Abstract:
A multi-strike ballast to ignite an electrodeless lamp is disclosed, and includes an inverter circuit, a protection circuit, and a controller. The inverter circuit, upon activation, sends an ignition pulse to the lamp. The inverter circuit shuts down upon receiving a deactivation signal, and activates upon receiving an activation signal, triggering another ignition pulse. The protection circuit senses a change in a voltage associated with the lamp. The sensed changed may indicate that the lamp has not yet ignited or that the lamp is broken. The controller receives the sensed change in voltage and, in response, sends a deactivation signal to the inverter circuit. The controller waits a predetermined time and then sends an activation signal to the inverter circuit. The controller repeats until a change in voltage associated with the lamp is not sensed, or until a predefined number of repeats occur, providing multiple ignition pulses to the lamp.
Abstract:
A multi-strike ballast to ignite an electrodless lamp is disclosed, and includes an inverter circuit, an output voltage detection circuit (OVDC), and an inverter shutdown circuit. The inverter circuit, upon activation, sends an ignition pulse to the electrodeless lamp. The inverter circuit shut downs upon receiving a deactivation signal, and activates upon receiving an activation signal, triggering another ignition pulse. The OVDC detects an output voltage across the lamp. The inverter shutdown circuit includes a multi-strike diac and receives the detected output voltage. The multi-strike diac breaks upon the output voltage reaching a predetermined level. In response, a deactivation signal is sent to the inverter circuit. The multi-strike diac turns off upon the output voltage falling below the predetermined level. In response, an activation signal is sent to the inverter circuit, triggering a further ignition pulse. The process repeats, providing multiple ignition pulses to the lamp.
Abstract:
A multi-strike ballast to ignite an electrodless lamp is disclosed, and includes an inverter circuit, an output voltage detection circuit (OVDC), and an inverter shutdown circuit. The inverter circuit, upon activation, sends an ignition pulse to the electrodeless lamp. The inverter circuit shut downs upon receiving a deactivation signal, and activates upon receiving an activation signal, triggering another ignition pulse. The OVDC detects an output voltage across the lamp. The inverter shutdown circuit includes a multi-strike diac and receives the detected output voltage. The multi-strike diac breaks upon the output voltage reaching a predetermined level. In response, a deactivation signal is sent to the inverter circuit. The multi-strike diac turns off upon the output voltage falling below the predetermined level. In response, an activation signal is sent to the inverter circuit, triggering a further ignition pulse. The process repeats, providing multiple ignition pulses to the lamp.
Abstract:
A three light level electronic ballast, and methods of operating lamps at three light levels, are provided. The ballast includes a rectifier, a power factor correction circuit, an inverter circuit, a first circuit, a second circuit, and a control circuit. The rectifier receives an AC voltage signal and produces a rectified voltage signal, which the power factor correction circuit receives and uses to provide a corrected voltage signal. The inverter circuit receives the corrected voltage signal and provides an energizing signal to power at least two lamps. The first circuit selectively reduces the current applied to the lamps by the energizing signal. The second circuit selectively prevents the second lamp from being energized by the energizing signal. The control circuit controls the first circuit and the second circuit.
Abstract:
A electrodeless lamp including a fluorescent discharge vessel, a tip, an amalgam, a lamp core, and a heater. The vessel contains a gas having a partial vapor pressure and a fluorescent material. The tip has an inner end engaging the vessel, and an opening in communication with the gas. The amalgam is positioned within the opening, in heat transfer relation with the tip. When the temperature of the amalgam decreases, mercury vapor in the gas condensates onto the amalgam, causing a decrease in the partial vapor pressure of the gas. The opposite occurs when the amalgam temperature increases. The lamp core generates a magnetic flux, causing an electrical discharge in the gas. The heater includes a positive temperature coefficient connected to a winding of the lamp core. The heater is in heat transfer relation with the tip and heats the tip when the electrodeless lamp is in a dimming mode.
Abstract:
A ballast for dimming a lamp is provided. The ballast includes an inverter circuit for providing a lamp current for energizing the lamp and a dim interface for receiving an input indicative of a selected lighting level. A control circuit is connected to the dim interface for generating a pulse-width-modulated signal having a duty cycle corresponding to the selected lighting level. A switching network is connected to the control circuit for receiving the pulse-width-modulated signal. The switching network operates between a conductive state and a non-conductive state as a function of the pulse-width-modulated signal. An impedance device is connected across the switching network and is configured for connecting in series with the lamp so that the impedance device receives the lamp current when the switching network is operating in the non-conductive state and the lamp current bypasses the capacitor when the switching network is operating in the conductive state.
Abstract:
A lamp driver circuit to selectively energize one or more lamps is provided. The inverter circuit has a transformer with primary and secondary windings to provide voltage to the lamps. A filter is connected to the primary winding to receive a primary winding signal representative of the voltage across the primary winding. The primary winding signal has a frequency spectrum and the filter detects a particular characteristic of the frequency spectrum that is indicative of an end of life (EOL) condition of the one or more lamps. A control circuit is connected to the inverter circuit and to the filter. The control circuit is configured to discontinue energizing of the one or more lamps by the inverter circuit when the particular characteristic of the frequency spectrum of the primary winding signal is detected by the filter.
Abstract:
A ballast to energize a lamp at a selected lighting level is provided. The ballast includes a rectifier, a buck converter, and a controller. The rectifier produces a DC voltage with a substantially constant magnitude. The buck converter generates a lamp voltage output from the DC voltage based on a duty cycle. The output has a magnitude that is varied based on the duty cycle to energize the lamp at a selected lighting level. The controller receives a dim input signal indicating the selected lighting level, and provides an appropriate control signal to the buck converter. The appropriate control signal indicates a particular duty cycle corresponding to magnitude of the output to produce the selected lighting level. In response to receiving the control signal, the buck converter adjusts the duty cycle accordingly, producing the output having the magnitude to energize the lamp at the selected lighting level.
Abstract:
A bi-level lamp ballast to selectively operate two lamps is provided. The ballast includes a control circuit having an input, connected to a switching network, and an output, which provides a particular control signal based on the state of the switching network. The ballast also includes respective lamp control switches, each having respective outputs. The first switch is connected to the output and a ballast power supply. In its first state, it connects the ballast power supply to its first output, and in its second state, it connects the ballast power supply to its second output. The second switch is connected to the output and a ground. In its first state, it connects the ground to its first output, and in its second state, it connects the ground to its second output. The state of each lamp control switch depends on the control signal generated by the control circuit.
Abstract:
A lighting system converter circuit of a lamp power converter to selectively operate a plurality of lamps connected thereto is provided. The lighting system converter circuit includes a first impedance circuit and a second impedance circuit. Each impedance circuit includes an input terminal, an impedance component, and a switching network. The impedance components are each configured to connect in series with the lamps. Each input terminal is configured to receive a control signal that indicates a state of a switch. Each control signal has a first logic level, indicating the switch is non-conductive, and a second logic level, indicating the switch is conductive. Each switching network is connected to its respective input terminal and in parallel with its respective impedance component, and is configured to selectively operate between a conductive state and a non-conductive state, as a function of the logic level of its respective control signal.