Electrical module and method for reducing power consumption of an incandescent light bulb

The invention relates to a modular system and method for converting sinusoidal AC waves into a DC pulse train of extremely narrow pulse width which are amplified and directed to a fast switching power transistor. When the power transistor conducts, DC current flows from the module through the load for a time interval equal to the rectangular pulse width. The resting time between pulses, which is considerably greater than the pulse width, accounts for a significant saving in energy.

BACKGROUND OF THE INVENTION 
This invention relates to reducing the consumption of electrical power 
necessary for the production of light and, more specifically, to a circuit 
module for converting AC current to a train of DC pulses flowing to a 
light-emitting load resistor. 
In view of the ever rising cost of electrical power, there exists a 
commensurately growing need to find additional novel means for achieving 
energy savings by increased efficiency. 
Various improvements have therefore been introduced since the advent of 
Edison's light bulb such as, to mention a few, using a tungsten filament 
and metal halide as incandescent material, coating the inner surface of 
the glass bulb or mounting the bulbs on specular reflectors. In addition, 
a power saving has been provided by the wide spread, if not universally 
desirable replacement of incandescent light sources by fluorescent lamps. 
The general objective has been directed to increasing the luminosity per 
unit electrical power consumed by improving the light-emitting load of a 
given circuit. 
The purpose of my invention is therefore to provide a new power supply to 
reduce the consumption of electricity, by, more particularly, a low cost, 
small size and easily produced converting circuit for altering the 
conventional sinusoidal AC waveform into direct current voltages. The 
network according to my present invention generates a train of pulse waves 
of extremely narrow pulse width. These pulses are amplified and directed 
into a fast switching power transistor. When the power transistor conducts 
the pulse train, current flows through the load for a time interval equal 
to the pulse width which may be measured in nanoseconds or microseconds. 
Since the useful energy is expended mainly during the pulse width but not 
during the resting period between pulses, which is relatively much larger 
than the pulse width, yet too short to be perceptible to the human eye, 
considerable energy can be saved while nevertheless maintaining brightness 
of illumination. In other words, the light-producing ultra short DC pulses 
are selected sufficiently close in sequence (say 4,000 pulses per second) 
to prevent the human eye because of its natural retentivity, to discern 
the intervening resting or nonpulsed periods as shadows. As is well-known 
in the lighting art, fluorescent light is perceived continuous at 60 
cycles AC per second, which is above the time-resolving ability of the eye 
or critical fusion frequency (CFF). Another- benefit on my present 
invention is to increase the longevity of incandescent load resistor 
elements. 
Preliminary aspects of my invention were disclosed on Nov. 27, 1989 to the 
United States Patent Office and received the receipt No. 240124. 
SUMMARY OF THE INVENTION 
It is therefore an object of my invention to provide a small size and 
low-cost means to effect a saving in the electrical power used by light 
emitting loads, or increasing luminosity per electrical energy unit. 
It is another object of my invention to provide a module for converting AC 
input into a pulsating DC output of sufficient power to cause 
incandescence of a light-emitting load. 
It is a further object of my invention to provide a circuit module or 
attachment for reducing the average power needed for lighting an 
incandescent lamp or luminaire without, however, appreciably sacrificing 
illumination. 
It is a particular object to provide a circuit for reducing power 
consumption of an incandescent light bulb, which comprises means for 
converting an input AC sinewave to output DC, means for transforming said 
output DC into sequential pulses at a controlled pulse repetition rate 
(PRR) or frequency and means for controlling pulse width (PW); said PRR of 
said DC output causing said light bulb to be incandescent for a load time 
period equal to the width of said pulse; the pulse width being between 
about 0.1 microseconds and 50 microseconds. 
It is a particular object of my invention to provide an electrical circuit 
for keeping the time between pulses relatively long in comparison with 
pulse width in order to diminish the effective load-time of incandescence. 
It is an object of my invention to provide a circuit for converting AC 
voltage to a pulsating DC output at a frequency, that upon translation to 
light, generates a sufficiently high pulse repetition rate so that shadow 
period between pulses is imperceptible. In this context, it is the object 
of my invention to provide a train of very short output DC pulses to a 
light-producing load resistor, the output peaks being separated by 
so-called periods of shadow or nonincandescent intervals which are held so 
short as to be imperceptible to the human eye, while being considerably 
greater than the pulse widths. 
It is a further object of my invention to provide, in combination, an 
economical means for controlling the pulse repetition rate of the DC 
output, a circuit for eliminating or suppressing excessive spikes and 
negative pulses, and an average power proportional to the product of the 
peak power and DC, wherein DC is proportional to the pulse width and 
inversely proportional to the period of the pulse frequency. 
It is in particular, the object of my invention to provide a network 
producing a train of pulses at an extremely narrow pulse width, e.g. 40 
microseconds, which are amplified and directed to a fast switching power 
transistor conducting the current to the load at a time interval equal to 
the pulse width. In this context, it is the object of my invention to 
provide a modular system for converting sinusoidal AC waves into a DC 
pulse train of extremely narrow pulse width which are amplified and 
directed to a fast switching power transistor. 
The present invention is further to provide a network wherein, whenever the 
power transistor conducts, DC flows from the module through the 
light-emitting load for a time interval equal to the rectangular pulse 
width, and the resting time between light producing DC pulses, which is 
considerably greater than the pulse width, accounts cumulatively for a 
significant saving in energy. It is therefore a particular object to 
produce a preferred pulse repetition rate of more than about 1,000 cycles 
per second, and a preferred pulse width of about 10 microseconds. 
It is an object to provide the above-described module as an attachment for 
supplying a train of DC pulses to a light-emitting load resistor or a 
plurality of parallel light-emitting load resistors wherein the load 
resistors comprise luminaires or lamps of the tungsten filament or 
tungsten halogen. 
A further object is to provide a combination of any inventive circuit 
module with a street lamp type lighting system. 
Another object is to provide lighting systems in combination with my 
inventive converting circuit in order to achieve major savings in energy 
as well as longevity of the load-emitting resistors. 
A particular object is to provide electric power-saving lighting systems 
which in combination comprise my inventive converter module and either a 
filamentous lamp or a nonfilamentous, pressurized gaseous type lamp as 
used in street lighting. 
It is an object to provide a method for transforming AC power into DC 
pulses and delivering DC pulses to a light-emitting load resistor using 
the module of my invention thereby effecting an energy saving equivalent 
to the resting interval period between the energy consuming light 
producing narrow DC pulses. 
It is, more particularly, an object of my invention to provide a method for 
reducing the power consumption of incandescent light-emitting load 
comprising using a circuit for reducing power consumption of a 
light-emitting load, which comprises means for converting an input AC 
sinewave to output DC, means for transforming said output DC into 
sequential pulses at a controlled pulse repetition rate (PRR) or 
frequency, and means for controlling pulse width (PW), said PRR of said DC 
output causing said light bulb to be incandescent for a load time period 
equal to the width of said pulse, and said load comprising a luminaire or 
bulb of tungsten filament or tungsten/halogen type. 
It is a further object to provide a method for transforming, in a module, 
input AC power to an output DC pulse series for delivery to a load 
resistor (RL) comprising a bridge full wave rectifier being connected to 
an AC power source for output DC conversion and delivery through a filter/ 
storage capacitor to a pulse generating network combining functions of a 
plurality of resistors and filter capacitors as a positive pulse rating 
device having a microprocessor as timer and a diode as negative pulse 
suppressor; said pulse generating network being connected to a pulse 
transforming network combining a pulse transformer with a plurality of 
resistors and capacitors; and said pulse transforming network being a 
bridge between a buffer transistor connected to said pulse generating 
network and a switching power transistor; the DC output pulse being 
delivered from said switching power resistor into said load resistor upon 
electrical energy release from said filter/storage capacitor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference is now taken to the drawing, FIG. 1, wherein the schematic 
circuit of the preferred module 10 is illustrated. 
The dashed lines indicate the approximate encasing of the transformer 
module which receives AC power and delivers it as DC pulse series to a 
load resistor. Within said encasing module, a plurality of insulated 
electrical leads are laid out throughout the rectangular circuit board 
portion 10 of the module. The leads in FIG. 1 are numbered 3, 4, 6, 7, and 
8. 
The AC power input is shown in FIG. 1 propagating in the form of a sine 
wave as further illustrated in FIG. 2. The power input leads 3 and 4 
conduct the AC power which is turned on once the switch 5 is closed, to a 
bridge full wave rectifier BR11 for conversion to DC. A filter/storage 
capacitor C12 follows the bridge rectifier and serves to smooth out any 
positive DC ripples. 
Moreover, the capacitor C12 discharges its stored energy into the load RL26 
when the switching power transistor Q24 is turned on. As is known to one 
skilled in the art, a dropping resistor R13 can be used to lower the DC 
potential to a safe operating level suitable for IC microprocessor chip 
18. 
The IC microprocessor chip 18 can be a conventional timer, e.g. type 555, 
which characteristically serves to form pulses. The pulses are regulated 
according to the combined functions of resistors R14, R15 and capacitor 
C16. The so-called pulse repetition rate (PRR) or frequency is controlled 
by a time constant resulting from an RC network which is formed by the sum 
of resistors R13, R14 and R15 in conjunction with capacitor C16. 
Specifically, the pulse width (PW) is controlled by R15. Negative pulses 
are eliminated by the diode D17. In addition, capacitor C27 filters out 
any excessive spikes in the PRR cycle. From the IC chip 18, positive 
pulses are fed to a buffer (NPN) transistor Q21. At this stage, the pulse 
series receives its operating potential through the dropping resistor, 
R20. The output resistor of R20 is coupled to pulse transformer, Tp 23, 
over a capacitor, C22. Resistor R29 serves to maintain proper bias for 
said stage. The output of transistor Q21 are coupled to pulse transformer 
Tp23 via a capacitor C22. 
The secondary of the pulse transformer, Tp 23, is connected to the base of 
a fast switching power transistor (PNP), Q24. In addition, a capacitor C25 
serves to keep harmful DC from entering the base of Q24. 
In the operation of the module, a pulse flow to the base of said fast 
switching power transistor, and the energy stored in capacitor C12 is 
released. The DC potential charges across the load target, RL26, such that 
an operating current flows through the resister load, RL26, during the 
short pulse width. The pulse peak (Pk) is controlled to not exceed the 
working resistance or wattage of the light-emitting load resistor. 
Consequently, the light emitting load is activated only during the short 
period commensurate with the operating pulse width. 
Except perhaps for some fractional energy consumed by the operating module 
itself, energy consumption is at a minimum during the resting periods 
which are alternating intervals in a series of positive pulses as energy 
to light the bulb is only drawn from the load during the pulse (load time 
period) for the approximate pulse width. 
Without wishing to engage in theory, it is assumed here that the 
relationships between the parameters used in the network are well-known in 
the art. The period of the pulse frequency is reciprocal of the PRR 
(period=1/PRR). The DC, also designated as duty cycle, is directly 
proportional to pulse width (PW) and inversely proportional to the period. 
With those relationships in mind, the measured average power (Pav.) 
consumed is proportional to the product of peak power (Pk) and DC as shown 
in the Equation I, e.g., 
Pav=Pk.times.DC; 
Pav=Pk.times.PW/(1/PRR); or 
Pav=Pk.times.PW.times.PRR 
EXAMPLE 1 
In one example, the module circuit is adjusted to produce 4,000 pulses per 
second with a pulse width of about 10 microseconds (with an average 
resting interval of about 240 microseconds), a load of 100 ohms, and a 
charging potential of 100 volts. Using Ohm's Law, these conditions would 
produce 100 watts of peak power. Using Equation I, the average power in 
the Example 1 can thus be calculated, i.e., about 4 watts. Assuming that 
the power dissipated in the module itself is approximately 8 watts, the 
total average energy consumed is the sum of energy expenditure due to load 
and energy dissipated in the working module, namely a grand total of about 
12 watts. Clearly, the average power consumed in the pulsed incandescence 
of a light bulb under the control of the inventive module of this example 
is as low as almost one-tenth the amount consumed in a conventional AC 
power supply for an incandescent light bulb. 
The module can be understood to be similarly used in combination with a 
plurality of parallel incandescent lamps or luminaires. Furthermore, the 
present invention is suitable for use in a lighting system combined either 
with a filamentous (e.g. tungsten or tungsten-halogen) lamp or a 
nonfilamentous lamp such as a pressurized gas lamp as used in street 
lighting systems. 
While the invention has been described with reference to the presently 
preferred embodiment, it should easily be apparent to one skilled in the 
art that modifications and changes in construction can be incorporated 
depending on specific use without departing from the true spirit of the 
invention as defined in the appended claims.