JPH02197084A - Discharge lamp lighting circuit block - Google Patents

Abstract

PURPOSE:To absorb the noise from the second oscillation circuit with a smoothing capacitor and prevent the noise trouble by mounting each electric pats on a printed substrate so that the smoothing capacitor is positioned between both of the first and the second oscillation circuits. CONSTITUTION:A choke coil CH, a semiconductor S1 and a diode D composing the first oscillation circuit A for power rectifying is adjacent to the 4 terminals rectifying device F. Semiconductors S2, S3 composing the second oscillation circuit B for discharge lamp lighting is adjacent to the first oscillation circuit A through a smoothing capacitor C. The oscillation circuits A, B are located across the smoothing capacitor C in light and left of it. As a result, the noise from the second oscillation circuit B for discharge lamp lighting is absorbed by the smoothing capacitor C, and the noise form both of the oscillation circuits A, B are overlapped each other to prevent the leakage to the commercial power side.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the mounting of a molded lamp lighting circuit block in which an electronic circuit of a discharge lamp lighting device for lighting a discharge lamp at high frequency is mounted on a printed wiring board. Concerning configuration.

[Prior art]

Conventionally, lighting methods have been known in which AC power is rectified and smoothed to obtain DC, and a discharge lamp is lit by inverter oscillation.Also, in order to improve the power factor, the rectified AC power is further oscillated by chopper oscillation. A method is also known in which the smoothed voltage is oscillated by an inverter to obtain a high-frequency voltage, and the discharge lamp is lit using the high-frequency voltage. An example of the circuit configuration of this method is as shown in Fig. 2(a), in which AC power source E is rectified by a four-terminal rectifier R, and then chopper oscillation is performed by a choke coil CH and semiconductor S1, and second rectification is performed by a diode D. The DC voltage smoothed by the smoothing capacitor C of the DC power supply is oscillated by the semiconductors S2 and S3 in the subsequent stage, and the discharge lamp is lit at high frequency through the paralast choke 11. Further, an inverter oscillation control unit 12 connected to the base of the semiconductor S3 is provided to perform dimming by changing the on-off time duty ratio of the semiconductor S3 by switching the contacts of the dimming switch Sw. Resistors rl and r2 are detection resistors for making constant the voltage across the smoothing capacitor C, and the midpoint voltage thereof is provided to the voltage regulating control circuit 13. The arrangement of various electronic components in a discharge lamp lighting circuit block formed by mounting an electronic circuit having such a configuration on a printed wiring board is as shown in FIG. 3(a). Each figure number in the same figure is the second
They are attached in the same way as each circuit element in FIG. As shown in the figure, the choke coil CH, semiconductor St, and diode D that constitute the first oscillation circuit A for rectifying the power supply are adjacent to the four-terminal rectifier R, and constitute the second oscillation circuit B for lighting the discharge lamp. Semiconductors S2 and S3 are further arranged adjacent to this, and a smoothing capacitor C is arranged further adjacent to this. That is, in terms of the circuit, the smoothing capacitor C was positioned after the second oscillation circuit B, as shown in FIG. 2(C). Although this was done simply for the convenience of the arrangement of the various electronic components rather than the intended circuit function, the inventors realized that such a mounting method would lead to the following inconvenience. That is, in such a conventional example, the second oscillation circuit B
This means that the noise generated in the first oscillation circuit is superimposed on the noise generated in the first oscillation circuit, leaks to the commercial power supply side, and tends to cause noise disturbances to other electrical equipment. In addition, Fig. 2 (C
r3 and r4 in ) indicate wiring resistance.

[Problem that the invention seeks to solve]

The present invention provides a discharge lamp lighting circuit block including a first oscillation circuit for power rectification and a second oscillation circuit for lighting the discharge lamp, in which noise from both oscillation circuits is superimposed and leaks to the commercial power supply side. The purpose is to eliminate the

[Means for solving problems]

In the present invention, each electronic component is mounted on the printed wiring board so that the smoothing capacitor is located between the first and second oscillation circuits.

[Effect]

The noise from the second oscillation circuit for lighting the discharge lamp is absorbed by the smoothing capacitor C, and the noise from both oscillation circuits is not superimposed and leaked to the commercial power supply side.

〔Example〕

FIG. 1(a) and FIG. 1 et al.) show embodiments of the present invention,
The overall configuration of the discharge lamp lighting circuit is the same as that shown in FIG. 2(a), so this will be used here. In this embodiment, the various electronic components in the discharge lamp lighting circuit block are arranged as shown in FIG. 1(a). Each figure number in the same figure is the second
They are labeled in the same way as each circuit element in Figure (a). As shown in the figure, a choke coil CH1 constituting a first oscillation circuit A for rectifying a power supply, a semiconductor Si diode D are adjacent to a four-terminal rectifying element R, and a semiconductor S2 constituting a second oscillation circuit B for lighting a discharge lamp. , S3 are adjacent to the first oscillation circuit A via a smoothing capacitor C. In terms of the circuit, this arrangement has the first and second oscillation circuits A as shown in Figure 1(b).
, B are distributed to the left and right sides of the smoothing capacitor C, and the noise from the second oscillation circuit B for lighting the discharge lamp is absorbed by the smoothing capacitor C, and the noise from both oscillation circuits ASB is absorbed by the smoothing capacitor C. This prevents superimposed noise from leaking to the commercial power supply side.

〔Effect of the invention〕

As described above, according to the present invention, the noise from the second oscillation circuit is reduced because each electronic component is mounted on the printed wiring board so that the smoothing capacitor is located between the first and second oscillation circuits. It is absorbed by the smoothing capacitor, and the noise from both oscillation circuits is superimposed and does not leak to the commercial power supply side, making it difficult to cause noise interference to other electrical equipment.

[Brief explanation of the drawing]

1(a) and 1(b) show an embodiment of the present invention, FIG. 1(a) is a layout diagram of electronic components, FIG. 1(a) is a circuit diagram of the main part, and FIG. a) to FIG. 2(C) show conventional examples, FIG. 2(a) is a layout diagram of electronic components, and FIG. 2(b)
is the overall circuit diagram, and FIG. 2(C) is the circuit diagram of the main parts. A...First oscillation circuit B...Second oscillation circuit C
・・・Smoothing condenser

Claims (1)

[Claims] (1) A first oscillation circuit for power rectification, a second oscillation circuit for lighting the discharge lamp, and a smoothing capacitor that smooths the oscillation output of the first oscillation circuit and serves as a DC drive source for the second oscillation circuit. and lighting a discharge lamp, the smoothing capacitor being mounted between the first oscillation circuit and the second oscillation circuit when electronic circuit components constituting an electronic circuit are mounted on a printed wiring board. circuit block.