A fluorescent lamp lighting arrangement for "Smart" buildings

Abstract: A fluorescent lamp lighting arrangement controlled by both a motion detector and a light sensing detector operable when said motion detector senses motion.

Description: This is an invention in the lighting art. More particularly, it involves a fluorescent lamp lighting arrangement with an integral motion detector and light sensing detector for controlling the light intensity of fluorescent lamps. A prior art fluorescent lamp lighting arrangement is described in U.S. Patent No. 4 663 521. One of the objects of this invention is to conserve energy. One of the advantages of the invention is that it increases the life of fluorescent lamps operated under its control. One of the features of the invention is that it is useful in so-called "Smart" buildings. In this respect, it will dim fluorescent lamps under its control in areas in which no activity is sensed and will vary the amount of artificial light in such areas in accordance with how much natural light strikes such areas, when activity is sensed. In accordance with one aspect of the invention, there is provided a fluorescent lamp lighting arrangement including a fluorescent lamp and lamp controller means for controlling the light intensity of the lamp. A control signal means is also included which responds to a predetermined stimulus and produces a control signal when the stimulus occurs. Operating means are provided to respond to the control signal to cause the controller means to change the light intensity of the fluorescent lamp. The operating means includes first and second stages. The first stage includes amplifier means for amplifying the control signals. The second stage includes a voltage regulating means for regulating a first operating voltage applied to the amplifier means for its operation. The voltage regulating means receives a second operating voltage for its operation from the lamp controller means. The amplifier means includes a comparator circuit means operating to render the lamp controller means insensitive to signals from said control signal means less than a predetermined magnitude. In accordance with another aspect of the invention there is provided a fluorescent lamp lighting arrangement including a fluorescent lamp and lamp controller means for controlling the light intensity of the lamp. A control signal means is also included which responds to a predetermined stimulus and produces a control signal when the stimulus occurs. Operating means are provided to respond to the control signal to cause the controller means to change the light intensity of the lamp. The operating means includes a light control circuit which responds to the control signal and operates to control the amount of light provided by the fluorescent lamp at a prescribed location in accordance with a predetermined curve. The light control circuit includes light sensing means sensing the amount of illumination at the prescribed location provided by natural light and by the fluorescent lamp. The predetermined curve has a steep slope when the light sensing means indicates the fluorescent lamp should provide a high amount of light and a more moderate slope when the light sensing means indicates the fluorescent lamp should provide a lesser amount than the high amount. The light control circuit includes determination means for determining at what amount of light from the fluorescent lamp the curve is transposed from the steep slope to the more moderate slope. In accordance with a still further aspect of the invention, there is provided a fluorescent lamp lighting arrangement including a fluorescent lamp and lamp controller means for controlling the light intensity of the lamp. A control signal means is also included which responds to a predetermined stimulus and produces a control signal when the stimulus occurs. Operating means are provided to respond to the control signal to cause the controller means to change the light intensity of the lamp. The operating means includes first and second stages. The first stage includes amplifier means for amplifying the control signal. The second stage includes a voltage regulating means for regulating a first operating voltage applied to the amplifier means for its operation. The voltage regulating means receives a second operating voltage for its operation from the lamp controller means. The operating means includes a light control circuit which responds to the control signal and operates to control the amount of light provided by the fluorescent lamp at a prescribed location. The light control circuit includes light sensing means sensing the amount of illumination at the prescribed location provided by natural light and by the fluorescent lamp. The light control circuit includes determination means for determining what amount of light is to be provided by the fluorescent lamp. Other objects, features and advantages of the invention will be apparent from the following description and appended claims when considered in conjunction with the accompanying drawing in which: Fig. 1 is a circuit diagram of a motion and light sensor in accordance with the invention, and Fig. 2 is a graph plotting the illumination at the light sensor of the circuitry of Fig. 1 against the amount of artificial light provided by the lighting arrangement of the invention. A preferred embodiment of a sensor circuitry for use with for instance a dimmable fluorescent lamp controller is shown in Figure 1. The sensor circuit comprises terminals 113' and 114' suitable for connection to input terminals of the dimmable fluorescent lamp controller. In operation the sense circuit receives power via terminals 113' and 114'. Furthermore the sensor circuit adjusts the voltage present between terminal 113' and terminal 114', this voltage serving as a dimming signal for the dimmable fluorescent lamp controller and determining the light output of the lamps operated by the dimmable fluorescent lamp controller. Such a sensor circuit would be useful in dimming lamps in a room when there is no activity in the room and for brightening those lamps when the sensor senses that there is activity in the room. The apparatus comprises a pyroelectric motion sensor PS. This unit produces signals which vary in time and whose amplitude increases as it senses increasing infrared radiation. In operation with resistors R 1 and R 2 , capacitances C 1 and C 2 and transistor Q 1 , the signals from sensor PS are applied to the positive input of a first amplifier stage IC 1 . As indicated in Figure 1, capacitance C 1 , sensor PS, resistor R 2 and capacitor C 2 are all connected to a common return line as are various other elements of Figure 1 as indicated by the small horizontal line shown at the bottom of each of the elements connected to the return line. Resistors R 3 , R 4 and R 5 together with capacitors C 3 and C 4 are selected in order to give operational amplifier IC 1 a high AC gain. The output of operational amplifier IC 1 is fed through capacitor C 5 and resistor R 8 to the inverting input of a second stage amplifier formed by operational amplifier IC 2 . Resistors R 6 , R 7 , R 9 and capacitor C 6 are selected to provide operational amplifier IC 2 with a high AC gain also. Since the input from operational amplifier IC 1 is applied to the inverting input of operational amplifier IC 2 , the output of the latter amplifier is an amplified inversion of its input. The output of amplifier IC 2 is fed to what is termed a "window comparator" formed by amplifiers IC3 and IC 4 . Amplifier IC 3 filters out positive signals received from amplifier IC 2 below a particular value whereas amplifier IC 4 filters out negative signals above a particular value. In this way, background radiation which might impinge on pyroelectric sensor PS is filtered such that the apparatus is insensitive to such background radiation. The magnitudes of the positive and negative signals which are filtered out is determined by the resistance values of resistors R 10 , R 11 and R 12 . The outputs of amplifiers IC 3 and IC 4 pass through resistors R 13 and R 14 , respectively to turn on either of transistors Q2 and Q3 in the presence of sufficient motion as sensed by sensor PS. With either of transistors Q2 or Q3 on, capacitor C 7 is discharged quickly through either of the low impedance collector-emitter paths so provided. Motion sensed by pyroelectric sensor PS discharges capacitor C 7 rapidly to brighten lamps operated by the dimmable fluorescent lamp controller with a relatively short time delay if they were at their-dimmed condition, as will be explained. In response to the indication of a lack of motion by pyroelectric sensor PS, capacitor C 7 charges slowly through rheostat R 15 . The lack of motion dims the lamps from their brightened condition after a time delay determined by the magnitudes of capacitor C 7 and rheostat R 15 which is relatively longer than the time delay for brightening the lamps. The voltage representative of the charge on capacitor C 7 is applied to the positive input of comparator IC 5 which compares it with a threshold voltage established by resistors R 16 and R 17 . If the voltage at the positive input is higher than the threshold voltage, the output of comparator IC 5 is high and is applied through resistor R 18 to turn on transistor Q 4 . Transistors Q 4 and Q 5 together with resistor R 19 , and zener diode IC 6 form a switch for switching the voltage across terminals 113' and 114' depending upon whether or not pyroelectric sensor PS senses motion. If motion is sensed, the output of comparator IC 5 is low and transistor Q 4 is turned off. As a result, transistor Q 5 is also maintained in an off condition and resistor R 20 is in series circuit with Adjustable Micropower Voltage Reference IC 6 . Under these conditions, the voltage applied across terminals 113' and 114' by the dimmable fluorescent lamp controller can remain high. As a consequence the lamps can operate at what may be called a "fully lit" condition. Should motion in the vicinity of pyroelectric sensor PS cease, comparator IC 5 produces a high signal to turn transistor Q 4 on. As a result, transistor Q 5 is also turned on short-circuiting resistor R 20 . This causes the current being sourced by terminals 113' and 114' to increase in value while the voltage across those terminals decreases in value to approximately the voltage drop across Adjustable Micropower Voltage Reference IC 6 (such as a National Semiconductor Corp. LM 185). This voltage causes the lamps to operate in a "dimmed" condition. Adjustable Micropower Voltage Reference IC 6 forms a voltage regulating means for producing the operating voltage for amplifiers IC 1 through IC 5 along line V cc . The voltage regulating means is capable of maintaining the voltage along lines V cc within an acceptable range for the operation of amplifiers IC 1 through IC 5 notwithstanding the voltage across terminals 113' and 114' changes from high to low depending upon whether resistor R 20 is in series circuit with Adjustable Micropower Voltage Reference IC 6 or whether it is shorted by transistor Q 5 . From the foregoing, it will be understood that the switch formed by transistor Q 4 and Q 5 together with the voltage regulating means identified above receive their operating voltage across terminals 113' and 114' and their power for operation from the (dimmable fluorescent) lamp controller. The amplifiers IC 1 through IC 5 of the control signal means of Figure 1 receive their operating voltage through the voltage regulator means along line V cc . As a consequence, none of the previously described controlled signal means of Figure 1 requires a source of voltage independent of the lamp controller. Superimposed upon the previously described motion sensor of Figure 1 is a light sensor arrangement including light sensor LS and transistors T 1 - T 4 with associated resistive elements and capacitors. This circuitry is connected to terminal 113' and line V cc . As can be seen in Figure 1, there is provided a light sensor LS which senses light at a particular location. Light sensor LS is connected across capacitor C, one end of which is connected to the base of NPN transistor T 1 . The other end of capacitor C is connected to the collector of transistor T 1 . The emitter of transistor T 1 is connected to one end of rheostat R h , the other end of which is connected to one end of light sensor LS and to the base of transistor T 1 . The emitter of transistor T 1 is also connected to the base of NPN transistor T 3 and to the emitter of NPN transistor T 2 . The bases of transistor T 1 and T 2 are interconnected. The collector of transistor T 2 is connected to one end of resistor R y , the other end of which is connected to the other end of capacitor C. The emitter of transistor T 2 is also connected to one end of resistor R b , the other end of which is connected to line V cc . Connected across the emitter and collector of transistor T 2 is resistor R x . The collector of transistor T 3 is connected to one end of resistor R p , the other end of which is connected to the other end of capacitor C. The one end of resistor R p is also connected to the base of PNP transistor T 4 . The other end of resistor R p is connected to the emitter of transistor T 4 . The emitter of transistor T 4 is also connected to terminal 113'. The collector of transistor T 4 is connected to line V cc . When transistor Q 5 is non-conducting, because the motion sensor senses activity, the voltage present between terminal 113' and terminal 114' is controlled by the light sensor arrangemnent including light sensor LS and transistor T 1 -T 4 with associated resistive elements and capacitors. The curve shown in Figure 2 is the result of experimentation at work places, and shows the amount of artificial light as a function of the Illumination (IL) at sensor LS. Those skilled in the art will understand from the disclosure herein that different curve slopes may be employed. The curve of Figure 2 represents the output of fluorescent lamps controlled in accordance with the invention versus the illumination at the light sensor. The upper steep slope portion of the curve, that is, the portion from A to B provides lumen maintenance control and ambient light regulation. The lower part with the more moderate slope, that is, portion B to C of the curve performs ambient light regulation only. It is to be understood that this curve has been selected to provide optimum electrical energy use and optimum quality of lighting. In operation, transistors T 1 , T 2 , T 3 and T 4 are provided power for operation from the dimmable fluorescent lamp controller. No auxiliary power supply is required. Rheostat R h acts as a threshold control or selection means. Transistor T 4 is the main current sink of the invention. Transistor T 3 operates as a regulation amplifier and as a partial current sink. Transistors T 1 and T 2 form a variable gain photo current amplifier. Transistors T 1 and T 2 work in such a way that at low natural light levels they have a high current gain. At this high gain the upper portion A to B of the curve of Figure 16 is provided substantially by the fluorescent lamp or lamps being controlled. At higher natural light levels transistor T 2 saturates and this results in a relatively low current gain of the amplifier formed by transistors T 1 and T 2 . This provides the more moderate portion of each curve from point B to point C. The value of resistor R y and the current gain of transistors T 1 and T 2 determine the location B on each of the curves of Fig. 2. Resistors R y and R x are selected to obtain the desired steep slope of the curve between its A point and its B point. R p serves to establish a bias for transistor T 4 . R b serves to establish initial voltage gain for the circuit. Capacitors C and C' provide voltage filtering.

Claims: A fluorescent lamp lighting arrangement, suitable for operating at least one fluorescent lamp, comprising lamp controller means (Q5) for controlling the light intensity of said fluorescent lamp, and a sensor circuit comprising control signal means (P5) responding to a predetermined stimulus and producing a control signal when said stimulus occurs, and comprising operating means (IC1-IC6) responding to said control signal to cause said controller means (Q5) to change the light intensity of said lamp, said arrangement further comprising a light control circuit (T1-T4) which operates to control the amount of light provided by said lamp at a prescribed location, said light control circuit including light sensing means (LS) sensing an amount of illumination at the prescribed location, characterized in that the light sensing means (LS) sense the amount of illumination provided by natural light and by said fluorescent lamp, in that said light control circuit controls the amount of light provided by said fluorescent lamp at said prescribed location in accordance with a predetermined curve, said predetermined curve having a steep slope (A-B) when said light sensing means indicates said fluorescent lamp should provide a high mount of light and a more moderate slope (B-C) when said light sensing means indicates said fluorescent lamp should provide a lesser amount than said high amount, said light control circuit including determination means (Ry, T1, T2) for determining at what amount of light from said fluorescent lamp said curve is transposed from said steep slope to said more moderate slope. A fluorescent lamp lighting arrangement as claimed in claim 1, wherein said operating means includes first and second stages, said first stage (IC1, IC2) including amplifier means for amplifying said control signals, said second stage (IC3-IC6) including a voltage regulating means (IC6) for regulating a first operating voltage applied to said amplifier means for its operation, said voltage regulating means receiving a second operating voltage for its operation from said lamp controller means. A fluorescent lamp lighting arrangement as claimed in claim 2, wherein said voltage regulating means (IC6) includes switch means for reducing the second operating voltage applied to said voltage regulating means in the absence of said control signal from the magnitude of said second operating voltage applied in the presence of said control signal, said voltage regulating means providing substantially the same first operating voltage to said amplifier means regardless of the magnitude of said second operating voltage applied to said voltage regulating means. A fluorescent lamp lighting arrangement as claimed in claim 1 or 2, wherein said control signal means includes a pyroelectric sensor (PS) serving as a motion detector. A fluorescent lamp lighting arrangement as claimed in claim 1 or 2, wherein said operating means operates in response to said control signal to cause said controller means to raise the light intensity of said lamps in the presence of movement sensed by said motion detector (PS) and to cause said controller means to dim the light intensity of said lamp in the absence of motion sensed by said motion detector. A fluorescent lighting arrangement as claimed in claim 5, wherein said controller means raises the light intensity of said lamp from a dimmed condition with a shorter time delay than the time delay which it provides when it dims said lamp in the absence of motion. A fluorescent lamp lighting arrangement according to claim 1 or 2, wherein said light control circuit includes a photo amplifier comprising a pair of transistors (T1, T2) which operate at a high current gain at low natural light levels. A fluorescent lamp lighting arrangement according to claim 7, wherein one (T2) of said pair of transistors saturates at a relatively high natural light level. A fluorescent lamp lighting arrangement according to claim 8, wherein said determination means includes a resistor (Ry) connected to the collector of said one (T2) of said pair of transistors. A fluorescent lamp lighting arrangement according to claim 9, wherein said determination means includes a resistor (Rx) connected across the collector and emitter of said one (T2) of said pair of transistors. A sensor circuit suitable for use in a fluorescent lamp lighting arrangement according to any of the previous claims, comprising control signal means responding to a predetermined stimulus and producing a control signal when said stimulus occurs, and comprising operating means responding to said control signal to cause said controller means to change the light intensity of said lamp, said operating means comprising a light control circuit which responds to said control signal and operates to control the amount of light at provided by said lamp at a prescribed location, said light control circuit including light sensing means sensing an amount of illumination at the prescribed location, characterized in that the light sensing means sense the amount of illumination provided by natural light and by said fluorescent lamp, in that said control circuit controls the amount of light provided by said fluorescent lamp at said prescribed location in accordance with a predetermined curve, said predetermined curve having a steep slope (A-B) when said light sensing means indicates said fluorescent lamp should provide a high mount of light and a more moderate slope (B-C) when said light sensing means indicates said fluorescent lamp should provide a lesser amount than said high amount, said control circuit including determination means (Ry, T1, T2) for determining at what amount of light from said fluorescent lamp said curve is transposed from said steep slope to said more moderate slope.

Inventors: SZUBA STEFAN, SZUBA, STEFAN
Applicants: KONINKL PHILIPS ELECTRONICS NV, KONINKLIJKE PHILIPS ELECTRONICS N.V.
Application year: 1992
Main classification: H05B41
IPC codes: H05B41, H05B37