JP2600155Y2 - DC-AC inverter power supply for cathode tube lighting - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a lighting device for a cathode ray tube used as a backlight source of a liquid crystal display unit.
The present invention relates to a C-AC inverter power supply, and more particularly to a cathode-ray tube lighting DC-AC inverter power supply in which a bias power supply for driving a liquid crystal is integrated.

[0002]

2. Description of the Related Art A liquid crystal display unit requires a power supply for logic and a bias power supply for driving liquid crystal. In addition, since the liquid crystal does not emit light by itself, the transmission type liquid crystal display requires a backlight and also requires a power supply for lighting a cathode ray tube used as a light source.

[0003]

Since each of these power supplies is individually arranged and mounted, the number of components of the liquid crystal display unit application equipment increases, and the size of the apparatus increases, and workability and reliability are increased. There was a problem.

The present invention reduces the number of components and reduces the size of liquid crystal display unit-applied equipment by integrating a separately arranged and mounted liquid crystal drive bias power supply and a cathode-ray tube lighting DC-AC inverter power supply. It is another object of the present invention to provide a DC-AC inverter power supply for lighting a cathode ray tube with a bias power supply for driving a liquid crystal, which can improve workability and reliability.

[0005]

In order to achieve the above object, the present invention provides a DC-AC inverter power supply for lighting a cathode tube .
Series provided LC resonant circuit the main winding of Lee down inverter transformer, rectifying retrieves the resonance voltage is obtained by adding the ability to retrieve the DC voltage.

[0006]

The DC-AC inverter power supply for lighting the cathode tube according to the present invention eliminates the necessity of a separately provided and mounted bias power supply for driving the liquid crystal, thereby reducing the number of components, miniaturizing the device, and improving workability and reliability. It is planned.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

[0008]

[0009]

[0010]

[0011]

[0012]

FIG. 1 shows that a primary winding n1 of an inverter transformer T of a DC-AC inverter power supply for lighting a cathode tube has an LC
4 shows a circuit of a resonance system in which a resonance circuit is provided to extract a bias voltage for driving a liquid crystal.

The inductance L in the inverter circuit 21
The resonance voltage generated in the resonance circuit composed of the capacitor C1 and the capacitors C2, C3, C4, the rectifiers D1,
D2, is input to a chopper circuit 23 composed of a control circuit 22, and is taken out as a DC voltage Vout.

Although FIG. 2 shows a negative voltage output by the constant voltage control, the negative voltage is changed from the negative voltage to the positive voltage similarly to the method using the tertiary winding method, and the constant voltage control is changed from the constant voltage control to the constant current control. Clearly applicable. Further, when the fluctuation of the output voltage Vout is within the allowable range that can be used as the bias voltage for driving the liquid crystal without control, the control circuit can be omitted.

[0016]

As described above, by using the DC-AC inverter power supply for lighting the cathode ray tube integrated with the bias power supply for driving the liquid crystal of the present invention, no separate bias power supply for driving the liquid crystal is required. The liquid crystal display unit can be simplified, the number of parts can be reduced, the size can be reduced, and workability and reliability can be improved.

[Brief description of the drawings]

FIG. 1 shows a DC for lighting a cathode ray tube according to a first embodiment of the present invention.
FIG. 3 is a circuit diagram of an AC inverter power supply.

[Explanation of symbols]

 21 Inverter circuit 23 Chopper circuit

Claims (2)

(57) [Scope of request for utility model registration] 1. A cathode-ray tube lighting DC-AC inverter characterized in that a voltage is taken out from an LC resonance circuit connected in series with an inverter transformer main winding, rectified, and a liquid crystal drive bias DC voltage can be taken out. Power supply. 2. The DC-AC inverter power supply for lighting a cathode ray tube according to claim 1, wherein the bias DC voltage for driving the liquid crystal can be taken out as a constant voltage or a voltage subjected to a constant current control.