WO2007033526A1

WO2007033526A1 - Improved led string

Info

Publication number: WO2007033526A1
Application number: PCT/CN2005/001552
Authority: WO
Inventors: Qingbiao Wu
Original assignee: Qingbiao Wu
Priority date: 2005-09-23
Filing date: 2005-09-23
Publication date: 2007-03-29

Abstract

An improved LED string includes at least a dual-semiwave rectifying circuit and at least a group of LED groups of which positive terminals are connected to a common output terminal of the corresponding dual-semiwave rectifying circuit. Resistance elements are respectively connected between positive terminals of rectifying tubes of the dual-semiwave rectifying circuit and an AC power, and diodes are respectively serially connected with the same polarity direction between negative terminals of the LED groups and both terminals of the AC power. With the above solution, the improved LED string of the present invention decreases voltage and limits current using one resistance for each semiwave. Four resistances corresponding to each group of LED groups are provided in such a manner that two resistances of four resistances and the other two resistances are respectively commonly connected to a same input terminal of the AC power. One LED string may include a plurality of dual-semiwave rectifying circuits, so there are sufficient voltage and current to be supplied to each LED when a plurality of groups of LED groups are provided in each LED string.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light string, particularly a light string using a light emitting diode as a light source. BACKGROUND OF THE INVENTION Existing light strings, such as the Chinese utility model "a decorative lantern for decoration" (patent number 03273878. 1), its working circuit is shown in Figure 1, including a rectifier circuit and a light string, and its rectifier circuit A rectifier bridge is used. The input end of the rectifier bridge is connected to an AC power source, and its string is connected in series by a 10-50 light-emitting diode (LED) on the load circuit of the rectifier circuit. This kind of string, due to the power of the rectifier bridge and the AC voltage, the number of light-emitting diodes in each string cannot be too much.

In actual use, it is often a power supply to be used for multiple strings. The general method is as shown in Figure 2. The power cable is pulled from the output of the rectifier bridge and the cathode of the last LED of the previous string. An electrical connector, the next string of strings is connected to the electrical connector via another electrical connector that is adapted to obtain power. This type of light string is limited by the power of the rectifier bridge, and the number of strings that can be connected in series is also limited. Another method is shown in Figure 3. The power lines from the two AC input terminals of the rectifier bridge are respectively connected to the electrical connector to provide power for the next string of lights, and then the electrical connector is inserted into another suitable electrical connection. The device draws AC power, connects to another rectifier bridge, and then accesses the next string of lights. The light string is solved because the power supply of each string of lights is rectified by the respective rectifier bridges, which solves the problem that the number of strings is limited by the power of the rectifier bridge, but since the power of each string passes through the power line Introduced from the AC input end of the previous string of lights, so that the length of the entire string is increased by two power lines. Since the wires are more expensive, the strings have a certain length, and the addition of two wires greatly increases the number of lights. The cost of the string.

There is a more wire-saving method. As shown in Figure 4, the rectifier circuit uses a double-half-wave rectifier circuit. The output of the double-half-wave rectifier circuit is connected to the positive terminal of an LED lamp group. The negative terminal of the LED lamp group. The two sets of half-wave ripple rectification voltages are obtained by connecting the resistors of the respective load circuits to the two ends of the alternating current, so that the LED lamp sets and resistors connected to the common output ends of the double half-wave rectifier circuits are obtained. When the LED string is connected in multiple strings, in the length direction of each string, except for the two power lines that introduce AC power, there is only one power line connecting the LED string as the output circuit of the rectifier circuit, and the length direction Saves on one power cord, which reduces costs. However, this circuit has the disadvantage that the two resistors and the AC power source have formed a loop, and the resistor generates a large amount of heat and consumes a large amount of power. And such an LED string, when the number of LEDs in a string of LED strings is too large, the LED often fails to work due to the voltage drop. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved LED light string that consumes less power and can be connected more LEDs.

The technical solution of the present invention is as follows: an improved LED light string, comprising at least one set of double half-wave rectifying circuits and at least one set of LED lamp sets whose positive ends are connected to a common output end of the corresponding double half-wave rectifying circuit, An impedance element is connected between the positive terminal of the rectifier of the double half-wave rectifier circuit and the AC power source, and a diode is connected in series with the opposite ends of the LED lamp group and the AC power supply in the same polarity direction.

A common set of the above LEDs is connected to a common output of each of the above-mentioned double half-wave rectifier circuits.

Common output terminal each said double half-wave rectifying circuit is connected to two sets of the LED lamp set ₀

The positive terminals of the respective diodes are respectively connected to the negative terminals of the LED groups of the respective groups, and the negative terminals of the respective diodes are respectively connected to the two ends of the AC power source through resistors.

The double half-wave rectifying circuit has a complex array, and a pair of LED lamps connected to a common output end of the next set of double half-wave rectifying circuits and a set of LED lamps connected to a common output end of the last set of double half-wave rectifying circuits The negative terminals of the group are connected, and a diode is connected in series with the same polarity direction between the negative terminal of the other LED lamp group connected to the common output end of the next set of double half wave rectifier circuits and the two ends of the AC power source.

The two output ends of the above AC power source are respectively led to an electrical connector through a power line. The above electrical connector is an electrical socket.

After adopting the above scheme, an improved LED string of the present invention uses a resistor to reduce voltage and current limit for each half wave, thereby reducing heat generated by the resistor, thereby saving power and reducing production cost. Moreover, the four resistors corresponding to each group of LED lamps can be connected to the same input end of the AC power source, and the structure is compact and the volume is small, thereby further saving cost. In the present invention, a plurality of double half-wave rectifying circuits can be disposed in one LED string, so that when there are multiple sets of LED lamp groups in each string, there is still enough voltage and current for each LED to work. Compared with the prior art, the present invention has the characteristics of low power consumption, low cost, and a large number of connectable LEDs. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a circuit schematic of a conventional one.

Figure 2 is a schematic circuit diagram of the second item.

Figure 3 is a circuit schematic of the third item.

Figure 4 is a circuit schematic of the fourth item. FIG. 5 is a schematic circuit diagram of a first embodiment of the present invention.

FIG. 6 is a schematic circuit diagram of a second embodiment of the present invention.

Fig. 7 is a circuit schematic diagram of a third example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an improved LED light string of the present invention is shown in FIG. 5, including diodes VD1, VD2, rectifiers VD3, VD4, resistors R1, R2, R3, R4, and a plurality of light-emitting diodes D1- The LED lamp group 1 in which Dn is serially connected in the same polarity direction, and the electric socket P1. One end of the AC power supply is respectively connected to one end of the resistors R1 and R3, and the other ends of the resistors R1 and R3 are respectively connected to the negative end of the diode VD1 and the positive end of the rectifier VD3; the other end of the AC power supply is respectively connected to one end of the resistors R2 and R4 The other ends of the resistors R2 and R4 are respectively connected to the negative terminal of the diode VD2 and the positive terminal of the rectifier VD4; the positive terminal of the diode VD1 and the positive terminal of the diode VD2 are commonly connected to the negative terminal of the LED D1, and the negative terminal of the rectifier VD3 The negative terminal of the rectifier VD4 is connected in common to the positive terminal of the light emitting diode Dn. Both ends of the AC power source are respectively connected to the two input terminals of the electrical socket P1.

In the working of this embodiment, if the alternating current is in the first positive half cycle, the output end of the alternating current is positive, the end b is negative, the rectifier VD3 and the diode VD2 are turned on, and the current is passed from the output end of the alternating current through the resistor R3. The rectifier VD3, the LED lamp group 1, the diode VD2, the resistor R2 and the output terminal b of the alternating current form a loop, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 1. When the second half cycle (negative half cycle) comes, the output terminal of the alternating current is negative, the b terminal is positive, the rectifier VD4 and the diode VD1 are turned on, and the current flows from the output terminal b of the alternating current through the resistor R4 and the rectifier VD4. The LED lamp group 1, the diode VD1, the resistor R1 and the output end of the alternating current terminal a form a loop, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 1. By repeating this, a double-half-wave pulsating rectification voltage is obtained on the LED lamp group 1, and the LED lamp group 1 does not flicker when it emits light, thereby prolonging its service life.

A second embodiment of an improved LED light string of the present invention is shown in FIG. 6 and includes diodes VD1, VD2, VD5, VD6, rectifiers VD3, VD4, resistors R1, R2, R3, R4, R5, R6, LED light group 1 in which light-emitting diodes D1_Dn are sequentially connected in the same polarity direction, LED light group 2 which is formed by sequentially connecting several light-emitting diodes Dn+1-Dm in the same polarity direction, and electric socket P1 One end of the AC power supply is respectively connected to one end of the resistors R1, R3, and R5', and the other ends of the resistors R1, R3, and R5 are respectively connected to the negative terminal of the diode VD1, the positive terminal of the rectifier VD3, and the negative terminal of the diode VD5; The other end of the power supply is respectively connected to one end of the resistors R2, R4, and R6, and the other ends of the resistors R2, R4, and R6 are respectively connected to the negative terminal of the diode VD2, the positive terminal of the rectifier VD4, and the negative terminal of the diode VD6; the positive terminal of the diode VD1 The positive terminal of the diode W2 is connected to the negative terminal of the LED D1, and the negative terminal of the rectifier VD3 and the negative terminal of the rectifier VD4 are connected to the positive terminal of the LED Dn and the positive terminal of the LED Dn+1. The positive terminal of the VD5 and the positive terminal of the diode VD6 are commonly connected to the negative terminal of the LED Dm, and are connected at both ends of the AC power supply to the two input terminals of the electrical socket P1.

In the working of this embodiment, if the alternating current is in the first positive half cycle, the output end of the alternating current is positive, the end b is negative, the rectifier VD3, the diode VD2 and the diode VD6 are turned on, and the current is from the output end of the alternating current a. A circuit is formed through the resistor R3, the rectifier tube VD3, the LED lamp group 1, the diode VD2, the resistor R2 and the output terminal b of the alternating current, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 1; meanwhile, the current is output from the alternating current terminal a The terminal forms a loop through the resistor R3, the rectifier VD3, the LED lamp group 2, the diode VD6, the resistor R6 and the output terminal b of the alternating current, and obtains a half-wave rectified voltage on the loop of the LED lamp group 2. When the second half cycle (negative half cycle) comes, the output end of the alternating current is negative, the b terminal is positive, the rectifier VD4, the diode VD1 and the diode VD5 are turned on, and the current flows from the output terminal b of the alternating current through the resistor R4, The rectifier tube VD4, the LED lamp group 1, the diode VD1, the resistor R1 and the output end a of the alternating current form a loop, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 1; at the same time, the current passes from the output end b of the alternating current The resistor R4, the rectifier VD4, the LED lamp group 2, the diode VD5, the resistor R5 form a loop with the output end a of the alternating current, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 2. By repeating this, a double half-wave ripple rectification voltage is obtained on the LED lamp group 1 and the LED lamp group 2, respectively.

A third embodiment of an improved LED light string of the present invention is shown in FIG. 7 and includes diodes VD1, VD2, VD5, VD6, VD9, VD10, rectifiers VD3, VD4, VD7, VD8, resistors Rl, R2, R3, R4, R5, R6, R7, R8, R9, RI O, LED lamp group 1 which is formed by sequentially connecting a plurality of light-emitting diodes D1-Dn in the same polarity direction, and is composed of a plurality of light-emitting diodes Dn+1-Dm The LED lamp group 2 in which the same polarity direction is serially connected in series, the LED lamp group 3 which is formed by sequentially connecting a plurality of light-emitting diodes Dm+1-Dx in the same polarity direction, and a plurality of light-emitting diodes Dx+1- Dy LED lamp group 4 which is connected in series with the same polarity direction, and electric socket PL. One end of the AC power supply is respectively connected to one end of the resistors R1, R3, R5, R7, R9, and the resistors Rl, R3, R5, R7 The other end of the R9 is connected to the negative terminal of the diode VD1, the positive terminal of the rectifier VD3, the negative terminal of the diode VD5, the positive terminal of the rectifier VD7, and the negative terminal of the diode VD9; the other end of the AC power source is connected to the resistors R2 and R4, respectively. , one end of R6, R8, RI O, resistors R2, R4, R6, R8 The other end of the RI O is respectively connected to the negative terminal of the diode VD2, the positive terminal of the rectifier VD4, the negative terminal of the diode VD6, the positive terminal of the rectifier VD8, and the negative terminal of the diode VD10; the positive terminal of the diode VD1 and the positive terminal of the diode VD2. Connected to the negative terminal of the LED D1, the negative terminal of the rectifier VD3 and the negative terminal of the rectifier VD4 are connected to the positive terminal of the LED Dn and the positive terminal of the LED Dn+1, the positive terminal of the diode VD5 and the diode VD6. The positive terminal is commonly connected to the negative terminal of the LED Dm and the negative terminal of the LED Dm+1, and the negative terminal of the rectifier VD7 and the negative terminal of the rectifier VD8 are commonly connected to the positive terminal of the LED Dx and the LED Dx+1. The positive terminal of the diode VD9 and the positive terminal of the diode VD10 are connected together to emit light. The positive terminal of diode Dy. Both ends of the AC power source are respectively connected to the two input terminals of the electrical socket PI.

In the working of this embodiment, if the alternating current is in the first positive half cycle, the output end of the alternating current is positive, and the end b is negative, and the rectifier VD3, the diode VD2, the diode VD6, the rectifier VD7 and the diode VD10 are turned on, current From the output end a of the alternating current, a loop is formed through the resistor R3, the rectifier VD3, the LED lamp group 1, the diode VD2, the resistor R2 and the output end b of the alternating current, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 1; The current is formed from the output end of the alternating current through the resistor R3, the rectifier VD3, the LED lamp group 2, the diode VD6, the resistor R6 and the output terminal b of the alternating current to form a loop, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 2; The current is formed from the output end of the alternating current through the resistor R7, the rectifier VD7, the LED lamp set 3, the diode VD6, the resistor R6 and the output end b of the alternating current to form a loop, and a half-wave rectified voltage is obtained on the loop of the LED lamp set 3; At the same time, the current flows from the output terminal a of the alternating current through the resistor R7, the rectifier VD7, the LED lamp group 4, the diode VD10, the resistor R10 and the alternating current The b-side of the output forms a loop, and a half-wave rectified voltage is obtained on the LED lamp set 4 loop. When the second half cycle (negative half cycle) comes, the output terminal of the alternating current is negative and the b terminal is positive. The rectifier VD4, the diode VD1, the diode VD5, the rectifier VD8 and the diode VD9 are turned on, and the current is output from the alternating current. The terminal b terminal forms a loop through the resistor R4, the rectifier tube VD4, the LED lamp group 1, the diode VD1, the resistor R1 and the output end a of the alternating current, and obtains a half-wave rectified voltage on the loop of the LED lamp group 1; meanwhile, the current is from The output terminal b of the alternating current forms a loop through the resistor R4, the rectifier VD4, the LED lamp group 2, the diode VD5, the resistor R5 and the output terminal a of the alternating current, and a half-wave rectified voltage is obtained on the loop of the LED lamp group 2. At the same time, the current is formed from the output terminal b of the alternating current through the resistor R8, the rectifier VD8, the LED lamp group 3, the diode VD5, the resistor R5 and the output end of the alternating current terminal a, forming a loop on the LED lamp group 3 loop. Rectifying voltage; At the same time, the current is formed from the output terminal b of the alternating current through the resistor R8, the rectifier VD8, the LED lamp group 4, the diode VD9, the resistor R9 and the output end of the alternating current terminal a, forming a loop on the LED lamp group 4 loop. A half-wave rectified voltage is repeated in this way, and a double-half-wave ripple rectification voltage is obtained on the LED lamp group 1, the LED lamp group 2, the LED lamp group 3, and the LED lamp group 4, respectively.

The above three embodiments are merely illustrative of the present invention and are not intended to limit the scope of the present invention. If the present invention does not consider the line loss problem, each string of strings may be provided with an infinite set of LED light groups, that is, connectable The number of LEDs is not limited.

Claims

Rights request

1 . An improved LED light string, comprising at least one set of double half-wave rectifying circuits and at least one set of LED lamp sets whose positive ends are connected to a common output end of the corresponding double half-wave rectifying circuit, characterized in that: the double half wave An impedance element is connected between the positive terminal of the rectifier of the rectifier circuit and the AC power source, and a diode is connected in series between the negative terminal of the LED lamp group and the two ends of the AC power source in the same polarity direction.

2. A modified LED light string as claimed in claim 1, characterized in that: a common set of said LEDs is connected to a common output of said set of said double half-wave rectifier circuits.

3. A modified LED light string according to claim 1, wherein: a plurality of said LED lamp groups are connected to a common output of each of said double half-wave rectifier circuits.

4. The improved LED light string according to claim 2 or 3, wherein the positive ends of the respective diodes are respectively connected to the negative ends of the LED groups of the respective groups, and the negative ends of the respective diodes are respectively Connect to both ends of the AC power supply through resistors.

5. A modified LED light string according to claim 1 or 3, wherein: said double half-wave rectifying circuit has a complex array and is connected to a group of LEDs at a common output of the next set of double half-wave rectifying circuits The negative terminal of the lamp group is connected to the negative terminal of a group of LED lamp groups connected to the common output end of the previous set of double half-wave rectifier circuits, and the other group of LED lamps connected to the common output end of the next set of double half-wave rectifier circuits A diode is connected in series between the negative terminal of the group and the two ends of the AC power source in the same polarity direction.

6. The improved LED light string of claim 1, wherein: the two output ends of the AC power source are respectively led to an electrical connector through a power line.

7. A modified LED light string as claimed in claim 1 wherein: said electrical connector is an electrical socket.