JPH05211098A - Inverter lighting circuit - Google Patents

Abstract

PURPOSE:To improve simply an added function of a fluorescent lamp inverter lighting device. CONSTITUTION:In a fluorescent lamp inverter lighting circuit to light/drive a switching element of a lighting circuit in a prescribed high frequency by means of a control circuit 5, the control circuit 5 is constituted of a general purpose microcomputer 8 to issue a pulse signal of Duty 50%, and the switching element is excited by means of the pulse signal of this general purpose microcomputer 8. A Duty variable circuit 9 is also connected to the rear stage of the general purpose microcomputer 8, and the switching element is excited by means of the pulse signal of the optimal Duty. Thereby, besides a varaible light dimming or the other lighting driving can be set freely by means of the microcomputer, an added function requiring a program control such as a remote control or a wait lighting can be set freely. The reliability of the circuit can be obtained by giving the pulse signal of the optimal Duty.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a general-purpose microcomputer as a control circuit for driving and controlling a switching element of an inverter lighting circuit of a fluorescent lamp, especially a high-frequency lighting circuit, so that the control circuit can be constructed inexpensively and multifunctionally. The present invention relates to a fluorescent lamp inverter lighting circuit.

[0002]

2. Description of the Related Art Inverter lighting circuit 1 for this type of fluorescent lamp
For example, as shown in FIG.
The so-called high-frequency drive system is adopted, in which the high-frequency power source 4 is connected via the drive circuit and the fluorescent lamp 2 is driven by a high-frequency current of about 40 to 50 KHz, compared to a conventional lighting circuit driven at a commercial frequency. , Flicker less, bright, high-efficiency lighting is possible, and it tends to be used frequently these days. This high frequency lighting inverter lighting circuit 1
The brightness of the fluorescent lamp can be changed by changing the lighting frequency of the fluorescent lamp. Normally, as shown in the figure, the control circuit 5 changes the oscillation frequency of the high frequency power source 4 to obtain the dimming function of the lighting device. It is configured as follows.

FIG. 4 shows a concrete circuit example of the inverter lighting circuit 1 for high frequency lighting, which is a typical separately-excited inverter lighting circuit, in which a capacitor C1 connected in parallel to a fluorescent lamp 2 and an inductance connected in series thereto. A series resonance circuit is formed with L1. Further, the commercial AC power supply 6 is rectified and smoothed by the DC power supply circuit 7 to obtain a DC voltage + B for lighting, and an inductance L2 and a capacitor C2 are provided between the DC voltage + B and the switching element Q1.
The parallel connection circuits of are connected to form a switching circuit. The switching element Q1 has a power MOS-
The FET is used, and the lighting control circuit 5 is connected to the gate of the FET to drive and control the FET. The control circuit 5 has a function of protecting the fluorescent lamp 2 from starting overheat, overvoltage, and overcurrent,
A pulse signal having a lighting frequency including dimming is generated and applied to the switching element Q1 to drive lighting at a predetermined high frequency.

By the way, as described above, the switching element Q
The control circuit 5 for driving the 1 to light at a predetermined high frequency is conventionally composed of various analog circuits. However, although this analog circuit is basically capable of stepless dimming, it has a drawback that there are errors due to variations in circuit components and the adjustment becomes difficult. For this reason, recently, a digital circuit type has been developed which allows extremely easy frequency setting (Japanese Patent Application No. 1-96303). However, this digital circuit thing has many resistors, capacitors,
Since parts such as diodes are used, it is usually a dedicated L
Used by being incorporated into SI.

[0005]

However, in the lighting fixture for the fluorescent lamp of the inverter lighting whose lighting control has been developed in this way, recently, in addition to the above-mentioned dimming function, remote control, delay light-off, Various additional functions such as sequence control are required, and in order to realize these functions, the control circuit has been developed with a microcomputer capable of program control in addition to the dedicated LSI described above. However, the luminaires equipped with these additional functions have traditionally been used exclusively for illuminating lights, such as starting residual heat of lamps, protection from overvoltage and overcurrent, and dimming function during lighting.
I and a microcomputer for additional functions such as remote control, delayed light-off, and other sequence control, which mainly require program control, have been developed with their respective roles allotted. Although apparently rational, additional functions are added or changed. In doing so, it was necessary to add or change the hardware in the dedicated LSI. In particular, a dedicated LSI has a large number of circuit components mounted on a substrate pattern, is expensive, and has a drawback that it is difficult to change the circuit configuration.

Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to obtain an inverter lighting control circuit capable of easily adding or changing an additional function without using an expensive dedicated LSI. There is. As a result of extensive studies, the present inventor has thought that the switching element of the above lighting circuit is directly controlled by a general-purpose microcomputer, and has a lighting control for lighting the lighting fixture and a control for an additional function that requires program control. This is achieved with a single microcomputer.

[0007]

In order to achieve the above object, the present invention provides a lighting circuit having a resonance circuit connected to a DC power source, in which a control circuit excites a switching element in accordance with a predetermined frequency to provide an illumination lamp. In the inverter lighting circuit for lighting at a high frequency, the control circuit is configured by a microcomputer that emits a pulse signal of duty 50% divided by varying a clock division ratio, and the switching element is excited by the pulse signal of the microcomputer. It is a thing. Further, a duty variable circuit is connected to the latter stage of the microcomputer, and the switching element is excited by a pulse signal having a varied duty.

[0008]

In the inverter lighting circuit having the above-mentioned structure, the switching element of the high-frequency lighting circuit is directly excited by a general-purpose microcomputer to drive and control it. The microcomputer program is set to start residual heat of the fluorescent lamp, overvoltage, and overcurrent. In the past, mainly with microcomputers such as lighting control for lighting lighting, which was mainly composed of a dedicated LSI, remote control control, delayed lighting, other sequence control, etc. It is possible to perform control for additional functions that require the configured program control. Also, in this case, when it is necessary to modify lighting control or additional function control,
The setting can be appropriately made only by changing the setting of the program of the microcomputer, and since no hardware is added or changed, the function can be easily changed. In addition, since the pulse signal of the general-purpose microcomputer is configured to drive the switching element by the duty variable circuit with the duty pulse signal suitable for the high frequency lighting circuit, the switching element is prevented from generating heat and the reliability of the lighting circuit is improved. can get.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a control circuit 5 for an inverter lighting circuit of a fluorescent lamp according to the present invention, in which the switching element Q1 of the high frequency inverter lighting circuit 1 of FIG. 4 is driven and controlled by a general-purpose microcomputer 8. Although not shown, the general-purpose microcomputer 8 has a built-in crystal oscillator, and a clock signal of the crystal oscillator is variably set at its output terminal A at a predetermined frequency division ratio to divide it into a predetermined lighting frequency. Figure 2
A square wave pulse with a duty of 50% is output as shown in (A). Reference numeral 9 designates a square wave pulse having a duty of 50% of the general-purpose microcomputer 8 as a power MOS for the switching element Q1.
A duty variable circuit for converting into a square wave pulse having an optimum duty suitable for driving an FET. Duty variable circuit 9
2 is a square wave output with a duty of 50% from the general-purpose microcomputer 8 at the upper end B of C3 by the integrating circuit of C3 and R1.
The triangular wave pulse as shown in
Input to the negative input terminal (-) of P1. Further, at the positive input terminal (+) of the comparator CP1, the triangular wave pulse is smoothed by C4, divided by VR1 and VR2, and a reference voltage as shown in (C) of FIG. Get and enter this. The comparator CP1 compares these two inputs, the region where the reference voltage is above becomes high, and as shown in FIG. 2 (D), the square wave pulse having changed Duty is output to its output terminal D. Output. The duty of the square wave pulse output is adjusted to an arbitrary value by varying VR1 of the variable circuit 9, and the power MOS-FET of the switching element Q1 is set to a predetermined optimum duty.
Can be set to drive. The optimum duty of this square wave pulse is given to the power MOS-FET of the switching element Q1 by applying square wave pulses of various duties.
The lamp is actually driven to be driven, and the temperature rise of the switching element Q1 is checked to determine.

[0010]

As described above, since the inverter lighting circuit of the fluorescent lamp of the present invention is configured to directly drive and control the switching element of the high frequency power source by using the general-purpose microcomputer in the control unit, a dedicated LSI is used. It is possible to realize lighting control for lighting lighting and control of additional functions such as remote control and delayed lighting without using the microcomputer. Also,
The circuit can be configured very easily, and the function can be easily changed without adding or changing hardware. Further, since the drive control is configured via the duty variable circuit, the lighting circuit can be driven to be driven with the optimum duty,
The reliability of the lighting device can be ensured.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of an inverter lighting circuit of the present invention.

FIG. 2 is a waveform diagram of signals at various parts in FIG.

FIG. 3 is an inverter lighting circuit diagram of a fluorescent lamp.

4 is a concrete inverter lighting circuit diagram of FIG. 3. FIG.

[Explanation of symbols]

 1 Inverter lighting circuit 2 Fluorescent lamp 5 Control circuit 7 DC power supply 8 Microcomputer 9 Duty variable circuit L1, C1 resonance circuit Q1 switching element

Claims (2)

[Claims] 1. An inverter lighting circuit for driving a lighting circuit having a resonance circuit connected to a DC power supply, wherein a switching element is excited by a control circuit in accordance with a predetermined frequency to light an illumination lamp at a high frequency, the control circuit comprising: An inverter lighting circuit comprising a microcomputer that emits a pulse signal of 50% duty that is divided by changing a clock division ratio, and the switching element is excited by the pulse signal of the microcomputer. 2. The inverter lighting circuit according to claim 1, wherein a duty variable circuit is connected to a stage subsequent to the microcomputer, and a switching element is excited by a pulse signal whose duty is varied.