JP2000353598A - Fluorescent lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and inexpensive fluorescent lamp lighting device without constituting a trigger circuit and a transistor drive circuit independently. SOLUTION: This device is provided with a capacitor 4 connected to output terminals of a rectifying circuit 3, a fluorescent lamp 8, an inductor 10, and a serial body of an N type transistor 5 and a P type transistor 6. Two constant voltage elements 15, 16 and a capacitor 14 are serially connected between a gate terminal of the N type transistor 5 and a source terminal of the P type transistor 6. A resistor 13 placed between a connected point of the two constant voltage elements 15, 16 and the source terminal of the P type transistor 6, and a resistor 12 placed between a drain terminal and the gate terminal of the N type transistor 5 are provided. A serial body of a secondary winding 10A of the inductor 10 and an inductor element 11 are connected between the gate terminal of the N type transistor 5 and the source terminal of the P type transistor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluorescent lamp lighting device using an inverter circuit.

[0002]

2. Description of the Related Art Conventional fluorescent lamp lighting devices include:
A general series inverter as shown in FIG. 3 is known. In FIG. 3, 1 is an AC power supply, 2 is a noise prevention capacitor, 3 is a rectifier circuit, 4 is a smoothing capacitor, 5 and 6 are FETs, 7 is a resonance capacitor, 8 is a fluorescent lamp, and 9 is a fluorescent lamp. A preheating capacitor, 18 is a choke coil, 14 is a trigger capacitor, 19 is a resistor,
Reference numeral 20 denotes a trigger diode, and 21 denotes a current transformer.

In FIG. 3, first, before starting the fluorescent lamp 8,
The AC voltage is rectified from the AC power supply 1 via the rectifier circuit 3, and the smoothing capacitor 4 is charged. At the same time as the smoothing capacitor 4 is charged, the trigger capacitor 14 is also charged via the resistor 12.

When the charging voltage of the trigger capacitor 14 reaches the trigger voltage of the trigger diode 20,
The charge of the trigger capacitor 14 is supplied to the gate terminal of the FET 6, and the FET 6 is turned on. F
When the ET 6 is turned on, the voltage of the smoothing capacitor 4 is lower than the voltage value of the AC power supply 1 when the ET 6 is turned on. One of the filaments 8A,
Further current flows through the preheating capacitor 9, the other filament 8B of the fluorescent lamp 8, the choke coil 18, the primary winding 21B of the current transformer 21, and the FET 6.

On the other hand, the primary winding 2 of the current transformer 21
Since an induced voltage is generated in the secondary winding 21C of the current transformer 21 by the current flowing through the FET 1B, the gate voltage can be supplied to the FET 6, so that the FE
T6 can maintain the ON state.

However, when the current flowing through each winding of the current transformer 21 increases, the core itself of the current transformer 21 becomes magnetically saturated after a certain period of time. When the core of the current transformer 21 is magnetically saturated, no induced voltage is generated in the secondary winding 21C.
Can no longer supply the gate voltage of
Is turned off.

The secondary winding 2 of the current transformer 21
Since the current flowing through 1A has the opposite winding direction to the secondary winding 21C, when the FET 6 is turned off, the voltage between the gate terminal and the source terminal of the FET 5 increases. Therefore,
The FET 5 is turned on by such a voltage rise.

When the FET 5 is turned on, the current becomes FE
It flows through a closed circuit composed of T5, current transformer 21, choke coil 18, filament 8B of fluorescent lamp 8, preheating capacitor 9, filament 8A of fluorescent lamp 8, and resonance capacitor 7. This current is applied to the choke coil 1
8, the resonance capacitor 7 and the preheating capacitor 9 resonate.

Further, when the current flowing through each winding of the current transformer 21 increases, the core itself of the current transformer 21 is magnetically saturated again. When the core of the current transformer 21 is magnetically saturated, the output of the secondary winding 21A disappears,
The gate voltage cannot be supplied to FET5,
FET 5 is turned off. Thereafter, by repeating the above-described operation, the FET 5 and the FET 6 are turned on / off.
The off state can be switched alternately.

The current flows through the preheating electrode of the fluorescent lamp 8 to heat the electrode. At the same time, a large voltage is applied between the electrodes of the fluorescent lamp 8 by resonance, and the electrode temperature rises, so that the fluorescent lamp 8 can be turned on.

[0011]

As described above, in the conventional fluorescent lamp lighting apparatus, the trigger circuit and the transistor control circuit have independent circuit configurations with the current transformer as a boundary.

However, in order to reduce the size of the fluorescent lamp lighting device itself, the fact that the trigger circuit and the transistor control circuit are independent of each other is a major obstacle to the miniaturization of the fluorescent lamp lighting device, and furthermore, it is difficult to manufacture the fluorescent lamp lighting device. There was a problem that the cost would be high.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compact and inexpensive fluorescent lamp lighting device without solving the above problem by using a trigger circuit and a transistor control circuit independent of each other.

[0014]

To achieve the above object, a fluorescent lamp lighting device according to the present invention comprises: a rectifier circuit to be connected to an AC power supply; a capacitor connected to an output terminal of the rectifier circuit; A fluorescent lamp having a pair of electrodes, an inductor, an N-type transistor and a P-type transistor are connected in series, and when the N-type transistor is turned on, functions as a trigger circuit for lighting the fluorescent lamp. When the P-type transistor is on, it functions as a transistor control circuit after the fluorescent lamp is turned on.

A fluorescent lamp lighting device according to the present invention comprises a rectifier circuit to be connected to an AC power supply, a capacitor connected to an output terminal of the rectifier circuit, a fluorescent lamp having a pair of electrodes, and an inductor. And an N-type transistor and a P-type transistor are connected in series, and 2 is connected between the gate terminal of the N-type transistor and the source terminal of the P-type transistor.
A constant voltage element and a capacitor are connected in series, and a resistor located between a contact point of the two constant voltage elements and a source terminal of the P-type transistor and a resistor located between a drain terminal and a gate terminal of the N-type transistor are connected. The secondary winding of the inductor and the inductor element are connected in series between the source terminal of the P-type transistor and the gate terminal of the N-type transistor.

With such a configuration, the transistor circuit operates as a trigger circuit before the fluorescent lamp is turned on, and operates as a transistor control circuit after the fluorescent lamp is turned on, so that two independent circuits are not provided for each transistor. A compact and inexpensive fluorescent lamp lighting lamp device can be obtained.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fluorescent lamp lighting device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a fluorescent lamp lighting device according to the present invention. In FIG. 1, 1 is an AC power supply, 2 is a noise prevention capacitor, 3 is a rectifier circuit, 4 is a smoothing capacitor, 5 and 6 are FETs, 7 is a resonance capacitor, and 8 is a fluorescent light, as in FIG. A lamp, 9 a preheating condenser,
10 is a choke coil, 14 is a trigger capacitor,
15 and 16 are Zener diodes, 19 is a resistor,
Shown respectively.

As shown in FIG. 1, a fluorescent lamp lighting device according to an embodiment of the present invention comprises a resonance capacitor 7, a fluorescent lamp 8, a choke coil 10, and a source terminal of a P-type FET 6 serving as a first switch element. The drain terminals are sequentially connected in series;

Further, one end of the resonance capacitor 7 and the FET 6
A smoothing capacitor 4 is connected between the drain terminal
A closed circuit is configured. Choke coil 10 and FET
6 and between the connection point between the resonance capacitor 7 and the smoothing capacitor 4 are N-type F
ET5 is connected.

Further, the input terminal of the rectifier circuit 3 is connected to the AC power supply 1 via the noise prevention capacitor 2. A preheating capacitor 9 is connected between the pair of electrodes 8A and 8B of the fluorescent lamp 8 on the side opposite to the power supply, and constitutes a high-frequency inverter circuit as a whole circuit.

That is, the DC obtained by rectifying and smoothing the commercial AC power supplied from the AC power supply 1 is connected in parallel between the smoothing capacitor 4 and the fluorescent lamp 8.
The signal is input to a series circuit of FETs 5 and 6, which are switch elements that oscillate at a high frequency. Further, the inverter circuit is capable of generating high-frequency power by being input to an LC resonance circuit composed of a resonance capacitor 7 and a choke coil 10 connected to the FET 6 and connected in series to the fluorescent lamp 8. .

As a starting means of the high-frequency inverter circuit, a secondary winding 10A of a choke coil 10 forming a closed loop between the gate terminals and the source terminals of the FETs 5 and 6 and a trigger capacitor 14 are connected in series. One side of the trigger capacitor 14 is connected to the source terminals of the FETs 5 and 6.

In the fluorescent lamp lighting apparatus according to the present embodiment, first, before the fluorescent lamp 8 is started, the commercial AC power is supplied from the AC power supply 1 to the noise preventing capacitor 2 and the pulsating current flows through the rectifier circuit 3. Voltage is generated. The current due to the pulsating voltage charges the smoothing capacitor 4 to the power supply voltage.

The resonance capacitor 7 is connected via a resistor 19.
And the preheating capacitor 9 is charged. At the same time, resistance 12,
The trigger capacitor 14 is also charged via the inductance element 11, the secondary winding 10A of the choke coil 10, and the resistor 13.

When the charging voltage of the trigger capacitor 14 reaches the threshold voltage of the Zener diode 15, the charge of the trigger capacitor 14 is supplied to the gate terminal of the FET 5, and the FET 5 is turned on. When the FET 5 is turned on, charges of the resonance capacitor 7 and the preheating capacitor 9 flow into the source terminal of the FET 5 via the primary winding 10B of the choke coil 10.

The primary winding 1 of the choke coil 10
An induced voltage is generated in the secondary winding 10A of the choke coil 10 by the current flowing through 0B, a current is supplied to the gate terminal of the FET 5, and the FET 5 can be maintained in the ON state.

At the same time, the trigger capacitor 14 is connected to the secondary winding 10A of the choke coil 10 and the inductance element 1
1. FET 5 via Zener diodes 15 and 16
Is charged as shown in FIG. Here, FIG. 2A is a waveform diagram of a voltage between the gate terminal of FET5 and the source terminal of FET6.
FIG. 2B shows a waveform diagram of the voltage between the terminals of the trigger capacitor 14. It can be seen that both voltage waveforms are square waves, and the phases are reversed.

At this time, the secondary winding 1 of the choke coil 10
The current flowing through 0A flows in the opposite direction due to the resonance of the inductance element 11 and the capacitor 17 connected to the secondary winding 10A and the charge of the trigger capacitor 14,
Since the voltage supplied between the gate terminal of the FET 5 and the source terminal of the FET 6 decreases below the threshold voltage of the Zener diode 15, the voltage cannot be continuously supplied to the gate terminal of the FET 5, and the FET 5 is turned off. State.

On the other hand, the secondary winding 10 of the choke coil 10
A reverse voltage is generated at A, and a voltage is supplied to the gate terminal of the FET 6, so that the FET 6 is turned on.

When the FET 6 is turned on, a current flows from the smoothing capacitor 4 through a closed circuit composed of the resonance capacitor 7, the fluorescent lamp 8, the choke coil 10, and the FET 6, and this current flows through the primary winding 10B of the choke coil 10 to the primary winding 10B. It resonates with the resonance capacitor 7 and the preheating capacitor 9.

At this time, the secondary winding 1 of the choke coil 10
The current flowing through 0A flows in the opposite direction due to the resonance of the inductance element 11 and the capacitor 17 connected to the secondary winding 10A and the trigger capacitor 14, and the FET
Since the voltage supplied between the gate terminal of the FET 6 and the source terminal of the FET 5 decreases below the threshold voltage of the Zener diode 16, the voltage cannot be continuously supplied to the gate terminal of the FET 6, and
Is turned off. Then, the FET 5 is turned on again. Thereafter, the above-described operation is repeated, and the ON state and the OFF state are alternately repeated between the FETs 5 and 6.

The above current flows through the preheating electrode of the fluorescent lamp 8 to heat the electrode. At the same time, a large voltage is applied between the electrodes of the fluorescent lamp 8 by resonance, and the fluorescent lamp 8 rises in electrode temperature and is turned on.

As described above, according to the present embodiment, when the circuit functions as a trigger circuit, the trigger capacitor 14 functions as a trigger capacitor, and after the fluorescent lamp is turned on, one of the transistor control circuits. Act as a unit. Therefore, a compact and inexpensive fluorescent lamp lighting device can be realized without providing a trigger circuit and a transistor control circuit independently.

An embodiment of the fluorescent lamp lighting device according to the present invention will be described below. In the circuit configuration shown in FIG. 1, under the input condition of an AC power supply voltage of 100 V, the inductance of the choke coil 10 is 0.75 mH, the capacitance of the resonance capacitor 7 having 10 turns is 0.1 μF, and the capacitance of the preheating capacitor 9 is 6800 pF. , The capacity of the smoothing capacitor 4 is 1
5 μF, the capacitance of the trigger capacitor 14 is 0.033 μF
In the case of the constant of the above, it functioned sufficiently as an inverter circuit. The total weight of the conventional product is 23 g, but the total weight is 15 g in the present embodiment, so that a considerable reduction in weight and size is realized.

[0035]

As described above, according to the fluorescent lamp lighting device of the present invention, the trigger circuit is used as a part of the control circuit of the transistor after the fluorescent lamp is turned on, so that the fluorescent lamp having a small and inexpensive structure can be obtained. A lamp lighting device can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a fluorescent lamp lighting device according to an embodiment of the present invention.

FIG. 2 is a voltage waveform diagram

FIG. 3 is a circuit diagram of a conventional fluorescent lamp lighting device.

[Explanation of symbols]

 Reference Signs List 1 AC power supply 2, 17 Noise prevention capacitor 3 Rectifier circuit 4 Smoothing capacitor 5 N-type FET 6 P-type FET 7 Resonant capacitor 8 Fluorescent lamp 8A, 8B Filament 9 Preheating capacitor 10, 18 Choke coil (inductor) 10A Secondary of choke coil Winding 10B Primary winding of choke coil 11 Inductance element 12, 13, 19 Resistance 14 Trigger capacitor 15, 16 Zener diode (constant voltage element) 17 Capacitor 20 Trigger diode 21 Current transformer 21A, 21C Secondary winding of current transformer 21B Primary winding of current transformer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroki Nakagawa 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Miho Katayama 1006 Kadoma Kadoma Kadoma City Osaka Pref. Term (reference) 3K072 AA02 BB01 BC01 BC03 DB03 DD04 GA02 GB12 GC02

Claims (2)

[Claims] A rectifier circuit to be connected to an AC power supply;
A capacitor connected to the output terminal of the rectifier circuit, a fluorescent lamp having a pair of electrodes, an inductor, an N-type transistor and a P-type transistor are connected in series, and the N-type transistor is turned on. In that case, it functions as a trigger circuit for lighting the fluorescent lamp,
When the P-type transistor is turned on, the fluorescent lamp lighting device functions as a transistor control circuit after lighting the fluorescent lamp. 2. A rectifier circuit to be connected to an AC power supply;
A capacitor connected to the output terminal of the rectifier circuit, a fluorescent lamp having a pair of electrodes, an inductor, an N-type transistor and a P-type transistor are connected in series, and a gate terminal of the N-type transistor and the P-type transistor. Two constant voltage elements and a capacitor are connected in series between the source terminals of the transistor, and a resistor located between a contact point of the two constant voltage elements and a source terminal of the P-type transistor;
A resistor located between a drain terminal and a gate terminal of the N-type transistor; a secondary winding of the inductor and an inductor between the source terminal of the P-type transistor and the gate terminal of the N-type transistor; A fluorescent lamp lighting device, wherein the elements are connected in series.