阅读说明：本技术 一种无电解去频闪电路 (Electroless stroboscopic removing circuit ) 是由 吴群民 王炳生 陈立言 王发生 苏剑辉 于 2019-10-23 设计创作，主要内容包括：本发明提供了一种无电解去频闪电路,包括两路BUCK回路,以及用于控制两路BUCK回路导通的第一开关管和第二开关管；所述第一开关管和第二开关管分别受第一PWM信号和第二PWM信号驱动,所述第一PWM信号与第二PWM信号的频率、占空比均相同,且高电平的持续时间小于低电平的持续时间,并且第二PWM信号的高电平与第一PWM信号的高电平相错开；所述两路BUCK回路的输出端连接至同一路LED光源。上述的无电解去频闪电路,无需使用电解,起到降低输出波纹和提升效率的作用。(The invention provides an electrolytic stroboscopic-removing circuit which comprises two BUCK loops, a first switch tube and a second switch tube, wherein the first switch tube and the second switch tube are used for controlling the conduction of the two BUCK loops; the first switch tube and the second switch tube are respectively driven by a first PWM signal and a second PWM signal, the frequency and the duty ratio of the first PWM signal and the second PWM signal are the same, the duration time of a high level is less than the duration time of a low level, and the high level of the second PWM signal is staggered with the high level of the first PWM signal; and the output ends of the two BUCK loops are connected to the same LED light source. The non-electrolysis stroboscopic removing circuit does not need electrolysis, and plays roles in reducing output ripples and improving efficiency.)

1. An electroless stroboscopic removal circuit, comprising: the control circuit comprises two BUCK loops, a first switch tube and a second switch tube, wherein the first switch tube and the second switch tube are used for controlling the conduction of the two BUCK loops;

the first switch tube and the second switch tube are respectively driven by a first PWM signal and a second PWM signal, the frequency and the duty ratio of the first PWM signal and the second PWM signal are the same, the duration time of a high level is less than the duration time of a low level, and the high level of the second PWM signal is staggered with the high level of the first PWM signal;

and the output ends of the two BUCK loops are connected to the same LED light source.

2. The electroless stroboscopic removal circuit of claim 1, wherein: the rising edge starting time of the second PWM signal is the same as the falling edge signal starting time of the first PWM signal.

3. The electroless stroboscopic removal circuit of claim 1, wherein: the first switch tube and the second switch tube are MOS tubes respectively, the source electrodes of the MOS tubes are grounded, the drain electrodes of the MOS tubes are connected to the input ends of the two BUCK loops respectively, and the grid electrodes of the two BUCK loops are connected with the first PWM signal and the second PWM signal respectively.

4. An electroless stroboscopic removal circuit as in claim 3, wherein: in the two BUCK loops, a first BUCK loop comprises an inductor L1 and a diode D5 which are connected in series, and a second BUCK loop comprises an inductor L2 and a diode D6 which are connected in series;

the inductor L2 and the dotted terminal of the diode D6, and the inductor L1 and the dotted terminal of the diode D5 are respectively connected with the first switching tube and the second switching tube;

the cathodes of the diode D5 and the diode D6 are connected to each other, and the inductor L1 and the inductor L2 are connected to each other and to the positive output terminal of the rectifier circuit.

5. The electroless stroboscopic removal circuit of claim 1, wherein: the duration of the low level is greater than 2 times the duration of the high level.

Technical Field

The invention relates to an LED, in particular to an LED driving circuit.

Background

In recent years, with the increasing tension of global energy problems, the requirements for energy conservation and environmental protection are more and more prominent. The traditional incandescent lamp and the energy-saving lamp are replaced by the LED lamp with long service life, high efficiency, energy conservation and high luminous efficiency. The common LED illumination can realize high luminous efficiency and long service life, the power factor can realize the power factor of 0.9, but the problem of power frequency flicker cannot be solved; and the stroboscopic of the LED light source has some harm, easily causes visual fatigue, causes the visual impairment. High PF, no stroboflash, LED power are energy-concerving and environment-protective, have solved the light source stroboflash problem moreover, can not cause the damage to the eyesight, are safe green light source.

The LED lamp has the characteristics of no stroboflash, high efficiency, high PF value and the like, has high energy-saving efficiency and is convenient for large-scale production in the era of advocating energy conservation and emission reduction and low-carbon economy, and becomes a mainstream technology for LED market development. At present, the fluorescent lamp is mainly used in the application fields of fluorescent lamps, street lamps, automobile lamps and the like.

In order to achieve the purpose of stroboscopic removal, the common practice in the industry is as follows:

1. the ripple wave is reduced by adopting a two-stage loop cascade mode;

the mode is used in large quantity at present, two paths are connected in series, the efficiency is low, and electrolysis cannot be used. If APFC + FLYBACK, or FLYBACK + BUCK, or PPFC + HB (BRI DGE), or FLYBACK + LDO is adopted, the two ways of rectification are adopted to realize the two-way output of the system circuit, and the models of the PFC inductor and the main isolation transformer are more than those of the BUCK inductor, so that the cost is high.

Disclosure of Invention

The invention aims to solve the main technical problem of providing an electrolysis-free stroboscopic removing circuit which does not need electrolysis and has the functions of reducing output ripples and improving efficiency.

In order to solve the technical problem, the invention provides an electrolysis-free stroboscopic-removing circuit, which comprises two BUCK loops, a first switch tube and a second switch tube, wherein the first switch tube and the second switch tube are used for controlling the conduction of the two BUCK loops;

the first switch tube and the second switch tube are respectively driven by a first PWM signal and a second PWM signal, the frequency and the duty ratio of the first PWM signal and the second PWM signal are the same, the duration time of a high level is less than the duration time of a low level, and the high level of the second PWM signal is staggered with the high level of the first PWM signal;

and the output ends of the two BUCK loops are connected to the same LED light source.

In a preferred embodiment: the rising edge starting time of the second PWM signal is the same as the falling edge signal starting time of the first PWM signal.

In a preferred embodiment: the first switch tube and the second switch tube are MOS tubes respectively, the source electrodes of the MOS tubes are grounded, the drain electrodes of the MOS tubes are connected to the input ends of the two BUCK loops respectively, and the grid electrodes of the two BUCK loops are connected with the first PWM signal and the second PWM signal respectively.

In a preferred embodiment: in the two BUCK loops, a first BUCK loop comprises an inductor L1 and a diode D5 which are connected in series, and a second BUCK loop comprises an inductor L2 and a diode D6 which are connected in series;

the inductor L2 and the dotted terminal of the diode D6, and the inductor L1 and the dotted terminal of the diode D5 are respectively connected with the first switching tube and the second switching tube;

the cathodes of the diode D5 and the diode D6 are connected to each other, and the inductor L1 and the inductor L2 are connected to each other and to the positive output terminal of the rectifier circuit.

In a preferred embodiment: the duration of the low level is greater than 2 times the duration of the high level.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

according to the invention, two staggered PWM signals are used for controlling the staggered conduction of switching devices such as two MOS tubes and the like, the conduction of two BUCK loops is respectively controlled, the output combines the two paths together, and the two paths are connected in parallel, so that the effects of reducing output ripples and improving efficiency are achieved.

Drawings

FIG. 1 is a circuit diagram of a preferred embodiment of the present invention;

fig. 2 is a waveform diagram of a PWM signal according to a preferred embodiment of the present invention.

Detailed Description

The technical solution of the present invention is further explained with reference to the accompanying drawings and the detailed description.

Referring to fig. 1 and 2, an electrolytic stroboscopic removing-free circuit includes two BUCK loops, and a first switch Q1 and a second switch Q2 for controlling the conduction of the two BUCK loops;

the first switch tube Q1 and the second switch tube Q2 are respectively driven by a first PWM signal and a second PWM signal, the frequency and the duty ratio of the first PWM signal and the second PWM signal are the same, the duration time of a high level is shorter than the duration time of a low level, and the high level of the second PWM signal is staggered with the high level of the first PWM signal; the rising edge starting time of the second PWM signal is the same as the falling edge signal starting time of the first PWM signal. And the duration of the low level is greater than 2 times the duration of the high level.

As shown in fig. 2, at a time point, the first PWM signal and the second PWM signal may have three positional relationships:

1) the first PWM signal output is high and the second PWM signal output is low.

2) The first PWM signal output is low and the second PWM signal output is high.

3) The first PWM signal and the second PWM signal are both low.

Thus, after the first PWM signal is superimposed with the second PWM signal, as shown in fig. 2, the high level becomes wide and the low level becomes narrow on the basis of the first PWM signal, and in one high level signal, the first switching tube Q1 and the second switching tube Q2 are sequentially turned on, and the first switching tube Q1 and the second switching tube Q2 are kept turned on for the same time.

And the output ends of the two BUCK loops are connected to the same LED light source.

The electroless stroboscopic removing circuit controls the switching devices such as the two MOS tubes to be conducted in a staggered mode through the two staggered PWM signals, the two BUCK loops are respectively controlled to be conducted, the output is combined with the two BUCK loops, and the two BUCK loops are connected in parallel to play a role in reducing output ripples and improving efficiency.

Specifically, in the circuit of this embodiment, the first switch tube Q1 and the second switch tube Q2 are MOS tubes, and have grounded sources, drains respectively connected to the input terminals of the two BUCK circuits, and gates respectively connected to the first PWM signal and the second PWM signal.

In the two BUCK loops, a first BUCK loop comprises an inductor L1 and a diode D5 which are connected in series, and a second BUCK loop comprises an inductor L2 and a diode D6 which are connected in series;

the inductor L2 and the dotted terminal of the diode D6, and the inductor L1 and the dotted terminal of the diode D5 are respectively connected with the first switching tube and the second switching tube;

the cathodes of the diode D5 and the diode D6 are connected to each other, and the inductor L1 and the inductor L2 are connected to each other and to the positive output terminal of the rectifier circuit.

The above description is only a preferred embodiment of the present invention, and the scope of the present invention should not be limited thereby. Equivalent changes and modifications made according to the patent scope and the specification of the present invention should be covered by the present invention.