摘要:
An electronic ballast has control circuitry to provide a pre-heating signal to the filaments of a gas discharge lamp for a predetermined length of time before the lamp is ignited and, further, cease providing the pre-heating signal after the lamp has been ignited.
摘要:
An electronic ballast has control circuitry to operate a gas discharge lamp in both full and dimmed illumination modes. A dimming controller serves as the mechanism to permit a selection between full and dimmed illumination modes. The dimming controller signal has a dimming request range which describes the range of dimming controller signal magnitudes. The electronic ballast also includes a full power circuit having a power control coupled to the dimming controller output to receive the dimming controller signal. The full power circuit also has a full power output that can couple to the lamp. When the full power circuit receives the dimming controller signal, via the power control, and the dimming controller signal is not in the dimming request range (i.e. the full illumination mode has been selected), the full power circuit generates a full power signal capable of driving/operating the lamp(s) in the full illumination mode. A filament heating circuit has a heating input coupled to the reduced power circuit, to receive the reduced power signal, and a heating output that can couple to the filaments of one or more lamps. When the reduced power signal is present, the filament heating circuit generates and provides a filament heating signal to the filaments, via the heating output. The filament heating signal maintains the temperature of the filaments when the lamp(s) are operated in the dimmed illumination mode. Further, the filament heating signal is responsive to the reduced power signal.
摘要:
An arc protection circuit is provided for a current-fed, parallel-resonant inverter ballast, the circuit having a lamp signal sensing circuit coupled across one or more lamps and designed to detect a signal through the lamps, a shutdown circuit coupled to the sensing circuit and operable to disable the ballast in response to a disturbance such as an arc in the detected signal, at least a portion of the shutdown circuit defining a first time delay from detection of the disturbance in the signal during which the ballast operates normally, and after which the ballast may be disabled in response to the disturbance; and an automatic restart circuit coupled to the shutdown circuit and operable to enable restarting of the ballast, at least a portion of the restart circuit defining a second time delay during which the ballast remains disabled, after which the ballast may be restarted.
摘要:
A constant current source mirror tank dimmable ballast operates multiple high impedance lamps in a stable and balanced manner. The dimmable ballast has an inverter connected to two third-order resonant circuits. These third-order resonant circuits dominate the transfer function of the ballast circuits. Consequently, changes in the impedance of the lamp do not affect the current output to the lamps.
摘要:
A step dimming interface is utilized to operate a load such as a gas discharge lamp. The dimming interface has first and second switches for determining when the gas discharge lamp operates at either a normal power level or a dimming power level. A rectifier circuit is connected to a control signal production circuit. By manipulating the first and second switches, the rectifier sends either a full-wave rectified signal or a half-wave rectified signal to the control signal production circuit which determines the output of the control signal production circuit. The control signal production circuit may be connected to an electronic ballast which varies the power level of the lamp according to this output.
摘要:
The present invention is an overvoltage protection and automatic re-strike circuit for an electronic ballast. The electronic ballast has an inverter, a shut-down circuit, a safety circuit, a monitoring circuit, and an overvoltage protection circuit. The inverter provides an appropriate alternating current power supply to operate the lamp. The shut-down, safety, monitoring, and overvoltage protection circuits are coupled to the inverter and provide the overvoltage protection and automatic re-striking functions. During an overvoltage condition, the overvoltage protection circuit will temporarily disable the inverter. Subsequent to the overvoltage condition, the overvoltage protection circuit permits the inverter to attempt to re-ignite the lamp. After a predetermined number of unsuccessful re-ignition attempts, the safety circuit will permanently disable the inverter to avoid damage to the ballast.
摘要:
An electronic ballast for fluorescent lighting includes an inverter circuit having an output circuit coupled to a pair of lamp terminals. A protection circuit is coupled to one of the lamp terminals. The protection circuit includes a differential voltage sensing circuit that is functional to sense the lamp voltage pulses as sudden changes in voltage across a DC blocking capacitor and, in response, to provide a positive AC voltage pulse. A pulse accumulation circuit is coupled to the differential voltage sensing circuit. The pulse accumulation circuit is responsive to the positive AC voltage pulses from the differential voltage sensing circuit to accumulate the positive AC voltage pulses into the ballast shutdown signal.
摘要:
An electronic ballast circuit includes a striation reduction circuit that can create an asymmetry in a lamp power signal that powers a gas-discharge lamp. The striation reduction circuit may have first and second circuit paths to cause the asymmetry in the lamp power signal. The first circuit path transmits the AC component signal of an input signal associated with an AC voltage while the second circuit path transmits a DC component signal. A non-linear component in the second circuit path is utilized to generate a harmonic component signal. AC component signal, DC component signal, and harmonic component signal are superimposed onto one another to cause an asymmetry in the lamp power signal that powers the gas discharge lamp.
摘要:
An electronic ballast has control circuitry to operate a gas discharge lamp in both full and dimmed illumination modes. The electronic ballast also includes a full power circuit having a power control coupled to the dimming controller output to receive the dimming controller signal, a filament heating circuit having a heating input coupled to a reduced power circuit to receive a reduced power signal and a heating output that can couple to the filaments of one or more lamps. When the full power circuit receives the dimming controller signal, via the power control, and the dimming controller signal is not in the dimming request range (i.e. the full illumination mode has been selected), the full power circuit generates a full power signal capable of driving/operating the lamp(s) in the full illumination mode. When the reduced power signal is present, the filament heating circuit generates and provides a filament heating signal to the filaments, via the heating output.
摘要:
A transformer apparatus provides a primary winding and a secondary winding. The primary winding is divided into multiple primary winding layers. Each primary winding layer includes a number of primary layer turns. The secondary winding includes several secondary winding layers. In some embodiments, the transformer includes alternating primary and secondary winding layers wound around a bobbin structure. At least one secondary winding layer is positioned adjacent a primary winding layer. In some embodiments, the number of primary layer turns in each primary winding layer is equal to the total number of primary winding turns divided by the number of primary winding layers. A method of winding a transformer is also provided.