JPH04138698A - Electronic lighting device - Google Patents

Abstract

PURPOSE:To obtain linear light adjustment characteristic of an electronic lighting device by correcting and converting the nonlinear frequency characteristic of a main circuit to a linear one by means of the characteristic curve of a light adjusting circuit. CONSTITUTION:In a light adjusting circuit 6, a PWM signal supplied from the outside is compared to a lamp current detection signal from a load current detecting circuit 5 so as to control brightness and the like of a discharge lamp 9 via a switching control circuit 7. A diode 15 used for correcting characteristics is provided in the light adjusting circuit 6 and the modulation factor of the PWM signal is converted by the forward characteristic of the diode 15 to a detection signal having nonlinear characteristic and nonlinear frequency characteristic of the switching control circuit 7 and the like is corrected into a linear one. Thereby linear light adjustment characteristic can be obtained as to linearly varying PWM signals even when frequency characteristic of the main circuit is not linear.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an electronic lighting device for lighting a fluorescent lamp or the like.

(Prior art) In an electronic lighting device for lighting a fluorescent lamp, the brightness of the fluorescent lamp is dimmed by linearly changing the oscillation frequency of an inverter section using a PWM signal (pulse width modulation signal) input from the outside. There are many things.

(Problem to be Solved by the Invention) However, in the conventional electronic lighting device described above, if the frequency characteristics of the main circuit that determines the oscillation frequency of the inverter section are not linear with respect to frequency, the dimming characteristics are visually linear. There was a problem that it didn't work.

In view of the above circumstances, an object of the present invention is to provide an electronic lighting device that can ensure linear dimming characteristics for a PWM signal that changes linearly even when the frequency characteristics of the main circuit are not linear. It is said that

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, an electronic dog lighting device according to the present invention provides an electronic dog lighting device that controls the dimming degree of the discharge lamp based on a dimming designation signal inputted from the outside. In an electronic lighting device that lights up a discharge lamp, a main circuit that chops a DC voltage to generate an AC voltage based on an input frequency designation signal, and lights the discharge lamp with this AC voltage, and a frequency of this main circuit. It is characterized by comprising a dimming circuit that converts a dimming designation signal input from the outside into a frequency designation signal based on a characteristic curve for correcting characteristics, and supplies the frequency designation signal to the main circuit.

(Function) In the above configuration, the frequency characteristics of the main circuit are corrected by the characteristic curve of the dimming circuit, and even when the frequency characteristics of the main circuit are not linear, the output is output from the main circuit according to the value of the dimming designation signal. The frequency of the alternating current voltage generated is visualized linearly.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of an electronic lighting device according to the present invention.

The electronic lighting device shown in this figure includes a noise removal circuit 1, a rectification and smoothing circuit 2, a half-bridge inverter circuit 3, an output voltage detection circuit 4, a load current detection circuit 5, a dimming circuit 6, and a switching control circuit. The circuit 7 is equipped with a dimming designation input signal 1α indicated by the value of the AC voltage applied to the fluorescent lamp 9, the value of the load current, and the PWM signal input from the outside.
The fluorescent lamp 9 is oscillated at a frequency based on the AC voltage to generate an AC voltage, and the fluorescent lamp 9 is lit by this AC voltage.

The noise removal circuit 1 includes a transformer, a varistor, etc.
Noise components of an AC voltage supplied from a @ source such as a commercial power supply are removed and this is supplied to a rectifying and smoothing circuit 2.

The rectification and smoothing circuit 2 includes a rectification bridge circuit, a voltage adjustment circuit, etc., and rectifies the AC voltage supplied from the noise removal circuit 1 to generate a DC voltage having a predetermined voltage value, and converts this into a half-bridge inverter circuit. Supply to 3.

The half-bridge inverter circuit 3 includes switching elements, transformers, etc., and chops the DC voltage supplied from the rectifying and smoothing circuit 2 based on the switching signal input to the control terminal to generate an AC voltage, which is then converted into a fluorescent Supply the light to the lamp 9 and turn it on.

Further, the output voltage detection circuit 4 includes a rectifier circuit, a comparison circuit, etc., detects the value of the AC voltage supplied to the fluorescent lamp 9, and supplies the detection result to the switching control circuit 7.

Further, the load current detection circuit 5 includes a rectifier circuit, a comparison circuit, etc., detects the current value of the AC voltage supplied to the fluorescent lamp 9, and supplies the detection result to the switching control circuit 7.

Further, as shown in FIG. 2, the dimming circuit 6 includes two resistors 1o and 11 that divide the power supply voltage Vcc, a resistor 12 and a capacitor 1 that smooth the PWM signal input from the outside.
3, a resistor 14 that serves as a discharge path for this capacitor 13,
A characteristic correction diode 15 leads the voltage obtained by the resistor 10.11 to the capacitor 13, and a non-inverting input terminal takes in the voltage signal of the capacitor 13, and an inverting input terminal receives the voltage signal from the load current detection circuit 5. It is equipped with a two-man-operated arithmetic intensifier 16 that takes in the output load current detection signal (lamp current detection signal).

Further, the dimming circuit 6 includes a resistor 17 inserted between the inverting input terminal of the operational amplifier 16 and the power line of the power supply voltage Vcc, and a resistor 17 interposed between the inverting input terminal and the output terminal of the operational amplifier 16. A feedback resistor 18 is inserted, a resistor 19 and a capacitor 20 are connected in series, and a series circuit 21 for improving frequency characteristics is connected in parallel to the resistor 18. A diode 22 leading to the switching control circuit 7 is provided.

In this case, the diode 15 provided in the dimmer circuit 6 converts the modulation degree of the PWM signal into a detection signal having non-linear characteristics by its forward characteristic, and this detection signal causes the switching control circuit 7, etc. Correct the frequency characteristics and make them linear.

The dimming circuit 6 detects the degree of modulation of the PWM signal input from the outside and converts it into a detection signal having non-linear characteristics, and the detection signal A1 is supplied from the load current detection circuit 5. The comparison result is supplied to the switching control circuit 7.

The switching control circuit 7 includes a V/F conversion circuit, etc., and generates a switching signal by oscillating at a frequency corresponding to each detection signal output from the output voltage detection circuit 4, load current detection circuit 5, and dimming circuit 6. is generated and supplied to the control terminal of the half-bridge inverter circuit 3 to control the frequency of the AC voltage output from the half-bridge inverter circuit 3 and control its brightness.

As described above, in this embodiment, the diode 15 is provided in the dimming circuit 6, and the forward characteristic of the diode 15 converts the degree of modulation of the PWM signal supplied from the outside into a non-linear detection signal to perform switching control. Since the non-linear frequency characteristics of circuit 7 etc. are corrected,
Even when the frequency characteristics of the main circuit are not linear, linear dimming characteristics can be ensured for a PWM signal that changes linearly.

〔Effect of the invention〕

As described above, according to the present invention, even when the frequency characteristics of the main circuit are not linear, linear dimming characteristics can be ensured for a PWM signal that changes linearly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an electronic lighting device according to the present invention, and FIG. 2 is a circuit diagram showing a detailed circuit configuration example of the dimming circuit shown in FIG. 1. 3... Main circuit (half bridge inverter circuit) 6.
...Dimmer circuit 7...Main circuit (switching control circuit) 9...Discharge lamp (fluorescent lamp) 10...Nonlinear element (diode)

Claims (1)

[Claims] (1) In an electronic lighting device that lights up a discharge lamp while controlling the degree of dimming of the discharge lamp based on a dimming designation signal input from the outside, the DC voltage is chopped based on the input frequency designation signal. A main circuit that generates an alternating current voltage and lights up the discharge lamp using this alternating voltage, and a dimming designation signal input from the outside based on a characteristic curve that corrects the frequency characteristics of this main circuit. An electronic lighting device comprising: a dimming circuit that converts the signal into a signal and supplies the signal to the main circuit.