BACKGROUND OF THE DISCLOSURE

[0001] In recent years, the inefficiencies of conventional incandescent bulbs has lead to development of compact fluorescent lamps (CFLs), halogen lamps, LED array lighting devices, and other more efficient forms of light sources. High wattage CFL or covered CFLs, however, often suffer from slow run up of the lumen output when power is initially applied. Hybrid lamps have been proposed, including a main CFL lamp as well as an auxiliary lamp to augment the lighting provided by CFL, particularly at powerup. The secondary lamp, however, may generate heat and disrapt the operation of the CFL. Accordingly, there is a need for improved hybrid lamps which provide the advantages of CFL technology in terms of efficiency and light output, with the capability to provide supplemental lumen output at powerup while mitigating or avoiding excess thermal problems.

SUMMARY OF THE DISCLOSURE

[0002] The present disclosure provides hybrid lamp apparatus which turns the auxiliary lamp off after a time period following application of power to provide supplemental light output while the main lamp circuitry warms up and to avoid or mitigate adverse thermal effects associated with the operation of the secondary light source. The hybrid lamp includes a rectifier along with primary and secondary lamp circuits. The primary or main lamp circuit includes a compact fluorescent lamp (CFL) as well as an electronic ballast with an output coupled to provide AC output power to the compact fluorescent lamp. The auxiliary or secondary lamp circuit includes a lamp, a switching device and a control circuit. In certain embodiments, the auxiliary lamp is a halogen lamp coupled in series with the switching device between upper and lower DC bus outputs of the rectifier. In other implementations, an incandescent auxiliary lamp can be used. In some embodiments, moreover, the switching device can be a triac.

[0003] The control circuit provides a signal to the switching device to a first switching state allow current to flow in the auxiliary lamp when or shortly after AC input power is applied to the rectifier, and to thereafter turn off the auxiliary lamp a time period after the AC input power is applied to the rectifier. [0004] In certain embodiments, the auxiliary lamp on period is variable depending on the amount of time the rectifier was unpowered prior to the AC input power being applied to the rectifier. In this manner, the auxiliary lamp can be turned off quicker in conditions where the lumen output of the main light source will ramp up faster.

[0005] The control circuit in certain embodiments includes a timing circuit with one or more capacitances and the time period is determined based on the charging condition of the capacitance, such as capacitor charging or discharging times.

[0006] In certain embodiments, the control circuit includes first and second series branch circuits extending between upper and lower DC bus outputs of the rectifier. The first series circuit includes a resistance between the upper DC bus output and a first intermediate node, as well as a control switching device coupled from the intermediate node to the lower DC bus output. The second series circuit has a second resistance between the upper DC bus and a second intermediate node, a third resistance between the second intermediate node and the lower DC bus, and a capacitance in parallel with the third resistance. A zener diode is included, having an anode coupled with the control switch control terminal and a cathode terminal coupled with the second intermediate node of the second series circuit branch.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] One or more exemplary embodiments are set forth in the following detailed description and the drawings, in which:

[0008] Fig. 1 is a schematic diagram illustrating an exemplary hybrid lamp apparatus with primary and auxiliary lamp circuitry in accordance with one or more aspects of the disclosure;

[0009] Fig. 2 is a graph illustrating various exemplary waveforms in the hybrid lamp apparatus of Fig. 1 ;

[0010] Fig. 3 is a graph illustrating various exemplary auxiliary lamp on-time curves as a function of preceding device off-time for the hybrid lamp of Fig. 1 ; and

[0011] Fig. 4 is a sectional side elevation view of an exemplary hybrid lamp apparatus with a halogen auxiliary lamp axially disposed within loops of a CFL lamp. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Referring now to the drawings, like reference numerals are used to refer to like elements throughout and the various features are not necessarily drawn to scale.

[0013] Figs. 1 and 4 illustrate an exemplary hybrid lamp apparatus 100 with primary and secondary (auxiliary) lamp circuits 130 and 120, respectively. As seen in Fig. 1 , the apparatus 100 includes an input rectifier 110 including a full wave bridge formed by diodes Dl, D2, D3, and D4, providing an input connected to terminals 150a and 150b to receive AC input power from a single-phase AC source 102. The rectifier 1 10 provides a DC output creating a DC bus voltage used to power the lamp circuits 120 and 130 in certain embodiments. In other embodiments, the secondary lamp circuit 120 may be powered separately from the DC bus, such as using the line AC input power or a separate DC bus. The DC bus circuit in the illustrated example may also include one or more filter capacitors C2 coupled between the upper and lower DC bus outputs provided by the rectifier 110.

[0014] A switch SI (e.g., user-operated wall switch or other electrical switch) may be coupled in series between the hybrid lamp 100 and the AC source 102 for selective application or removal of AC power to/from the apparatus 100. In the embodiment of Fig. 4, an Edison base 150 provides a first (shell) contact 150a as well as an eyelet contact 150b with the lamp 100 receiving power via these connections from a corresponding lamp socket, and the primary and auxiliary lamps are housed within a transparent or translucent outer bulb structure 140.

[0015] The hybrid lamp apparatus 100 of Fig. 1 also includes a diode D6 with an anode coupled to the upper DC bus output of the rectifier 1 10 and a cathode coupled with the primary lamp circuit 130.

[0016] The primary lamp circuit 130 includes a compact fluorescent lamp (CFL) 132 along with an electronic ballast 134 receiving DC input power from the rectifier 110. The ballast 134 includes an inverter 136 and may also include a transformer (not shown) and provides AC output power to drive the compact fluorescent lamp 132 when or shortly after power is applied from the source 102 to the input of the rectifier 1 10, where the ballast 134 may begin operation sometime after the switch S I is closed due to startup circuitry and the rise time associated with charging the capacitor C2. [0017] The auxiliary lamp circuit 120 includes an auxiliary lamp 122 for supplementing the light output provided by the primary lamp 132, particularly during startup. Any form of auxiliary light source may be used, whether a single light or multiple lighting devices. In certain embodiments, a halogen lamp 122 is provided. In other embodiments, the auxiliary lamp 122 can be an incandescent lamp (not shown), with appropriate switched connection for powering the auxiliary lamp from a suitable AC or DC power source. In the embodiment of Fig. 4, a halogen auxiliary lamp 122 is located within loops of the primary CFL lamp 132 and is turned on by a switching device Q2 (Fig. 1) at or shortly after power is applied to the rectifier 1 10. In this regard, the initial application of power via the switch Q2 may by substantially concurrent with power being applied to the rectifier 1 10 (via closure of the switch S I) or may take a finite amount of time for response by the switch Q2 and associated triggering circuitry in the auxiliary lamp circuit 120.

[0018] Any type of switching device Q2 may be used, such as a triac as shown in Fig. 1. The device Q2 in this implementation is coupled with the rectifier 1 10 in series with the auxiliary lamp 122 between the upper and lower DC rectifier outputs, and the control terminal (gate) of the triac switch Q2 is operated by a control circuit 124. Q2 operates in a first switching state (e.g., ON when a certain positive voltage is applied between the control gate and the cathode of Q2) to allow current to flow in the auxiliary lamp 122 and Q2 is further operative in a second switching state (e.g., OFF when the control gate of Q2 is grounded via the control circuit 124) to prevent current flow ^r in the auxiliary lamp 122.

[0019] A first series circuit branch of the control circuit 124 is used to generate the control signal for operating Q2. The first circuit branch in the embodiment of Fig. I is coupled between upper and lower DC bus outputs of the rectifier 1 10 with the diode D6 connected in the upper DC circuit path between the connections of the auxiliary lamp 122 and the upper connections of the control circuit 124. The first circuit branch of the control circuit 124 includes a first resistor Rl coupled between the upper DC bus output and a first intermediate node coupled to the control gate of the triac Q2. A control switching device Ql is coupled from the first intermediate node to the lower DC bus output Ql to selectively ground the intermediate node and thus to turn Q2 off. When power is initially provided to the device 100, Ql is off (non-conductive), and the DC bus voltage provided by the rectifier 110 raises the control gate of Q2 through resistor Rl. In this manner, the auxiliary control circuit 124 provides the control signal to set the switching state of Q2 to the first switching state (ON) when or shortly after AC input power is applied to the rectifier 1 10. Ql can be any controllable switching device, such as a bipolar transistor in the embodiment of Fig. 1. Ql has a collector coupled with the resistor Rl and the gate of Q2 at the first intermediate node, as well as an emitter coupled with the lower DC bus output, along with a control terminal (base).

[0020] A second series circuit branch of the control circuit 124 extends between the upper and lower DC bus outputs of the rectifier 1 10, and includes a resistor R2 coupled between the upper DC bus output and a second intermediate node, as well as a parallel combination of a third resistor R3 and a capacitor CI coupled between the second intermediate node and the lower DC bus output. The capacitance C I can be one or more capacitive devices, coupled with one another in series and/or in parallel. A Zener diode DZl connects the two circuit branches of the control circuit 124, with an anode terminal coupled with the base of Ql and a cathode terminal coupled with the second intermediate node joining R2, R3, and CI .

[0021] As the system power is applied via switch SI, the Zener DZl will not conduct initially, and thus Ql is initially off. This allows the switch Q2 to conduct and turn on the auxiliary lamp 122 since the triac Q2 is triggered by the current through the resistor Rl from the upper DC bus connection. The application of pow er also begins charging of the capacitance C I by the current through the resistor R2. When the voltage across the capacitor C I (the second intermediate node voltage) reaches roughly the breakdown voltage of the Zener, DZl begins to conduct, thereby providing a base current to Ql . This turns Ql on (conductive), which pulls down the voltage between the gate and cathode of Q2 to around zero. The triac Q2 thus turns off the halogen lamp 122.

[0022] Referring also to Figs. 2 and 3, the control circuit 124 thus includes a timing circuit with the charging condition of CI deteraiining a time period T _L AMP between initial application of power to the rectifier 1 10 and the time when the auxiliary lamp 122 is turned off. In the illustrated embodiment, the halogen on-time is set by the values of the resistances R2 and R3, the capacitance and ESR (equivalent series resistance) of C I , and the breakdown voltage of the Zener diode DZl . Other timing circuits can be used in conjunction with halogen, incandescent or other types of secondary light sources to provide turn-off timing based on a charge state of a control circuit capacitance. In certain applications, typical desired on-times TLAMP may be in a range of about 30 seconds to about 2 minutes, depending on an expected ramp-up time for the primary lamp circuit, for instance, such that the auxiliary lamp 122 provides supplemental lumen output until the main lamp 132 is at or near rated light output, with considerations for thermal effects of the auxiliary lamp being on, with the control circuit design being tailored to a given set of these specifications.

[0023] Fig. 2 shows a graph 200 with waveform timing diagrams for various waveforms in the apparatus 100 of Fig. 1. A curve 210 shows the state of the power switch SI (ON or OFF), for an exemplary user switching pattern, and the resulting DC bus voltage waveform 220 (Vc ₂ ) is shown across the DC bus capacitor C2, which rises through rectification by the rectifier diodes D1-D4. Graph 200 also shows a voltage waveform 230 corresponding to the voltage Vci across the timing capacitor CI, which rises (beginning with the rise of the DC bus voltage Vc ₂ ) according to the associated time constant set by the control circuit resistor R2 and the capacitance value of CI to a threshold TH at which the Zener DZ1 turns on Ql (thereby turning off Q2 and the halogen lamp 122). When Vcl reaches threshold TH, the voltage of CI will be clamped slightly above TH (e.g., around TH + Vbe of Ql , around 0.7V).

[0024] Fig. 2 also shows a curve 240 representing the on/off (conductive/non- conductive) state of the switch Ql , as well as a switch state curve 250 representing the on/off (conductive/non-conductive) of the secondary lamp switch Q2. In this regard, the on condition of switch Q2 substantially represents the on-time T _L AMP of the auxiliary lamp 122 referenced to the time at which the power is applied to the apparatus 100 (e.g., when a user closes switch SI in Fig. 1), with minor variations for the rise of the DC bus voltage and operation to turn Q2 and the lamp 122 on.

[0025] The sequence shown in Fig. 2 assumes that the device 100 has been off for a lengthy period of time such that capacitor CI is completely discharged at time tO. As noted above, and as depicted in the exemplary switch sequence shown in Fig. 2, the DC bus 220 rises with switch S I being turned on (curve 210 in the 'closed' state) at time tl , and the switch Q2 (curve 250) turns on the lamp 122 substantially at tl. Thereafter, the rise time of Vci (curve 230) determines the time t2 at which the control circuit 124 turns off the auxiliary lamp 122 (when Vci reaches or exceeds the threshold TH). This sets the switching state of Q2 to the non-conductive or off state a time period TLAMPI after the AC input power is applied to the rectifier 1 10 (TLAMPI is approximately equal to t2-tl in this case).

[0026] Referring also to Fig. 3, since C I began charging at tl from a completely discharged state, the time TLAMPI is the maximum lamp on-time for the circuit, shown in Fig. 3 as time TL _A MP M _A X- Fig. 3 provides a graph 300 of auxiliary lamp on-time TLAMP as a function of preceding device off-time TOFF, including an exemplary curve 302a representing the response of the device 100 using a capacitor charging state of C I to set the time TLAMP, where the curves 302a, 302b, and 302c in this example have maximum values at TLAMP MAX- The embodiment of Fig. 1, moreover, provides a generally curvilinear relationship 302a based on capacitive charging, whereas other embodiments are possible in which a linear relationship can be provided (curve 302b) and/or where the relationship includes both linear and curvilinear portions (e.g., curve 302c), with or without a maximum value TLAMP MAX-

[0027] In the illustrated embodiment, moreover, the time period TLAMP is variable depending on the amount of time the rectifier 1 10 was unpowered prior to the AC input power being applied to the rectifier 110. This is due to the charging state of CI when power is applied. In general, if CI is completely discharged upon application of input AC power to the rectifier 1 10, the time period T _L AMP is generally TLAMP MAX, such as about 1 minute in one embodiment. Thus, if the system power is off for a long period, CI will completely discharge through R3. However, if CI is partially charged when the rectifier 1 10 turns on again, the lamp on-time T _L AMP will be less than TLAMP MAX, as shown in Fig. 2. In particular, Fig. 2 shows a discharge time TDISCHA GE for the voltage Vo across CI to fully discharge from its maximum value, in this case shown beginning at time t3 when the switch S I is opened. If the system is powered off for less than this threshold TDISCHARGE, the halogen on-time TLAMP will be less than TLAMP MAX- In the illustrated switching sequence of Fig. 2, the user waits a sufficient time TQFFI (longer than TDISCHARGE) before again closing the switch S 1 at time t4. In this case, the resulting time TLAMP2 (ending at time t5) during which the auxiliary lamp 122 is on will be equal to TLAMP MAX-

[0028] In the example of Fig. 2, the user then turns the switch SI off at t6, but waits a shorter time TQFF2 before again closing SI at t7. However, CI is not completely discharged at t7, with the capacitor voltage Vo having only reached a non-zero voltage level 233. The capacitor C I then begins charging and reaches the threshold TH at time t8 to turn off the auxiliary lamp 122, where the resulting halogen on-time T _L AMP3 (t8-t7) is less than TLAMP MAX- Thus, when the hybrid lamp apparatus 100 is turned off only for a shorter period than the threshold time TDISCHARGE, the secondary lamp 122 is not operated for as long a time, to accommodate designs in which the primary light circuit 130 has a faster lumen ramp-up as not yet having completely cooled down to the ambient temperature. This advantageously reduces or mitigates heat stress to the non-cooled components of the device 100. The example of Fig. 2 continues with the user switching off power at t9, and switching the power back on at tlO. In this situation, the capacitor voltage Vci has decreased to another non-zero level 234 at time tlO, whereupon the auxiliary lamp again goes on at about tlO and goes off at tl 1 once the capacitor voltage Vci has again reached the threshold TH. Again, the corresponding system off-time TOFF3 is less than TDISCHARGE and the resulting secondary lamp on-time TLAMP4 (tl 1-tlO) is less than TLAMP MAX-

[0029] As seen above, the exemplary hybrid lamp apparatus 100 combines the advantages of a CFL's high efficiency when the lamp 100 is operated for long periods of time (e.g., one or two minutes or more) and also provides stabilized light output from the initial user activation of the power switch SI through augmentation by powering the auxiliary lamp 122, while mitigating or avoiding excess thermal problems by intelligent adjustment of the halogen on-time based at least partially on the prior system off-time.

[0030] The above examples are merely illustrative of several possible embodiments of various aspects of the present disclosure, wherein equivalent alterations and/or modifications will occur to others skilled in the art upon reading and understanding this specification and the annexed drawings. In particular regard to the various functions performed by the above described components (assemblies, devices, systems, circuits, and the like), the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component, such as hardware, processor-executed software, or combinations thereof, which performs the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed stracture which performs the function in the illustrated implementations of the disclosure. Although a particular feature of the disclosure may have been illustrated and/or described with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, references to singular components or items are intended, unless otherwise specified, to encompass two or more such components or items. Also, to the extent that the terms "including", "includes", "having", "has", "with", or variants thereof are used in the detailed description and/or in the claims, such terms are intended to be inclusive in a manner similar to the term "comprising". The invention has been described with reference to the preferred embodiments. Modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations.