signal and outputs a rectified voltage Vs, a controller has a power input connected to Vs and outputs two out-of-phase signals, two transistors are connected in series between Vs and a ground and each of the two transistors has a gate connected to a respective one of the two out-of-phase signals, and a transformer that has a primary coil connected to a node between the two transistors and a secondary coil connected to a load feeds back current from the secondary coil to the power input of the controller to reduce power consumption.

Abstract: A ballast circuit for a light emitting diode (LED) based lamp including power factor correction with protective isolation. The circuit includes a transformer with electrically isolated windings and a power factor correction circuit that receives no feedback from a secondary winding side of the transformer. An LED-based lamp assembly and a method of driving an LED-based light source are also provided.

Abstract: A transient voltage protection circuit that protects a load from transient voltages is disclosed. The circuit includes a series combination of a thyristor surge protection device (TSPD), a resistor and a transorb coupled for coupling in parallel with the load, and a fuse coupled between an AC input and the series combination. The TSPD and the transorb are configured to enter a transient mode upon application of a transient voltage to the circuit to shunt current from the load and provide an AC output voltage to the load less than the transient voltage without opening the fuse.

Abstract: A bias circuit for a switching power supply includes a rectifier that is connected to an AC power source and outputs a full wave rectified voltage Vs; a voltage divider, a diode, a first transistor, and a second transistor connected in parallel between Vs and ground; a capacitor connected between a first terminal of the second transistor and ground; and a node between the capacitor and the first terminal of the second transistor providing an output bias voltage Vcc from the bias circuit. A voltage from the voltage divider is provided to a gate of the first transistor, and the diode and a first terminal of the first transistor are connected to a gate of the second transistor.

Abstract: A power converter and power conversion method converts an input AC signal to a voltage usable by a load while reducing power consumption, thereby making the converter and method suitable for a wider range of applications. A rectifier receives the AC input signal and outputs a rectified voltage Vs, a controller has a power input connected to Vs and outputs two out-of-phase signals, two transistors are connected in series between Vs and a ground and each of the two transistors has a gate connected to a respective one of the two out-of-phase signals, and a transformer that has a primary coil connected to a node between the two transistors and a secondary coil connected to a load feeds back current from the secondary coil to the power input of the controller to reduce power consumption.

Abstract: A bias circuit for a switching power supply includes a rectifier that is connected to an AC power source and outputs a full wave rectified voltage Vs; a voltage divider, a diode, a first transistor, and a second transistor connected in parallel between Vs and ground; a capacitor connected between a first terminal of the second transistor and ground; and a node between the capacitor and the first terminal of the second transistor providing an output bias voltage Vcc from the bias circuit. A voltage from the voltage divider is provided to a gate of the first transistor, and the diode and a first terminal of the first transistor are connected to a gate of the second transistor.

Abstract: An improved area monitor for detecting gas concentration is provided that requires a very infrequent calibration, and works reliably in detecting a particular target gas using only two semiconductor sensors. One of these sensors will exhibit a drift that is constantly monitored and automatically compensated for, while the other sensor exhibits a stable, repeatable response over very long periods of time. Once the "stable" has been initially calibrated, the concentration of the target gas can be discerned directly from the resistance of this sensor, although more that one particular chemical gas may cause the stable sensor to change resistance. The second sensor is then used to discern whether or not the change in resistance of the stable sensor was due to the actual target chemical, or due to some other similar chemical. The second sensor is selected to be of a type that responds in one direction (i.e.

Abstract: Cartridge (1) contains memory (40a-40h) and a back-up battery (13). Terminals (5a-5i) of the cartridge (1) plug into termnals (7a-7i) of a host machine (3). Positive deactivation of the write control is achieved by both the base and emitter of a bipolar transistor (52) being deactivated when the cartridge (1) is unplugged. Battery voltage then appears at read/write control line (64) through resistor (56) connected to the collector of the transistor (52). This brings the control line (64) to the read status and positively protects data in memory (40a-40h) against transient signals, which may occur especially during plug in when the host (3) is activated, or from electrostatic charges.