JPS59897A - Low voltage incandescent bulb capacitive stabilizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ballasts, particularly capacitive stabilization circuits that provide low voltage to incandescent light bulbs.

As is well known in the industry, incandescent light bulbs that operate at a nominal voltage of approximately 120 volts C tend to have lower voltage levels (i.e., similar efficiency, lumens per watt) at the same wattage than incandescent light bulbs that operate at a nominal voltage of about 120 volts C. does not demonstrate.

All conventional circuits that provide such lower voltage operation introduce undesirable cost, bulk, weight, and high levels of electromagnetic interference. In particular, some conventional low-voltage power supplies for incandescent light bulbs used magnetic components in the transformer stop. The cost of such magnetic components makes the resulting power supply device less economically attractive.

Other power supplies utilize phase-controlled techniques,43 which require very narrow pulses, draw high currents to the load, and often cause electromagnetic interference and reduced reliability. invited.

4) a3 J, electrically connected in parallel with the main capacitor in series with the incandescent lamp load, as disclosed in U.S. Pat. Capacitive ballasts for incandescent lamps, which consist of one or more auxiliary capacitors, solve the above-mentioned problems. However, the triac-like switching devices disclosed in the above-mentioned applications, which switch each auxiliary capacitor in electrical parallel relationship with the main capacitor, have several drawbacks, such as higher than desired "strength" and lower maximum operating temperatures. There is.

SUMMARY OF THE INVENTION In accordance with the foregoing, it is an object of the present invention to provide a novel and improved incandescent light bulb with a relatively low current and a relatively high maximum operating temperature; Our purpose is to provide switching devices.

The present invention, which accomplishes this object and other objects, utilizes one or more auxiliary capacitors in parallel with the main capacitor, as disclosed in the above-cited U.S. Patent Application. There is a switching device to connect.

More specifically, each switching device consists of a unidirectional conducting device tl, i and an active switching device electrically connected in parallel thereto, the combination being electrically connected in series with the auxiliary conductor. . Additionally, each of the eleven switching devices in the preferred embodiment is responsive to other ships from the control logic.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a circuit diagram of a low voltage incandescent light bulb F1 ballast incorporating the present invention. As shown in FIG.
Power is supplied from the In this case, ゛η constant device] 0 goes to ゛Power supply 1
2 to control the current supplied to the load 11. load 11
The lamp may be, for example, a low voltage incandescent lamp operating at a voltage in the range of about 24 to 36 volts. Ballast 10 allows bulb load 11 to operate at a selectable constant power output over a relatively narrow range of brightness. In such applications, the current of AC power ii2 is within a predetermined range, for example approximately 2.0%.
It is possible to maintain the bulb voltage within a relatively narrow range even when C varies over a range of .

The ballast 10 constitutes a capacitive voltage converter, and the minimum current flowing through the bulb is a current 1+f'' flowing through the capacitor CI (hereinafter referred to as the main capacitor).

An additional component of the bulb current is a current 12 flowing through one or more capacitors 02 (hereinafter referred to as auxiliary capacitors).
based on. Therefore, minimum bulb current and power occurs when no current flows through auxiliary capacitor C2, ie, when the capacitive reactance of ballast 10 is at its maximum. Conversely, when capacitor current 12 flows through Liebe's auxiliary capacitor C2, maximum bulb current and power occurs when the capacitive reactance of the ballast is at its minimum. Current I2
When the current flows through some of the auxiliary capacitors C2, an intermediate magnitude of bulb current and power is obtained.Thus, by varying the number of auxiliary capacitors C2 in parallel with the main capacitor C1, the load current , 15 and power are adjusted.

AC1 source 12 and light bulb 11 are connected to terminals 13-14, respectively.
and 1'5-16.

The main capacitor C1 is connected between terminals 13 and 15 and C
There is. For each auxiliary capacitor C2, switching device @
17 is provided in electrical connection between the terminal 15 and one terminal of each auxiliary capacitor C2. Each auxiliary capacitor C2
The remaining terminals are connected to terminal 13. Terminals 14 and 16 are directly electrically connected to each other.

Each switching device 17 establishes a low resistance bidirectional conduction path between terminal 15 and a terminal opposite terminal 13 of each auxiliary capacitor C2. Specifically, switching equipment@
17 is constructed by connecting a unidirectional conduction device 18, ie a rectifier, for example a diode, in parallel with an active switching device 19.

(- The active switching device 19 may be any active device that conducts in the opposite direction to the unidirectional conduction device 18 or in both directions. Preferably, the active switching device 19 conducts in response to a control signal from the control logic device 20. state and a non-conducting state. Such control logic devices are well known in the art. Each active switching device 19 is a 5CR (silicon controlled rectifier) 21 or a transistor, e.g. a junction or field effect transistor ( FE
T), 22, but is not limited to these.

In order to prevent undesirable currents from flowing through each switching device 17 and to limit the current flowing through the switching devices 17, the voltage across the main capacitor C1 and the voltage V2 across the auxiliary capacitor C2 are determined. are equal to each other, or are at the maximum voltage of the waveform of the AC power source 12, or both, which causes the auxiliary capacitor C to
Preferably, each switching device @17 is controllably switched "on" by the control logic device 20 only when the circulating current flowing between the capacitor C1 and the main capacitor C1 is substantially absent.

Furthermore, each switching device 17 using a transistor as the active switching device 19 is capable of operating at a temperature of 130° C. or higher, compared to conventional devices such as triacs, which have a maximum operating temperature of about 100° C. That is,
At temperatures above about 100 DEG C., a typical TRIAC switches to and remains conductive without a gate signal, resulting in unacceptable operation of the TRIAC.

As mentioned above, the ballast 10 of the present invention can be used for an incandescent light bulb 11.
By changing the capacitance in series with the main capacitor C1, the power supply to the incandescent bulb 11 is controlled. Specifically, the total capacitance in series with the incandescent bulb 11 is equal to auxiliary capacitor C2 through which the associated switching device 17 is conducting.
By changing the number of , the total volume ω in series with the incandescent bulb 11 can be changed, thus providing a ballast 10 that adjusts the power supplied to the incandescent bulb 11 and adjusts the bulb filament temperature.

Further, each switching device 17 has an AC power supply 81A 12
The auxiliary capacitor can be switched in electrical connection or disconnection in parallel with the main capacitor during one or more cycles of the waveform.

It should also be noted that the multiple auxiliary capacitors C2 can have the same or different capacitances.

It is also possible to switch each auxiliary capacitor independently from each other.

In a preferred embodiment, main capacitor C1 has a capacitance of about 25 microfarads, and auxiliary capacitor C2 has a total capacitance of about 2 microfarads.
AC power source 12 is approximately 120 volts, 60 Hz, and light bulb 11 operates at approximately 36 volts, 60 watts.

The number of auxiliary capacitors electrically connected in parallel with the main capacitor C1 and the capacitance of each capacitor will vary according to a number of factors, such as the magnitude of the AC power supply 12 voltage, the desired bulb current, bulb brightness, bulb operating voltage, etc.

Therefore, the present invention as described above is capable of correcting mill fluctuations in the AC power supply. That is, as the voltage magnitude of AC power source 12 increases or decreases, the number of auxiliary capacitors C2 is decreased or increased to maintain a substantially constant current and/or power to bulb 11.

Furthermore, load current, power and brightness can be set by adjusting each active switching device 19 manually or automatically. Specifically, the control logic circuit 20 is used to generate a feedback signal from, for example, an SCR.
) [is sent to the gate of the FET - (switches the active switching device into a conducting or non-conducting state, thereby causing terminal 1
It is possible to automatically adjust the total δI@ amount between 3 and 15. Such a feedback signal is transmitted to the load 1, for example.
The signal can be a signal corresponding to the current flowing through 1.

Still further, the present invention employing a capacitive ballast to apply a low voltage to the bulb 11, as disclosed in the aforementioned U.S. patent application, allows for undesirably high levels of electromagnetic interference, in contrast to the prior art. can be avoided. Moreover, and in contrast to the said patent application, the present invention can be manufactured at low cost and allows for higher maximum operating temperatures, especially when using transistors as active switching devices.

Although the invention has been illustrated and described with respect to a preferred embodiment thereof, other embodiments and modifications thereof will be apparent to those skilled in the art and are within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a low voltage incandescent lamp capacitive ballast incorporating the present invention. Explanation of main symbols 10...Ballast, 11...Incandescent light bulb, 12...AC side 13-16...Terminal, 17... ... switching device, 18 ... unidirectional conduction device, 19 ... active switching device, 20 ...
...Control logic unit, 21...5CR1 22...r: E-r. C1...Main capacitor, C2...Auxiliary capacitor. Attorney for patent applicant General Electric Company (76
30) Raw Numa Toku 2F7g, / Asahi

Claims (1)

[Claims] 1. Power from an AC power source to an incandescent light bulb is converted into an AC power waveform 11
(a) a first capacitive element electrically connected in series with the bulb across the ballast input terminals; (b) one or more capacitive elements; an auxiliary capacitive element, and (C) a switching device electrically connecting each of the auxiliary capacitive elements in parallel with the first capacitive element over one cycle or multiple cycles of the AC power waveform;
14. A ballast in which each auxiliary capacitive element is connected in series with a switching means which electrically connects a unidirectional conduction device and an active switching device in parallel. 2. Special feature 6 in which the LtiIj interrogation device is a diode.
110. The ballast according to item 110. 3. The ballast of claim 1, wherein the active switching device is a 5CH1 junction transistor or a field effect transistor. 4. The ballast of claim 1, wherein each of said active switching devices is switched between a conducting state and a non-conducting state in response to a control signal. 5. The ballast according to claim 4Ijf, wherein the control signal is generated in response to the current flowing through the incandescent lamp. 6. The ballast according to claim 1, wherein the switching devices are each independently switched. 7. When each auxiliary capacitive element is electrically connected in parallel with the first capacitive element, between both ends of all the auxiliary capacitive elements electrically connected in parallel with the first capacitive element. 2. The ballast of claim 1, wherein the voltage across the first capacitive element is exactly the same as the voltage across the first capacitive element. 8. The ballast according to claim 1, wherein the active switching device is a transistor, and the switching device is operable at a temperature of 130° C. or higher. 0. The incandescent light bulb operates at about 36 volts and 60 watts, the first capacitive element has a capacitance of about 25 microns, and the one or more capacitive capacitors have a capacitance of about 25 microns. It has a volume of 11 M,
2. The ballast of claim 1, wherein said AC mains voltage is approximately 120 pol 1- at 60 Hz.