CN101483960A - Light-adjusting matching circuit of discharge lamp - Google Patents

Abstract

A kind of discharge lamp adjusts luminance and matches the circuit, include: a resonance unit mainly comprising a first capacitor and a second capacitor connected in series, and a first inductor connected in parallel with the series combination of the first capacitor and the second capacitor; a rectifying unit connected to the resonance unit; a half-bridge output unit, which is mainly provided with two electric control switches and is connected in series with the rectifying unit; and a voltage feedback unit, mainly having a second inductor, a third capacitor and a fourth capacitor connected in series; wherein the resonant frequency of the resonant unit is about a predetermined multiple of the operating frequency of the half-bridge output unit. Therefore, the standard dimmer can be matched to dim the discharge lamp, the generation of the flicker phenomenon can be avoided, the cost is low, and the market acceptance is high.

Description

Discharge lamp dimming matching circuit

technical field

The present invention relates to a dimming device for a discharge lamp, in particular to a dimming matching circuit for a discharge lamp that is used to match a commercially available standard dimmer and has low-cost and non-flickering effects.

Background technique

Press, currently known commercially available dimmable discharge lamps or dimmable electronic ballasts for fluorescent tubes usually use the frequency conversion function of an IC (integrated circuit) chip to perform dimming control. However, this kind of IC chip with frequency conversion function is not cheap, so that the price of this kind of dimmable discharge lamp or dimmable electronic ballast remains high, and the degree of acceptance by consumers is not high.

In addition, some people proposed not to use IC chips with frequency conversion function, and to use them with dimmers. However, it may flicker during the adjustment process because the current cannot be maintained. In severe cases, the discharge lamp or the dimmer may even be burned out, and the flicker may cause discomfort to the user's eyes.

Contents of the invention

The object of the present invention is to provide a discharge lamp dimming matching circuit, which can be used with a commercially available standard dimmer to maintain the current during the process of dimming the discharge lamp and avoid flickering. At the same time, instead of using an IC chip with a frequency conversion function, only low-cost components are used, which has low cost and high market acceptance.

In order to achieve the above purpose, the discharge lamp dimming matching circuit provided by the present invention includes:

A resonant unit mainly has a first capacitor and a second capacitor connected in series, and a series combination of a first inductor connected in parallel with the first capacitor and the second capacitor;

a rectifier unit connected to the resonance unit for converting alternating current into direct current;

The half-bridge output unit mainly has two electronically controlled switches connected in series to the rectifier unit, each of the electrically controlled switches has a control terminal, and each of the control terminals is respectively connected to an oscillation unit; and

A voltage feedback unit mainly has a second inductor, a third capacitor and a fourth capacitor connected in series, the voltage feedback unit is connected to the half-bridge output unit, and connected to the rectification unit;

Wherein, the resonant frequency of the resonant unit is approximately a predetermined multiple of the operating frequency of the half-bridge output unit.

The matching circuit for dimming the discharge lamp, wherein: the resonant frequency of the resonant unit is ±10% of the predetermined multiple of the operating frequency of the half-bridge output unit.

In the matching circuit for dimming the discharge lamp, the predetermined multiple is an integer multiple.

Said discharge lamp dimming matching circuit, wherein: the predetermined multiple is 1/N times, wherein N is a natural number.

The discharge lamp dimming matching circuit, wherein: the resonant unit also has two third inductors, one end of the two third inductors is respectively connected to both ends of the second capacitor, and the other end of the two third inductors is connected to the two ends of the second capacitor. One end is respectively connected to two ends of a fifth capacitor.

The matching circuit for dimming the discharge lamp, wherein: the rectification unit is a bridge rectifier.

The matching circuit for dimming the discharge lamp, wherein: each of the electronically controlled switches is a transistor.

Said discharge lamp dimming matching circuit, wherein: each of the oscillation units is an RL oscillation circuit formed by a resistor and an inductor in series.

As can be seen from the above, the effect that the present invention can achieve is:

1. No flickering during the dimming process: This invention mainly uses the resonant frequency multiple relationship between the resonant unit and the half-bridge output unit to achieve the effect of improving the power factor and maintaining the current. After connecting with the dimmer, it can avoid dimming The TRIAC (two-way silicon controlled body) on the device is cut off, further avoiding the problem of flicker.

2. Low cost: the present invention mainly uses the resonant frequency multiple relationship between the resonant unit and the half-bridge output unit, so the effect of avoiding flickering can be achieved without using the frequency conversion function of the IC chip; the present invention only uses low-cost components, It has low cost and high market acceptance.

Description of drawings

Fig. 1 is a circuit structure diagram of a preferred embodiment of the present invention.

Fig. 2 is a timing diagram of frequency multiplication in a preferred embodiment of the present invention.

Fig. 3 is a circuit structure diagram of a standard dimmer according to a preferred embodiment of the present invention.

FIG. 4 is a power factor correction current waveform diagram of a preferred embodiment of the present invention.

Explanation of main component symbols in the attached drawings:

10 Discharge lamp dimming matching circuit

11 Resonant unit

21 rectifier unit

31 Half bridge output unit

41 Voltage feedback unit

51 standard dimmer

51 TRIAC bidirectional silicon controlled body

99 Discharge lamps

C1 first capacitor

C2 second capacitor

C3 third capacitor

C4 fourth capacitor

C5 fifth capacitor

L1 first inductance

L2 second inductance

L3 third inductance

N1, N2 power input

Q1, Q2 electric control switch

G control terminal

Detailed ways

The discharge lamp dimming matching circuit provided by the present invention includes: a resonant unit mainly having a first capacitor and a second capacitor connected in series, and having a first inductor connected in parallel to the first capacitor and the second capacitor A series combination; a rectifier unit connected to the resonance unit for converting alternating current into direct current; a half-bridge output unit mainly has two electronically controlled switches connected in series and connected to the rectifier unit, and each of the electronically controlled switches has a control Each of the control terminals is respectively connected to an oscillation unit; and a voltage feedback unit mainly has a second inductor, a third capacitor and a fourth capacitor connected in series, the voltage feedback unit is connected to the half-bridge output unit, And connected to the rectification unit; wherein, the resonant frequency of the resonant unit is about a predetermined multiple of the operating frequency of the half-bridge output unit. Therefore, the standard dimmer can be used to adjust the light of the discharge lamp, and the generation of flicker can be avoided, and the cost is low, and the market acceptance is high.

In order to describe the structure and characteristics of the present invention in detail, the following preferred embodiment is given and described in conjunction with the accompanying drawings as follows, wherein:

As shown in Figure 1, a discharge lamp dimming matching circuit 10 provided by a preferred embodiment of the present invention can be used to match a standard dimmer 51 for dimming function. The discharge lamp dimming matching circuit 10 of the present invention The circuit 10 is mainly composed of a resonance unit 11, a rectification unit 21, a half-bridge output unit 31, and a voltage feedback unit 41, wherein:

The resonant unit 11 mainly has a first capacitor C1 and a second capacitor C2 connected in series, and a first inductor L1 connected in parallel to the first capacitor C1 and the second capacitor C2 in series. The resonant unit 11 also has two third inductors L3, one end of the two third inductors L3 is respectively connected to the two ends of the second capacitor C2, and the other end of the two third inductors L3 is connected to a fifth capacitor C2 respectively. The two ends of the capacitor C5 and the fifth capacitor C5 are also used as two power input terminals N1 and N2.

The rectifying unit 21 is connected to the resonant unit 11 for converting AC power into DC power. The rectification unit 21 is a bridge rectifier in this embodiment.

The half-bridge output unit 31 mainly has two electric control switches Q1, Q2 connected in series to the rectifier unit 21, each of the electric control switches Q1, Q2 has a control terminal G, and each of the control terminals G is respectively connected to a Oscillating unit 35. Each of the electronically controlled switches Q1 and Q2 is a transistor in this embodiment. In this embodiment, each oscillation unit 35 is an RL oscillation circuit formed by a resistor R and an inductor L connected in series.

The voltage feedback unit 41 mainly includes a second inductor L2 , a third capacitor C3 and a fourth capacitor C4 connected in series. The voltage feedback unit 41 is connected to the half-bridge output unit 31 and the rectifier unit 21 .

Wherein, the resonant frequency of the resonant unit 11 is approximately a predetermined multiple of the operating frequency of the half-bridge output unit 31 . In more detail, it is ±10% of a predetermined multiple. And the predetermined multiple can be an integer multiple or 1/N times (N is a natural number), such as 1 times, 2 times, 3 times, 1/2 times, 1/3 times, 1/4 times, etc. . . . In this embodiment, 1/2 times ± 10% is used as an example. In this case, the operating frequency of the half-bridge output unit 31 is about 55KHz, so the resonant frequency of the resonant unit 11 is about 27KHz. The frequency-timing relationship is shown in Figure 2. The resonant frequency of the resonant unit 11 can be obtained by adjusting the values of the first capacitor C1, the second capacitor C2 and the first inductance L1 through the following formula (1):

$f=\frac{1}{2\mathrm{\&pi;}\sqrt{\mathrm{LC}}}=\frac{1}{2\mathrm{\&pi;}\sqrt{\frac{1}{\frac{1}{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="A200810002417E00101.png"\; state="\{\{state\}\}">C</figure-callout>}1}+\frac{1}{C2}}+\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="A200810002417E00101.png"\; state="\{\{state\}\}">L</figure-callout>}1}}$ Formula 1)

The present invention can be connected with a standard dimmer 51 (shown in FIG. 3 ) and a discharge lamp 99 when in use, and the standard dimmer 51 is connected to the two power supply input terminals N1, N2, and can be controlled by the standard dimmer 51 to adjust the brightness of the discharge lamp 99. The discharge lamp 99 is connected to the second inductor L2 and the rectifying unit 21 . The circuit structure of the standard dimmer 51 is shown in FIG. 3 , and since it is a known structure, its components and operating principles are not described in detail.

According to the above structure and frequency setting, the resonant frequency of the resonant unit 11 is 1/2 times the working frequency of the half-bridge output unit 31, so as to prevent the third capacitor C3 from feeding back current to the two power input terminals N1 , N2, thereby effectively improving the EMI interference.

During dimming, when the lamp is adjusted from bright to dark, the input power gradually decreases, and a "ringing" phenomenon will occur at the same time (the ringing phenomenon is explained in the next paragraph), at this time the first inductor L1 stores The electric energy can make the standard dimmer 51 obtain enough maintenance current, so that the TRIAC (bi-directional silicon IC) 52 in the standard dimmer 51 is not interrupted, so there is no problem of the discharge lamp 99 flickering. In addition, due to the DC impedance of the first inductor L1, it can effectively block the "ringing" amplitude caused during the dimming process, further suppressing the possible current cut-off phenomenon of the standard dimmer 51, Further avoiding the flickering problem during the dimming process.

The above "ringing" phenomenon is mainly due to the inherent resonant frequency of the combination of inductance and capacitance in the input part of the general circuit, and the leading edge current triggered by the dimmer contains a large number of high-order harmonics. At the same time, there are currents with the same frequency as the above-mentioned resonance frequency in the high-order harmonics, which will interact with each other to generate oscillation.

When the power is input, the discharge lamp 99 is activated to generate lamp tube voltage and current, and a feedback voltage is obtained from the place where the second inductor L2 is connected to the discharge lamp 99, due to the resonant frequency of the resonant unit 11 and the half-bridge output The resonance generated by the multiple relationship of the working frequency of the unit 31 improves the feedback voltage, so the power factor can be further improved so that the standard dimmer 51 has a conduction current in the entire half cycle of the current, conduction current and input current The voltage waveform of the voltage is shown in Figure 4, so that it can maintain the conduction condition without flickering. In addition, due to the discharge characteristics of the discharge lamp 99, when the lamp is dimmed from bright to dark, its lamp voltage will rise rapidly from normal, so the feedback voltage will also rise accordingly, so that the power factor is further improved, and the above-mentioned power is reached. The effect of increasing the factor makes flickering less likely to occur.

Claims (8)

1, a kind of light control matching circuit for discharge lamp includes:

One resonant element mainly has one first electric capacity and one second electric capacity is in series, and has the tandem compound that one first inductance is parallel to this first electric capacity and this second electric capacity;

One rectification unit is connected in this resonant element, in order to transfer alternating current to direct current;

Half-bridge output unit mainly has two electric-controlled switchs and is in series, and is connected in this rectification unit, and respectively this electric-controlled switch has a control end, and respectively this control end is connected to an oscillating unit; And

One voltage feedback unit mainly has one second inductance, one the 3rd electric capacity and one the 4th electric capacity and is in series, and this voltage feedback unit is connected in this half-bridge output cell, and is connected in this rectification unit;

Wherein, the resonance frequency of this resonant element is approximately the prearranged multiple of the operating frequency of this half-bridge output cell.

2, according to the described light control matching circuit for discharge lamp of claim 1, wherein: the resonance frequency of resonant element is prearranged multiple ± 10% of the operating frequency of this half-bridge output cell.

3, according to the described light control matching circuit for discharge lamp of claim 2, wherein: this prearranged multiple is an integral multiple.

4, according to the described light control matching circuit for discharge lamp of claim 2, wherein: this prearranged multiple is 1/N times, and wherein N is a natural number.

5, according to the described light control matching circuit for discharge lamp of claim 1, wherein: this resonant element has 2 the 3rd inductance, this 2 the 3rd inductance is connected to the two ends of this second electric capacity with the one end, this 2 the 3rd inductance and be connected to the two ends of one the 5th electric capacity with its other end.

6, according to the described light control matching circuit for discharge lamp of claim 1, wherein: this rectification unit is a bridge rectifier.

7, according to the described light control matching circuit for discharge lamp of claim 1, wherein: respectively this electric-controlled switch is a transistor.

8, according to the described light control matching circuit for discharge lamp of claim 1, wherein: respectively this oscillating unit is a RL oscillation circuit, is in series by a resistance and an inductance.

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