JP2000268987A - Bulb-type fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small, low-cost bulb-form fluorescent lamp by simplifying a starting-circuit and a gate drive circuit as a precondition for sharing the gate drive circuit to a pair of FETs. SOLUTION: In this bulb-form fluorescent lamp, an N-channel type FETSN and a P-channel type FETSP are serially connected between dc power sources 4, a gate drive circuit GC common to the FETSN and FETSP is disposed, and a starting-circuit ST is constructed so as to turn the N-channel type FETSN on first when activated. By starting the N-channel type FETSN first when activated, the starting-circuit ST can be simplified. Furthermore, by using a series resonant circuit SR serially resonating to the feedback voltage of a feedback winding (s) for the gate drive circuit GC, a gate drive voltage can be attained by serially resonating to boost voltage. Therefore, a feedback means (s) can be reduced in size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact fluorescent lamp having an improved high-frequency lighting device.

[0002]

2. Description of the Related Art On page 48 of the proceedings of the 30th Annual Meeting of the Illuminating Engineering Institute of Japan in 1997, a half-bridge inverter equipped with a pair of N-channel type FETs has a current-limiting main choke as an alternative to a current transformer. It is described that the miniaturization of the compact fluorescent lamp is achieved by utilizing the output of the secondary winding and employing a resonance drive method using a small inductor L2 and a capacitor C1 (prior art 1).

Japanese Patent Application Laid-Open No. Hei 9-190891 discloses an N-channel FET and a P-channel FET as complementary transistors T1 and T2 and a common gate as a driving circuit AS in FIG. It describes that a drive circuit is used (Prior Art 2).

[0004]

However, the prior art 1
However, since a gate drive circuit is required for each FET, there is a problem that the number of circuit components increases and further miniaturization cannot be achieved. Further, since the number of circuit components is large, a problem remains in terms of cost.

On the other hand, in the prior art 2, since the gate drive circuit is common, the number of parts can be reduced.
At start-up, the P-channel FET is turned on first, so a start-up circuit with resistors R1, R2, capacitor C5, diode D1 and diac DC is used. That is, since the number of components of the start-up circuit is large, there is a problem that the wiring board is correspondingly large, the bulb-type fluorescent lamp is enlarged, and the cost is increased.

In the prior art 2, since the gate drive circuit AS uses a parallel resonance circuit including the capacitor C4 and the inductance L4, an auxiliary winding provided on the resonance inductance L2 is required to obtain a required gate voltage. The number of turns of the wire HW1 needs to be relatively large, which is an obstacle to further miniaturization.

In order to incorporate a discharge lamp lighting device into a lighting device whose size and cost are being drastically reduced, such as a compact fluorescent lamp, the number of circuit components is reduced as much as possible, and the device is reduced in size. , Cost reduction must be realized.

An object of the present invention is to provide a compact and inexpensive bulb-type fluorescent lamp by simplifying a starting circuit and a gate drive circuit on the premise that a gate drive circuit is commonly used for a pair of FETs.

[0009]

According to a first aspect of the present invention, there is provided a bulb-type fluorescent lamp comprising: a DC power supply; an N-channel FET and a P-channel FE connected in series between the DC power supplies.
T; a load circuit that operates at a high frequency and includes a series circuit of a current-limiting inductance and a resonance capacitor and a fluorescent lamp connected in parallel to the resonance capacitor and generated by alternating switching of an N-channel FET and a P-channel FET. A feedback winding magnetically coupled to the current-limiting inductance and a series resonance circuit that resonates with a feedback voltage induced in the feedback winding, commonly acting on the N-channel FET and the P-channel FET. Drive circuit for driving an N-channel FET and a P-channel FET and alternately switching at a high frequency; N-channel FE at startup
And a starting circuit for turning on T first.

In the present invention and each of the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

<About the bulb-type fluorescent lamp> The bulb-type fluorescent lamp has a built-in lighting device so that it can be lit as it is when mounted on a lamp socket of an incandescent bulb for general lighting.
This is a light source whose external shape and size are made compact and as close as possible to an incandescent lamp, and whose base is the same as that of the incandescent lamp. The light bulb-type fluorescent lamp includes a light-transmitting globe made of glass or synthetic resin, such as an incandescent light bulb, and a light-emitting lamp that does not have a light-transmitting globe.

<Regarding DC Power Supply> The DC power supply may be any of a rectified DC power supply obtained by rectifying AC and a battery power supply. As the rectified DC power supply, a combination of a rectifier circuit and a smoothing capacitor or a combination of a rectifier circuit and a partial smoothing circuit can be used. The partial smoothing circuit includes a smoothing capacitor, an inductor, and a diode that are charged through the switching means of the high-frequency inverter, and switches the switching means of the high-frequency inverter during a period in which the instantaneous value of the terminal voltage of the DC power supply is lower than the terminal voltage of the smoothing capacitor. Further, it means a smoothing circuit means which constitutes a step-down chopper by the above-mentioned components to generate a high frequency and operate so as to compensate for a voltage during a low period of the DC power supply voltage.

When the partial smoothing circuit is used, the charging current can be configured to pass through the N-channel FET. Thereby, N-channel type FET
Has a lower on-resistance as compared with a P-channel FET of the same chip size, so that a relatively large drain current can flow. Then, the load current and the charging current of the smoothing capacitor become approximately 1.5 times the load current.
A device having the same chip size as the channel type FET can be used. For this reason, cost can be suppressed. Also, by using a partial smoothing circuit as the smoothing means, when rectifying an AC to obtain a DC power supply, the power factor of a load current flowing from the AC power supply can be increased and high-frequency distortion can be reduced.

The term "high frequency" refers to a frequency of 1000 Hz or more.

<Regarding N-channel FET and P-channel FET> To connect an N-channel FET and a P-channel FET in series between DC power supplies means that both FETs are connected in series as viewed from the DC power supply. In this case, another circuit component such as a resistor may be interposed between both FETs and the DC power supply. In addition, both FET
Other circuit components may be interposed between them.

<Regarding the Load Circuit> The load circuit operates at a high frequency generated by alternately switching the N-channel FET and the P-channel FET. The load circuit is configured to include a series circuit of a current limiting inductance and a resonance capacitor, and a fluorescent lamp connected in parallel to the resonance capacitor. The current limiting inductance is connected in series with the fluorescent lamp and acts as ballast means to compensate for the negative characteristics of the fluorescent lamp.

The fluorescent lamp is an N-channel type FE.
It becomes a load for the high frequency generated by the alternating switching between the T and P channel type FET. The fluorescent lamp is
In general, a filament electrode is used as an electrode, and the filament electrode is turned on and turned on by a hot cathode. In such a case, there are the following two methods for heating the filament electrode at startup.

One is to connect a resonance capacitor in parallel with the fluorescent lamp via at least one filament electrode at the time of starting. Then, a current flows through the filament electrode via the current-limiting inductance and the resonance capacitor at the time of starting, so that the filament electrode connected in series with these is heated. At the same time, the current limiting inductance and the resonance capacitor resonate appropriately in series, increasing the terminal voltage of the resonance capacitor,
This voltage is applied to the fluorescent lamp, thus facilitating the starting of the fluorescent lamp.

Second, the filament electrode is heated using a filament heating transformer. The filament heating transformer may be provided separately from the current limiting inductance, but if necessary, the filament heating winding can be magnetically coupled to the current limiting inductance. This can suppress an increase in the number of circuit components.

The load circuit can supply the energy for self-excited oscillation and the specified operating frequency to the gate drive circuit of the N-channel FET and the P-channel FET if necessary.

Further, the fluorescent lamp can be connected to a load circuit via an insulating transformer. However, they may be directly connected without using an insulating transformer. Direct connection is effective in reducing the size of the entire lighting device. In the case of a direct connection, it is preferable to connect a DC cut capacitor in series with the fluorescent lamp so that a DC component does not flow to the fluorescent lamp as a load.

<Regarding the Gate Drive Circuit> The gate drive circuit is provided so as to supply a required gate drive voltage commonly to the N-channel FET and the P-channel FET. That is,
A positive voltage is applied to the gate of the N-channel FET to turn it on, and a negative voltage is applied to the P-channel FET to turn it on. As is well known, the positive and negative voltages are relative to the source. Then, the N-channel type FET and the P-channel type FET are alternately turned on, that is, perform switching based on the gate drive voltage supplied from the gate drive circuit.

Further, the gate drive circuit includes a feedback winding and a series resonance circuit magnetically coupled to a current limiting inductance in order to form a gate drive voltage by self-excited oscillation. Since the feedback winding is magnetically coupled to the current limiting inductance, when a current flows through the current limiting inductance of the load circuit, a feedback voltage is induced there. The series resonance circuit is configured to resonate in series with the feedback voltage induced in the feedback winding and generate positive and negative oscillation voltages boosted by the resonance. The oscillating voltage is applied to the gates of the N-channel FET and the P-channel FET directly or via the gate protection means. Since the feedback voltage is boosted by series resonance in the series resonance circuit, the feedback voltage may be lower accordingly. This means that the size of the feedback circuit can be avoided and the size of the feedback circuit can be reduced. By the way, the feedback winding is provided with a core having a gap in the center leg and a load current winding wound on the center leg. To be wound around by magnetic coupling. Since the feedback winding is wound at a position separated from the gap of the center leg and is magnetically coupled to the load current winding, the coupling between the feedback winding and the load current winding is strengthened, and the feedback winding is correspondingly increased. The inductance can be increased even if the number of turns is small. Therefore, since the feedback voltage can be increased, it is possible to reliably drive the FET at the time of starting, generate a sufficient output voltage, and reliably operate the load. The core is EI
Shape, pot shape, etc. can be adopted. Also, the provision of the gap in the center leg means that the gap is formed by directly forming the gap in the center leg and by recessing the counterpart core between the center leg and the cooperating core. This includes the case where it is performed. This is because in any case, the gap affects the magnetic flux flowing through the central leg.

<Regarding the Starting Circuit> The starting circuit is configured to turn on the N-channel FET at the time of starting.

<Other Configurations> 1. Gate Protection Means The N-channel FET and the P-channel FE are used as the gate drive voltage with the resonance voltage of the series resonance circuit as it is.
In the case where an overvoltage occurs when the voltage is applied to T, a gate protection means for clamping the gate drive voltage to a required voltage value can be used. The gate protection means can be constituted by a plurality of constant voltage elements connected in opposite polarities. Then, this gate protection means may be connected between the gate and the source of the N-channel FET and the P-channel FET. Also, as a constant voltage element,
A Zener diode or the like can be used. The required number of constant voltage elements may be determined according to the relationship between the constant voltage and the gate voltage. Then, the voltage which becomes overvoltage with respect to the gate is short-circuited and absorbed by the gate protection means, so that only an appropriate voltage is applied to each gate. If an overvoltage is applied between the gate and the source of the FET, the FET may be destroyed. Therefore, it is effective to add a gate protection means. Thus, in the present invention, since a single gate drive circuit is used, even when gate protection means is used, only one set needs to be used. Can be achieved. 2. Gate Voltage Output Means An N-channel FET and a P-channel F are used as a gate drive voltage with an oscillating voltage caused by resonance of a series resonance circuit.
When applying the voltage between the gate and the source of the ET, a gate voltage output means can be provided. The gate voltage output means is composed of an appropriate impedance, for example, a capacitor, takes out a positive or negative boosted voltage generated in the series resonance circuit as a gate voltage, and applies it between the gate and the source of each FET.

<Operation of the Present Invention> A high frequency is generated by alternately switching the N-channel FET and the P-channel FET at a high frequency. The generated high frequency is applied to the load circuit, so that when a current flows through the load circuit, a feedback voltage is induced in the feedback winding of the gate drive circuit magnetically coupled to the current limiting inductance. When the feedback voltage is induced, the series resonance circuit resonates with the feedback voltage, and boosted positive and negative oscillating voltages are alternately generated between the terminals of the capacitor and the inductance forming the series resonance circuit. This oscillating voltage is used as a gate drive voltage for an N-channel FET and
Applied to the gate of a channel type FET. When a positive gate drive voltage is applied to the gate, the N-channel FET turns on. Next, when the polarity of the oscillation voltage is inverted and a negative gate drive voltage is applied to the gate, the P-channel FET turns on. As a result, the N-channel FET and the P-channel FET are switched alternately and operate continuously as a self-excited half-bridge inverter.

On the other hand, when a high frequency is applied to the load circuit,
The current limiting inductance and the resonance capacitor resonate in series. Then, the voltage between both ends of the resonance capacitor increases, and this high voltage is applied to both ends of the fluorescent lamp, so that the fluorescent lamp is easily started. As a result, the fluorescent lamp starts and lights up. At this time, the current-limiting inductance acts as ballast means, and compensates for the negative characteristics of the fluorescent lamp to stably turn on the fluorescent lamp. The present invention is characterized in that when the half-bridge inverter is started, the starting circuit turns on the N-channel FET first. That is, N-channel type FET
It is necessary to apply a positive gate drive voltage to its gate in order to turn on, but the positive gate drive voltage can be easily obtained from a DC power supply at startup with a simple circuit configuration. Therefore, for example, a start-up circuit can be configured only by adding a resistor. Further, as a complementary switching means, an N-channel FET and a P-channel FET are connected in series, and a single gate drive circuit is provided in common for each of these FETs. Can be simplified. As described above, according to the present invention, a compact and inexpensive bulb-type fluorescent lamp can be obtained by simplifying the starting circuit.

According to a second aspect of the present invention, there is provided a bulb-type fluorescent lamp according to the first aspect, wherein the drains of the N-channel FET and the P-channel FET are connected to a positive electrode of a DC power supply. The source is connected to the source of the P-channel FET, and the drain of the P-channel FET is connected to the negative terminal of the DC power supply; the starting circuit is connected to the first gate connected between the drain and the gate of the N-channel FET. , A second resistor connected to the gate drive circuit, and a third resistor connected between the source and the drain of the P-channel FET.
Or the third resistor is in a serial relationship with respect to the DC power supply;

The present invention provides an N-channel FET and a P-channel FET.
A preferred configuration of the connection of the channel type FET to the DC power supply and the starting circuit is defined. That is,
Since the N-channel type FET is disposed on the positive side of the DC power supply and the P-channel type FET is also disposed on the negative side, the configurations of the gate drive circuit and the starting circuit are simplified.

Further, the starting circuit is constituted by connecting the first to third resistors as described above, and the first to third resistors are connected in series, and a DC power supply voltage is applied to both ends thereof. Is applied. Accordingly, a voltage appears across the second resistor due to the voltage distribution of the DC power supply voltage by the first to third resistors, and this voltage is mainly applied as a positive voltage between the gate and source of the N-channel FET. Therefore, the N-channel type FET is turned on, and the half-bridge type inverter is started. Of course, in the present invention, the gate drive circuit is an N-channel FET
And a single gate drive circuit common to the P-channel FET is used, so that the same is applied to the P-channel FET, but since it has the opposite polarity,
Maintain off state. Note that “being in a series relationship” means that not only the first to third resistors are connected in series but also other circuit components are inserted in the middle. If the voltage drop due to the second resistance of the DC power supply voltage is applied to the gate of the N-channel FET to promote the start-up, this means that the present invention is also included in the present invention.

Thus, in the present invention, the configurations of the gate drive circuit and the starting circuit are simplified, and
It is possible to obtain a light bulb-shaped fluorescent lamp that starts by turning on the N-channel FET without fail.

The bulb-type fluorescent lamp according to the third aspect of the present invention is the bulb-type fluorescent lamp according to the first or second aspect, wherein the discharge path is bent and the base end is supported by the partition. Lead wires connected to the filament electrodes provided at both ends of the discharge path are led out to the partition body on the side opposite to the main part of the discharge path; And a wiring substrate on the opposite side to the main portion of the discharge channel; the wiring substrate is at least N-channel FET and P It is characterized by mounting a channel type FET.

The present invention specifies a preferred configuration of the component arrangement of the compact fluorescent lamp. That is, the fluorescent lamp is
Since the discharge path is not straight but bent, a compact shape can be obtained. However, the manner of bending of the discharge path varies. Among them, relatively many are 1
This is a configuration in which two glass bulbs are bent in a saddle shape, or a configuration in which a plurality of glass bulbs bent in a U-shape are connected in series to form one bent discharge path. Even in the latter case, the arrangement of the U-shaped glass tube varies. U
The number of glass tubes in the shape of a letter is often appropriately selected depending on the rated power consumption. In addition, there is one in which one discharge path is spirally bent. The present invention can be applied to any of the above configurations. Further, the light-transmitting globe may or may not be provided.

Next, in the present invention, the N-channel FE is formed on the surface of the wiring board facing the base end of the discharge path.
Mounting the T- and P-channel FETs on the wiring board means placing the N-channel FET and the P-channel FET on the fluorescent lamp side of the wiring board. Such a configuration is employed for the following reason. That is, these semiconductor devices are generally relatively short, but have a large mounting area. By mounting the wiring board as close to the base end of the fluorescent lamp as possible, it is possible to reduce the size of the compact fluorescent lamp. Even if such a configuration is adopted, it is possible to arrange short circuit components.

On the other hand, since there is a substantially hollow base on the base side of the wiring board, that is, on the power supply side,
Suitable for mounting tall circuit components. And
If circuit components with a short height and a large mounting area are mounted on this surface, there is no room for mounting other circuit components or the wiring board must be enlarged. However, in order to reduce the size of the bulb-type fluorescent lamp, the size of the wiring board must be avoided most.

For the reason described in detail above, it is meaningful to mount the FET on the surface of the wiring board on the fluorescent lamp side.

However, a pair of filament electrodes is sealed at both ends of the fluorescent lamp, and two filament electrodes are respectively provided to the outside.
A lead wire has been derived. Since the vicinity of the filament electrode is the region where the temperature is the highest in the fluorescent lamp,
The FET is mounted on the fluorescent lamp side surface of the wiring substrate at a position separated from the filament electrode so as not to be affected by the high temperature. Since the FET also generates heat by the flow of the load current, if it receives much heat from the filament electrode, it may easily exceed the temperature rating.

Thus, in the present invention, by providing the above configuration, a compact and highly reliable compact fluorescent lamp can be obtained by increasing the mounting density of the lighting device.

[0039]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of a compact fluorescent lamp of the present invention.
It is a partial sectional front view showing the embodiment.

In the figure, 10 is a bulb-type fluorescent lamp main body, 14 is a fluorescent lamp, and 15 is a lighting device, and these constitute a bulb-type fluorescent lamp.

The bulb-type fluorescent lamp body 10 includes the envelope 1
1, a base 12 and a partition 13.

The envelope 11 includes a light-transmitting globe 11a and a light-shielding base 11b.

The translucent globe 11a has a glass bottomed cylindrical shape with a light diffusing coating formed on the inner surface.

The light-shielding substrate 11b has a cup shape made of a synthetic resin, a base 12 is mounted on the base, and a translucent glove 11a is fixed to an open end.

The translucent glove 11a is adhered to the open end of the light-shielding substrate 11b using a silicone adhesive 16.

The partition 13 is formed by molding a white synthetic resin, and is fixed to the open end of the base 11b of the envelope 11 together with the translucent glove 11a by the silicone adhesive 16. Thus, the partition 13 divides the inside of the envelope 11 into a light-emitting room A and a circuit storage room B. The partition 13 has a fluorescent lamp support hole 13a and a silicone adhesive filling hole 13b.

The fluorescent lamp 14 includes a bulb 14a, a filament electrode 14b, a phosphor layer, and a discharge medium.

The bulb 14a is formed in a so-called saddle shape in which an elongated glass tube is bent in a U-shape at the center and further bent in a U-shape in directions different by 90 °.

The filament electrode 14b is of a hot cathode type,
A pair is sealed at both ends of the valve 14a.

The phosphor layer is formed on the inner side of the bulb 14a.

The discharge medium is composed of a rare gas of several torr such as mercury and argon, and is sealed in the bulb 14a after exhausting the interior of the bulb 14a.

Then, the fluorescent lamp 14 has both ends in the fluorescent lamp insertion hole 13a of the partition 13 from the light emitting chamber A side.
And is fixed to and supported by the partition 13 by the silicone adhesive 17 and is disposed in the light emitting chamber A of the envelope 11.

The intermediate portion of the fluorescent lamp 14 is fixed to the partition 13 by a silicone adhesive 18 filled from a silicone adhesive filling hole 13b.

The lighting device 15 includes a wiring board 15a and a circuit component 15b mounted on the wiring board 15a. The lighting device 15 is mounted on the partition 13 and arranged in the circuit storage room B of the envelope 11.

The lighting device 15 constitutes the lighting device shown in FIG. 2, and the fluorescent lamp 14 corresponds to the fluorescent lamp DL in FIG.

The base 12 is connected to the input terminal of the lighting device 15, and the output terminal of the lighting device 15 is connected to the fluorescent lamp 14.
Are connected to both electrodes 14b.

FIG. 2 shows a first embodiment of the compact fluorescent lamp of the present invention.
It is a circuit diagram showing a lighting device in an embodiment.

In the figure, 1 is an AC power supply and 2 is an overcurrent
Fuse, 3 is a noise prevention circuit, 4 is a rectified DC power supply, S_N
Is an N-channel FET, S_PIs a P-channel type FE
T, G _CIs a gate circuit, S_TIs the starting circuit, P_TIs the gate
The protection means, LC, is a load circuit.

AC power supply 1 is a commercial 100 V AC power supply.

The overcurrent fuse 2 is composed of a pattern fuse integrally formed on the wiring board, and protects the circuit from being burned out when an overcurrent flows and burnt out.

The noise prevention circuit 3 includes an inductance L1 interposed in series between the AC power supply 1 and the rectified DC power supply 4.
And a capacitor C1 connected in parallel with the AC power supply 1 on the AC power supply 1 side of the inductance L1 to form an inverted L-shaped circuit together with the inductance L1. Remove to prevent spill.

The rectified DC power supply 4 comprises a bridge type full-wave rectifier circuit 4a and a smoothing circuit 4b.

The bridge type full-wave rectifier circuit 4a has an AC input terminal connected to the AC power supply 1 via the noise prevention circuit 3, and a DC output terminal connected to the smoothing circuit 4b.

The smoothing circuit 4b comprises a series resistor R1 and a smoothing capacitor C2.

The series resistor R1 has a resistance value of several ohms or less, and acts to reduce the harmonic by making the current waveform when the charging current flows into the smoothing capacitor C2 gentle.

The drain of the N-channel type FET _SN is connected to the positive electrode of the smoothing capacitor C2.

[0068] On the other hand, P-channel type FETS _P has a source connected to the source of the N-channel type FETS _N,
The drain is connected to the negative electrode of the smoothing capacitor C2.

[0069] The gate circuit _{G C} is a feedback winding s, consisting of the series resonant circuit _{S R} and the gate voltage output means _{O G.}

The feedback winding s is composed of an auxiliary winding magnetically coupled to a current limiting inductance L2 described later.

[0071] series resonant circuit _{S R,} the inductance L3
And a series circuit of a capacitor C3, both ends of which are connected to both ends of the feedback winding s.

[0072] The gate voltage output means O _G is a resonance voltage appearing across the capacitor C3 of the series resonant circuit S _R to retrieve via a capacitor C4. One end of the capacitor C4 is connected to a connection point between the capacitor C3 and the inductance L3, and the other end of the capacitor C4 is connected to an N-channel FET _SN and a P-channel F
It is connected to the gates of the ETS _P.

Further, the other end of the capacitor C3 is connected to each FET.
Connected to the source. In this way, the resonance voltage appearing across the capacitor C3 via the gate voltage output means O _G gate of each FET, is applied between the source.

[0074] starting circuit _{S T} is first resistor R2, and a second resistor R3, and a third resistor R4.

The first resistor R2 has one end connected to the positive electrode of the smoothing capacitor C2 and the other end connected to an N-channel FET.
Together they are connected to the gate of S _N, the second resistor R3
One end and the gate circuit G _C of the gate voltage output means O _G of
Is connected to the output terminal on the gate side, that is, the other end of the capacitor C4.

The other end of the second resistor R3 is connected to the series resonance circuit L
It is connected to the connection point between the inductance L3 of C and the feedback winding s.

One end of the third resistor R4 is connected to each FETS.
_N, connected to the source side of the output end of the S _P output connection point or each of the source and the gate voltage output means O _G, the other end is connected to the negative electrode of the smoothing capacitor C2.

The gate protection means _PT has a gate voltage output means O by connecting a pair of zener diodes in series with opposite polarities.
Connected to _G.

The load circuit LC includes a fluorescent lamp D as a load.
L, current limiting inductance L2, DC cut capacitor C
5 and a resonance capacitor C6.

The fluorescent lamp DL has a pair of filament electrodes E1 and E2 at both ends of the discharge path. The one power supply side terminal of the filament electrode E1 is connected to one end of the DC cut capacitor C5, and the non-power supply side terminal is left open.

The other end of the other filament electrode E2 is connected to the filament heating winding wh.
Further, the power supply side terminal of the other filament electrode E2 is
It is connected to the drain of the P-channel-type FETS _P.

The filament heating winding wh is magnetically coupled to the current limiting inductance L2 to heat the other filament electrode E2 of the fluorescent lamp DL. Instead of the filament heating winding wh, the lower terminal in the drawing of the resonance capacitor C6 may be connected to the non-power supply side terminal of the filament electrode E2 in the drawing of the fluorescent lamp DL. In this case, the filament electrode E2 is connected to the resonance capacitor C6.
Is heated by the current flowing through it.

[0083] limiting inductance L2 has one end connected to the source of the FETS _{N, S P,} the other end is connected to the negative terminal of the DC cut capacitor C5.

The resonance capacitor C6 is connected between the power supply side terminals of the filament electrodes E1 and E2 of the fluorescent lamp DL and is connected in parallel to the fluorescent lamp DL.

Thus, the load circuit LC includes the current limiting inductance L2, the capacitor C5, and the resonance capacitor C6.
Is formed.

[0086] Further, the capacitor C7 is connected between the source and drain of the P-channel type FETS _P, to reduce the load during switching of the P-channel type FETS _P.

Next, the circuit operation in this embodiment will be described.

When the AC power supply 1 is turned on, a DC voltage smoothed by the rectified DC power supply 4 appears at both ends of the smoothing capacitor C2. Then, DC voltage is applied between both drains of the series-connected N-channel type FETS _N and P-channel type FETS _P. However, both FETS _N ,
Since the gate voltage is not applied to S _P, both F
ETS _{N, S P} remains in the off state.

The DC voltage is simultaneously supplied to the starting circuit S_TAlso applied
Therefore, both ends of the second resistor R3 are mainly
Each resistance value of the resistor R2, the second resistor R3, and the third R4
A voltage corresponding to the proportional ratio appears. And the second resistor R
3 is connected to each FETS _N, S_PGate source
It is applied as a positive voltage in between. As a result, N channel
LEFETS_NExceeds the threshold voltage
Is turned on. In contrast, P
Channel FETS_PApplied between gate and source
Since the voltage is of opposite polarity to the required gate voltage,
It remains off.

When the N-channel FET _SN is turned on,
A current flows from the rectified DC power supply 4 through the load circuit LC, that is, the current limiting inductance L2, the DC cut capacitor C5, and the resonance capacitor C6 in series via the drain and source of the N-channel FET _SN . Load circuit L
C current limiting inductance L2, DC cut capacitor C
5 and the resonance voltage of the resonance capacitor C6, and the terminal voltage of the resonance capacitor C6 increases.

On the other hand, when a current flows through the current limiting inductance L2, a voltage is induced in the feedback winding s and the filament heating winding wh which are magnetically coupled.

[0092] As a series resonant circuit S _R by the voltage induced in the feedback winding s by the current starts to series resonance. Since the negative voltage boosted in the capacitor C3 by the series resonance occurs, applied between each gate and the source of the gate protection means P _T is regulated to a constant voltage by the P-channel type FETS _P and N-channel type FETS _N Is done. Thus, the gate of the P-channel type FETS _P is to exceed the threshold voltage, is turned on. On the other hand, the N-channel type FET _SN which has been turned on until now has the opposite polarity and has no predetermined gate voltage, so it is turned off.

[0093] When the P-channel-type FETS _P is turned on,
The load circuit LC electromagnetic energy and N-channel type FET the closed circuit of the source and drain and the load circuit LC of the electric charge is released P-channel type FETS _P of the capacitor C6 are stored in the current limiting inductor L2 of
A current flows in a direction opposite to that when _SN is turned on.

On the other hand, an AC voltage is induced in the filament heating winding wh as a current in the alternating current flows through the current-limiting inductance L2 to heat one filament electrode E2 of the fluorescent lamp DL. Electron emission is performed in the DL.

Since a high resonance voltage appearing at both ends of the resonance capacitor C6 is applied to the fluorescent lamp DL together with the above-described electron emission, the fluorescent lamp DL is soon started and lights up.

[0096] The current flowing in the P channel type FETS _P is turned on, the current of the current of the same polarity flows through the starting circuit _{S T} the feedback winding s flows, and on again N-channel type FETS _N, P Channel type FETS
_P turns off. Thereafter each FETS _{N, S P} is alternately turned on,
When turned off, high frequency is generated and applied to the load circuit LC, so that the fluorescent lamp DL is turned on at high frequency.

FIG. 3 shows a second embodiment of the compact fluorescent lamp of the present invention.
It is a principal part expanded sectional view which shows embodiment of FIG.

FIG. 4 is a conceptual diagram showing the positional relationship between the wiring board and the fluorescent lamp as a plane viewed from the right side of FIG.

In each figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment is different mainly in the configuration of the fluorescent lamp 14 and the lighting device 15.

That is, the fluorescent lamp 14 is bent by arranging three U-shaped bulbs 14a concentrically as shown in FIG. 4 and connecting them by a thin connecting pipe 14c. A discharge path is formed.

The pair of filament electrodes 14b are sealed at both ends of the discharge path via pinch seals 14d. In addition, 14e is a pair of lead wires derived from the filament electrode 14b, and 14f is an exhaust pipe.

The fluorescent lamp 14 has its base end 14g supported by the partition 13 with a silicone adhesive (not shown) or the like.
Although 4h is located below the partition 13 in FIG. 3, the lead wire 14e is led out to the upper side of the partition 13 in FIG. 3, that is, the side opposite to the main portion 14h side.

On the other hand, the lighting device 15 is surface-mounted on the surface of at least the N-channel type FET SN and the P-channel type FET SP facing the base end 14g of the fluorescent lamp 14 of the wiring board 15a, that is, the lower surface in FIG. . Although not shown, relatively short circuit components are also surface-mounted.

However, the N-channel type FET SN and the P-channel type FET SP are arranged at positions separated from the filament electrode 14b of the fluorescent lamp 14, as can be understood from FIG. Then, the remaining circuit components 1
5b is mounted on the surface of the wiring board 15a opposite to the fluorescent lamp 14. Most of the remaining circuit components 15b are tall, but some of them are also short.

FIG. 5 shows a third embodiment of the compact fluorescent lamp of the present invention.
It is a circuit diagram showing a lighting device in an embodiment.

In the figure, the same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment is different from the first embodiment in the structure of the smoothing circuit 4b.

That is, the smoothing circuit 4b forms a partial smoothing circuit described below. The partial smoothing circuit has a first
, A second diode D2, an inductor L3, and a smoothing capacitor C7.

[0110] The first diode D1 has an anode connected to a connection point of the N-channel type FETS _N and P-channel type FETS _P, the cathode is connected to one end of the inductor L3.

The second diode D2 has an anode connected to one end of the inductor L3 and a cathode connected to the positive electrode of the full-wave rectifier circuit 4a.

The other end of the inductor 13 is connected to one end of a smoothing capacitor C7.

[0113] The other end of the smoothing capacitor C7 is connected to the negative electrode of the full-wave rectifier circuit 4a.

Thus, the smoothing capacitor C7 is charged from the full-wave rectifier circuit 4a via the N-channel FET S _N , the first diode D1, and the inductor L3.
When the instantaneous value of the voltage of the full-wave rectifier circuit 4a is higher, the charge of the smoothing capacitor C7 is higher than the second diode D2.
And is not discharged.

When the instantaneous value of the voltage of the smoothing capacitor C7 becomes higher than the voltage of the full-wave rectifier circuit 4a, the P-channel type F
ETS _P, the first diode D1, an inductor L3 and a smoothing capacitor C7 is to constitute a step-down chopper acts to generates a high frequency to compensate for voltage periods of low DC voltage of the full-wave rectifier circuit 4a.

FIG. 6 shows a fourth embodiment of the compact fluorescent lamp of the present invention.
FIG. 8 is a magnetic circuit diagram showing a current limiting inductance and a feedback winding in the embodiment.

[0117] That is, current limiting inductance L2 is composed of a core k and load current windings _{w L.}

The core k includes an E-shaped core k _E and an I-shaped core k
_I. E-shaped core k _E is provided with a central leg l _C and a pair of side legs l _S, in order to center leg l _C is slightly shorter form than side legs l _S, when joining the I type core k _I gap g is formed between the central leg l _C and I-shaped core k _I.

[0119] Load current windings w _L is formed by approximately 100 turns wound on the central leg l _C of E-shaped cores k _E, the required current limiting inductance L2 by the leakage inductance due to the gap g.

[0120] On the other hand, the feedback winding s, by that several turns wound at a position spaced apart proximal end side from the gap g of the central leg l _C of E-shaped cores k _E, the load current windings w
It is formed by strong magnetic coupling to _L.

[0121]

According to the first to third aspects of the present invention, the load circuit operating at a high frequency generated by the alternating switching of the N-channel FET and the P-channel FET connected in series between the DC power supplies is limited. Including a series circuit of a diverted inductance and a resonance capacitor and a fluorescent lamp connected in parallel to the resonance capacitor, a gate drive circuit is commonly arranged for alternate switching of the N-channel FET and the P-channel FET. In addition, by providing a starting circuit for turning on the N-channel type FET first, the starting circuit can be simplified and a compact and inexpensive bulb-type fluorescent lamp can be provided.

According to the invention of claim 2, in addition, the N-channel FET is connected to the P-channel FE on the positive side of the DC power supply.
T is connected to the negative side of the DC power supply, and the starting circuit has a first resistor connected between the drain and the gate of the N-channel FET, a second resistor connected to the gate drive circuit, and a source / source of the P-channel FET. Since a third resistor connected between the drains is provided, and the first to third resistors are in a serial relationship as viewed from the DC power supply, the configuration of the gate drive circuit and the starting circuit is simplified, and N It is possible to provide a bulb-type fluorescent lamp that reliably turns on the channel-type FET first and starts the channel-type FET.

According to the third aspect of the present invention, in addition, the discharge path of the fluorescent lamp is bent and its base end is supported by the partition, and the lead wire connected to the filament electrode is connected to the discharge path of the partition. The main body portion is led out on the side opposite to the side where the partition member supports the wiring board, and the wiring board has at least an N-channel FET on a surface facing the base end portion of the discharge path.
Since the P-channel FET is mounted at a position separated from the filament electrode, the mounting density of the lighting device can be increased, and a compact and highly reliable compact fluorescent lamp can be provided.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view showing a first embodiment of a bulb-type fluorescent lamp of the present invention.

FIG. 2 is a circuit diagram showing a lighting device according to the first embodiment of the bulb-type fluorescent lamp of the present invention.

FIG. 3 is an enlarged sectional view of a main part showing a second embodiment of the bulb-type fluorescent lamp of the present invention.

FIG. 4 is a conceptual diagram showing a positional relationship between the wiring board and the fluorescent lamp as a plane viewed from the right side of FIG. 3;

FIG. 5 is a circuit diagram showing a lighting device according to a third embodiment of the bulb-type fluorescent lamp of the present invention.

FIG. 6 is a magnetic circuit diagram showing a current-limiting inductance and a feedback winding in a fourth embodiment of the bulb-type fluorescent lamp of the present invention.

[Explanation of symbols]

1 ... AC power source 2 ... overcurrent fuse 3 ... noise prevention circuit 4 ... rectified DC power supply 4a ... full-wave rectifier circuit 4b ... smoothing circuit DL ... fluorescent lamp G C _... gate circuit L2 ... limiting inductance LC ... load circuit O _G ... gate voltage output unit P T _... gate protection s ... feedback winding S _N ... N-channel type FET _{S P} ... P-channel type FET S R _... series resonant circuit S T _... starting circuit wh ... filament heating windings

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Kazuyuki Uraya, Inventor Kazuki 4-3-1 Higashi-Shinagawa, Shinagawa-ku, Tokyo Inside Toshiba Lighting & Technology Corporation (72) Inventor Fuminori Nakaya 4-chome, Higashi-Shinagawa, Shinagawa-ku, Tokyo No. 1 Toshiba Litec Co., Ltd. (72) Inventor Tsutomu Araki Inside Toshiba Litec Co., Ltd. 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo

Claims (3)

[Claims] 1. An N-channel FET and a P-channel FET connected in series between a DC power supply and a DC power supply.
A load circuit that includes a series circuit of a current limiting inductance and a resonance capacitor and a fluorescent lamp connected in parallel to the resonance capacitor and that operates at a high frequency generated by alternating switching of an N-channel FET and a P-channel FET; It includes a feedback winding magnetically coupled to the current limiting inductance and a series resonance circuit that resonates with a feedback voltage induced in the feedback winding, and acts commonly on the N-channel FET and the P-channel FET. N-channel type FET and P-channel type F
A gate drive circuit for driving the ET and alternately switching at a high frequency; an N-channel FET at startup
And a starting circuit for turning on the lamp first. 2. An N-channel FET and a P-channel FET, wherein the drain of the N-channel FET is connected to the positive electrode of the DC power source, the source is connected to the source of the P-channel FET, and the drain of the P-channel FET is connected to the drain of the P-channel FET. The starting circuit is connected to the negative terminal of the DC power supply; the first resistor connected between the drain and the gate of the N-channel FET, the second resistor connected to the gate drive circuit, and the source of the P-channel FET. 2. The fluorescent lamp according to claim 1, further comprising a third resistor connected between the drains, wherein the first to third resistors are in a serial relationship as viewed from the DC power supply. . 3. A fluorescent lamp according to claim 1, wherein the discharge path is bent and the base end is supported by the partition, and the lead wires connected to the filament electrodes provided at both ends of the discharge path are formed on the partition. On the other hand, the main body of the discharge path is led out on the side opposite to the side where the main part is located; the partition body supports the wiring board on the side opposite to the side where the main part of the discharge path is located;
At least an N-channel FE is located at a position separated from the filament electrode on the surface facing the base end of the discharge path.
3. The bulb-type fluorescent lamp according to claim 2, wherein T- and P-channel FETs are mounted.