WO2008011794A1

WO2008011794A1 - A hot cathode electronic ballast filament control device and design method thereof

Info

Publication number: WO2008011794A1
Application number: PCT/CN2007/002002
Authority: WO
Inventors: Yonglin Teng; Chengyuan Lin
Original assignee: Suzhou Kun Shi Lai Illumination Technology Co., Ltd
Priority date: 2006-07-19
Filing date: 2007-06-27
Publication date: 2008-01-31
Also published as: CN101111115B; CN101111115A

Abstract

A hot cathode electronic ballast filament control device includes : a tube (1), a semi bridge driving circuit (2), and an electronic rectifier control integrated circuit (3). There is an inductor L and a resonance capacitor C2 connected in series between the semi bridge driving circuit (2) and the tube (1). The two ends of the capacitor C2 are connected to one end of the filament that is at two ends of the tube in parallel. Preheating capacitor C1 is connected to the other end of the filament that is at two ends of the tube in parallel. A resonance switch (7) for controlling resonance capacitor C2 is in series connected between the resonancecapacitor C2 and the tube (1). There is a switch controlling circuit (9) between the electronic rectifier control integrated circuit (3) and the resonance switch (7) and the preheating switch (8). Through the switch controlling circuit (9), the electronic rectifier controls integrated circuit (3) controls the tube (1) to be connected with the preheating capacitor (8) and at the same time to cut off the resonance capacitor (7) during preheating the filament, and to cut off the preheating capacitor C1 and at the same time to connect the resonance capacitor C2 during the working of the filament, with respect to a determined preheating time, andcontrols the preheating switch (8) and the resonance switch (7) to be connected in turn, so as to achieve normally working of the tube (1) and at the same time to make the filament open.

Description

Hot cathode electronic ballast filament control device to design method. Technical field

The invention belongs to an electronic ballast circuit, and particularly belongs to a fluorescent lamp hot cathode electronic ballast filament control circuit and a design method thereof.

Background technique

Fluorescent lamp triggering requires preheating and then starts to illuminate, but in the prior art, after the fluorescent lamp is triggered, the filament is still in a conducting state. Especially when the T5 fluorescent lamp is used, it is found that its filament current is greater than that of the lamp tube when it is powered by a conventional electronic ballast. Current defects. Although many improvements have been made, it can only be arrogant to small currents. Due to the geometrical and physical characteristics of T5 fluorescent lamps, to achieve its high luminous efficiency and long life, it must be done in the power supply part of the electronic ballast. New improvements. Summary of the invention

In order to remedy the above deficiencies, the present invention provides a hot cathode electronic ballast filament control device and a design method capable of realizing zero current of a filament when a fluorescent lamp emits light.

The invention is implemented in the following manner: A hot cathode electronic ballast filament control device, comprising a lamp tube and a half bridge driving circuit for starting the lamp tube, further comprising:

1) controlling an electronic ballast control integrated circuit activated by the half bridge driving circuit;

2) The half bridge driving circuit and the lamp tube are sequentially connected in series to form an inductance L of the resonant circuit and a resonant capacitor C2, and both ends of the resonant capacitor C2 are simultaneously connected in parallel to one pole of the filament at both ends of the lamp;

3) the other pole of the filament at both ends of the lamp is connected in parallel with the preheating capacitor C1;

4) a resonant switch connecting the resonant capacitor C2 and the filament of the lamp to control the resonant capacitor C2 to be connected or disconnected, and the preheating capacitor C1 is also connected in series with the filament of the lamp to control the preheating capacitor C1. A preheat switch that is connected or disconnected.

5) a switching control circuit is provided between the electronic ballast control integrated circuit and the resonant switch and the preheat switch, the switching control circuit has a signal control input end of the electronic ballast control integrated circuit, and has a control a resonant output terminal to which the resonant switch is connected or disconnected and a preheating output terminal for controlling the opening or opening of the preheating switch, so as to facilitate control of the lamp tube to be connected to the preheating capacitor while the filament preheating phase is simultaneously disconnected The resonant capacitor, while the filament is in the working phase, disconnects the preheating capacitor and simultaneously accesses the resonant capacitor, so that the lamp is opened by the preheating conversion and the filament is open.

As a further improvement of the present invention, a DC blocking capacitor C3 is connected in series between the half bridge driving circuit and the inductor L.

As a further improvement of the present invention, the electronic ballast control integrated circuit controls the switching access between the preheat switch and the resonant switch through the switching control circuit according to the set filament warm-up time.

As a further improvement of the present invention, the switching control circuit has a setting for controlling the preheating of the filament The time is from 0.4s to Is.

As a further improvement of the present invention, the resonant switch and the preheat switch are gate switches, and the switching control circuit is a gate circuit.

As a further improvement of the present invention, the resonant capacitor has a capacity of at least a hundred times that of the preheat capacitor.

A design method for manufacturing the above-mentioned hot cathode electronic ballast filament control device comprises the following steps:

1) The frequency of the output signal of the half bridge driving circuit is set to belong to the resonant high frequency range of the resonant circuit which is composed of the inductor L and the resonant capacitor C2, and the resonant capacitor C2 has the capacity of the preheating capacitor C1 of at least one hundred times;

2) Deform the circuit diagram into an equivalent circuit diagram. During the preheating phase of the filament, the resonant switch is turned off and the preheat switch is closed, and the equivalent circuit parameters are set:

Ik is the introduction of cathode current

Is for filament current

Ic is the resonant capacitor current

The frequency of the output signal of the half bridge driving circuit is far away from the high frequency range of the resonant circuit and the preheating capacitor. The voltage of the output signal of the half bridge driving circuit is low, which is insufficient for the lamp to ignite, and the equivalent circuit is equivalent to the lamp. Open the way,

That is: I ik I « I is I , and I id I « 0;

3) In the working phase of the filament, the resonant switch is closed and the preheating switch is turned off, and the frequency of the output signal of the half bridge driving circuit is between the resonant high frequency range of the resonant circuit composed of the inductor and the resonant capacitor, and the output of the half bridge driving circuit is The voltage of the signal is high enough to make the tube ionized and turned on, and the equivalent circuit is equivalent to the short circuit of the tube.

That is: I ik I « I id I , I ic I « 0;

The switching control circuit has a set time for controlling the filament warm-up from 0.4 s to Is. Advantageous technical effects of the present invention:

The frequency of the output signal of the half bridge driving circuit is set in a high frequency range in which the resonant circuit and the resonant capacitor form a resonant circuit, and the resonant capacitor and the capacity of the preheating capacitor are different by a hundred times.

In the lamp preheating phase, the switching control circuit controls the preheating capacitor to be closed, and the resonant capacitor is disconnected, and the frequency of the output signal of the half bridge driving circuit is away from the resonant circuit composed of the inductor and the subpage thermal capacitor. Frequency, so the voltage of the output signal of the half-bridge driving circuit is very low, so that the lamp is ionized and turned on, equivalent to the open circuit of the lamp, and the half-bridge driving circuit supplies the filament through the inductor and the preheating capacitor. Preheat current. During the operation of the lamp, the switching control circuit controls the preheating capacitor to be disconnected? The resonant capacitor is closed, and the frequency of the output signal of the half-bridge driving circuit is located in a high-frequency frequency range in which the resonant circuit and the resonant capacitor form a resonant circuit, so that the output signal of the half-bridge driving circuit has a high voltage, which is sufficient for the The lamp is ionized and turned on, which is equivalent to the short circuit of the lamp.

The electronic ballast control integrated circuit controls the preheat switch to be turned off and the resonant switch is connected according to the set filament current warm-up time: 0.4s to: Is range, and the lamp is preheated The stage is converted to a working stage.

Therefore, the switching filament, the resonant tank capacitance and its capacity are realized to be disconnected during the normal operation phase of the lamp lighting, thereby realizing zero current operation of the lamp.

DRAWINGS

1 is a schematic view showing the circuit principle of the filament control device for a hot cathode electronic ballast according to the present invention. detailed description

To start the fluorescent lamp lighting work, the following requirements must be met:

1) In the preheating stage of the lamp, on the one hand, it is necessary to provide sufficient preheating current of the filament. On the other hand, the voltage across the lamp should be low enough to ensure that the lamp is not conducting substantially, and the cathode of the fluorescent lamp is not cold excited and the filament is damaged. ;

2) During the working period of the lamp, the voltage at both ends of the lamp should be high enough to prompt the lamp to start quickly. At the same time, after the fluorescent lamp is started, the filament of the lamp should not be turned on, thus prolonging the life of the filament.

Further description is made below with reference to Figure 1:

A hot cathode electronic ballast filament control device, comprising a lamp tube 1, a half bridge driving circuit 2 for starting the lamp tube, further comprising:

1) controlling the electronic ballast control integrated circuit activated by the half bridge driving circuit 2;

2) The half bridge driving circuit 2 and the lamp tube 1 are sequentially connected in series to form an inductance L harmonic resonant capacitor C2 of the resonant circuit, and both ends of the resonant capacitor C2 are simultaneously connected in parallel to one pole of the filament at both ends of the lamp tube 1;

3) the other end of the filament of the lamp 1 is connected in parallel with the preheating capacitor C1;

4) The resonant capacitor C2 and the lamp filament are connected in series with a resonant switch 7 for controlling the resonant capacitor C2 to be connected or disconnected. The preheating capacitor C1 is also connected in series with the lamp filament to control the preheating capacitor. The preheat switch 8 is connected or disconnected by C1.

5) The electronic ballast control integrated circuit 3 and the resonant switch 7 and the preheat switch 8 are provided with a switching control circuit 9 having a signal control input end of the electronic ballast control integrated circuit, And having a resonant output terminal for controlling the access or disconnection of the resonant switch and a preheating output terminal for controlling the opening or opening of the preheating switch, so as to facilitate controlling the lamp to be connected to the preheating capacitor during the preheating phase of the filament At the same time, the harmonic silver capacitor is disconnected, and the preheating capacitor is turned off during the working phase of the filament. At the same time, the resonant capacitor is connected, and the lamp is opened by the preheating conversion while the filament is open. A DC blocking capacitor C3 is connected in series between the half bridge driving circuit 2 and the inductor L. The resonant switch and the preheat switch are gate switches, and the switch control circuit is a gate circuit.

The electronic ballast control integrated circuit 3 controls the switching access between the preheat switch and the resonant switch by the switching control circuit 9 according to the set filament warm-up time of 0.4s to the Is range. The resonant capacitor has at least a hundred times the capacity of the preheat capacitor.

The circuit principle of the above-mentioned hot cathode electronic ballast filament control device is designed in such a manner that the design steps include:

2). Deform the circuit diagram into an equivalent circuit diagram. During the filament warm-up phase, the resonant switch 7 is turned off and the preheat switch 8 is closed, and the equivalent circuit parameters are set:

Ik is the introduction of cathode current

Is for filament current

Ic is the resonant capacitor current

That is: I ik I « I is I , and I id I « 0;

That is: I ik I « I id I , I ic I « 0;

4) The switching control circuit (9) has a set time for controlling the preheating of the filament from 0.4s to Is, which conforms to the GB15143 standard. The electronic ballast control integrated circuit controls the conversion access between the preheat switch and the resonant switch through the switching control circuit according to the set preheating time of the filament, and switches from the preheating phase of the lamp to the working phase.

In the working phase, the frequency of the output signal of the half-bridge driving circuit 2 is located in the high-frequency range of the resonant circuit composed of the inductor L and the resonant capacitor C2, so that the lamp has a higher voltage at both ends, which is sufficient to ionize the lamp Conduction, the equivalent circuit is a short circuit of the lamp, the filament of the lamp is in an open state due to the opening of the preheat switch, so the lamp filament is operated at zero current, prolonging the life of the filament.

Claims

Claim

A hot cathode electronic ballast filament control device, comprising a lamp tube (1), a half bridge driving circuit (2) for starting the lamp tube, characterized in that:

1) controlling the electronic ballast control integrated circuit (3) activated by the half bridge driving circuit (2);

2) The half bridge driving circuit (2) and the lamp tube (1) are sequentially connected in series to form an inductance L of the resonant circuit and a resonant capacitor C2, and both ends of the resonant capacitor C2 are simultaneously connected in parallel to the filament of the lamp tube (1) One pole

3) the other end of the filament (1) is connected to the other end of the filament preheating capacitor C1;

4) The resonant capacitor C2 and the lamp filament are connected in series with a resonant switch (7) for controlling the connection or disconnection of the resonant capacitor C2. The preheating capacitor C1 is also connected in series with the filament of the lamp to control the pre-control. a preheat switch (8) with a thermal capacitor C1 connected or disconnected;

5) The electronic ballast control integrated circuit (3) is provided with a switching control circuit (9) between the resonant switch (7) and the preheating switch (8), and the switching control circuit has the electronic ballast control a signal control input end of the integrated circuit, and having a resonant output terminal for controlling the access or disconnection of the resonant switch and a preheating output terminal for controlling the opening or opening of the preheating switch, thereby facilitating control of the lamp tube to be preheated in the filament The preheating capacitor is connected to the phase while the resonant capacitor is turned off, and the preheating capacitor is turned off while the filament is in the working phase, and the resonant capacitor is simultaneously connected, so that the lamp is opened by the preheating conversion and the filament is opened. .

2. A hot cathode electronic ballast filament control device according to claim 1, wherein a DC blocking capacitor C3 is connected in series between the half bridge driving circuit (2) and the inductor L.

3. The hot cathode electronic ballast filament control device according to claim 1, wherein the electronic ballast control integrated circuit (3) passes the switching control circuit according to the set filament warm-up time ( 9) Control the conversion access between the preheat switch and the resonant switch.

A hot cathode electronic ballast filament control device according to claim 3, wherein the switching control circuit (9) has a set time for controlling the filament warm-up from 0.4s to Is.

5. The fluorescent lamp preheating control device according to claim 1, wherein the resonant switch and the preheat switch are gate switches, and the switching control circuit is a gate circuit.

6. The fluorescent lamp filament preheating control device according to claim 1, wherein the resonant capacitor has a capacity of at least one hundredth of a magnitude of the preheating capacitor.

7. A method of fabricating a hot cathode electronic ballast filament control device according to claim 1, comprising the steps of:

1) The frequency of the output signal of the half bridge driving circuit is set to belong to the resonant high frequency range of the resonant circuit which is composed of the inductor L and the resonant capacitor C2, and the resonant capacitor C2 has the preheating capacitor C1 to Less than a hundred times the order of magnitude capacity;

2) Deform the circuit diagram into an equivalent circuit diagram. During the preheating phase of the filament, the resonant switch (7) is opened and the preheat switch (8) is closed, and the equivalent circuit parameters are set:

Ik is the introduction of cathode current

Is for filament current

Ic is the resonant capacitor current

That is: I ik I « I is I, and I id I « 0;

That is: I ik I « I id I , I ic I * 0;

4) The switching control circuit (9) has a set time for controlling the warm-up of the filament from 0.4s to the Is range.

S