JPS6121394B2 - - Google Patents

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 that causes a discharge lamp to glow discharge with a relatively short-term pulse voltage with a high peak value, and with a relatively long-term oscillation output with a low peak value. The present invention relates to a discharge lamp lighting device that starts and lights a discharge lamp by causing an arc discharge.

FIG. 1 is a diagram showing conditions for lighting a discharge lamp. In the figure, if the vertical axis is the peak value Vp of the applied voltage and the horizontal axis is the voltage application time width _tp , then the relationship between the peak value of the applied voltage and the application period required to start and light the discharge lamp is It is shown as a hyperbola in the figure. As is clear from the diagram, if you try to start and light a discharge lamp with a relatively short pulse voltage (for example, one pulse voltage), the peak voltage of the oscillation pulse needs to be extremely high; It can be seen that if an attempt is made to reduce the peak value, a relatively long application period (width) is required. Conventionally, as a starter circuit for starting a discharge lamp, two pulse circuits are used: one is a pulse circuit that generates a pulse with a high peak value in a short period of time and uses the characteristic region to start and light the pulse, and the other is a pulse circuit that generates a pulse with a high peak value in a short period of time and uses the characteristic region to start lighting. An oscillation circuit that operates in oscillation for a period and starts using a characteristic region has been used.

The apparatus for starting and lighting a discharge lamp using the pulse circuit is inferior to the oscillation circuit in that it can reliably start and light the discharge lamp regardless of the type of discharge lamp. In other words, hot cathode fluorescent lamps can be roughly divided into two types: preheating start type FL and instant start type FLR.The former has capacitive discharge breakdown, while the latter has resistive discharge breakdown. Has a suitable starting method.

Since the pulse generation circuit shortens the oscillation period and increases the pulse peak value, it is advantageously used in preheat-start type fluorescent lamps FL, which have capacitive discharge breakdown, but is useful for instant-start type fluorescent lamps, which have resistive discharge breakdown. The optical lamp FLR had the disadvantage that it could not be used as a starter circuit because the energy of the pulse voltage was small. Also, because it generates extremely high voltage pulses, the power line
In the case of 200V, each element used in the circuit was required to have extremely high voltage resistance, which had the disadvantage of increasing the size of the device.

On the other hand, in the case of an oscillation circuit, large oscillation energy can be obtained to ensure starting and lighting, but on the other hand, if discharge breakdown (glow discharge) occurs in the cold cathode state before the filament is sufficiently preheated, The problem was that the damage to the electrodes was relatively large.

Therefore, the main purpose of the present invention is to combine the advantages of both methods so that the device can be made relatively compact.
Moreover, it is an object of the present invention to provide a discharge lamp lighting device that can reliably start and light the discharge lamp regardless of the type of discharge lamp.

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

To summarize the invention, there is provided a pulse generation circuit that generates a relatively short pulse with a high peak value;
Equipped with an oscillation circuit that generates an oscillation voltage with a relatively long period of time and a low peak value, the discharge lamp is glow-discharged with short-term pulses with a high peak value, and discharged with a relatively long-term oscillation output with a low peak value. The discharge lamp is started and lit by transitioning the lamp to arc discharge or by preheating the electrodes.

FIG. 2 is a block diagram showing an example of the principle of the invention. In the figure, a current limiting choke 2 as an example of a current limiting device and a discharge lamp 3 are connected in series to an AC power source serving as a low frequency AC power source. A series circuit of a pulse generation circuit 4 and an oscillation circuit 5 is connected in parallel to the discharge lamp 3. As this pulse generating circuit 4, a circuit that generates a pulse with a high peak value in a relatively short period of time is used. Oscillation circuit 5
For example, a continuous oscillation circuit that generates an oscillation output with a low peak value for a relatively long period of time or an intermittent oscillation circuit that oscillates intermittently every half cycle of the power supply voltage is used.

Then, when the AC power is turned on, the oscillation circuit 5 is energized by the low frequency AC voltage of the AC power and performs high frequency oscillation for a relatively long period of time, and the pulse generating circuit 4 generates a pulse with a high peak value in a relatively short period of time. is generated (preferably generated later than the oscillation operation of the oscillation circuit 5), and this oscillation output and pulse output are superimposed and applied to the discharge lamp 3. discharge lamp 3
starts glow discharge with a pulse output with a high peak value given from the pulse generation circuit 4, and a high frequency oscillation voltage (voltage with high energy) with a low peak value from the oscillation circuit 5 is supplied, causing the discharge lamp 3 to arc discharge. Migrate. In this case, the oscillation voltage alone will not cause discharge breakdown, and therefore the discharge lamp 3 can be started and lit by a short glow discharge period after the filament has been sufficiently heated.

FIG. 3 is a block diagram of another example illustrating the principle of the invention. In this block diagram, a pulse generating circuit 4 is inserted in a series circuit of an AC power source, a current limiting choke 2, and a discharge lamp 3, and an oscillation circuit 5 is connected in parallel to the discharge lamp 3. Even in such a block circuit, the discharge lamp 3 can be started and lit in the same manner as shown in FIG.

Next, a detailed circuit configuration of the basic block diagram of the present invention shown in FIG. 2 or 3 will be explained.

FIG. 4 is an electrical circuit diagram of a discharge lamp lighting device using an every-cycle start lighting method according to an embodiment of the present invention. In particular, an intermittent oscillation circuit 5' is applied as the oscillation circuit 5 in the block shown in FIG. It is something. In the configuration, a discharge lamp 3 is connected in series to an AC power source via a current limiting choke 2. The filaments 31, 3 of this discharge lamp 3
An oscillation capacitor 51 is connected in parallel to the power supply side end of 2. At the non-power supply side ends of the filaments 31 and 32, an intermittent oscillation capacitor 55, a secondary winding 412 and a primary winding 411 of the pulse transformer 41, a capacitor 43, a boost inductor 52, and a thyristor 5 are connected.
Three series circuits are connected in parallel. A thyristor 42 is connected in parallel to the series circuit of the primary winding 411 of the pulse transformer 41 and the capacitor 43. This pulse transformer 41, thyristor 42, and capacitor 43 constitute a pulse generating circuit 4. In addition, the oscillation capacitor 51 and the boost inductor 5
2, thyristor 53, and intermittent oscillation capacitor 55
Intermittent oscillation circuit 5' as another example of the oscillation circuit.
Configure.

FIG. 5 is a waveform diagram for explaining the operation of FIG. 4, and especially the pulse voltage V 4 of the pulse generation circuit ₄ .
A voltage waveform obtained by superimposing the intermittent oscillation voltage V ₅ ' of the intermittent oscillation circuit 5' is shown.

Next, the operation will be explained with reference to FIGS. 4 and 5. When the AC power is turned on, the oscillation capacitor 51 is charged via the current limiting circuit 2.
The terminal voltage of this oscillation capacitor 51 is applied to the thyristor 53 through the path of filament 31 - intermittent oscillation capacitor 55 - secondary winding 412 - primary winding 411 - capacitor 43 - boost inductor 52 - thyristor 53 - filament 32. Ru. Therefore, when the terminal voltage of the oscillation capacitor 51 exceeds the breakover voltage of the thyristor 53, the thyristor 53 becomes conductive, and the oscillation capacitor 51 and the step-up inductor 52 cooperate to perform oscillation operation to generate a high frequency signal with a low peak value. An oscillation voltage V ₅ ' is generated. This oscillation current and the input current to the intermittent oscillation circuit 5' flow through the filaments 31 and 32, and preheat the filaments 31 and 32. Also, thyristor 5
Due to the conduction of thyristor 3, the capacitor 43 is rapidly charged, and the terminal voltage of the capacitor 43 is increased to thyristor 4.
When the breakover voltage of 2 is exceeded, the thyristor 42 becomes conductive. By this, capacitor 4
3, the primary winding 411, and the thyristor 42 in a closed circuit generate a relatively short-term pulse voltage with a high peak value, and this pulse voltage is boosted by the secondary winding 412. This pulse voltage V ₄ is superimposed on the oscillation voltage V ₅ ' and applied to the discharge lamp 3. Note that, if the intermittent oscillation capacitor 55 is not provided, the oscillation operation of the intermittent oscillation circuit 5' will continue for a half cycle period of the power supply voltage e;
5 is gradually charged by the input current to the intermittent oscillation circuit 5', and its terminal voltage acts in a direction to cancel the power supply voltage, so the oscillation operation of the intermittent oscillation circuit 5' is intermittently only for a predetermined phase period of each half cycle. This results in oscillating operation.

Thereafter, the above-described operation is repeated every half cycle of the power supply voltage, and the filament 31,
32 is sufficiently preheated, the discharge lamp 3 starts a low-energy glow discharge by the pulse voltage _V4 of the pulse generation circuit 4, and then starts a glow discharge with low energy by the intermittent oscillation voltage V5' of the intermittent oscillation circuit 5'. Arc discharge occurs and the light starts to light up. Once the discharge lamp 3 is lit, a tube current flows through the current limiting tube 2 and its impedance changes, so the oscillation period of the intermittent oscillation circuit 5' becomes shorter than at the time of startup, and the oscillation period is shortened every half cycle. It is turned on in a start mode every cycle while being re-ignited by the intermittent oscillation output voltage V5' of the oscillation circuit 5'.

As described above, according to this embodiment, when starting the discharge lamp, the intermittent oscillation voltage V5' and the pulse voltage _V4 having a high peak value are superimposed to control the discharge lamp 3.
, the discharge lamp 3 can be reliably started and lit, and since the intermittent oscillation circuit 5' continues the intermittent oscillation operation every half cycle while the discharge lamp 3 is lit, the discharge lamp 3 can be operated only by the power supply voltage. Compared to the normal lighting method in which the lighting is maintained by re-igniting the current, the current limiting choke 2 can be made smaller and lighter, and the fluctuation rate can be improved.

FIG. 6 is a specific electrical circuit diagram of a discharge lamp lighting device using the every-cycle start lighting method according to a preferred embodiment of the present invention.
An intermittent oscillation circuit 5' is used as the oscillation circuit in the block diagram shown in the figure, and the operation of the pulse generation circuit is stopped after the discharge lamp is lit. In the configuration, the AC power supply includes a current limiting station 2, a block inductor 61, and a discharge lamp 3.
are connected in series. At the non-power supply side ends of the filaments 31 and 32 of the discharge lamp 3, there is a canceling winding 62 which is magnetically coupled to the block inductor 61 and wound so as to generate a magnetic flux in a direction that cancels the magnetic flux generated by the current flowing through the inductor 61. A series circuit of an intermittent oscillation capacitor 55, a boost inductor 52, and a thyristor 53 are connected in parallel. An oscillation capacitor 51 is connected between the connection point between the current limiting choke 2 and the inductor 61 and the power supply side end of the filament 32 . The current limiting chain 2 has an intermediate tap 23 and is divided into a primary winding 21 and a secondary winding 22. This intermediate tap 23 and filament 3
A series circuit of a resistor 461, a capacitor 43, and a triac 42' is continued between the power supply side end of the transistor 2 and the power supply side end of the transistor 2. Also, for AC power supply, triax 4
Capacitor 47 and resistor 46 for starting 2'
Two series circuits are connected in parallel. capacitor 47
A resistor 463 is connected in parallel. A diode 48 is connected between the connection point of the capacitor 47 and the resistor 462 and the gate of the triac 42'. Between one end of the resistor 463, that is, the power supply end of the filament 32 and the other end of the resistor 463, an inductor 63 and a resistor 4 that are magnetically coupled to the inductor 61 to detect the tube current i _T are connected.
64 and a series circuit of diode 49 are connected.
Note that, if necessary, a noise removal capacitor 7 is connected in parallel to the AC power source.

In operation, when AC power is turned on,
At the same time as the oscillation capacitor 51 is charged, the capacitor 47 is charged according to a time constant determined by the resistance value of the resistor 462 and the capacitance of the capacitor 47.
When the terminal voltage of the oscillation capacitor 51 exceeds the breakover voltage of the thyristor 53, the thyristor 53 becomes conductive, and the oscillation capacitor 51 - blocking inductor 61 - filament 31 - offset winding 62 - intermittent oscillation capacitor 55 - boost inductor 52 - Starts high frequency oscillation operation on the path of thyristor 53 - filament 32. At this time, the oscillation current and input current of the intermittent oscillation circuit 5' flow through the block inductor 61 and the cancellation winding 62, but the winding directions of the block inductor 61 and the cancellation winding 62 are opposite, so that the oscillation current and the input current flow in the canceling direction. Therefore, the blocking inductor 61 is disabled and no voltage is induced in the inductor 63. When the charging voltage of the capacitor 47 exceeds the breakover voltage of the thyristor 48 later than the oscillation operation of the intermittent oscillation circuit 5', the thyristor 48 becomes conductive and gate current is supplied to the triac 42'. In response, the triac 42' becomes conductive, and the pulse generating circuit 4 generates a pulse voltage of relatively short duration and high peak value. This pulse voltage is induced to rise in the secondary winding 22 of the current limiting choke, is superimposed on the intermittent oscillation voltage, and is applied to the discharge lamp 3.
After repeating this operation every half cycle, the filaments 31 and 32 of the discharge lamp 3 are sufficiently preheated by the oscillation current and the input current to the intermittent oscillation circuit 5', and then the pulse generation circuit 4 is heated. The pulse voltage causes a glow discharge, and the intermittent oscillation voltage of the intermittent oscillation circuit 5' causes an arc discharge, so that the discharge lamp 3 is started and lit. When the discharge lamp 3 is started and lit, a tube current i _T flows through the discharge lamp 3 via the current limiting choke 2 and the inductor 61. On the other hand, when the discharge lamp 3 is started and lit, its terminal voltage decreases to the tube voltage, so the thyristor 53 is turned off. Therefore, the magnetic flux due to the tube current flowing through the inductor 61 is no longer canceled out by the canceling winding 62, and therefore a voltage correlated to the tube current is induced in the inductor 63. As a result, the charging voltage of the capacitor 47 is lowered and the thyristor 48
Triack 4 works to prevent conduction.
2' becomes non-conductive, and the pulse generating circuit 4
stops the pulse generation operation. Thereafter, only the intermittent oscillation circuit 5' oscillates intermittently during a predetermined phase period for each half cycle of the power supply voltage, and the discharge lamp is re-ignited and lit with a voltage that is the superposition of the oscillation voltage and the power supply voltage. maintain. In this way, the discharge lamp 3
After lighting, the pulse generation operation is stopped, so a pulse voltage with a high peak value is applied to the discharge lamp 3.
This has the advantage of preventing the electric current from being applied to both ends of the filaments 31 and 32, and thus extending the life of the discharge lamp 3. Note that if the diode 45 is connected in series with the resistor 462 and the charging time constant of the resistor 462 and capacitor 47 is made sufficiently large,
Similarly to FIGS. 6, 8, and 9, the pulse generating circuit 4 can be configured to generate a pulse voltage after the filaments 31, 32 are sufficiently heated by the intermittent oscillation circuit 5'. .

As described above, according to the present invention, a pulse voltage is generated by superimposing a relatively short-term pulse voltage with a high peak value and a relatively long-term oscillation voltage with a low peak value and applying it to the discharge lamp. The discharge lamp is caused to glow discharge by the pulse voltage of the circuit, and arc discharged by the oscillation voltage of the oscillation circuit to start and light the discharge lamp.After the discharge lamp is started and lit,
Since the discharge lamp is re-ignited every half cycle by the oscillation voltage of the intermittent oscillation circuit, the life of the discharge lamp can be extended without damaging the filament of the discharge lamp 3 due to glow discharge. The withstand voltage of the parts of the pulse generation circuit can be lowered, and the circuit can be made smaller. Further, the circuit of the present invention can advantageously start and light the discharge lamp, whether it is a preheating start type FL or an instant start type FLR.
Moreover, it is possible to maintain the lighting by starting the lighting every half cycle.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the relationship between the peak value of the applied voltage and the application period for lighting the discharge lamp. FIGS. 2 and 3 are block diagrams of the principle of this invention. 4 and 6 are electrical circuit diagrams of a discharge lamp lighting device of an every-cycle start lighting method using an intermittent oscillation circuit as an oscillation circuit, which are different embodiments of the present invention. FIG. 5 is a voltage waveform diagram for explaining the operation of FIG. 4. In the figure, 1 is an AC power source, 2 is a current limiter (current limiting device), 3 is a discharge lamp, 4 is a pulse generation circuit, 5 is an oscillation circuit, and 5' is an intermittent oscillation circuit.

Claims (1)

[Claims] 1. In a discharge lamp lighting device comprising a low frequency AC power source, a current limiting device, and a discharge lamp connected in series, a pulse having a high peak value and energized by the low frequency AC power source is provided. Pulse generation circuit that generates voltage,
and an intermittent oscillation circuit that is energized by the low frequency AC power source and generates an oscillation voltage with a low peak value, and superimposes the pulse voltage of the pulse generation circuit and the intermittent oscillation voltage of the intermittent oscillation circuit to generate the The voltage is applied to the discharge lamp to start and light the discharge lamp, and after starting the discharge lamp, the pulse generation circuit stops generating pulse voltage, and the intermittent oscillation circuit generates an oscillation voltage every half cycle to start the discharge. A discharge lamp lighting device characterized in that the lamp is re-ignited.