JPS5960897A - Device for firing discharge lamp - 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 a discharge lamp lighting device, and more particularly, to a discharge lamp lighting device connected to a remote control type dimmer that turns off the light by making a phase control element inserted in series between an AC power source and a load non-conductive. The present invention relates to a discharge lamp lighting device which performs good dimming lighting using a controlled lighting system.

2. Description of the Related Art Conventionally, a discharge lamp lighting device is known that supplies a filament current for preheating only at the time of starting, and cuts the filament current after lighting to save power consumption. This device measures the preheating time until the filament power is cut as described above, or maintains the voltage across the discharge lamp lower than the ignition voltage for a certain period of time when starting the discharge lamp to generate residual heat, which has a negative impact on the life of the discharge lamp. In order to measure a so-called soft start time to prevent a cold start, one or more timers are provided to measure the elapsed time after the power is turned on. This timer has as a time constant element a capacitor and a resistor whose charge is discharged when the power is cut off.

FIG. 1 shows the configuration of a discharge lamp dimmer in which such a discharge lamp lighting device is connected to a phase control type dimmer. The device shown in the figure includes a dimmer 2 that generates a phase-controlled AC output from an AC power source 1 such as a commercial power source, and a two-wire wiring connected to the dimmer 2, which responds to the dimmer output. A discharge lamp lighting device (electronic ballast) 4 is provided to control and light the discharge lamp 3.

The dimmer 2 is a phase control element such as a triac Q1 inserted in series between the AC power source 1 and the electronic ballast 4. The dimmer 2 is selected by a remote control input from a controller 5 provided externally to the dimmer. A gate circuit 6 generates a gate pulse in phase to ignite the triac Q, and a resistor called a snubber circuit is connected in parallel to the live circuit Q to prevent malfunction of the triac Q due to noise from the AC power supply 1. A series circuit including R and a capacitor C is provided. This dimmer 2 can be turned off by controlling the spider 1. When the light is turned off, the gate circuit 6 does not apply a gate signal to the i-live switch Q.

The electronic ballast 4 includes a high frequency generator, such as an inverter, that generates high frequency output from the output of the dimmer 2, as will be described later.

By the way, in this dimmer 2, as mentioned above, the light is turned off by making the triac Q non-conductive, but a snubber circuit for preventing malfunction is connected in parallel to the triac Q, and this Since the impedance of the snubber circuit is about the same or lower than the starting resistance value of the electronic ballast 4, even if the triac Q is made non-conductive, the inverter that constitutes the electronic ballast 4 is supplied with power through the snubber circuit and continues to operate. It will continue. For this reason,
The capacitor as a timer element in the electronic ballast 4 is not completely discharged when the lamp is turned off, resulting in malfunctions such as the time after the power is turned on being shorter than the set value or the timer not operating, and the discharge lamp is not sufficiently preheated. There are disadvantages in that the discharge lamp does not turn on or the soft start does not work sufficiently, resulting in a cold start, which shortens the life of the discharge lamp.

FIG. 2 shows an equivalent circuit when the triac Q is made non-conductive. Here, R and C are the resistor R and capacitor C, R3 which constitute the snubber circuit, are the starting resistance of the inverter in the electronic ballast 4, and Rf' is the filament!・The load is converted to the inverter input side. In this case, assuming that the input and output voltages of the inverter circuit are linearly proportional, the output of the inverter circuit is at full light (R=O, C=
Oo)... (1) times, and in such a device where the filament is always connected, for example, 40W to a 200V16A dimmer.
When one X2 lamp is connected, the inverter oscillation voltage is about 1/10 of that at full light, so no particular problem occurs.

However, when using the electronic ballast 4 that cuts off the filament power after starting as described above,
) In the equation, Rf-■, E5 = The output of the inverter circuit is twice that of full light.For example, if one 40W x 2 lamp is connected to a 200V 16Δ dimmer as described above, the oscillation voltage will be double that of full light. It will be about 1/3 of the time.

FIG. 3 shows a timer circuit used for filament cutting, soft start, etc. This circuit connects the tertiary winding output of the inverter transformer to diode D and capacitor Cs.
The rectified and smoothed voltage, ie, the base drive voltage VD of the output transistor of the inverter, is used as a power source. In the same figure, capacitor C3 is a high frequency smoothing capacitor,
The resistor Rt and the capacitor Ct are time constant elements, and the capacitor Ct is charged through the resistor Rt as shown in FIG. When the voltage of this capacitor Ct exceeds the zener voltage VZo of the zener diode ZD, the output of the operational amplifier A becomes "L II level" and the transistor 7r is turned off to cut off the filament power or cancel the soft start.

When the power supply is cut off in a CR charging type timer with such a configuration, the charge on the capacitor Ct is discharged to the drive circuit through the resistor R11, but when the inverter oscillates and a voltage Voff' is generated on the capacitor C8, In this case, the voltage of capacitor C[ does not become lower than the voltage VoH across capacitor C3. Therefore, when the triac Q of the dimmer is turned on and the power is turned on with this charge remaining, the 1-transistor Tr is turned on in a time T1 shorter than the time TO when the charge on the capacitor Ct is zero, as shown in Figure 4. OFF, and if vzD>Vorf, the timer circuit does not operate. By setting Vz o >Voff, the worst situation in which the timer does not operate can be avoided, but since the voltage V off across the capacitor C8 varies depending on the number of connected appliances, the timer time changes depending on the number of connected appliances. Further, the situation changes depending on whether the power source is turned on and off using a contact switch such as a breaker (not shown) or when the triac Q of the dimmer 2 is turned on and off as a switch. That is, in the conventional filament cut type electronic ballast, malfunctions such as the timer not operating or the operating time being inconsistent have occurred.

The purpose of the present invention is to solve the above-mentioned problems in the conventional type.
In a discharge lamp lighting device, the filament power is cut off at least during full light after the discharge lamp starts, and the power is turned on and off by a phase control element inserted in series between an AC power source and the discharge lamp lighting device. The purpose of this invention is to prevent malfunctions of a timer circuit due to power flowing in through a snubber circuit connected in parallel with the phase control element at the time of shutoff, thereby preventing discharge lamp malfunctions, cold starts, and shortening of lamp life.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 5 shows a filament cut cancel circuit and a timer circuit according to one embodiment of the present invention.

This circuit is different from the timer circuit shown in Fig. 3 by inverting the input polarity of operational amplifier A and connecting npn to the output terminal of operational amplifier A.
pnp type transistor Tr through a resistor Rf instead of the pnp type transistor Tr.
In addition to connecting a transistor Trf for controlling the filament of the mold, a filament cut cancel circuit 7, which is a feature of the present invention, is added. Therefore, when the timer circuit times out, the operational amplifier 8 outputs "l-".
1" and turns off the transistor rrf to cut the filament power. This circuit 7 includes a zener diode ZDI, resistors R1, R2, R3, R4, and transistors Tr1 and Tr2, and Detect the aforementioned drive voltage Vo that is approximately proportional to.
Threshold voltage vth=vbe1(R1+R2)/R2+Vz o
1... (1) (However, Vbe1 is the base-emitter ON voltage of transistor Tr1, VZDI is the zener voltage of the zener diode) is smaller than the voltage Vo when lighting the lamp, and the dimmer switch is The voltage Vo is selected to be higher than the voltage Vo when the lamp is turned off in the "off" position, that is, when the thyristor is non-conducting.

Therefore, when the dimmer switch is in the "on" position and the inverter is oscillating, that is, when the dimmer is turned off and at full light, the transistor Tr1 is on and the transistor Tr2 is off. On the other hand, when the dimmer switch is in the "off" position and the inverter is oscillating, the transistor Tr1 is turned off and the transistor Tr2 is turned on, so the transistor Trf is turned on and the filament of the discharge lamp is connected to the inverter output. Therefore, the inverter output voltage and the inverter transformer tertiary winding output are multiplied by a factor of 1/10, for example, as shown in equation (1) above with respect to the full-light condition.
The voltage across the timing capacitor Ct of the timer element becomes substantially zero.

FIG. 6 shows a circuit configuration of a discharge lamp lighting device according to another embodiment of the present invention. In the figure, 1 is an AC power source such as a commercial power supply, 2 is a dimmer that generates phase-controlled AC output from the AC power source 1, 3a and 3b are discharge lamps, and 4 is a dimmer with two lines drawn. This is a discharge lamp lighting device that is wired and inputs the dimmer output to light the discharge lamps 3a and 3b.

The discharge lamp lighting device 4 includes a rectifier circuit 8, a high frequency generation circuit 9,
Filament control circuit 10. The soft star 10 is provided with a start circuit 11 and a filament cut cancel circuit 12, which is a feature of the present invention.

Next, detailed operation of the discharge lamp lighting device 4 will be described.

Now, when the AC power m1 is turned on, AC output is supplied to the discharge lamp lighting device 4 via the dimmer 2. This discharge lamp lighting device 4 is used as a high frequency generator 9, for example, in Japanese Patent Application Laid-Open No. 56-12
5970! It uses the pushy cobble inverter shown in the publication, includes a full-wave rectifier circuit as the rectifier circuit 8, and generates a high-frequency output from the non-smooth direct current (rectified output) generated by the rectifier circuit 8. . The rectified output generated by the full-wave rectifier circuit 8 is applied via an inductor L1 to an inverter 9 having output transistors Ql, Q2 and an output transistor T1. As a result, in the inverter 9, the rectified output is applied as a base current to the transistors Ql and Q2 via the capacitors C11 to C14, the starting resistor R11, the diode D11, the IC2 of the soft start circuit 11, and the bias resistors R12 and R13.

Then, one of the transistors Q1 and Q2 turns on first due to a slight imbalance, but if the transistor Q1 turns on first, current flows to the primary winding T11 of the output transformer T1. Therefore, in this state, an oscillating voltage is generated by the inductance of the primary winding T11 and the resonant capacitors C15 and C16, which generates an electromotive force in the base winding T1b, which in turn turns on the transistor Q2. Therefore, similarly, transistor Q1. Q2 is alternately turned on and off to cause oscillation. Note that after the oscillation starts, the induced output of the tertiary winding T13 of the output transformer T1 is connected to the diode DI2.
A drive voltage rectified and smoothed by a capacitor C17 is applied to bias resistors R12 and R13. As a result, a bias current proportional to the voltage of the primary winding T11 of the output transformer T1 of the inverter 9 is supplied to the transistors Q1 and Q2. Therefore, in this inverter 9, when the input voltage to the inverter is high, that is, when the load power is large, the drive current is increased,
On the other hand, when the load power is small, by lowering the drive current, an optimum drive current is provided to the power transistors Ql and Q2, thereby preventing an increase in switching loss and saturation loss. In addition, the current limit 1 to
Lance T2 and diode [)13. A rectified output is generated through a rectifier circuit consisting of [ ) 14, and this output is given to capacitors 011 to 14 as a feedback output. Thereby, the capacitors 011 to 14 are charged in a predetermined direction. Further, the capacitors 011 to 14 are discharged when the rectified output of the rectifier circuit 8 becomes equal to or less than a predetermined voltage every half cycle, that is, the charging voltage of the capacitors 011 to 14 in this embodiment, and provides this discharge output to the inverter 9. As a result, a high frequency output with no rest period is generated at the secondary winding T11 of the output transformer T1 of the inverter 9, and thus at the tertiary winding T13 side. Note that the diode D1
Reference numeral 5 is for isolation for separating the capacitors 011-14 from the circuit when the charging voltage of the capacitors 011-14 is lower than the rectified output of the rectifier circuit 8.

Next, detailed operation of the filament control circuit 10 will be described. This control circuit 10 includes envelope detection circuits 31 and 13, a differentiation circuit 32, a timer circuit 33, and a switching circuit 34.
, a power supply circuit 35, and a voltage obtained by rectifying and smoothing the tertiary winding output of the output transformer T1 and the drive voltage V.
It operates using o as a power source and input signal.

The power supply circuit 35 includes a diode 021, a resistor R21, and a capacitor C21, and generates a smoothed DC output by rectifying and smoothing the output voltage of the output transformer tertiary winding T13, and supplies power to the switching circuit 34.

The timer elements of the timer circuit 33 are a capacitor C23 and resistors R24, R25, and R26, and the capacitor C23 is charged by the drive voltage Vo via the resistors R24, R25, and R26. Note that the resistor 26 is connected to the inverter INV1.
The resistance value is negligible compared to the resistor 25°26. , the input terminal of the inverter INV2 is connected to the connection point between the resistors R24 and R25 via a zener diode ZD23. Capacitor C2
4 is for preventing malfunction due to noise. Also, inverter INV2. The 14-closed loop of INV3, resistor Rf, R28 and zener diode ZD23 is used to prevent malfunctions due to noise.

Now, when the power is turned on, the terminal voltage of the capacitor C23, that is, the input terminal voltage of the inverter INV2 is O, so the input of the inverter TNV2 is L'', so the output is 118 II. Therefore, the output of the inverter INV3 is L ( L II, and the transistor Trr is the resistor R
[Driven through and turned on.

This transistor Trf short-circuits the DC terminals of a full-wave rectifier circuit 36 made up of diodes 031 to 34 of the same switching circuit 34, and thus short-circuits the AC terminals of this rectifier circuit 36. Therefore, the high frequency output of the inverter 9 is supplied to the filaments of the discharge lamps 3a and 3b via the filament winding 71r of the output transformer T1 and the filament transformer 3, and the filaments are preheated.

When the filament is sufficiently preheated, the discharge lamp 3
a.

3b, the output transformer secondary winding starts discharging by the high frequency output without any rest period, which is supplied from T12.

On the other hand, the drive voltage Vo is connected to the diode D36 and the resistor R3.
5 and a capacitor C26.
The envelope F8 waveform is differentiated in a differentiating circuit 32 consisting of capacitors C27 and R37 and the input impedance of an open collector inverter INV1. This differential waveform is the discharge lamp 3a, 3b
The peak value is low when all lights are on. Therefore, the collector of the inverter INVI is open, and the capacitor C23 is connected to the resistors R24, R25, R26 from the drive voltage Vo without being affected by the inverter INV1.
is charged via. Assuming that the impedance seen on the right side from the connection point between the resistors 24 and 25 is ■, the voltage Vin at this connection point is Vin=Vc3+ (Vo -Vc3) x (R25
+R26) /(R24+ R25+ R26)...
...(3) (However, the envelope voltage of the drive voltage VD,
Vc3 is the charging voltage of capacitor C23 during timer operation)
It is. In this 1=full light state, a predetermined time elapses and the voltage VC3 between the terminals of the capacitor 023 rises (3
) is the voltage Vin shown by the zener diode ZD23.
When the zener voltage becomes higher than the sum of the zener voltage and the threshold voltage of the inverter INV2, the output of the inverter INv2 becomes '
L'', input t<-input I The output of NV3 becomes H'', transistor Trf is turned off, and the current is cut off. Further, during dimming, the peak value of the differential circuit output is high as described above. Therefore, the output of the inverter INV1 becomes "L", the capacitor C23 is discharged, the timer circuit 33 is reset, and power is supplied to the filament in the same manner as when the power is turned on above. In addition, diode D3
7 is the 1=th one that rapidly discharges the capacitor C23 when the power is turned off to prepare for the next power on.

The soft start circuit 11 is a soft start IC (IC
2). This IC2 is a timer whose timer elements are a capacitor C31 and a resistor built into IC2.
After this timer times up, it becomes conductive, shorting the resistor R31 and connecting the drive winding, that is, the output transformer tertiary winding T1.
3 to transistors Ql and Q2, and during preheating of the discharge lamp before the timer times out, the transistor Q1
, Q2 to make the drive insufficient, the output voltage of the inverter 9, that is, the voltage applied to the discharge lamps 3a and 3b, is maintained below the ignition voltage. This prevents a cold start in which the discharge lamp is turned on without sufficient preheating, thereby preventing a short circuit of lamp life.

The filament cut cancel circuit 12 includes a resistor R41,
It consists of R42, R43 and inverters INV4 and INV5. This filament cut cancel circuit 12 connects the drive winding T13 to the diode [)12. Q41
And it is determined whether the dimmer switch is on or off based on the power supply voltage VSS for IC2, which is supplied via the resistor R44 and smoothed by the capacitor C41. Therefore, when the dimmer switch is "off" and the voltage VSS is lower than the threshold voltage of the inverter INV4, the output of the inverter INV4 is "H" and the output of the inverter INV5 is "L".
Filament via resistor 18-43] Control transistor Trf
is driven, and the filament circuits of the discharge lamps 3a and 3b are connected to the inverter output. Also, the dimmer switch is turned on and off.
1 and the voltage Vss is higher than the threshold Nrf of the inverter INV4, the output of the inverter INv4, that is, the input of the inverter INV5 becomes 11 L II, the collector of the inverter INV5 becomes open, and the transistor Trf becomes ``l-'' of the output of the inverter INV3. ”
or 'H' to turn on or off.

In this way, by resetting the capacitor C31 as a soft start timer element when the inverter 9 is oscillating when the power is cut off, it is possible to prevent the malfunction of the soft start timer, that is, a cold start, and thereby extend the life of the lamp. can be prevented from shortening.

Although a push-pull type self-excited inverter is used in the above description, a passive or single type inverter may also be used. Furthermore, although a two-lamp type discharge lamp lighting device is used in the above description, a one-lamp type discharge lamp lighting device may also be used. Further, the timer element is not limited to filament control or soft start, but can be used for any purpose as long as it is an electronic type that is reset when the power is cut off. Furthermore, the filament control circuit may be of a type that detects the light output of the lamp or the tube wall temperature and cuts the filament power. Furthermore, in the above-described embodiment, power cutoff was detected from the drive voltage, that is, the tertiary winding voltage of the output transformer. Power cutoff may be detected based on. In this case, when using a signal such as the input voltage whose high frequency component level is 0 or extremely low, the envelope detection circuit can be omitted.

As described above, according to the present invention, when the power is cut off by the phase control element, if the voltage supplied through the snubber circuit is below a predetermined level, the inverter is loaded with the discharge lamp filament, thereby reducing the supply voltage and the inverter. Since the output voltage is lowered to a low level and the timer capacitor is substantially reset, malfunctions of the timer circuit can be prevented. Therefore, it is possible to prevent shortening of lamp life due to a cold start due to malfunction of the timer for soft star 1 to, and malfunction of the discharge lamp due to insufficient preheating or inability to preheat due to malfunction of the filament control timer.

[Brief explanation of drawings]

Figure 1 is a circuit configuration diagram of a general discharge lamp dimmer, Figure 2 is an equivalent circuit diagram when the triac in the device shown in Figure 1 is made non-conductive, and Figure 3 is the dimmer of Figure 1. 4 is a circuit diagram of a timer circuit included in the discharge lamp lighting device in FIG. FIG. 6 is a circuit diagram of a discharge lamp lighting device according to another embodiment of the present invention. 1... AC power supply, 2... Dimmer, 3... Discharge lamp, 4... Discharge lamp lighting device (electronic ballast), 5...
Remote control [1-ra, 6...gate circuit, 2
1-7...Filament cutter 1-cancellation circuit, 8...
・Rectifier circuit, 9... Inverter,
DESCRIPTION OF SYMBOLS 10... Filament control circuit, 11... Soft start circuit, 12... Filament cup 1~cancellation circuit, 33
...Timer circuit, Q...Phase control element,
R...Resistance, C, Ct, C23, C31...
Capacitor, T1... Output transformer, II3... Output transformer tertiary winding. Patent Applicant Toshiba Electric Materials Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Neiro Ito-22= Figure 1 + J-0 Figure 4 Vz. off 1 Figure D-1 Figure 5

Claims (1)

[Claims] 1. A series circuit of a resistor and a capacitor is connected to an AC power source via a phase control element connected in parallel, and a rectifier circuit that generates a rectified output from the output of this phase control element, and a capacitor that is discharged when the power is cut off. It includes one or more timers as time constant elements that measure the elapsed time after the power is turned on, and at least during full light after starting the discharge lamp, disconnects the filament from the output of the high frequency generator to cut off the power, and controls the phase. In a discharge lamp lighting device in which the power supply is cut off when an element becomes non-conductive, either the input voltage of the high frequency generator or the output voltage of the primary or tertiary winding of the output transformer is detected, and this detected voltage is detected. A discharge lamp lighting device comprising a filament cut cancel circuit that connects the filament to the high frequency generator when the voltage is below a predetermined voltage.