JPH0541098U - Inverter device for fluorescent lamp - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent malfunction of the fluorescent lamp inverter device 11 due to high frequency noise. [Configuration] A detection AC signal from the current detection transformer 6 (6A, 6B, 6C) is converted into an AC / DC conversion circuit 7 (7A, 7C).
B, 7C) to convert to a DC signal and apply it to the lighting control element 4, a series of AC / DC conversion circuits 7 (7
(A, 7B, 7C) are arranged in parallel in a column, and these are grounded to the adjacent ground pattern 10. [Effect] Each signal pattern 8 (8A, 8B, 8C), 9
Prevents the influence of high frequency noise on (9A, 9B, 9C),
The detected AC signal is applied to the lighting control element 4 without variation, and malfunction does not occur.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention is an inverter device in which an oscillating element and a drive element are incorporated in a circuit board, and in particular, an AC signal used for drive control of the inverter device is accurately converted into a DC signal and supplied to a control element to accurately light the device. The present invention relates to an inverter device for a fluorescent lamp that is driven.

[0002]

[Prior Art]

 This type of fluorescent lamp inverter device incorporates an oscillating element and a drive element into the circuit board to drive the fluorescent lamp at high frequency, and is less flicker, smaller, and more efficient than the ballast type. It has the characteristics that can be obtained.

The inverter device for a fluorescent lamp having such excellent characteristics is a fluorescent lamp that is supplied with light from a commercial-frequency power source after converting it into a high frequency and then lighting it. There is a risk of damaging the oscillator circuit. For this reason, normally, a configuration is adopted in which the lamp current of the fluorescent lamp is detected, and the drive element is turned on / off based on the detection signal to cut off the power supply.

A current detection transformer is generally used to detect the lamp current, but this detection signal is an AC signal, which is usually converted into a DC signal by an AC / DC conversion circuit and supplied to the drive element. , The lighting of the device is controlled.

For example, FIG. 2 is a front view of a fluorescent lamp inverter device 1 used for a fluorescent lamp lighting device such as a vending machine, in which a power supply unit is formed on a circuit board 2 including printed wiring. Power supply circuit element 3, lighting control element 4 including a high-frequency oscillator, drive circuit element 5 (5A, 5B, 5C) for three lights including semiconductor switching elements, lamps for three fluorescent lights (not shown) The current detection transformers 6 (6A, 6B, 6C) arranged in the circuit are mounted respectively, and further, an AC / DC conversion circuit is provided between each current detection transformer 6 (6A, 6B, 6C) and the lighting control element 4 described above. 7 (7A, 7B, 7C) are arranged, and these are connected by a thin line AC signal pattern 8 (8A, 8B, 8C) and a DC signal pattern 9 (9A, 9B, 9C). In addition, a strip-shaped earth pattern 10 is printed and wired between the current detection transformer 6, the AC / DC conversion circuit 7, the lighting control element 4, and the power supply circuit element 3 in the vicinity thereof.

More specifically, the lighting control element 4 is composed of, for example, an LSI in one chip, and when a power switch (not shown) is turned on, the commercial frequency of the power supply circuit element 3 of the power supply unit is set to several tens of KHz. To drive the drive circuit element 5 (5A, 5B, 5C) to turn on and drive a desired fluorescent lamp (not shown). At this time, a detection signal (AC signal) such as a lamp current detected by the current detection transformer 6 (6A, 6B, 6C) is converted into a DC signal by the AC / DC conversion circuit 7 (7A, 7B, 7C), This is input to the lighting control element 4, and if there is an abnormality, the drive circuit element 5 (5A, 5B, 5C) is driven, and if necessary, the power supply circuit is turned off.

[0007]

[Problems to be solved by the device]

 By the way, the lamp currents are detected by the current detection transformers 6 (6A, 6B, 6C) in this way, and the AC signals detected by the current detection transformers 6 (6A, 6B, 6C) are converted into the respective AC / DC signals. When the conversion circuit 7 (7A, 7B, 7C) converts to a DC signal and supplies it to the lighting control element 4, a large level difference in the detection level between the AC / DC conversion circuits 7A, 7B, 7C, for example, about 1v. Was found. Therefore, even when the lamp is normally lit, this is regarded as an emission defect, which causes the power to be turned off and the error to be controlled. For this reason, conventionally, the circuit configuration is such that a bias corresponding to the detected level difference is added to each input terminal from the AC / DC conversion circuits 7A, 7B, 7C of the lighting control element 4. The circuit was complicated, the assembly work was complicated, and the cost of the device was high.

Therefore, the present invention has been made in view of the above, and an AC signal detected by a current detection transformer or the like is converted into a DC signal by an AC / DC signal conversion circuit without variation and is supplied to a lighting control element. However, it is an object of the present invention to provide a fluorescent lamp inverter device having a simplified circuit configuration that does not require a bias.

As a result of various studies by the inventor of the present invention, the detection level difference in the DC signal generated at each input terminal of the lighting control element 4 of the fluorescent lamp inverter device 1 is determined by the ground pattern of each AC / DC signal conversion circuit 7. It has been found that this is solved by making the connection points of each AC / DC signal conversion circuit 7 to the ground pattern 10 close to each other, which is related to the layout structure with 10. The cause of the level difference in the DC signal of the AC / DC signal conversion circuit 7 can be inferred as follows. That is, the fluorescent lamp inverter device 1 applies a high frequency of several tens KHz to the fluorescent lamp as compared with the power source of the commercial frequency. In this case, the fluorescent lamp is driven and controlled by the drive circuit element including the semiconductor switch element. Since high frequency noise is likely to occur, the potential of the signal pattern on the signal patterns 8 and 9 and the ground pattern 10 of the circuit board 2 is increased due to the high frequency of the power source and the high frequency noise due to the drive circuit element driving. It is considered that this causes a difference due to the arrangement position of each signal pattern, etc., which causes a difference between the detection levels.

[0010]

[Means for Solving the Problems]

 The present invention has been made on the basis of the above assumptions. The power supply circuit 3, the lighting control element 4, the drive circuit element 5, the current detection transformer 6 (6A, 6B, 6C) and the AC / AC circuit board 2 are provided on the circuit board 2. A DC conversion circuit 7 (7A, 7B, 7C) is provided, and the AC signal detected by the current detection transformer 7 is converted into a DC signal by the AC / DC conversion circuit 7 and applied to the lighting control element 4. In the fluorescent lamp inverter device 1, a plurality of the above-mentioned AC / DC conversion circuits 7 (7A, 7B, 7C) are arranged in parallel in parallel, and the AC / DC conversion circuits 7 (7A , 7B, 7C), and the ground pattern 10 is disposed along the ground pattern 10 and each AC / DC conversion circuit 7 (7A, 7B, 7C) is connected to the ground pattern 10 for grounding.

[0011]

[Action]

 According to the configuration of the present invention, the AC / DC conversion circuits 7 (7A, 7B, 7C) are arranged close to each other, and are arranged and connected at substantially the same location with respect to the ground pattern 10. Further, the influences of the high frequency power supply and the high frequency noise of the drive circuit element on the signal patterns 8 and 10 and the ground pattern 10 are at substantially the same level. The output level difference can be reduced. Therefore, it is not necessary to add a bias or the like to the lighting control element 4, and it is possible to provide an inverter device for a fluorescent lamp whose circuit configuration is extremely simplified.

[0012]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a fluorescent lamp inverter device 11 used for a vending machine crystal fluorescent lamp lighting device according to the present invention. As with the inverter device 1 of FIG. In addition, a power supply circuit element 3 of the power supply section, a lighting control element 4 including a high frequency oscillating section, and a drive circuit element 5 (5A, 5B, 5C) for three lights including a semiconductor switch element, and three fluorescent lamps. The current detection transformers 6 (6A, 6B, 6C) arranged in the circuit are arranged as shown in the drawing, and an AC / DC conversion circuit 7 (7A) is provided between each current detection transformer 6 and the lighting control element 4. , 7B, 7C), which are connected by a thin AC signal pattern 8 (8A, 8B, 8C) and a DC signal pattern 9 (9A, 9B, 9C). In addition, a band-shaped earth pattern 10 is printed and wired between each current detection transformer 6, the AC / DC conversion circuit 7, the lighting control element 4, and the power supply circuit element 3 in the vicinity thereof.

This embodiment is different from the inverter device 1 shown in FIG. 2 in that the AC / DC conversion circuits 7 are arranged in a line on the circuit board 2 and that the AC / DC conversion circuits 7 are arranged in this line. The ground pattern 10 is printed and wired along the AC / DC conversion circuit 7, and the ground wirings are respectively grounded. The other parts have the same structure. The explanation is omitted.

According to the configuration of the present invention, the AC / DC conversion circuits 7 (7A, 7B, 7C) are arranged adjacent to each other in a column, and the current detection transformers 6 (6A, 6B, 6C) and the thin line-shaped AC signal pattern 8 (8A, 8B, 8C) and the DC signal pattern 9 (9A, 9B, 9C) that connect between the lighting control elements 4 are arranged on the circuit board 2 at substantially the same arrangement position. Also, since the position is almost the same for the ground pattern 10 where the problem of floating potential is expected, the variation of the detected potential due to high frequency is small, and in fact it is 0.2 V or less, which is 1/5 or less of the conventional value. It was the one.

[0015]

[Effect of the device]

 As described above, according to the present invention, the AC signal detected by the current detection transformer is converted into the DC signal without variation in the AC / DC conversion circuit, and is not affected by high frequency noise, etc., and the circuit configuration is simple and malfunctions are prevented. It is possible to provide an inverter device for fluorescent lamps.

[Brief description of drawings]

FIG. 1 is a front view of an inverter device for a fluorescent lamp according to the present invention.

FIG. 2 is a front view of a conventional inverter device for a fluorescent lamp.

[Explanation of symbols]

 2 circuit board 4 lighting control element 5 drive circuit element 6 current detection transformer 7 AC / DC conversion circuit 8 AC signal pattern 9 DC signal pattern 10 ground pattern 11 fluorescent lamp inverter device

Claims (1)

[Scope of utility model registration request] 1. A power supply circuit 3, a lighting control element 4, a drive circuit element 5, and a current detection transformer 6 (6) on a circuit board 2.
A, 6B, 6C) and AC / DC conversion circuit 7 (7A,
7B, 7C), the AC signal detected by the current detection transformer 7 is converted into a DC signal by the AC / DC conversion circuit 7, and the DC signal is applied to the lighting control element 4. The AC / DC conversion circuit 7
(7A, 7B, 7C) are arranged in parallel in a plurality of columns, and the earth pattern 10 is arranged along the AC / DC conversion circuits 7 (7A, 7B, 7C) arranged in parallel. Each AC / DC on the earth pattern 10
An inverter device for a fluorescent lamp, characterized in that the conversion circuit 7 (7A, 7B, 7C) is connected to be grounded.