Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
  • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters
  • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices
  • H05B41/2825—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices by means of a bridge converter in the final stage
  • H05B41/2828—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices by means of a bridge converter in the final stage using control circuits for the switching elements
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
  • H05B41/14—Circuit arrangements
  • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
  • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters

Definitions

• a gas discharge lamp is one example of what is known as a "negative resistance" device, which is a device that is capable of drawing an increasing amount of current until it either burns out the power source or itself.
• a ballast may be as simple as resistor in series with a lamp, such as is utilized for the relatively low- powered neon lamp. More complex ballasts may be utilized for higher power applications, and may comprise resonant components such as capacitor and inductors. Typically, a reactive ballast is more efficient than a simple resistor.
• Electronic ballasts utilize electronic circuitry to stabilize current for fluorescent lamps, high-intensity discharge lamps, and the like.
• Electronic ballasts may be started using one of several starting techniques, including “instant” start, “rapid” start, and “programmed” start.
• the instant start starts a lamp in the short term, because it starts and operates the ballast without preheating a cathode associated therewith, which results in low energy cost to start but wears out the lamp more rapidly than other starting protocols due to the violent nature of the starting method.
• the rapid starting technique starts the ballast and heats the cathode concurrently, resulting in a relatively long start time while mitigating the deleterious effects of a cold start on the lamp's cathode.
• the programmed start technique employs a cathode preheating period at low glow discharge current which increases the lamp's life for frequency switching applications.
• a lamp and/or ballast may be designed to minimize power losses as well as to effectively minimize power consumed by the lamp and/or ballast.
• manufacturing cost it may be desirable to minimize a number of circuit components needed to perform a given function, as well as to design circuits such that perform a given function using a number of least-expensive parts and to avoid costly components such as integrated circuits and the like.
• ballast size it may be desirable to design a circuit that occupies as little space as possible to perform the given function in order to facilitate utilization of the ballast in applications where space conservation is an issue.
• a system that facilitates automated shutdown and restart of a ballast circuit for a lamp comprises a capacitor positioned in a parallel orientation to a base drive winding for a first transistor in an inverter circuit, a control line coupled to a voltage source that supplies a voltage to the ballast, and a switch in the control line that is manipulated to concurrently disable inverter oscillation and supply voltage to a trigger circuit coupled to the inverter.
• a method of automatically shutting down and restarting a ballast circuit for a lamp comprises employing a capacitor in parallel with a base drive winding for a bipolar junction transistor (BJT) in an inverter circuit, employing a control line with a switch from a voltage source to a trigger circuit coupled to the inverter circuit, and selectively closing the switch to supply a voltage to the trigger circuit and shut down the inverter circuit.
• BJT bipolar junction transistor
• a system that facilitates selectively shutting down and restarting an inverter in a ballast circuit for a lamp comprises means for providing a control signal to a trigger circuit coupled to an inverter in the ballast circuit, means for placing a capacitor in parallel with a base drive winding of a transistor in the inverter to shut down the inverter when a switch in the control line is closed, and means for placing the inverter in an oscillatory state when the switch is open.
• FIGURE 1 illustrates a schematic diagram of a ballast topography, wherein the ballast permits bi-level control for a lighting system by providing a line control step-level switching mechanism for the ballast.
• FIGURE 2 is an illustration of a schematic diagram of a ballast topography, that shows an EOL shutdown protection circuit with an optocoupler for output isolation.
• FIGURE 3 illustrates a high-level ballast arrangement wherein a plurality of inverters are coupled to a single power factor correction (PFC) circuit in order to reduce manufacturing cost, energy consumption, and device size, in accordance with one or more features described herein.
• PFC power factor correction
• FIGURE 4 illustrates a method for performing control line step switching for a lamp ballast, in accordance with various aspects.
• FIGURE 5 illustrates a method for employing a capacitor in parallel with a BJT device in an inverter portion of a ballast circuit, such that the parallel capacitor and the BJT permit the inverter to oscillate during an active phase.
• aspects and features described herein may comprise reducing load power consumption by, for example, turning off one or more lamps associated with a given lamp ballast circuit and/or dimming a given lamp's power level to reduce power consumption.
• a control point may be inserted into a lamp ballast circuit, such as by connecting a switch to a hot or neutral power line.
• the electronic ballast may be a trigger-start self-oscillating electronic ballast, and may be controlled using a few passive components and an active switcher without integrated circuits, if desired, even if the device to be controlled is a floating gate device.
• the electronic ballast may be a trigger-start self-oscillating electronic ballast, and may be controlled using a few passive components and an active switcher without integrated circuits, if desired, even if the device to be controlled is a floating gate device.
• inverter oscillation and the trigger circuit may be concurrently controlled. Accordingly, repetitive triggering may be mitigated after the ballast is shut down.
• a similar and/or identical control technique can be used for an end of lamp's life (EOL) protection circuit.
• Bi-level control has become popular for high-intensity discharge (HID) lamp systems due to its simplicity and cost-efficiency. This control has also gained popularity for fluorescent discharge lighting systems with electronic ballasts due to high energy savings at low cost.
• a current-fed self-oscillating program start ballast is described, such as may be utilized in a T5 lamp application, and is designed in a manner that mitigates problems associated with conventional integrated circuit (IC) controlled ballasts, which tend to be expensive. Additionally, IC driven ballasts tend to be less robust to operating conditions of the lighting system, and are therefore subject to higher failure rates that non-IC driven ballasts.
• ballast when a connection is made from a switching line to a neutral line, a signal is fed to a ballast control IC.
• the ballast responds to the signal by disabling the output of the control IC which, in turn, shuts down the lamps that are controlled by the IC.
• ballast 100 permits bi-level control for a lighting system by providing a line control step-level switching mechanism for the ballast 100.
• ballast 100 may facilitate lamp shut-off.
• the ballast 100 may be utilized in conjunction with a T5 discharge lamp, as well as other size discharge lamps, including but not limited to T8, T4, T3, T2, or any other size lamp in which line control step-level switching is desired.
• the ballast 100 comprises an input and power factor control (PFC) portion 102 comprising a first set of components, and an inverter portion 104.
• the input-PFC portion 102 includes a full-bridge rectifier (D1-D4), inductor Ll, diode D5, capacitors Cl, C2, C3, and switch Ql.
• the inverter portion 104 includes switching portions (Q2, R2, W2) and (Q3, R3, and Wl), as well as capacitors C4, C5, C6, inverters L2, L3, diode D6, diac D7, resistor R4, and winding Tl.
• the PFC 102 and inverter 104 are coupled by a switching line 106 that facilitates triggering a shutdown/restart mechanism in accordance with various aspects.
• a switch 108 in switching line 106 may be triggered by a remote sensor (not shown), such as a motion sensor or the like, which detects a presence or absence of an occupant in an area that is illuminated by one or more lamps associated with ballast 100.
• a remote sensor such as a motion sensor or the like
• the switch 108 may be in an open state to permit the ballast to operate normally.
• the switch 108 may be triggered to close, resulting in an initiation of the aforementioned events.
• capacitor C5 is charged up by resistor R4.
• a voltage across C5 reaches a breakdown voltage of diac D7
• a high di/dt current is applied to the base drive winding Wl to initiate inverter oscillation.
• a diode D6 discharges the capacitor C5 when Q3 is on.
• Q3 may be a bipolar junction transistor (BJT).
• a low-voltage MOSFET Q4 is connected in parallel with diac D7.
• Zener diode D8, resistor R5 and capacitor C7 are in parallel and connected from gate to source of Q4.
• a resistor Rl is connected to one end of the switching line 106, and the other end of the switching line 106 is connected either to a "Neutral" or a "Hot" input line.
• the switch 108 in the switching line 106 When the switch 108 in the switching line 106 is in an "off position (e.g., the switch 108 is open), there is no voltage developed across the Q4 gate-to-source of a trigger circuit 110. Therefore, the Q4 switch is the off position, and the current- fed inverter 104 is in a normal operating condition.
• the switching line 106 When the switching line 106 is on (or off in a case where reverse logic is utilized), the half-rectified input voltage will be scaled down and the averaged voltage is applied to the gate-to-source of the switch Q4. This voltage turns on Q4 and puts the capacitor C5 in parallel with winding Wl and resistor R3. The capacitor C5 effectively bypasses the base drive current away from Q3, and the inverter oscillation stops.
• the switch Q4 prevents a voltage build up on the capacitor C5 from startup resistor R4.
• the Q4 gate-to-source voltage drops and Q4 turns off, and allow the C5 to charge by R4 at which point, the breakdown of the diode D7, the inverter restarts and ballast operation resumes.
• the PFC section 102 upon applying power to the ballast 100 (e.g., turning on a light switch connected thereto), the PFC section 102 is operational. Current traversing the resistor R4 charges up capacitor C5. Once the voltage on capacitor C5 reaches a breakdown point of diac D7, the diac D7 breaks down and a high current (di/dt) is applied to the base of Q3, which turns on Q3. During a subsequent half-cycle of an applied voltage waveform, Q2 turns on and Q3 turns off. This sequence may repeat every half cycle with switches Q2 and Q3 alternating respective on and off states. Whenever switch Q3 turns on, capacitor C5 begins to discharge because D6 is conducting. However, when switch Q3 turns off the capacitor C5 is charging.
• capacitor C5 Because the time constant associated with capacitor C5 is longer than the half-cycle period for which switch Q3 is in the off state, the voltage on C5 does not reach the breakdown voltage of the diac D7. By positioning capacitor C5 in parallel with the base drive winding Wl of Q3, current through the base of Q3 is reduced, thereby turning Q3 off and shutting down its portion of the circuit, and thus the ballast 100 shuts down as well.
• FIGURE 2 is an illustration of a schematic diagram of a ballast 200 topography, which may be similar to the ballast topography 100 described above, and which shows an EOL shutdown protection circuit inverter 202 with an optocoupler 204 for output isolation.
• the ballast 200 represents an example of an end-of-lamp-life (EOL) protection circuit that may be utilized in conjunction with the various features described herein.
• EOL end-of-lamp-life
• an EOL pin associated with a controller Upon relamping, an EOL pin associated with a controller (MC) outputs a low signal (e.g., such as a binary 0 in terms of digital logic), the ballast restarts, and normal operation resumes.
• a low signal e.g., such as a binary 0 in terms of digital logic
• the ballast restarts, and normal operation resumes.
• the capacitor C5 is oriented in the same parallel configuration described above with regard to Figure 1, and functions similarly.
• ballast 200 may be shut off and restarted as desired to mitigate re-triggering events that may overheat the ballast and/or lamp couplings.
• FIGURE 3 illustrates a high-level ballast 300 arrangement wherein a plurality of inverters are coupled to a single power factor correction (PFC) circuit in order to reduce manufacturing cost, energy consumption, and device size, in accordance with one or more features described herein.
• Ballast 300 comprises a voltage source 302 that is operatively coupled to the PFC circuit 304, which in turn is operatively associated with a plurality of inverter circuits 306 A -306 N (collectively referred to as inverters 306), where N is an integer.
• Inverters 306 are connected to PFC 304 via connection 312, which may represent one or more physical wire connections between PFC 304 and a given inverter 306, such as described above with regard to the single inverter-PFC ballast designs of the preceding figures. Additionally, each inverter 306 is connected to PFC 304 by a respective switching line 308 with a switch 310 (both labeled A-N, where N is an integer, and corresponding to respective inverters 306 A -306 N ). Each switch 310 may be triggered by a signal from a remote sensor (not shown), such as a motion sensor that senses the presence or absence of an occupant in an area illuminated by one or more lamps (not shown) associated with each inverter 306.
• a remote sensor not shown
• a motion sensor that senses the presence or absence of an occupant in an area illuminated by one or more lamps (not shown) associated with each inverter 306.
• PFC circuit 304 may be operatively associated with four inverters 306, each of which may in turn be connected to two lamps.
• Each switch 310 may receive a signal from an independent source (e.g., a sensor), from a common source, or from some permutation thereof.
• switches 310 for two of the inverters 306 may be coupled to a common source or sensor, while switches for the other two of the inverters each have an independent source, for a total of three sources providing switching signals to the four inverters' switches 310. It will be appreciated that other combinations of sensor-to-switch connections are possible, and that the subject features are not limited to the foregoing example.
• the switch 310 may be desirable to close the switch 310 for that inverter 306 to cause the ballast, and thus the associated lamps to shut down in order to conserve energy.
• the indication of the absence of an occupant may be an absence of a signal from a motion sensor.
• a switch 310 may remain open so long as a signal from a motion sensor associated with the switch is detected, and may close when the signal is no longer detected. Closing of the switch 310 may trigger the events described above with regard to Figure 1.
• FIGURE 4 illustrates a method 400 for performing control line step switching for a lamp ballast, in accordance with various aspects.
• a switch may be closed in a control signal line that connects a power-factor control (PFC) portion of a ballast to an inverter portion of the ballast.
• Closing of the switch may be designed to occur upon the occurrence of a predefined event.
• the predefined event may be the cessation of a signal from a remote sensor, such that when a condition that causes the remote sensor signal ceases to be present, the remote sensor signal ceases, causing the switch to close.
• the remote sensor may be a motion sensor that detects the presence of an occupant in a space illuminated by a lamp associated with the inverter.
• the motion sensor will relay the signal and the control line switch may remain open.
• the signal will cease and the switch may close.
• a simple logic inverter may be placed between the remote sensor and the switch, such that the detection of an occupant may be perceived by the switch as an absence of a signal, a "low” signal (e.g., a zero-bit in binary), or the like, and the departure of the occupant from the monitored space be perceived by the switch as a "high” signal (e.g., and inverted low signal in this example).
• "Low” and “high” as used herein may relate to binary Os and Is, respectively, and may additionally or alternatively describe voltage and/or current amplitudes at which a respective signal is relayed form the sensor to the switch.
• the closing of the switch causes a voltage to be applied to a gate-to- source portion of a MOSFET device connected between the switching line and the inverter, which places a capacitor in parallel with a base drive winding for a base junction of a BJT in the inverter circuit, such as is described above with regard to Figure 1.
• the capacitor may draw current away from the base drive winding, which in turn causes the inverter to shut down (e.g., inverter oscillation stops).
• the switch may be opened again (e.g., due to a detected presence of an occupant, according to the above example). The opening of the switch causes the gate-to-source voltage at the MOSFET to drop, causing the inverter to restart, at 408.
• FIGURE 5 illustrates a method 500 for employing a capacitor in parallel with a BJT device in an inverter portion of a ballast circuit, such that the parallel capacitor and the BJT permit the inverter to oscillate during an active phase.
• power may be applied to a lamp ballast circuit, which may comprise a power factor correction portion and an inverter portion.
• the inverter may be connected to a switching line that permits the inverter to be shut down upon closing of a switch in the switching line, as described above.
• the parallel capacitor When the inverter is on, the parallel capacitor may be permitted to charge until a breakdown voltage for a diac between the parallel capacitor and the BJT is reached, at which point the diac will pass current to the BJT and permit it to operate, at 504.
• the BJT may be, for example, component Q3 described above with regard to Figure 1.
• the parallel capacitor may be permitted to discharge while the Q3 BJT is on, which may be a period associated with a first half-cycle of a high-frequency waveform reaching Q3.
• Q3 may be turned off and a second BJT, such as component Q2 described above, may be turned on for the duration of the second half-cycle of the waveform, at 508.
• the parallel capacitor may be permitted to charge by resistor R4.
• Q2 may be turned off and Q3 may be turned on again, at which point the parallel capacitor begins to discharge by D6.
• the method may then revert to 506 for further iteration and oscillation of the inverter portion of the ballast.
• the inverter portion of the circuit may be maintained in an on state until a switch in a switching line is closed to turn the inverter off.

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• Circuit Arrangements For Discharge Lamps (AREA)
• Inverter Devices (AREA)
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• 2006
  • 2006-12-27 US US11/645,939 patent/US7315130B1/en not_active Expired - Fee Related
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