JP3763837B2 - Fluorescent lamp lighting device - Google Patents

Description

  The present invention relates to a fluorescent lamp lighting device, and more particularly to a starting device using a semiconductor switch element for a fluorescent lamp having a preheating electrode.

  Conventionally, the starting devices that have been used in fluorescent lamp lighting devices are mainly glow starters. However, the glow starter has drawbacks such as a long time required for starting and a short life. Recently, starters using semiconductor switch elements have been developed, but they are expensive and have limited demand. Therefore, development of an inexpensive starter is expected, and a starter using a transistor as a semiconductor switch element as shown in FIG. 6 is currently proposed (Japanese Patent Laid-Open No. 3-252096).

  The conventional fluorescent lamp lighting device shown in FIG. 6 is a circuit including an AC power source 1, a ballast 2, a fluorescent lamp 3 having a pair of preheating electrodes 4 and 5, and a starting device 7. The circuit configuration of this fluorescent lamp lighting device is as follows. One terminal of the AC power source 1 and the ballast 2 is connected. The other terminal of the ballast is connected to one terminal of the power supply side electrode terminal of the fluorescent lamp 3. A starting device 7 and a noise prevention capacitor 6 are connected to both ends of the non-power supply side electrode terminals of the preheating electrodes 4 and 5 of the fluorescent lamp 3.

  The circuit of the starting device 7 connected to both terminals of the non-power supply side electrode terminal of the fluorescent lamp 3 is configured as follows. The diode 8, the resistor 30, and the collector and emitter of the transistor 31 are connected in series between the non-power supply side electrode terminals of the preheating electrodes 4 and 5 of the fluorescent lamp 3. The resistor 32 is connected between the diode 8 and the base of the transistor 31. The timer circuit configured by connecting the resistor 37 and the capacitor 36 in series is connected between the diode 8 and the non-power supply side electrode terminal of the preheating electrode 5. A thyristor 33 controlled by a timer circuit is connected between the base and emitter of the transistor. A resistor 34 and a Zener diode 35 are connected between the capacitor 36 and the resistor 37 and between the gates of the thyristor 33.

Next, the operation of this conventional fluorescent lamp lighting device will be described.
When the AC power supply 1 is turned on and the power supply voltage is in a positive cycle, a base current is supplied to the base of the transistor 31 via the diode 8 and the resistor 32. Since the base current is supplied to the transistor, the collector current flows between the collector and the emitter of the transistor 31 via the first rectifier 8. In this way, a half-wave preheating current flows and the preheating electrodes 4 and 5 of the fluorescent lamp 3 are preheated. At the same time, a reverse voltage is applied across the Zener diode 35. When the reverse voltage reaches a certain value (hereinafter referred to as a Zener voltage), a current flows in the reverse direction. The electric charge accumulated in the capacitor flows to the gate of the thyristor 33 through the Zener diode 35 and the resistor 34, the thyristor 33 is turned on, and a current flows between the anode and the cathode of the thyristor 33. For this reason, no current flows through the collector of the transistor 31, and the transistor 31 is turned off. As a result, a kick voltage due to the inductance of the ballast 2 is generated, and the fluorescent lamp 3 is turned on.
Japanese Patent Laid-Open No. 3-252096

  In the starting device used in the conventional fluorescent lamp lighting device, the operation of the timer circuit is determined by the sum of the voltage between the collector and the emitter of the transistor 31 and the voltage applied across the resistor 30. The voltage applied between the collector and emitter of the transistor 31 and across the resistor 30 varies depending on the preheating current flowing between the collector and emitter of the transistor 31, and the operation time of the timer circuit also varies.

  In the case of a low-power fluorescent lamp lighting device using a ballast 2 having a large inductance, the preheating current is small, so that the operation time of the timer circuit becomes long. In the worst case, the voltage charged in the capacitor 36 of the timer circuit. Is stable at low voltage. As a result, no current flows through the gate of the thyristor 33, and a preheating current flows continuously. Accordingly, heat is generated from the ballast 2 and the end portion of the fluorescent lamp 3 is blackened, which causes a problem that the fluorescent lamp 3 cannot be started. Further, when the voltage of the AC power supply 1 is instantaneously decreased while the fluorescent lamp 3 is lit and the voltage is restored after the fluorescent lamp 3 is extinguished, the thyristor 33 is kept on by the gate current from the AC power supply 1 and the capacitor 36. . Then, since the transistor 31 is maintained in the off state, the restart operation is not performed and the fluorescent lamp 3 remains off, and there is a problem that it does not light unless the power switch is operated again.

  In order to solve the above problems, the present invention has a starting device that can be applied universally to ballasts and fluorescent lamps having different rated powers, and a starting device that automatically turns on when the lamp goes off due to a momentary low voltage of the power supply. I will provide a.

  The fluorescent lamp lighting device of the present invention is a fluorescent lamp lighting device having a ballast and a fluorescent lamp having two preheating electrodes, and having a starting device for turning on the fluorescent lamp by inputting an AC power source. The starting device includes: a first rectifying unit having one end connected to one end of two preheating electrodes of the fluorescent lamp; the other end of the first rectifying unit; and another preheating of the fluorescent lamp. A first series connection body of the first resistance means and the semiconductor switch element, both ends of which are connected between one end of the electrodes, and a second end of which is connected to one end of the first series connection body, And at least one Zener diode set so that the Zener voltage is greater than the product of the sum of the on-resistance of the semiconductor switch element and the resistance of the first resistor means and the preheating current, Rectifying means and a second connected in series A column connection, a first capacitor connected between the other end of the second series connection and the other end of the first series connection, the second series connection and the first DC voltage between the first connection point, which is a connection point with the capacitor, and the second connection point, which is the connection point between the first resistance means and the semiconductor switch element, is input, and the output voltage is Control means for controlling the semiconductor switch element by inputting to the control terminal of the semiconductor switch element, the control means, third resistance means having one end connected to the first connection point, A second capacitor and a fourth resistor are charged with a time constant longer than a conduction period of the semiconductor switch element when one end is connected to the other end of the third resistor means and the semiconductor switch element is turned on. A parallel connection with the means, and one end at the other end of the parallel connection A second transistor having the other end connected to the second connection point, and a fifth resistance means connected between the first connection point and the control terminal of the semiconductor switch element; A first transistor connected between a control terminal of the semiconductor switch element and the second connection point, a control terminal connected to a connection point of the third resistor means and the parallel connection body; A second Zener diode connected between the first connection point and the control terminal of the second transistor; and a connection between the control terminal of the semiconductor switch element and the control terminal of the second transistor. And a third Zener diode, wherein when the voltage across the second capacitor becomes higher than a predetermined voltage, the semiconductor switch element is cut off.

  According to the present invention, by providing the starting device constituting the fluorescent lamp lighting device with the first timer means and the control means, the same starting device can be used for the fluorescent lamp lighting device having ballasts and fluorescent lamps having different rated powers. The fluorescent lamp can be automatically turned on again when the lamp is extinguished.

  According to the present invention, the first timer constituting the fluorescent lamp lighting device having a ballast or fluorescent lamp with different rated power and the starting device of the fluorescent lamp lighting device that automatically relights the fluorescent lamp when the lamp goes off. Means can be configured.

  According to the present invention, by using the field effect transistor, a surge voltage suppressor for protecting the semiconductor switch element is unnecessary, and on / off control can be performed by a voltage signal.

  According to the present invention, the fluorescent lamp lighting device has the functions of stopping the lamp relighting operation after a predetermined time, protecting the semiconductor switch element, and preventing the lamp from blinking.

  According to the present invention, a socket of a glow starter lighting tube of an existing lighting fixture can be used for storing a starting device.

As described above, according to the present invention, the starter is provided with the first timer means and the control means, so that the lamp can be reliably turned on with respect to the fluorescent lamp lighting devices having ballasts and fluorescent lamps having different ratings. In addition, the lamp can be automatically lit again when the voltage of the AC power supply instantaneously becomes a low voltage and the fluorescent lamp goes off. By connecting the resistor, the Zener diode, the rectifier diode and the capacitor in series, a circuit having the function of the first timer means can be configured.
Further, by using a field effect transistor having an avalanche resistance as a semiconductor element, a surge voltage suppressor for protecting the semiconductor switch element becomes unnecessary.
Further, by providing the control means with the second timer means, it is possible to stop the lamp relighting operation after a predetermined time, protect the semiconductor switch element, and prevent the lamp from blinking.
Furthermore, the storage container of the starter can be used for an existing lighting fixture by making the shape compatible with the glow starter of the fluorescent lamp fixture.

  Hereinafter, embodiments of the present invention will be described with reference to FIG.

<Circuit configuration>
As shown in FIG. 1, the fluorescent lamp lighting device of one embodiment of the present invention is a circuit including an AC power source 1, a ballast 2, a fluorescent lamp 3 having a pair of preheating electrodes 4 and 5, and a starting device 7. . The circuit configuration of this fluorescent lamp lighting device is as follows. One terminal of AC power supply 1 and ballast 2 is connected. The other terminal of the ballast is connected to one terminal of the power supply side electrode terminal of the fluorescent lamp 3. A starting device and a noise prevention capacitor 6 are connected to both ends of the non-power supply side electrode terminal of the fluorescent lamp 3.

  The circuit of the starting device 7 connected to both terminals of the non-power supply side electrode terminal of the fluorescent lamp 3 is configured as follows. The starting device 7 includes a first rectifying means 8, a semiconductor switch element 9, a first resistance means 10, a first timer means 11 and a control means 16. Semiconductor switch element 9 having a control terminal so as to be in series between non-power supply side electrode terminals of preheating electrodes 4 and 5 of fluorescent lamp 3, first resistance means 10 for detecting a current flowing through semiconductor switch element 9, and first The rectifying means 8 is connected. As the semiconductor switch element, there is a junction transistor or the like, but a field effect transistor having an avalanche resistance is used as the semiconductor switch element 9. In addition, the surge voltage suppressor for protecting a semiconductor switch from a kick voltage becomes unnecessary by using a field effect transistor. The first timer means 11 is connected in parallel with the series circuit of the semiconductor switch element 9 and the first resistance means 10. The first timer means 11 is configured by connecting a resistor 12, a Zener diode 13, a diode 14 and a capacitor 15 in series. The Zener voltage of the Zener diode 13 is set to be larger than the product of the sum of the ON resistance of the semiconductor switch element 9 and the resistance of the first resistance means 10 and the preheating current. The control means 16 is connected to three terminals of both ends of the series circuit of the capacitor 15 and the first resistance means 10 and the gate of the semiconductor switch element 9. The control means 16 includes a second timer means 17, a transistor 21, a transistor 25, a Zener diode 22 and a Zener diode 23. Note that the Zener voltage of the Zener diode 22 is set higher than the Zener voltage of the Zener diode 23. The second timer means 17 comprises a parallel circuit of a capacitor 19 and a resistor 20 and a series circuit of a resistor 18. One end of the resistor 18 of the second timer means, one end of the resistor 24 and the cathode of the Zener diode 22 are connected to a connection point between the capacitor 15 and the diode 14. The base of the transistor 25 is connected to the connection point between the resistor 18 and the capacitor 19. As the transistor 25, for example, a transistor having a base-emitter voltage of about 0.6 V for turning on the transistor is used. The other end of the second timer means 17 is connected to the collector of the transistor 21. The emitter of the transistor 21 is connected to the resistor 10 and the source of the semiconductor switch element 9. The base of the transistor 21 is connected to the anode of the Zener diode 22 and the anode of the Zener diode 23. The anode of the Zener diode 22 and the anode of the Zener diode 23 are connected to each other. The other end of the resistor 24 is connected to the cathode of the Zener diode 23, the collector of the transistor 25, and the gate of the semiconductor switch element 9. The emitter of the transistor 25 is connected to the first resistance means 10, the source of the semiconductor switch element 9, and the emitter of the transistor 21.

  The storage container of the starter is shaped to be compatible with the glow starter as shown in FIG. This makes it possible to use it for existing lighting fixtures.

<Operation>
Next, the operation of the fluorescent lamp lighting device shown in FIGS. 1 and 2 will be described with reference to FIGS.
As shown in FIG. 3A, before the AC power supply 1 is turned on, that is, before time T1, no charge is accumulated in the capacitor 15, and the voltage across the capacitor is zero. Therefore, as shown in FIG. 3B and FIG. 3C, the transistor 21 and the transistor 25 are in the off state.

When the AC power source 1 is turned on at time T1 and the AC power source 1 is in a positive cycle, a current flows through the resistor 12, the Zener diode 13, and the diode 14 to the capacitor 15, and the capacitor 15 is charged. Since the diode 14 exists between the capacitor 15 and the Zener diode 13, the charge charged in the capacitor 15 does not discharge through the resistor 12 and the Zener diode 13.
At the same time, a current flows through the resistor 18 to the base of the transistor 25, and the transistor 25 is turned on as shown in FIG.
Since the voltage applied to the Zener diode 22 is equal to or lower than the Zener voltage, the base current of the transistor 21 is blocked by the Zener diode 22, and the transistor 25 is turned on, so that the base current of the transistor 21 is blocked by the Zener diode 23. The For this reason, the transistor 21 maintains the OFF state as shown in FIG.
Since the transistor 21 is in the OFF state, no charge is accumulated in the capacitor 19 of the second timer means 17, and the voltage of the capacitor 19 is zero.
On the other hand, as shown in FIG. 3A, the voltage of the capacitor 15 is quickly charged by the half-wave AC voltage and reaches the first predetermined voltage which is the Zener voltage of the Zener diode 22.
In this example, the time from time T1 to time T2 is set in the range of 0.1 seconds to 0.2 seconds.

Since the voltage of the capacitor 15 reaches the first predetermined voltage at time T2, a current flows from the capacitor 15 to the base of the transistor 21 through the Zener diode 22, and the transistor 21 is turned on as shown in FIG. It becomes.
When the transistor 21 is turned on at time T2, the voltage of the capacitor 19 is zero, so that the base voltage of the transistor 25 becomes 0V. Since this voltage is about 0.6 V or less of the voltage for turning on the transistor 25, the transistor 25 is turned off as shown in FIG.
When the transistor 25 is turned off at time T2, the voltage of the capacitor 15 is equal to or higher than the Zener voltage of the Zener diode 23, so that the base current is supplied from the capacitor 15 to the base of the transistor 21 through the resistor 24 and the Zener diode 23. . Since the base current is supplied to the base of the transistor 21, the transistor 21 is kept on and the transistor 25 is kept off as shown in FIGS. 3B and 3C.
At this time, a voltage substantially equal to the Zener voltage of the Zener diode 23 is applied to the gate of the semiconductor switch element 9, and the semiconductor switch element 9 is turned on as shown in FIG.
When the semiconductor switch element 9 is turned on, the preheating current is supplied from the AC power source 1 to the ballast 2, the preheating electrode 4 of the fluorescent lamp 3, the semiconductor switching element 9, the first resistance means 10, the diode 8, and the preheating electrode 5 of the fluorescent lamp 3. Flowing through.
When the semiconductor switch element 9 is in the ON state, the voltage applied to both ends of the starting device 7 is the product of the sum of the ON resistance of the semiconductor switch element 9 and the resistance of the first resistance means 10 and the preheating current. V. Further, the Zener voltage of the Zener diode 13 constituting the first timer means 11 is set larger than the product of the sum of the ON resistance of the semiconductor switch element 9 and the resistance of the first resistance means 10 and the preheating current. The current flowing to the capacitor 15 is blocked by the Zener diode 13.

The electric charge accumulated in the capacitor 15 is discharged through the second timer means 17 and the collector of the transistor 21, and is discharged through a route connecting the resistor 24, the Zener diode 23 and the base of the transistor 21. For this reason, the voltage of the capacitor 15 gradually decreases.
When the voltage of the capacitor 15 decreases and becomes the second predetermined voltage that is the Zener voltage of the Zener diode 23, the base current from the capacitor 15 to the base of the transistor 21 flowing through the resistor 24 and the Zener diode 23 does not flow. . Therefore, the transistor 21 is turned off at time T3 as shown in FIG.
When the transistor 21 is turned off, a base current is supplied from the capacitor 15 through the resistor 18 to the transistor 25, the transistor 25 is turned on, and the gate voltage of the semiconductor switch element 9 becomes zero. For this reason, the semiconductor switch element 9 is turned off.
Since the preheating current flowing at this time is rapidly cut off, a kick voltage due to the inductance of the ballast 2 is generated and the fluorescent lamp 3 is turned on.

After the transistor 25 is turned on, the base current of the transistor 21 is blocked by the Zener diode 23. Therefore, the transistor 21 is maintained in an off state, and the transistor 25 is thereby maintained in an on state. As a result, the semiconductor switch element 9 maintains the off state, and the fluorescent lamp 3 maintains the lighting state.
When the fluorescent lamp 3 is lit, the voltage at both ends of the fluorescent lamp 3 is sufficiently lower than the voltage of the AC power supply 1, and therefore the voltage of the capacitor 15 constituting the first timer means 11 is the first predetermined voltage. The transistor 21 remains off. For this reason, the semiconductor switch element 9 is never turned on again.
When the fluorescent lamp 3 disappears at time T4 (FIG. 3) due to a decrease in power supply voltage or the like, the voltage at both ends of the fluorescent lamp 3 becomes equal to the voltage of the AC power supply 1, and the first timer means 11 is restarted and time T1 is reached. Until the time T4, the fluorescent lamp 3 is turned on again.

  In this example, the time required until the fluorescent lamp 3 is lit is equal to the time from time T1 to time T3. The time from time T1 to time T2 is set in the range of 0.1 second to 0.2 second. Further, the time from time T2 to time T3 is determined as follows. This time is a time during which a preheating current is flowing, and this preheating time is substantially determined by the capacitance value of the capacitor 15, the resistor 18 for discharging, the resistor 24, the first predetermined voltage value, and the second predetermined voltage value. The Accordingly, the preheating time is substantially constant regardless of the preheating current value due to the power value of the fluorescent lamp 3 and the impedance of the ballast 2.

  For this reason, the same starting device can be used for the fluorescent lamp lighting device having the ballast 2 and the fluorescent lamp 3 having different rated powers.

  In this example, the preheating time was set from 0.8 seconds to 1.2 seconds for a fluorescent lamp over a wide range of power values from 4 W to 30 W, and a reliable starting performance could be obtained. Furthermore, even when the AC power source 1 is lower than the rated value or when the ambient temperature of the fluorescent lamp 3 is low and it is difficult to light up, the starting operation is repeated and reliable starting performance can be obtained.

Further, the operation when the fluorescent lamp lighting device is turned on will be described with reference to FIGS.
FIG. 4 is an enlarged view of the time axis at time T3 in FIG. 4F is the voltage of the capacitor 15, FIG. 4G is the voltage of the first resistance means 10 viewed from the emitter of the transistor 21, and FIG. 4H is the voltage of the capacitor 15 viewed from the emitter of the transistor 21. 4 (i) shows the operating state of the transistor 21, FIG. 4 (j) shows the operating state of the transistor 25, FIG. 4 (k) shows the operating state of the semiconductor switch element 9, and FIG. l) is the preheating current, and (m) in FIG. 4 is the kick voltage.

When the preheating current shown in (l) of FIG. 4 flows through the first resistance means 10 while the semiconductor switch element 9 is on, a voltage drop due to the preheating current occurs at both ends thereof. As shown in FIG. 4G, the voltage of the first resistance means 10 has a negative polarity when viewed from the emitter of the transistor 21. Also, the voltage at the positive terminal of the capacitor 15 viewed from the emitter of the transistor 21 shown in FIG. 4H is the sum of FIG. 4F and FIG. 4G, which is a DC voltage having ripples. . This voltage is opposite in polarity to the preheating current shown in FIG. 4L, and decreases as the preheating current increases. When the voltage shown in (h) of FIG. 4 drops due to the discharge of the capacitor 15, this voltage always reaches the second predetermined voltage at a phase in which the preheating current is near the maximum.
At this moment, the base current from the capacitor 15 to the transistor 21 flowing through the resistor 24 and the Zener diode 23 does not flow, and the transistor 21 is turned off at time T3 as shown in FIG. 4 (i). When the transistor 21 is turned off, the base current is supplied from the capacitor 15 to the transistor 25 via the resistor 18, and the transistor 25 is turned on. For this reason, the gate voltage of the semiconductor switch element 9 becomes zero, and the semiconductor switch element 9 is turned off. The preheating current flowing at this time is cut off, a kick voltage due to the inductance of the ballast 2 is generated, and the fluorescent lamp 3 is turned on.
The current value at which the preheating current is interrupted is always a peak value, and the energy of the kick voltage from the ballast is large, and the fluorescent lamp 3 can be started reliably.

Next, the operation of the fluorescent lamp lighting device when the fluorescent lamp is a fluorescent lamp that has reached the end of its life or a defective fluorescent lamp will be described with reference to FIGS.
5 (n) shows the voltage of the capacitor 15, FIG. 5 (o) shows the operating state of the transistor 21, FIG. 5 (p) shows the operating state of the transistor 25, and FIG. FIG. 5 (r) shows the preheating current, and FIG. 5 (s) shows the voltage of the capacitor 19 in the operating state.
Since the operation of the fluorescent lamp lighting device from time T1 to time T3 is the same as that when the fluorescent lamp is normal, the details are omitted, but when the AC power source 1 is turned on at time T1, as shown in FIG. When the preheating current flows, the preheating current is cut off at time T3, and a kick voltage due to the inductance of the ballast 2 is generated.
However, when the fluorescent lamp 3 does not turn on due to a defect or the like, the same starting operation is repeated again from time T1 to time T3. For example, from time T2 to time T3, while the semiconductor switch element 9 is in the ON state, a preheating current flows through the semiconductor switch element 9, and the semiconductor switch element 9 generates heat due to resistance loss due to the preheating current and the temperature rises. . Further, the transistor 21 is on while the preheating current is flowing. Since the transistor 21 is in the on state, a current flows from the capacitor 15 through the resistor 18 to the capacitor 19, the capacitor 19 is charged, and the voltage of the capacitor 19 rises.
After repeating the same starting operation from time T1 to time T3, the voltage of the capacitor 19 reaches a base-emitter voltage of 0.6 V at which the transistor 25 can be turned on at time T5. For this reason, the current flowing from the capacitor 15 through the resistor 18 to the capacitor 19 almost does not flow, flows through the resistor 18 to the base of the transistor 25, and the transistor 25 is turned on. When the transistor 25 is turned on, the semiconductor switch element 9 is turned off, the preheating current stops flowing, and the starting operation is stopped. After the preheating current stops flowing, the voltage of the capacitor 15 reaches the first predetermined voltage due to the voltage of the AC power supply 1, and the transistor 21 is turned on. However, since the voltage of the capacitor 19 has already reached 0.6V, the transistor 25 is not turned off and remains on.
As a result, the voltage of the capacitor 15 is the first predetermined voltage, the voltage of the capacitor 19 is 0.6 V, the transistors 21 and 25 are kept on, and the semiconductor switch element 9 is kept off.
Therefore, unlike the conventional glow starter, the lamp does not repeat blinking when the lamp is at the end of its life.
Thereafter, when the AC power supply 1 is turned off, the charge of the capacitor 15 passes through the resistor 18 or 24 and the charge of the capacitor 19 is gradually discharged through the resistor 20 to return to the initial state before the AC power supply 1 is turned on. .
The time from the time T2 to the time T5, which is the time for stopping the starting operation, can be almost determined by the time constant of the capacitor 19 and the resistor 18, and is set in advance so that the temperature rise of the semiconductor switch element 9 is within the rating. Even when a fluorescent lamp that has reached the end of its life or a defective fluorescent lamp is used, the preheating current can be reliably stopped without damaging the semiconductor switch element 9. In this example, the time from time T2 to time T5 is set to 3 seconds or less to protect the semiconductor switch element 9 from heat generation.

  By providing the second timer circuit, it has a function of stopping the relighting operation of the lamp, preventing the blinking operation of the lamp, and protecting the semiconductor switch element.

  The present invention can be used, for example, as a fluorescent lamp lighting device.

The figure which shows the circuit structural example of the fluorescent lamp lighting device which implemented this invention The figure which shows the external appearance of the starting device which comprises the fluorescent lamp lighting device which implemented this invention The figure showing operation | movement of the fluorescent lamp lighting device which implemented this invention (a) Voltage of the capacitor | condenser 15 (b) Operation state of the transistor 21 (c) Operation state of the transistor 25 (d) Operation state of the semiconductor switch element 9 (e) Preheating current (F) Voltage of capacitor 15 (g) Voltage of first resistance means 10 viewed from emitter of transistor 21 (h) Voltage of capacitor 15 viewed from emitter of transistor 21 Positive Voltage (i) Operation State of Transistor 21 (j) Operation State of Transistor 25 (k) Operation State of Semiconductor Switch Element 9 (l) Preheating Current (m) Kick Voltage (N) Voltage of capacitor 15 (o) Operating state of transistor 21 (p) Operating state of transistor 25 (q) Operating state of semiconductor switch element 9 (r) Preheating current (s) Voltage of capacitor 19 The figure which shows the circuit structure of the conventional fluorescent lamp lighting device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power source 2 Ballast 3 Fluorescent lamp 4 Preheating electrode 5 Preheating electrode 6 Noise prevention capacitor 7 Starter 8 Second rectifying means 9 Semiconductor switching element 10 Second resistance means 11 First timer means 16 Control means 17 First Second timer means

Claims (1)

A fluorescent lamp lighting device having a ballast and a fluorescent lamp having two preheating electrodes, and having a starting device for turning on the fluorescent lamp by inputting an AC power source,
The starter is
A first rectifying means having one end connected to one end of two preheating electrodes of the fluorescent lamp;
A first series connection body of the first resistance means and the semiconductor switch element, both ends of which are connected between the other end of the first rectifying means and one end of the other one preheating electrode of the fluorescent lamp; ,
A second resistance means having one end connected to one end of the first series connection body; and a Zener voltage of a sum of an ON resistance of the semiconductor switch element and a resistance of the first resistance means, and a preheating current. A second series connection body in which at least one Zener diode set to be larger than the product and a second rectifying means are connected in series;
A first capacitor connected between the other end of the second series connection body and the other end of the first series connection body;
A first connection point that is a connection point between the second series connection body and the first capacitor, and a second connection point that is a connection point between the first resistance means and the semiconductor switch element. A control means for controlling the semiconductor switch element by inputting a DC voltage therebetween and inputting an output voltage to a control terminal of the semiconductor switch element;
Have
The control means includes
Third resistance means having one end connected to the first connection point;
A second capacitor and a fourth resistor are charged with a time constant longer than a conduction period of the semiconductor switch element when one end is connected to the other end of the third resistor means and the semiconductor switch element is turned on. A parallel connection with the means;
A second transistor having one end connected to the other end of the parallel connection body and the other end connected to the second connection point;
Fifth resistance means connected between the first connection point and a control terminal of the semiconductor switch element;
A first transistor connected between a control terminal of the semiconductor switch element and the second connection point, and having a control terminal connected to a connection point of the third resistor means and the parallel connection;
A second Zener diode connected between the first connection point and the control terminal of the second transistor;
A third Zener diode connected between a control terminal of the semiconductor switch element and a control terminal of the second transistor;
A fluorescent lamp lighting device, wherein when the voltage across the second capacitor becomes higher than a predetermined voltage, the semiconductor switch element is cut off.

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