KR200339242Y1 - Driving circuit for suppressing the trembling of a flame in the electronic ballast for high pressure discharge lamp - Google Patents

Abstract

According to the present invention, the noise filter unit for receiving a direct current to filter the noise to output a DC voltage; A DC-DC converter unit for converting an input DC voltage at high speed by switching the DC voltage received from the noise filter unit to generate another DC voltage; An inverter unit for making a low-speed switched AC power source from the DC voltage input from the DC-DC converter unit; And a drive circuit for suppressing the vibration of the flame of the electronic ballast for high-pressure discharge lamp comprising a control unit for switching control of the DC-DC converter unit and the inverter unit.

Description

Driving circuit for suppressing the trembling of a flame in the electronic ballast for high pressure discharge lamp

The present invention relates to a driving circuit for suppressing flame tremor of an electronic ballast for a high-pressure discharge lamp, and more particularly, a short period during a period of a waveform in a high-pressure discharge lamp such as a metal halide lamp, a xenon lamp, or an ultra-high pressure mercury lamp employing a low frequency method. The present invention relates to a driving circuit that can suppress sparking by suppressing arc jumping by changing a current by changing a waveform of a voltage larger or smaller than a normal waveform over time.

When driving with electronic ballast in high voltage discharge lamp series such as metal halide lamp, xenon lamp or ultra high pressure mercury lamp, the arc is made at a constant position between the electrodes, so that the spark discharge is smooth and the position of the arc jumps to make the flame tremble or wave. Often hitting. In order to suppress this, a low frequency method of 1 KHz or less is used when the direct current is alternating current, but in this case, there is a problem in that spark vibration still remains by driving a discharge lamp with a waveform having a constant voltage magnitude.

Accordingly, an object of the present invention is to provide a drive circuit capable of suppressing the vibration of the flame of the electronic ballast for high-pressure discharge lamps.

1 is a block diagram of a driving circuit for suppressing the flame vibration of the electronic ballast for high-pressure discharge lamp according to a preferred embodiment of the present invention;

2A-2C are circuit examples for the DC-DC converter of FIG. 1;

3 is a circuit diagram showing a case in which a buck circuit is employed as a DC-DC converter in a driving circuit for suppressing flame tremor of an electronic ballast for a high voltage discharge lamp according to a preferred embodiment of the present invention; And

4 is a waveform diagram of each part of FIG. 3.

* Explanation of symbols for main parts of the drawings

100: noise filter unit 200: DC-DC converter unit

210: current detection unit 300: inverter unit

310: starting unit 400: control unit

410: high frequency generation unit 420: constant power control unit

430: low frequency conversion unit 440: PWM or PFM control unit

450: high frequency drive unit 460: voltage detector

470: inverter drive unit

According to the present invention, the noise filter unit for receiving a direct current to filter the noise to output a DC voltage; A DC-DC converter unit for converting an input DC voltage at high speed by switching the DC voltage received from the noise filter unit to generate another DC voltage; An inverter unit for making a low-speed switched AC power source from the DC voltage input from the DC-DC converter unit; And a drive circuit for suppressing the vibration of the flame of the electronic ballast for high-pressure discharge lamp comprising a control unit for switching control of the DC-DC converter unit and the inverter unit.

The inverter unit preferably generates a voltage applied to the lamp by periodically repeating the DC voltage in a section shorter than this period within a period of low frequency to be lower or higher than the average voltage.

In addition, the control unit may periodically generate a signal for driving the switching element of the DC-DC converter unit by periodically repeating the frequency modulation and the pulse width modulation for a period shorter than this period of one period of the inverter unit.

In addition, the control unit preferably repeats the frequency modulation for a time shorter than this period in a period of low frequency in generating the gate signal repeated by the high frequency generator.

In addition, the control unit preferably repeats the pulse width modulation for a time shorter than this period in a period of low frequency in generating the gate signal repeated by the high frequency generator.

In addition, the control unit preferably includes a low frequency conversion unit.

In addition, the control unit preferably includes a PFM control unit to control the PFM for a shorter time than this period within one period of the low frequency of the inverter unit.

In addition, the control unit preferably includes a PWM control unit for performing a PWM control for a time shorter than this period within one period of the low frequency of the inverter unit.

In addition, the control unit preferably includes a constant output control unit.

Hereinafter, with reference to the accompanying drawings will be described in more detail with respect to the drive circuit for suppressing the vibration of the flame of the electronic ballast for high-pressure discharge lamp according to a preferred embodiment of the present invention.

FIG. 1 is a block diagram of a driving circuit for suppressing flame tremor of an electronic ballast for a high voltage discharge lamp according to a preferred embodiment of the present invention, and FIGS. 2A to 2C are examples of a DC-DC converter circuit.

As shown in FIG. 1, a driving circuit for suppressing flame tremor of an electronic ballast for a high voltage discharge lamp according to a preferred embodiment of the present invention is largely a filter unit 100, a DC-DC converter unit 200, an inverter unit 300. ), And the control unit 400.

The filter unit 100 removes noise of a load and provides a DC voltage to the DC-DC converter 200.

As illustrated in FIGS. 2A to 2C, the DC-DC converter unit 200 may include a FLY-BACK or a forward converter of FIG. 2A, a buck circuit of FIG. 2B, or FIG. 2C. BOOST circuit and the like can be employed.

In the driving circuit for suppressing the flame vibration of the electronic ballast for a high-pressure discharge lamp according to a preferred embodiment of the present invention, a case in which a buck circuit is employed as a DC-DC converter will be described as an example.

3 is a circuit illustrating a case in which a buck circuit is employed as a DC-DC converter in a driving circuit for suppressing flame tremor of an electronic ballast for a high voltage discharge lamp according to a preferred embodiment of the present invention. It is a waveform diagram about each part of FIG.

As shown in FIG. 3, the DC-DC converter 200 includes a switching element Q1, a diode D1, an inductor L1, a capacitor C1, and a current detector 210. The DC power supply V1 passed through the filter is switched by the switching element Q1 and is flywheeled by the diode D1, and is smoothed by the inductor L1 and the capacitor C1 and lower than the input voltage V2. Is supplied to the inverter unit 300.

At this time, the high frequency generator 410 generates a gate signal to perform the high frequency switching of the input DC power supply V1 by the switching element Q1. The waveform of the gate signal is a pulse width modulation (PWM) for a period T1 time, as shown in the gate waveform 1 of the DC-DC converter of Figure 4, or as the gate waveform 2 of the DC-DC converter of Figure 4, It becomes a waveform that performs frequency modulation (PFM) for the period T1 time, and by switching the switching element Q1 to the waveform, the input DC voltage V1 is transformed during the period T1 as shown by the waveform V2 of FIG. Supply to the inverter unit 300.

The current detector 210 includes a resistor R1 and a capacitor C10. The current detector 210 detects a current and smoothes the voltage drop caused by the resistance to convert the current for the watt control of the constant output unit 420 into a voltage.

The inverter unit 300 includes a starter 310 and includes switching elements Q2, Q3, Q4 and Q5, a transformer TRANS, and an inductor L2. The inverter unit 300 converts the input DC voltage V2 into a square wave as shown in FIG. 4 and supplies it to the lamp. The waveform of the square wave changes the current by decreasing or increasing the voltage of the section T1 in one low frequency cycle, thereby suppressing the flame of the lamp.

The controller 400 includes a high frequency generator 410, a constant output controller 420, a low frequency converter 430, a PWM or PFM controller 440, a high frequency driver 450, a voltage detector 460, and a low frequency driver 470. )

The high frequency generator 410 generates a gate signal of a high frequency for high frequency switching the direct current V1 of the DC-DC converter 200, and the constant output controller 420 has a function of controlling the constant output, The low frequency converter 430 generates a high frequency waveform for the low frequency switching of the inverter unit 300 and a low frequency waveform for PWM or PFM control during the period T1 of FIG. 4.

The PWM or PFM controller 440 performs PWM control for a short time T1 within one cycle through dead time control of the high frequency generator 410 or controls the voltage of the terminal Rt for frequency generation for a short time. (T1) Perform PFM control.

The high frequency driver 450 makes a waveform generated by the high frequency generator 410 into a waveform for switching the switching element Q1, and the voltage detector 460 resistances the voltage V2 to the voltage input of the microprocessor IC1. The low frequency driving unit 470 generates a signal for alternately switching the switching elements Q2-Q5 of the inverter unit 300.

The high frequency generator 410 includes a PWM generation IC IC5, resistors R9-R14 and R16-R24, capacitors C7 and C8, and a transistor TR3. The high frequency generator generates a high frequency ranging from tens to hundreds of KHz by the resistor R14 and the capacitor C7.

The constant output control unit 420 is composed of a microprocessor IC1, resistors R4-R8, and capacitors C3-C6. It receives the current and voltage from the current detector 210 and the voltage detector 460 to the terminals (A1, A0) and multiplies them internally and sends out a PWM signal to the terminal (B7) and the resistors (R6, R7), Switching element Q1 is smoothed with capacitor C6 to control the voltage at dead time control terminal DT of high frequency generator 410 until the lamp output wattage reaches a reference point programmed in the microprocessor IC1. The gate pulse width of is controlled to be a constant output.

The low frequency converter 430 is configured of a counter IC3. This receives the signal input from the high frequency generator 410 to the terminal (CLK) and converts it to a low frequency within 1KHz to be input to the PWM or PFM controller 440 and the inverter driver 470.

The PWM or PFM control unit 440 includes a NAND gate IC4, resistors R25-R28, a capacitor C9, and transistors TR1 and TR2. The PWM or PFM controller 440 inputs a waveform of the terminal Q6 of the counter IC3 of the low frequency converter 430 through the resistor R25 to one input of the NAND gate and the other input of the resistor R26. The input waveform is delayed by the capacitor C9 and the output waveform of the NAND gate IC4 is generated as shown in the IC4 output waveform of FIG. The IC4 output waveform of FIG. 4 is applied to the bases of the transistors TR1 and TR2 through the resistors R27 and R28 to generate a waveform for PWM / PFM control, that is, a DC-DC gate waveform 1 / DC-DC gate waveform 2. . That is, the transistor TR1 controls the voltage of the dead time control terminal (terminal DT of IC5) of the high frequency generator 410, and as shown in the DC-DC gate waveform 1 of FIG. T2) is switched to the time of Ton1, and in the section T1 to the time of Ton2, the V2 waveform of FIG. 4 is generated in the end, and the frequency control terminal of the high frequency generator 410 is generated by the transistor TR2 { By controlling the voltage of the terminal RT of IC5}, as shown in the DC-DC gate waveform 2 of FIG. 4, switching is performed at a frequency of f1 in the section T2 and at a frequency of f2 in the section T1. In the end, the V2 waveform of Fig. 4 is generated. These two methods may be applied separately or simultaneously.

The high frequency driving unit 450 is composed of a high frequency switching IC (IC2), a resistor (R30), a capacitor (C2) and a diode (D2). This is a circuit inserted in order to switch the waveform generated from the high frequency generator 410 to the switching element Q1 of the DC-DC converter.

The voltage detector 460 is a voltage divided by a resistor divided through the resistors R2 and R3 to use the DC voltage V2 as the voltage input of the positive output controller 420.

Therefore, in transforming some sections of the low frequency voltage waveform driving the lamp in the electronic ballast to keep the high-voltage discharge lamp on, high frequency is generated in order to make some sections of one cycle section of the low frequency lower or higher than the average voltage. When converting DC voltage through DC-DC converter by frequency modulation or pulse width modulation such as changing frequency or controlling dead time voltage only for a certain period of time, this period is synchronized for low frequency inverter period. By changing the current which is repeated periodically to increase or decrease the DC voltage in a shorter period, it is possible to suppress the flame shake that is common in high-pressure discharge lamps, thereby achieving stable lighting.

Claims (9)

A noise filter unit for receiving a DC and filtering noise to output a DC voltage; A DC-DC converter unit for converting an input DC voltage at high speed by switching the DC voltage received from the noise filter unit to generate another DC voltage; An inverter unit for making a low-speed switched AC power source from the DC voltage input from the DC-DC converter unit; And And a control unit for switching control of the DC-DC converter unit and the inverter unit. The high voltage of claim 1, wherein the inverter unit generates a voltage applied to a lamp by periodically repeating the DC voltage in a section shorter than this period within a period of low frequency to be lower or higher than an average voltage. Drive circuit for suppressing sparkling of electronic ballasts for discharge lamps. The method of claim 1, wherein the control unit periodically generates a signal for driving the switching element of the DC-DC converter unit by repeatedly performing frequency modulation and pulse width modulation for a period shorter than this period of one period of the inverter unit. A drive circuit for suppressing sparkling of electronic ballasts for high-pressure discharge lamps. The method of claim 1, wherein the control unit in the generation of the gate signal to be repeated by the high frequency generator to suppress the flame shake of the electronic ballast for the high-pressure discharge lamp, characterized in that the frequency modulation is repeated for a time shorter than this period. Driving circuit. 2. The flame suppression of the electronic ballast of claim 1, wherein the control unit repeats pulse width modulation for a time shorter than this period in a period of low frequency in generating the gate signal repeated by the high frequency generator. Driving circuit for. The driving circuit of claim 1, wherein the control unit comprises a low frequency conversion unit. The drive circuit of claim 1, wherein the control unit includes a PFM control unit configured to perform PFM control for a shorter time than this period within one cycle of the low frequency unit of the inverter unit. The driving circuit of claim 1, wherein the control unit includes a PWM control unit configured to perform PWM control for a shorter time than this period within one cycle of the low frequency unit of the inverter unit. The driving circuit of claim 1, wherein the control unit comprises a constant output control unit.