WO2008125040A1

WO2008125040A1 - A power source apparatus, a display apparatus

Info

Publication number: WO2008125040A1
Application number: PCT/CN2008/070489
Authority: WO
Inventors: Dongping Yang
Original assignee: Proview Technology (Shenzhen) Co., Ltd.
Priority date: 2007-04-17
Filing date: 2008-03-13
Publication date: 2008-10-23
Also published as: CN201038013Y

Abstract

A power source apparatus for outputting the voltage signal to drive a lamp and a display apparatus that comprises the power source apparatus. The power source apparatus comprises: a stray transformer, wherein the synonym end of the first secondary winding is connected with the homonym end of the second secondary winding; the homonym end of the first secondary winding and the synonym end of the second secondary winding work as the voltage output side of the power source apparatus to output the voltage signal that driving the lamp.

Description

Power supply device

The present application claims priority to Chinese Patent Application No. 2007. 290, filed on Apr. 17, 2007, the entire disclosure of which is hereby incorporated by reference.

Technical field

The utility model relates to the field of electrical appliances, in particular to a power supply device for driving a lamp tube and a display device comprising the same.

Background technique

At present, two high-leakage transformers each having a secondary winding or a high-leakage transformer having two secondary windings are generally used as the driving power source for the lamp, although the magnetic leakage used in the driving power source is high. The number of transformers is different, but the number of secondary windings of the high leakage transformer is the same, that is, both.

Figure 1 shows a power supply for driving a lamp. The power supply includes: a high leakage transformer T1, a high leakage transformer T2, a resistor R1 and a resistor R2, capacitors C1 and C2, and a high leakage transformer T1 and T2. The primary winding is respectively connected to the voltage output end of the inverter, one end of the capacitor C1 is connected to the same name end of the high leakage magnetic transformer T1, the other end of the capacitor C1 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the high leakage magnetic transformer T2. The different name end, the same name end of the high side magnetic transformer T1 secondary winding and the different name end of the high leakage magnetic transformer T2 secondary winding are used as the voltage signal output end of the power supply device, and the output of the voltage signal output is used to drive the lamp work. The voltage signal, the high-leakage transformer T1 secondary winding of the different-name end series resistor R1 is grounded, the high-leakage transformer T2 secondary winding of the same name is connected to the series resistor R2 and grounded. Among them, the resistance values of the resistors R1 and R2 are generally small. When the driving power supply is working, the voltage drop on the resistors R1 and R2 is much smaller than the output voltage of the high leakage transformer, so the voltage drop generated on the resistors R1 and R2 is negligible. According to Ohm's law, the voltage signals on the resistors R1 and R2 reflect the magnitude of the electric power in the lamp.

When the lamp is working, the capacitance to the ground will be generated at both ends of the lamp. The transmission line connecting the lamp and the high leakage transformer will also generate the capacitance to the ground, and the leakage inductance of the high leakage transformer and the ground generated at both ends of the lamp. Capacitance, the capacitance to the ground generated by the transmission line and the resonance of the capacitors C1 and C2 will affect the voltage across the lamp. The leakage inductance of the two secondary windings of the high leakage transformer will be different, which will cause the voltage across the lamp to be different. The brightness at both ends of the tube is different, and the uniformity of illumination of the tube is affected. The following is a detailed analysis of the above issues:

2 is a circuit topology diagram of the power supply device shown in FIG. 1, wherein VI and V2 represent output voltages of the secondary windings of the high leakage magnetic transformers T1 and Τ2, V1 = V2; L1 is the leakage inductance of the high leakage magnetic transformer T1. L2 is the leakage inductance of the high leakage magnetic transformer T2. Usually, because the manufacturing materials and processes of the two high-leakage transformers are different, the leakage inductances L1 and L2 are not equal; C11 and C22 are the capacitances to the ground generated by the lamps at the working of the lamps, and the transmission lines are generated. The capacitance to ground and the equivalent capacitance of capacitors C1 and C2, because the capacitance of the ground line generated by the transmission line is not completely equal, therefore, the size of C11 and C22 are not completely equal. For the convenience of analysis, C11=C22 is set. Due to the leakage inductance LI, L2 is usually 4 艮 large, the capacitance C11, C224 is small, and the resistances R1 and R2 are generally 4 , small. Therefore, the first resonant circuit composed of VI, LI, C11, and R1 is composed of V2, L2, The quality factor of the second resonant circuit formed by C22 and R2 is very high. When L1 is not equal to L2, the resonance curves of the two resonant circuits will be inconsistent, and the slopes of the working segments of the two resonant curves are large, as shown in Fig. 3. At the same operating frequency fs, the voltage at two points A and B in Figure 2 will have a voltage difference of XV, which sometimes reaches 1/3 of the operating voltage of the lamp, because there is a voltage difference between the two points of A and B, The voltage across the lamp is not equal, and the voltage difference is relatively large. Therefore, the brightness at both ends of the lamp will be inconsistent, the high voltage end is bright, and the low voltage is dark, which affects the uniformity of lamp illumination.

Utility model content

The utility model provides a power supply device, which ensures uniform light emission when the power supply is used for the lamp.

In order to solve the above technical problem, the object of the present invention is achieved by the following technical solutions: A power supply device, comprising: a high leakage magnetic transformer;

The different end of the first secondary winding is connected to the same end of the second secondary winding; the same end of the first secondary winding and the different end of the second secondary winding serve as the voltage output of the power supply The output drives the voltage signal of the lamp.

Preferably, the power source further includes: a current transformer;

The opposite end of the first secondary winding is connected to one end of the primary side of the current transformer, and the other end of the primary side of the current transformer is connected to the same end of the second secondary winding.

Preferably, the power supply further includes: a capacitor;

One end of the capacitor is connected to one end of the voltage output terminal having a high voltage to ground, the capacitor The other end is grounded.

Preferably, the first secondary winding and the second secondary winding belong to the same high leakage transformer; or the first secondary winding and the second secondary winding respectively belong to two high leakage transformers.

A display device comprising: a power source, a plurality of parallel cold cathode fluorescent lamps;

The power source comprises: a high leakage magnetic transformer;

The opposite end of the first secondary winding is coupled to the same end of the second secondary winding; the first secondary winding drives a voltage signal for operation of the plurality of parallel cold cathode fluorescent lamps.

Preferably, the above display device further comprises: a current transformer;

Preferably, the above display device further includes: a capacitor;

One end of the capacitor is connected to one end of the voltage output terminal having a high voltage to ground, and the other end of the capacitor is grounded.

The above technical solution can be seen that since the connection point of the first secondary winding and the secondary secondary winding is not grounded, only one resonant circuit exists in the power supply, so the voltages at both ends of the lamp are equal, and the brightness at both ends of the lamp is uniform, thereby ensuring The uniformity of the illumination of the tube.

DRAWINGS

Figure 1 is a schematic diagram of the composition of a conventional power supply device;

Figure 2 is a circuit topology diagram of a conventional power supply device;

Figure 3 is a resonance diagram of a conventional power supply device;

4 is a schematic diagram showing the composition of a power supply device provided by Embodiment 1 of the present invention;

Figure 5 is a circuit topology diagram of a power supply device according to Embodiment 1 of the present invention;

Figure 6 is a schematic view showing the composition of a power supply device provided by Embodiment 2 of the present invention;

Figure 7 is a schematic view showing the composition of a power supply device provided by Embodiment 3 of the present invention;

Figure 8 is a schematic view showing the composition of a power supply device provided by Embodiment 4 of the present invention;

Figure 9 is a schematic view showing the composition of a power supply device according to Embodiment 5 of the present invention; Figure 10 is a schematic view showing the composition of a display device provided in Embodiment 6 of the present invention;

Figure 11 is a schematic view showing the composition of a display device provided in Embodiment 7 of the present invention.

detailed description

The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

4 is a schematic diagram showing the composition of a power supply device according to Embodiment 1 of the present invention. The power supply includes: high leakage magnetic transformers T1 and T2, capacitors C1 and C2, and high leakage magnetic transformers T1 and T2 each having a secondary winding;

Wherein, the primary windings of the high leakage magnetic transformers T1 and T2 are respectively connected to the voltage output end of the inverter, one end of the capacitor C1 is connected to the same end of the high leakage magnetic transformer T1, and the other end of the capacitor C1 is connected to one end of the capacitor C2. The other end of the capacitor C2 is connected to the different name end of the high leakage magnetic transformer T2, and the different name end of the secondary winding of the high leakage magnetic transformer T1 is connected with the same name end of the secondary winding of the high leakage magnetic transformer T2, and the secondary side of the high leakage magnetic transformer T1 The same name end of the winding and the different name end of the secondary winding of the high leakage magnetic transformer T2 are the voltage output end of the power supply device, and the voltage signal output end outputs a voltage signal for driving the operation of the lamp.

The following briefly describes the operation of the above power supply unit. Figure 5 is a circuit topology diagram of the power supply device shown in Figure 4, VI, V2 represent the output voltage of the high side leakage transformer Tl, 副2 secondary winding, V1 = V2; L1 is the leakage inductance of the high leakage transformer T1, L2 is The leakage inductance of the high leakage magnetic transformer T2, usually the manufacturing materials and processes of the two high leakage transformers are different. Therefore, the leakage inductances L1 and L2 are not equal; Cll and C22 are generated at both ends of the lamp when the lamp is in operation. The capacitance to ground, the capacitance to the ground generated by the transmission line, and the equivalent capacitance of the capacitors C1 and C2, because the capacitance to the ground generated by the transmission line is not exactly equal, the sizes of C11 and C22 are not completely equal. Since the different name end of the secondary winding of the high leakage magnetic transformer T1 is connected to the same name end of the secondary winding of the high leakage magnetic transformer T2 in the first embodiment of the present invention, only VI, LI, C11, C22, L2 are shown in FIG. , V2 constitutes a resonant circuit, and the leakage inductance of the high leakage transformer LI, L2 is equivalent to an inductance, the difference between the two does not affect the voltage of A, B two points, the voltage of point A and point B is completely divided by Cll, C22 It is decided that if C11 and C22 are substantially equal, the potentials of the two points A and B are also substantially equal, and the voltages across the lamp are equal. When the voltage across the lamp is equal, the brightness at both ends of the lamp will be the same, thus ensuring the uniformity of the lamp illumination.

Embodiment 1 is a power supply device composed of two high-leakage magnetic transformers each having a secondary winding. FIG. 6 is a schematic diagram showing the configuration of a power supply device according to Embodiment 2 of the present invention. The high leakage transformer T1 of the secondary winding constitutes a power supply device, and the power supply device is the same as that mentioned in Embodiment 1. The difference between the supply devices is that the two secondary windings of the device belong to the same high leakage transformer. The connection mode of the primary and secondary windings of the power supply device provided in the second embodiment is the same as that of the first embodiment, and details are not described herein again.

When the power supply device provided by the above embodiment drives the lamp tube, the capacitance to the ground generated at both ends of the lamp tube is substantially equal, and the capacitance to the ground of the power supply line connected to the two ends of the lamp tube may be unequal, thereby affecting the two ends of the lamp tube. Capacitance, therefore, in order to solve the problem that the power supply line to ground capacitance is not equal, ensure that the capacitance to the ground at both ends of the lamp is substantially equal. When the capacitance of the power supply line to the ground is not equal, the capacitance of the power supply line to the ground can be smaller. External compensation capacitor. Normally, the power supply line for connecting the lamp and the voltage output of the power supply unit with a high output voltage to the ground has a small capacitance to ground.

FIG. 7 is a schematic diagram of a power supply device according to Embodiment 3 of the present invention. The power supply device further includes: a compensation capacitor CC according to the power supply device provided in Embodiment 1 and Embodiment 2; wherein one end of the compensation capacitor CC is connected One end of the voltage output terminal of the power supply device outputs a high voltage to the ground, and the other end of the compensation capacitor CC is grounded. The connection manner of the primary and secondary windings in the power supply device is the same as that of the first embodiment and the second embodiment, and details are not described herein again. Moreover, the two secondary windings in Embodiment 3 may belong to one high leakage magnetic transformer, or may belong to two high leakage magnetic transformers, and do not affect the implementation of the embodiment of the present invention.

FIG. 8 is a schematic diagram showing the composition of a power supply device according to Embodiment 4 of the present invention. The power supply device includes: a high leakage magnetic transformer T1 and T2, a current transformer Is, capacitors C1 and C2, and high leakage magnetic transformers T1 and T2. a secondary winding;

Wherein, the primary windings of the high leakage magnetic transformers T1 and T2 are respectively connected to the voltage output end of the inverter, one end of the capacitor C1 is connected to the same end of the high leakage magnetic transformer T1, and the other end of the capacitor C1 is connected to one end of the capacitor C2. The other end of the capacitor C2 is connected to the different name end of the high leakage transformer T2; the current transformer Is—the one end of the secondary side is connected to the different name end of the secondary winding of the high leakage transformer T1, and the current transformer Is—the other end of the secondary side The high-leakage transformer T2 has the same name end of the secondary winding, the current transformer Is secondary side series resistor Rs is grounded, the current transformer Is is used to measure the current value flowing through the secondary winding of the high leakage transformer; high leakage transformer The same name end of the T1 secondary winding and the different end of the high leakage magnetic transformer T2 secondary winding are the voltage output end of the power supply device, and the voltage signal output terminal outputs a voltage signal for driving the operation of the lamp.

In order to solve the problem that the power supply line to ground capacitance is not equal, the basic capacitance of the ground capacitance at both ends of the lamp tube is guaranteed. The power supply device provided in Embodiment 5 of the present invention can be further added to the power supply device provided in Embodiment 4. As shown in FIG. 9, one end of the compensation capacitor CC is connected to the output terminal of the voltage output terminal of the power supply device. At the end of the ground voltage, the other end of the compensation capacitor CC is grounded.

In Embodiment 4 and Embodiment 5, the two secondary windings may also be provided by the same high leakage transformer without affecting the implementation of the embodiment of the present invention.

The above is an embodiment of the power supply device provided by the embodiment of the present invention. The display device including the above power supply device will be specifically described below.

Figure 10 is a diagram showing a display device according to Embodiment 6 of the present invention, comprising: a power supply device, a plurality of parallel cold cathode fluorescent lamps (CCFL); wherein, the power supply device comprises: high leakage magnetic transformers T1 and T2, capacitor C1 And C2, the high leakage magnetic transformers T1 and T2 each have a secondary winding; the CCFL is connected in series with a capacitor c.

Wherein, the primary windings of the high leakage magnetic transformers T1 and T2 are respectively connected to the voltage output end of the inverter, one end of the capacitor C1 is connected to the same end of the high leakage magnetic transformer T1, and the other end of the capacitor C1 is connected to one end of the capacitor C2. The other end of the capacitor C2 is connected to the different name end of the high leakage magnetic transformer T2, and the different name end of the secondary winding of the high leakage magnetic transformer T1 is connected with the same name end of the secondary winding of the high leakage magnetic transformer T2, and the secondary side of the high leakage magnetic transformer T1 The same name end of the winding and the different name end of the secondary winding of the high leakage magnetic transformer T2 output a voltage signal for driving the CCFL operation at the voltage output end of the power supply device.

In order to solve the problem that the power supply line to ground capacitance is not equal, and ensure that the capacitance to the ground at both ends of the lamp tube is substantially equal, a compensation capacitor CC may be further added to the power supply device; wherein one end of the compensation capacitor CC is connected to the voltage output end of the power supply device. At the end of the ground voltage, the other end of the compensation capacitor CC is grounded.

In order to facilitate measuring the current value flowing through the secondary winding, the power supply device may further include: a current transformer Is; wherein, the current transformer Is-the one end of the secondary side is connected to the different end of the secondary winding of the high leakage transformer T1 The current transformer Is—the other end of the secondary side is connected to the same name end of the secondary winding of the high leakage magnetic transformer T2, and the secondary transformer of the current transformer Is is grounded in series with the resistor Rs, and the current transformer Is is used to measure the flow leakage. The current value of the secondary winding of the transformer.

In the above display device, the CCFL is driven by a power supply device composed of two high-leakage transformers each having a secondary winding, and the CCFL can be driven by a power supply device composed of a high-leakage transformer having two secondary windings. A display device provided in Embodiment 7 of the present invention shown in FIG. By The difference between a power supply device composed of a high leakage transformer and a power supply device composed of two high leakage transformers is that the two secondary windings are provided by a high leakage transformer, and the connection relationship of the power supply device is composed of two The power supply device composed of the high leakage magnetic transformer is the same and will not be described here.

The above is a detailed description of a power supply device and a display device provided by the present invention. The principles and implementations of the present invention are described in the following by using specific examples. The description of the above embodiments is only for helping to understand the utility. At the same time, in the light of the above, the contents of the present specification should not be understood as Limitations on the present invention.

Claims

Rights request

A power supply device comprising: a high leakage magnetic transformer, characterized in that

The different end of the first secondary winding is connected to the same end of the second secondary winding;

The same-name end of the first secondary winding and the different-name end of the second secondary winding serve as a voltage output terminal of the power supply, and output a voltage signal for driving the lamp.

2. The power supply of claim 1, further comprising: a current transformer; the different end of the first secondary winding is connected to one end of the primary side of the current transformer, the current transformer The other end of the primary side is connected to the same end of the second secondary winding.

3. The power supply according to claim 1 or 2, further comprising: a capacitor; one end of the capacitor is connected to one end of the voltage output terminal having a high voltage to ground, and the other end of the capacitor is grounded.

The power supply according to claim 3, wherein the first secondary winding and the second secondary winding belong to the same high leakage transformer, or the first secondary winding and the second secondary The windings belong to two high leakage transformers.

5. A display device, comprising: a power source, a plurality of parallel cold cathode fluorescent lamps;

The power source comprises: a high leakage magnetic transformer;

A different end of the first secondary winding and a different end of the second secondary winding serve as a voltage output of the power supply, and a voltage signal for driving the plurality of parallel cold cathode fluorescent lamps is output.

6. The apparatus according to claim 5, further comprising: a current transformer; a different end of the first secondary winding is connected to one end of the primary side of the current transformer, the current transformer The other end of the primary side is connected to the same end of the second secondary winding.

7. The apparatus according to claim 5 or 6, further comprising: a capacitor; one end of the capacitor is connected to one end of the voltage output terminal having a high voltage to ground, and the other end of the capacitor is grounded.

The device according to claim 7, wherein the first secondary winding and the second secondary winding belong to the same high leakage transformer; or, the first secondary winding and the second secondary The windings belong to two high leakage transformers.