Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~ 5~39 58-BD-6336
The present invention relates to a circuit for operating
a gaseous discharge lamp from -the AC mains as well as from
an auxiliary DC source, and more particularly, to a circ~lit
for operating such a lamp under normal corlditions at power
frequency from an AC line source of electrical enexgy in
conjunction with a reactor ballast, and, under emergency
conditions, at high frequency from an inverter powered by
an auiliary DC electrical energy source.
A power failure, no matter what the cause may be, amy
very well jeopardize human life due to lighting system
failure. There are therefore, many installations which
require some type of emergency ligh-ting system which will
automatically come into operation upon the occurrence of a
power failure; the high efficiency of a fluorescent lamp
makes it especially valuable for use in such a system.
Presently available emergency lighting systems are
generally of the type using a transistor switching inverter
and wherein a single fluorescent lamp, or group of lamps,
is used both for normal AC operation of the lighting system
2Q and for the emergency system, a battery being used as the
power source for energizing the transistor inverter and the
lamp, or lamps, upon loss of AC line voltage. Ideally, such
an inverter is of the high efficiency type and is provided
with means for controlling its operation; such a system is
disclosed and claimed in U.S. Patent No.3,921,005 dated
November 18, 1975 - Watrous, assigned to the assignee of the
present invention.
When attemps were made to apply an emergency lighting
system, such as for example that described in U.S. Pat.No.
3Q 3,906,243 dated Sept/16/1975 - Herzog, assigned to the
-- 1 --
~ZS~3~ 5~-BD-6336
assignee of the present invention, to fluorescent lamps in
the size range of 20 watts and less for operation in the rapid
start mode, the isolated secondary winding of the ballas-ts
was found to have too low an impedance at high ~requency.
Designing this winding with a suficient~ hiyh impedance
makes it large, with too high an open circuit voltage
(causes rapid s~art lamps to instant start) and hence lossy.
Examining other ways of starting fluorescent lamps
suggests the use of a manual starter, a gas-filled bi-metal
starter or a solid-state equivalent. While the manual
starter is compatible with a high frequency emergency
inverter, where emergency lighting is needed, a manual starter
is not desirable nor suitable. Both the gas-filled bi-
metal starter and the solid state equivalent will act to short
out the frequency inverter rather than start the fluorescent
lamp in the emergency modeO This means that, if the
fluorescent lamp could be started with the reactor, but
without the normally employed starting methods, an emergency/
normal lighting system coula be developed for 20 watt or
2Q lower wattage lamps and as well as for the overseas market
where, with the 220 V AC supply, reactor ballasts are
employed for la~ps up to the 65 watt level~
It is desirable, therefore, to provide a lighting
system wherein a high frequency inverter is compatible with
a reactor ballast for operating a gaseous discharge lamp
both from the AC mains, and upon the failure thereof, from
an auxiliary DC source.
Accordingly, it is an object of the present to pxovide
a lighting system including a circuit having a reactor for
3~ operating a gaseous discharge lamp during normal conditions
from the AC mains, and having a controlled transistor
switching inverter for starting the lamp during normal
conditions and for starting and operating the lamp during
j~ 58-BD--6336
emergency conditions: ie, when the AC line voltage has d~opped
below a predetermined level.
In accordance with the present invention, there is
provided a circuit for operating a gaseous dischar~e lamp
from a source of AC line voltage, and al~ernatel~, from an
auxiliary DC electric energy source. Means are provlded
including a reactor for connection to such an AC line
voltage source for operating the lamp at power frequency
during normal conditions when the AC line voltage ls above
a first predetermined level. Means are also provided in~
cluding an inverter connected to the DC electrical energy
source for starting the lamp during normal conditions and
for starting and operating the lamp during emergency con-
ditions upon failure of the AC line voltage. The inverter
supplies AC electrical energy to the lamp at a frequency
substantially higher than the power frequency.
The accompanying drawing is a detailed schematic re-
presentation of the preferred embodiment of the circuit of
the present invention.
2Q In accordance with the present invention and referring
now to the drawin~l there is shown a circuit for operating
a gaseous discharge lamp from a source of AC line voltage
and, upon the failure thereof, from an auxiliary source of
DC electrical energy. Means are provided including an
inverter lO connected to a source of DC electrical energy
such as battery 14 of starting the gaseous discharge lamp,
such as fluorescent lamp 12, during emergency conditions,
inverter 10 supplying AC electrical energy to the lamp 12 at
a frequency substantially higher than the AC line power
frequency. Means are also provided including a reactor 16
arranged for connection through a pair of input terminals
l and 2 to a source of AC line voltage, such as for e~ample
~z5~3g 53-~D-6336
220 volts, for operating the lamp 12 at line power frequency,
for example, 50 Hz, during normal conditions: that is, when
the AC line voltage is above a first predetermined leve~.
Emergency conditions are hereby defined to be when the ~C
line voltage falls below a second predetermined level.
Inverter 10 is of the tuned type and includes a pair o
transistors QA and QB capable of operation in a low-loss
switching mode. Means are providea enabling the transistors
to operate in the low loss switching mode and includes
inductor Ll, a buffer inductance, connected serially with
battery 14. A first transformer Tl serves to couple the
inverter 10 wi~h the lamp 12 and is resonated with capacitances
C101 and C102 to set the operating frequency of the inverter
and to establish a sinusoidal output voltage. Inductor Ll is
electxically connected at point 22 with a center tap on
primary winding P of transformer Tl. Means are provided
for controlling the inverter 10 and which takes the form
of a controller 20, in the preferred e~bodiment, a ten pin
integrated circuit (IC). Further details ~f this integrated
circuit controller may be held by above reference to U.S.
Patent No. 3,921,005 - Watrous, assigned to the assignee
of the present invention. Controller 20 includes means
supplying base drive for switching transistors QA and QB at
zero collector voltage: tha-t is, when the instantaneous
voltage across capacitor C101 is zero. As the primary
voltage across transformer Tl varies at fundamental frequency,
the voltage at point 22 and hence across inductor Ll varies
at twice the fundamental frequency. The current through Ll
is DC with a second harmonic component. This same current
3Q is alternately carried by the two transistors QA and QB.
~hile the transistors are required to switch collector
current, they do so at essentially zero collector voltage
~z5~3~ 58-BD-6336
with a resultant low power dissipation.
Means are included providing timing information to the
controller 20 for effecting switching of the respective
transistors QA and QB is step with the natural reso~ant
frequency of the inverter and takes the Eor~l oE an ~-uxiliar~
winding S2 magnetically coupled with the primary winding
P of first transformer Tl. Thus, controller 20, and more
specifically, a zero crossing detector set circuit therein,
tracks the resonant frequency of first transformer Tl and
insures that transistor switching occurs when the voltage
across capacitor C101 is zero.
Higher efficiency can be achieved in inverter 10 by
making the base drive of the respective transistors pro-
portional to the collector current thereof. To this end
there is included means providing a feedback current to the
controller 20 to effect transistor base drive proportional
to transistor collector current, which in the preferred
embodiment, takes the form of a feedback transformer T2.
Transformer T2 has a feedback winding D magnetically coupled
to the respective collectors of the transistors QA and QB
through a pair of windings A and B, respectively. Thus, the
power consumed by the controller 20 can be limited to that
required to start and control the oscillation of the
inverter 10.
A high leakage reactance transformer T3 is provided
for connecting the inverter circuit 10 to the 220 volt 50
Hz line voltage source. Circuit means are provided for
monitoring the AC source voltage and for coupling the
secondary winding S of high reactance trans~ormer T3 with a
non-linear load during one half cycle of the AC source
voltage to supply charging current for battery 14. Half-
wave charging current is supplied to the non-linear load,
~583~ 58-BD-6336
bat-tery 14, through diode D101 and is limited in magnitude
by the reactance of the transformer T3. Because of this
transformer reactance, the sinusoidal voltaye of the
terminals of winding S is clamped at the battery voltage
when D101 conducts. On the alternate half c~cle, dlode ~103
conductors halfwave current through indicator lamp 24 and
the dual-prong battery plug 26. The battery must be plugged
in and the 220 volts AC available to energize lamp 24 in-
dicating that the battery 14 is charging. Using the alternate
half cycle reduces the volt-amp rating of the transformer T3.
For monitoring AC source voltage, means are provided for
coupling secondary winding S of transformer T3 with a linear
load during an alternate half cycle. To this end, during
the half cycle alternate from that in which the battery
14 is charge, capacitor C104 is charged through diode D102.
This provision of a single secondary windings S associated
with transformer T3 for providing, in a substantial nonin-
teracting manner, a voltage proportional to the AC voltage
and for providing energy to charge battery 14 is disclosed
2Q and claimed in U.S. Patent No. ~ 5C~3
dated ~e~u4~y~/iq~ and is assigned to the assignee of
the present invention. The resultant DC voltage is connected
to pin 7 of controller 20 through a linear load comprising
resistor divider R104 and R105. The DC voltage at terminal
7 is proportional to the average value of the 50 Hz supply
voltage and is not influenced by the aforesaid clamping
action of the ~attery. A zener diode D120 is connected in
circuit between diode DlQ2 and capacitor C104 as shown to
prevent the battery voltage from battery 14 from keeping
3Q inverter lQ biased off. Furthermore, a heater winding H is
provided on transformer T3 for heating filament 27 of lamp
12 for assisting in starting the lamp.
~Z5B3~ 58-BD-6336
Controller 20 includes means for turning on the inverter
lQ when the AC line voltage is below the second predeter-
mined level and for turning off the inverter 10 when the
the AC line voltage is above the first predetermined le~el.
To accomplish these ends, controller 20 also includes a first
sensor (in the form of an AC voltage inhibit subcircuit) ~or
sensing the voltage of the AC line source and a second sensor
(in the form of a low battery ~oltage inhibit subcircuit~ f~r
sensing the DC battery voltage and includes logic means (in
the form of a start-stop logic subcircuit) combining the
.-outputs of the first sensor and the second sensor to enable
inverter 10 when the battery voltage is above a predeter-
mined level and the AC voltage is below the second pre-
deter~ined level and to disable the inverter when the battery
voltage is below a predetermined level or the AC line voltage
is above first predetermined level.
Operation of the circuit including the inverter 10
during emergency conditions will now be discussed. Assuming
that the inverter 10 is enabled to run, controller 20
supplies a small base drive signal to one of the transistors
2~ QA and Q~. Assuming further that this base drive is applied
to QA, transistor QA turns on and current starts to flow
through Ll, the center tap of the primary P of transformer
Tl thence through P and through the A winding of feedback
transformer T2, to transistor QA and thence back to the
battery 14. The base drive originally supplied to tran-
sistor QA is augmented by a current flow from winding D of
feedback transformer T2 to the controller 20 to exit from
pin 1 thereof ~hence to flow through the base of transistor
QA. This base drive is proportional to the collector current
3Q of transistor QA and is designed to be adequate to keep the
transistor in saturationO
At some volt-second product, feedback transformer T2 ,~
~5~3~ 58-BD-6~36
saturates sharply, suddenly reducing the output current of
winding D thereof thereby reduciny the base drive to tran-
sistors QA. A sudden rise in collector-emitter voltage on
transistor QA sharply reduces the rate of current rise in
this DC circuit. This change in collector current with
respect to time reverses the polarity of the S2 winding o
transformer Tl and hence the polarity of the voltage on pins
3 and 4 of controller 20. This reversal of polarity signals
the controller 20. This reversal of polarity signals the
controller to change the base drive from transistor QA to
transistor QB.
Controller 20 now applies a small amount of base drive
through pin 9 to the base of transistor QB, and simultaneously
connects the base of QA to the emitter thereof to hasten
the turnoff process of transistor QA. Transistor QB starts
to conduct as a result of this small base drive signal from
the controller and current flows through winding B of feed-
back transformer T2 to induce a current in winding D thereof
and this current is supplied to the controller 20. Controller
20 now supplies th;s current as base drive out of pin 9 to
the base of QB; thus the base drive of QB is proportional
to the collector current thereof such that the transistor
is kept ïn saturation.
The P winding of transformer Tl has some leakage re-
actance and becomes an oscillating system with capacitor
C101. This oscillating system goes through the next half-
cycle and forces the current flowing through winding B of
feedback transformer T2 toward zero and thus the base drive
of transistor QB is also reduced. When the ~-oltage across
3Q winding P of transformer Tl, and thereby the voltage on
winding S2 of that transformer, reaches zero, this event is
signaled to the controller 20 which again switches the base
~ 5~3~ S8-BD-6336
drive circuitry to transistor QA from ~ and connects the
base of QB to the emitter thereof to hasten the switching
off of transistor QB. The circui-t is then ready to go
through the next hal~-cycle with ~A conducting.
If switching could be accomplished in absolute zero
time, the above described circuit operation would be entirely
correct. However, normally the switching is accomplished
in periods of less than one microseco~d and the current flow
from battery 14 is essentially at a constant level with a
small ripple content. ThiS ripple content is determined
by the inductance of Ll which adds or subtracts from the
battery voltage as applied to the tap of the primary P of
transformer Tl. It is this inductor Ll which adjusts the
voltage at point 22 in such a way that the transistors may
be switched at zero collector voltage. As long as this
inductance Ll has a value exceeding a critical value, this
circuit will function as described. In the event that both
transistors QA and QB are in the "off" state, the rate of
current change in Ll forces the voltage thereacross to a
value where zener diode D104 starts conducting to limit the
voltage applied to the circuit. This clipping action rapidly
reduces circu.it efficiency and hence is an operational
mode to be avoided. Such clipping action can occur momen-
tarily during the starting process or when the inverter is
turned off and under these conditions represents an
acceptable design operating condition.
The load for the inverter 10 including lamp 12 is
connected to a winding Sl of transformer Tl. For fluorescent
emergency lighting purposes, the ballast.ing is done by
3Q capacitors C102 which determine the load current th~ough
the lamp 12. This capacitance in conjunction with C101 and
inductance TlP determine the operational frequency of the
~S~3~ 58-sD-6336
system (the inductance of the P winding and a capacitance
of C101 determine the oscillating frequency when Sl is
unloaded). A double capacitive ballast system is used ~o
reduce the voltage across a single unit thus to enhance the
reliability of the complete system. The voltaye output o
the inverter circuit is high enough to instant start 40 watt
and 65 watt rapid start lamps under fairly adverse cOndi~ions~
~ s hereinbefore stated, charging of battery 14 is
accomplished from winding S of 50 Hz transformer T3. This
lQ is the same winding that applied DC energy to the indicator
lamp 24. Current flows from the finish of winding S to the
plus terminal of the battery 14 thènce through diode D101
and to the start of winding S. In the alternate half-cycle,
current flows from the start of winding S through diode
D103 to the lamp 24 thènce to the two-prong plug 26 and on
to the finish of winding S of transformer T3. If the
battery is not plugged in, the indicator lamp is not energized
signifying that the system needs attention. Also, if the
indicator lamp or its associated circuit becomes defective
2a. (open or shorted~, the main charging cycle for the battery
is uninterrupted but the lamp 24 does not come on again,
therefore signifying that the syatem requires attention:
the system however remains operational. In the event that
the battery 14 is not connected in circuit and line voltage
is exceedingly high, there exists the possibility that this
voltage would be applied directly across pins 3 and 10 of
the controller 20. Such a high voltage could be destructive
to the IC; taking advantage of the current limiting charact-
eristic~ of the winding S, zener diode D104 conducts so as
3Q to clip the peaks of this vol-tage wave through inductor
Ll thereby to protect the IC controller 20. This means
th~t the zener diode DlQ4 must be sized so as to dissipate
-- 10 --
~Z5B~9 58-~D-6336
this expected energy.
Winding S of transformer T3 also supplies a half-wave
rectified signal over a diode D102 and a zener D120 to filter
capacitor C10~ and voltage divider network R10~ and R105
thence to apply a signal to pin 1 of con~rol.ler 20. ~
this half wave rectified voltage decreases with decreasiny
the voltage, it finally reaches a point where the controller
20 is allowed to function; this is the inverter turnon point.
Because of the nature of the half-wave rectified signal
and the differential in the IC controller 20, a hysteresis
is inherent in the IC operation. Thus, the inverter "turn
off" point as controlled by the AC line voltage will be
higher than the inverter "turn on" point. By ajusting the
ratios of R104 and R105, either the inverter "turn on" or
"turn off" point may be controlled over quite a wide range;
however, both inverter "turn on" and "turn off" points may
not be separately controlled because of the relatively
fixed value of this built-in bysteresis. DC battery voltage
or charging transformer winding voltage is applied between pins
3 and 10 of controller 20. This same voltage is applied
across voltage divider R102 and R103 to pin 5 (second sensor~
of the IC controller 20. When the voltage at pin 5 drops
below a value determined by the construction of the IC, the
controller 2Q stops driving transistors QA and QB thus
shuttîng down the inverter 10. This voltage is normally set
at approximately one half of the nominal battery voltage but
it may be adjusted by the ratio of resistors R102 and R103.
A certain amount of hysteresis is implemented in the way
this control function is done in the IC controller. This
hysteresis provides clean on/off switching of the inveter.
After the inverter switches off, the voltage rises causing it
to turn on again. This provides repeated flashing of the
LZ5~339 58-BD-6336
fluorescent lamp which in turn indicates that the battery
is discharged. '
As stated above, in the event that -the battery i5 not
connected, the voltage across pins 3 and 10 o~ controller 20
will rise to a point which is the peak of the AC WaVQ yen-
erated in winding S of 50 Hz transformer T3. This voltage
might be excessive for the integrated circuit and therefore,
when the voltage across pins 3 and 10 of controller 20
exceeds approximately 30 volts, an internal regulator in
la the controller 20 shuts down the function of this controller
in such a way as to minimize the voltage on variGus com-
ponents of this integrated circuit. Thus, the application
of too high a voltage to this inverter will inhibit its
operation. This enhances the reliability of the sys-tem in
that it distributes electrical stxess better in the in-
tegrated circuit. Since the voltage occurring during
operation across the transistors QA and QB is double the DC
battery supply voltage, by shutting off these transistors
under abnormally high voltage conditions, the voltage is
2Q reduced simply to battery voltage, reducing the probability
that the transistors QA and QB might fail under such
highly abnormal conditions. If the voltage across the
battery 14 rises above the zener voltage of D104, zener
di`ode DlQ~ starts to conduct and voltage regulation will be
accomplished by means of the inherent impedence of winding
S of transformer T3. The voltage applied to the circuit
is this limited to a safe value under quite severe over-
Yoltage conditions. In the event the voltage continues to
xise becau5e o~ a wrong voltage applied to the primary
winding P o~ transformer T3 and with no battery ~n circuit,
the most pr~bable mode of failure of zener diode ~104 is to
short and this then crowbars the DC supply voltage to the
- 12 -
~5~3~ 58-BD-6336
inverter.
Operation of the circuit will now be discussed for
normal conditions; that is, when the AC line voltage is
above a first predetermined level. Assuming that ~C line
voltage has already been applied to input terminals 1 and
2, a switch 28 is closed thereby allowing line voltage to
be applied across the lamp 12 through reactor 16. Since
no push-to-start button or voltage breakdown type of
starting device has been supplied for startiny lamp 12,
lQ in accordance with the present invention, means are provided
for overriding the inverter controller for turning on the
inverter to start the lamp during such normal conditions
and for turning off the inverter after the lamp is operating
from the AC line voltage. In the preferred embodiment this
includes lamp voltage monitoring means in the form of a
voltage breakdown device such as zener diode D122 connected
serially with a pair of diodes D124 and D126 and a resistor
RlQ7 across the lamp 12. ~ light emitting diode D130 is
also connected serially with -this string and a capacitor
2Q ClQ`7 is connected in parallel with the diode string. The
application of line voltage across the lamp 12 causes ~ener
diode D122 to conduct thereby allowing the LED D130 to
become operative. Photons emitted from the LED D130 effect
the turning on of a phototransistor QP thereby allowing the
discharge of t~le line monitoring capacitor C104 through a
current limiting resistor R108. Since the integrated
circuit controller 20 sees a loss of line voltage at pin 7,
the inverter i5 allowed to turn on thereby effecting starting
of the lamp 12. Upon lamp starting, after lamp voltage
3Q drops to the normal run level, zener diode D122 stops con-
ducting there~y ef~ecting the turning off of the ~ED and
the phototransistor QP. Means are provided for assuring
~ ~ ~ 5 ~ ~ 58-BD-6336
operation of inverter 10 for a predetermined time after
lamp voltage reaches a normal run level. In the preferred
embodiment, this includes RC timing means, including resistor
Rl09 and capacitor C104, which functions to provide a time
delay of predetermined value. Capacitor Cl04 then gradually
charges over a charging resistor DlO9 and after a short dela~,
pin 7 of the controller 20 senses an appropriate voltage and
turns off the inverter lO. The choice of value of resistor
RlO9 in combination with capacitor Cl04 may be varied to
effect longer or shorter charging time of the capacitor.
Thus, the amount of delay time before the inverter turn off
may be controlled to assure the adequate hot-spotting of the
lamp to insure its long life. It should be no-ted that the
LED D130 and the phototransistor QP form an optocoupler which
advantageously may be provided in the form of an integrated
circuit.
As can be seen, lamp 12 may be turned on and off by
opening and closing switch 28 without activating the inverter
lQ except for starting. The inverter therefore serves to
2Q start the lamp during normal conditions and also to start
and operate the lamp during emergency conditions: upon
failure of the AC line voltage.
With the arrangement as shown in the drawing, a lamp
socket may function as a safety disconnect lampholder. As
shown, means are provided in the circuit for connection to
lamp 12 and include a first pair of terminals 32, 32l and
a second pair of terminals 34, 34'. Terminal 32' is con-
nected to ground through input terminal 2. When lamp 12
is removed from the circuit, the lamp voltage monitoring
3Q subcircuit including zener diode D122 is open circuited
since its connection to ground through terminal 32 and
lamp filament 30 is broken. ~s a result, during normal
- 14 -
~IL2~33~
58-BD-633~
conditions, (when ~C line voltage is above a predetermined
level) the inverter 10 will not turn on. As a further
example, if the filament 27 end only of the lamp 12 is
removed from the circuit, an individual coming lnto con~ac~
with the lamp pins connected to filament 27 will eff~c~-tuall~
contact ground since filament 30 is grounded; no electrical
shock will result. If the filament 30 end only of lamp 12
is removed from the circuit, the inverter will not run and
an individual contacting the lamp pins connected to
lQ filament 30 will receive no electrical shock since the lamp
will not ionize without starting assisting from the inverter.
Should lamp 12 be removed partially from the circuit during
emergency conditions (when inverter 10 is operational), an
individual contacting the lamp pins connected to filament
30 will be protected from severe electrical shock due to
the fact that winding Sl of transformer Tl has been designed
with a very low capacitance to ground thereby limiting
current flow. This reduced capacitance to ground has been
accomplished primarily by keeping the winding physically
2Q small and as electrically decoupled as possible from the
outer case and other windings.
As sta~ed hereinbefore, the control circuit 20 may be
fabricated as a single, monolithic, integrated circuit.
In this form, the use of slaved current sources is
particularly practical. In the embodiment described in the
aforementioned U.S. Patent No. 3,921,005 dated November 18,
1975, the current consumption and hence, power dissipation,
in the controller 20 is essentially independent of battery
voltage over the operating range. Furthermore, the control
3Q circuit can be matched to different power level inverters by
scaling the currents in the control circuit.
The lighting circuit shown in the drawing has been
~ 15 -
5i t33~ 58-BD-6336
, ,
constructed and has operated satisfactorily with components
having the following value:
Transistors QA, QB D44C10
Trans:Eormer Tl Primary winding P, 50 turns,
.0253" wire
Load winding Sl, 1130 turns,
.0063" wire
Feedback winding S2, 3 turns,
.0063" wire
lû Transformer T2 Collector windings A and B,
6 turns ~0126" wire
Output winding D, 240 turns,
0071" wire
Transformer T3 Primary winding P, 3332 turns,
.0045" wire
Secondary winding S, 290 turns,
.OQ80" wire
Heater winding H, 66 turns,
.01006" wire
Inductor Ll 73 turns, ~032" wire
Lamp 12 F40 T12 7~ RS
Battery 14 7 cells, 1/2 D, high temp Ni - Cd
Reactor 16 KNOBEL #40-5340
Resistor R101 15K ohm 1/4 W
(all 5%1 R102 22K ohm 1/4 W .
R103 22K ohm 1/4 W
R104 lOOK ohm 1/4 W
R105 220K ohm 1/4 W
R107 lOQK ohm 2 W
R108 608K ohm 1/4 W
RlQ9 18K ohm 1/4 W
.
3i'3
58-BD-6336
Capacitor C101 .22 uf 50 V AC, 10
C102 (2) 5100 pf ~00 V, 5%
C104 2.0 uf 50 V, 20~
C105 .01 uf 100 V, 20%
C107 100 pf 500 V AC, 10
Diode D101, D102, D103,
D126, D124 IN 4004 lA., 400 V
Diode Dlll, D115 DA 1701 .24, 25 V
Zener Diode D104, D120 20 V, 1 W 5%
lQ Zener Diode D122 150 V DC, 1 W, 5
LED D130
Phototransistor QP ) IC Photocoupler HllA5 (GE)
Control circuit 20 has been built and has operated
satisfactorily in hoth discrete circuit form and as a
monolithic IC; See U.S. patent No. 3,921,005 dated November
18, 1975 for details.
The illustrated embodiment was designed to operate
a 4Q W rapid start fluorescent lamp from a 220 V, 50 Hz
source an, in the emergency mode at 5500 Hz, from battery
2Q (for 100 minutes). This circuit has also successfully
operated a 65 watt rapid start fluorescent lamp. Another
circuit has been built and has operated a 20 W rapid start
lamp from a 120 V, 60 Hz AC source and from a battery;
this circuit had the same component values as above, except
for the following:
Resistor R107 47 K ohm, 2 W
RlQ9 10 K ohm, 1/2 W
Transformer T3 Primary P 1690 turns, .0063"
dia. wire Secondary S 340
3Q turns. 0063" dia wire
H 80 turns. 0126" dla. wire
Zener Dioae D122 100 V, 1/2 W
I
~ 17 -
~ ~ S ~ ~ 58-BD-6336
LED D130
~ IC Photocoupler - HllA5 (GE)
Phototransistor QP ~
Capacitor C107 .001 uf, 200 V
C108 (not shown) .001 u~, 50 V (between base of
phototransistor and pin 10 of
controller 20)
Reactor 16 89G988 (GE)
While an embodiment and application of this invention
have been shown and described it will be apparent to those
lQ skilled in the art that modifications are possible without
departing from the inventive concepts herein described. The
invention, therefore, is not to be restricted except as is
necessary by the prior art and the spirit of the appended
claims.
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