TWI468074B - AC LED lights - Google Patents

Description

AC LED light

The invention relates to an alternating current type LED lamp, in particular to a circuit for driving an LED lamp by using an alternating current power source, and using a switching element and a voltage detecting circuit, thereby increasing the efficiency of using the LED and avoiding burning of the LED or reducing the service life.

According to the conventional LED, the LED has the advantages of shortness, lightness, long life, high efficiency, etc. Therefore, the white LED is regarded as the main illumination source of the next generation, but the LED is a semiconductor component that is driven by the current (DC), and must be driven by direct current, so The general AC (AC) mains must first be converted to DC, and the AC to DC converter is bulky and heavy, not only increases the cost, but also consumes power and cannot compete with the price of existing light sources. The scope and popularity are limited. Therefore, the team of the Institute of Optoelectronics of the Industrial Technology Research Institute broke through the problems of AC and DC conversion. Using the packaging technology to directly drive the LED chips with AC power, the world's first AC LED bulb was developed. Known bridge rectifiers, as shown in Figure 11, consist of four diodes (A). When the AC is in the positive half-wave, the upper left and lower right diodes (A) are turned on. When the current flows into the load and the alternating current is in the negative half-wave, the upper right and lower left two diodes (A) are turned on, and the current still flows from top to bottom into the load, and As shown in the twelfth picture, the team of the Institute of Optoelectronics of the Institute of Technology has changed the original four diodes (A) on the bridge rectifier to four sets of multiple LEDs (B), plus the load is also a series of strings. Connected to the LED (B), a total of five sets of multiple LEDs (B) are packaged together, and become an AC LED (B). When the AC is in the positive half-wave, the upper left And the lower right two groups of LEDs (B) are turned on, the current flows from top to bottom into the load end group of LEDs (B), and when the alternating current is in the negative half wave, the upper right and lower left two sets of LEDs (B) are turned on, and the current is still from above. A group of LEDs (B) flowing into the load end, compared with the DC LED (B), the AC LED (B) developed by ITRI does not require a rectifier transformer, which reduces the size and weight of the LED (B) and improves the application space. The cost of the converter component is reduced, and the power consumption of the LED (B) in the past between DC and AC is 15% to 30%, which improves the luminous efficiency of the overall LED (B).

However, its disadvantages are:

Conventional LEDs can only illuminate in part of the half cycle (positive half cycle or negative half cycle) of AC power, so if the LED is only turned on and illuminated for part of each cycle, the efficiency of its use. Lower, and when the voltage across the LED exceeds the LED withstand voltage, the LED will burn out, or although the voltage across the LED does not exceed the LED withstand voltage, but the voltage across the LED is too high, which will cause high temperature, and thus the LED Burnt or greatly reduced service life.

Therefore, in view of the absence of the conventional AC LED, the present invention provides an AC LED lamp comprising: a first circuit, the first circuit is provided with at least one LED, and the LED is connected in series with a switching element, A voltage detecting circuit is further connected to the two ends of the first circuit. The voltage detecting circuit further includes an AC power source electrically connected to the first circuit, and the AC power source is used to provide a power source of the first circuit.

The first circuit can be connected in series with a control unit, and the control unit is a control circuit or a protection circuit for controlling the amount of current of the first circuit to prevent the LED from being burned due to excessive current flow through the LED.

The method further includes a second circuit in parallel with the first circuit, the second circuit includes at least one LED, and the LED is connected in series with a switching element, and the second circuit includes a voltage detecting circuit connected in parallel on the second circuit. The LED and the switching element, and the polarity of the LED in the first circuit is opposite to the polarity of the LED in the second circuit.

The above system includes at least two or more combinations of the first circuit and the second circuit in parallel.

The first circuit and the second circuit are respectively connected in series with one of the control units, and each of the control units is a control circuit or a protection circuit for respectively controlling the amount of current of the first circuit and the second circuit.

The above switching element is an electronic switching element or an electromechanical switching element.

Another feature of the present invention includes: four first circuits and an AC power source, wherein the AC power source is electrically connected to the four first circuits to form a bridge rectifier, and in any two adjacent firsts. The circuit is not connected to the AC power source to form two nodes, the first circuit is respectively provided with at least one LED, and the LEDs of each of the first circuits are respectively connected in series with a switching element, and each of the first circuits respectively includes a voltage detecting circuit The LEDs and the switching elements of the first circuit are connected in parallel; a load end is electrically connected to the two nodes.

The load terminal includes at least one third circuit, the third circuit includes at least one LED having a polarity opposite to that of the LED in the first circuit, and the LED is connected in series with a switching element, and the third circuit is An LED and a switching element including a voltage detecting circuit connected in parallel to the third circuit are included.

The third circuit is connected in series with a control unit, and the control unit is a control circuit or a protection circuit for controlling the amount of current of the third circuit.

The above switching element is an electronic switching element or an electromechanical switching element.

The advantages of the invention are:

1. The LED of the invention does not need to use a rectifier transformer, and has small volume and low cost, which improves the application range.

2. In the era of energy crisis and high environmental protection appeal, the invention improves the luminous efficiency of the overall LED by saving the power loss of the conversion between the direct current transformer and the alternating current in the past.

3. The invention provides a switching element and a voltage detecting circuit on the first circuit, the second circuit and the third circuit, in order to prevent the voltage from exceeding the LED withstand voltage and thereby causing the LED to burn out, or, although not exceeding the LED withstand voltage, The high voltage generated by the LED is too high to cause the LED to burn out or the service life is greatly reduced.

4. The present invention uses the same number of LEDs of the same type as the conventional AC LEDs, but a relatively large luminance of the conventional AC LED can be obtained.

(1)‧‧‧First circuit

(11)‧‧‧LED

(12)‧‧‧Switching elements

(2) ‧ ‧ voltage detection circuit

(3) ‧ ‧ AC power supply

(4) ‧‧‧second circuit

(5) ‧‧‧Control unit

(6) ‧‧‧Load end

(61)‧‧‧ Third circuit

(A) ‧ ‧ diodes

(B)‧‧‧LED

The first figure is a circuit diagram of an LED of the present invention.

The second (a) diagram is a circuit diagram of the four LEDs of the present invention.

The second (b) diagram is a schematic diagram of the switch switching of the present invention.

The third figure is a diagram of the first embodiment of the present invention.

The fourth figure is a diagram of a second embodiment of the present invention.

The fifth drawing is a diagram of a third embodiment of the present invention.

The sixth drawing is a diagram of a fourth embodiment of the present invention.

The seventh drawing is a diagram of a fifth embodiment of the present invention.

The eighth figure is a time relationship diagram of light intensity discontinuous light intensity in the fourth embodiment of the present invention.

The ninth figure is a light intensity continuous time of the fourth embodiment of the present invention Diagram.

The tenth figure is a three-stage light intensity time relationship diagram of the present invention.

The eleventh figure is a circuit diagram of a conventional bridge rectifier.

The twelfth figure is a conventional modified AC LED circuit diagram.

The present invention is an AC LED lamp comprising: a first circuit (1) in the present embodiment, which is clearly described in conjunction with the preferred embodiments of the present invention. In the example, the first circuit (1) is provided with four LEDs (11) and is provided with a switching element (12), which is connected in series to the second LED (11) and the third Between the LEDs (11), the switching element (12) may be an electronic switching element, and the electronic switching element may be composed of two bipolar transistors (BJT) or two field effect transistors (FETs). Forming an open-close type switch, or alternatively, an electromechanical switching element with a fast switching speed, and a voltage detecting circuit (2) connected in parallel across the first circuit (1), the voltage detecting circuit (2) is for controlling the switching state (on or off) of the switching element (11), that is, the voltage detecting circuit (2) is for controlling the switching state of the switching element (11), thereby turning on the first And the second LED (11) emits light or turns on all of the first to fourth LEDs (11), and the voltage is detected. (2) is a voltage dividing circuit or other voltage dividing circuit that may include a resistor, and the voltage detecting circuit (2) further includes an AC power source (3) electrically connected to the first a circuit (1) for supplying a power source of the aforementioned first circuit (1), and a second circuit (4) connected in parallel to the first circuit (1), in this embodiment, Second circuit (4 There are also 4 LEDs (11), and the switching element (12) is also connected in series between the second LED (11) and the third LED (11), and in the second circuit (4) A voltage detecting circuit (2) is also connected in parallel with the terminal, and the voltage detecting circuit (2) is also used to control the switching state (on or off) of the switching element (11), that is, the voltage detecting circuit (2) is used. Controlling a switching state of the switching element (11), and a control unit (5) may be connected in series in the first circuit (1), and the control unit (5) is a control circuit or a protection circuit, wherein the control The main purpose of the unit (5) is to control the amount of current of the first circuit (1) to ensure that the amount of current flowing through the LED (11) in the circuit is not excessive and the LED (11) is burned, the switching element (12) ) can also be an electronic switching element or an electromechanical switching element, wherein the polarity of the LED (11) in the first circuit (1) is opposite to the polarity of the LED (11) in the second circuit (4), When the circuit is turned on to form a loop, when the AC input is in the positive half cycle or the negative half cycle, the entire circuit can be looped and the LED (11) can be illuminated, and The first circuit (1) and the second circuit (4) are respectively connected in series with the control unit (5), and each of the control units (5) can be a control circuit or a protection circuit for respectively controlling the first circuit ( 1) and the amount of current of the second circuit (4) to ensure that the amount of current flowing through the LED (11) in the circuit is not excessively large to cause the LED (11) to burn out, and in the above circuit, a first circuit can be further provided (1) And a second circuit (4) is a parallel connection of a group of circuits.

In use, please refer to the second (a) diagram and the second (b) diagram, the voltage detection circuit (2) can detect the voltage across the LED (11) on the circuit, when the voltage detection circuit (2) When detecting the voltage across the LED (11) on the circuit, if the input AC voltage is large enough to turn on the first and second LEDs (11), the turn-on voltage value is not large enough to make the first one When the fourth LED (11) is all turned on, at this time, the switching element (12) is not connected to the third LED (11) to form a loop. Will flow through the first and second LEDs (11) to cause the LED (11) to emit light; if the voltage detecting circuit (2) detects that the voltage across the LEDs (11) on the circuit is large enough to make the first When all of the fourth LEDs (11) are turned on, the switching element (12) is connected to the third LED (11) to form a loop, and the current flows through all the LEDs (11), thereby All four LEDs (11) are illuminated.

Furthermore, referring to the third figure, in this embodiment, the alternating current power source (3) is connected in parallel with the first circuit (1) and the second circuit (4). When the alternating current is input, the positive half wave of the alternating current is Or a negative half wave will form a loop via the first circuit (1) or the second circuit (4), thereby causing the LED (11) to emit light.

Furthermore, referring to the fourth figure, in this embodiment, the first circuit (1) and the second circuit (4) may be respectively connected in series with a control unit (5), and the control unit (5) is a control circuit or a protection circuit for controlling the amount of current of the first circuit (1) and the second circuit (4) to ensure that the amount of current flowing through the circuit is not excessively large and the life of the LED (11) is reduced. Even burned.

Furthermore, please refer to the fifth figure. In this embodiment, the first circuit (1) and the second circuit (4) of the two groups are sequentially connected in parallel, and the first circuit (1) And the second circuit (4) can be further connected to the foregoing control unit (5), wherein the control unit (5) controls the amount of current of the first circuit (1) and the second circuit (4) to ensure that the circuit is in the circuit. The amount of current is not too large to burn the LED (11). The two groups (the first circuit and the second circuit) are arranged in parallel to ensure that if any of the LEDs in the circuit are burned, there is no need to worry about affecting the entire circuit. action.

In addition, when using, please refer to the sixth figure, the present invention is an AC type LED lamp, comprising four aforementioned first circuits (1) and a load end (6). In this embodiment, the A circuit (1) is also provided with four LEDs (11), and a switching element (12) is connected in series between the second LED (11) and the third LED (11), and And the voltage detecting circuit (2) and the alternating current power source (3) are connected in parallel at both ends of the first circuit (1), and the alternating current power source (3) is electrically connected to the four first circuits (1) to form a bridge. a type of rectifier, the aforementioned AC power source (3) and providing a power source for the entire circuit, and the load terminal (6) includes at least one third circuit (61), the third circuit (61) is provided with at least one LED (11), in this embodiment, the third circuit (61) is provided with four LEDs (11), the polarity of the LED (11) in the third circuit (61) and the first circuit (1) The LED (11) has the opposite polarity and the same polarity as the LED (11) in the second circuit (4), and a switching element is connected in series between the second LED (11) and the third LED (11) ( 12), and the voltage detecting circuit (2) is connected in parallel at both ends of the third circuit (61), wherein the third circuit (61) may also be connected in series with a control unit (5), the control unit (5) Is a control circuit or a protection circuit, thereby controlling the amount of current of the third circuit (61) to ensure that the amount of current in the circuit is not excessively large and the LED (11) is burned, wherein the switching element (12) can also The above-mentioned electronic switch element Or an electromechanical switching element, and the third circuit (61) can be connected in series with a control unit (5), which is a control circuit or a protection circuit, thereby controlling the third circuit (61) Electricity flow.

Furthermore, referring to the seventh figure, in this embodiment, a plurality of load terminals (6) are connected in parallel in the previous embodiment, and the load terminals (6) are connected in series by a third circuit (61). A control unit (5) is formed. In addition, in the previous embodiment, a plurality of sets of load terminals (6) may be connected in parallel with the bridge rectifier type circuit, and the load terminal (6) includes the foregoing third circuit. (61), and the aforementioned control unit (5) may be connected in series on the plurality of sets of load terminals (6) to control the amount of current flowing through the circuits thereof.

Furthermore, please refer to the eighth and ninth diagrams. Since the current passes through any of the LEDs (11), a voltage drop V is generated. If there are n LEDs (11) in series, Then, when the voltage of the LED of the group is greater than n times the voltage of the LED (11), a large enough current flows, and since the LED (11) is a current-driven component, the luminous intensity (or The luminance of the light is increased as the current increases, that is, the LED (11) on the AC LED lamp is conductive only during part of each cycle of the alternating current. Taking the fourth embodiment of the circuit of the sixth figure as an example, the peak value of the mains must be greater than 3 n times of the LED (11) voltage to enable the LED (11) to illuminate after being connected to the market, that is, to connect too many LEDs in series ( 11), the LED (11) will not emit light, but if the voltage drop of each LED (11) is too large (ie, the peak of the mains is much larger than the LED (11) voltage of 3n times), it means the LEDs connected in series ( 11) The number is too small, the LED (11) may be burned because the input voltage exceeds the voltage of the LED (11), and the n LEDs (11) can be divided on the circuit by the electronic switch. Two segments, one segment is m LEDs (11), one segment is nm LEDs (11), when the electronic switch on the circuit sets the control voltage to be m times the LED (11) voltage drop and n times the LED (11) The pressure drop, the total light intensity will be discontinuous, but the two-stage illumination is more than the original AC LED circuit, so the average output light intensity will increase, and because of the persistence of human vision, Therefore, it does not cause discomfort to the human eye when the user distinguishes, but if the switching element (12) is set to the second stage control voltage is changed from n times the LED (11) voltage drop to n times the LED (11) voltage Drop plus 2 of a second LED (11) at a large current after the increase in the pressure drop, it LED (11) total light intensity emitted from the circuit to obtain the best performance.

Another embodiment, as shown in the tenth embodiment, differs from the previous embodiment in that if the original set of LEDs (11) is divided into three segments, the alternating current power source (3) is discharged at a half cycle voltage. The relationship between the light intensity and the brightness of the same LED (11) is also increased.

(1)‧‧‧First circuit

(11)‧‧‧LED

(12)‧‧‧Switching elements

(2) ‧ ‧ voltage detection circuit

(3) ‧ ‧ AC power supply

(5) ‧‧‧Control unit

(6) ‧‧‧Load end

(61)‧‧‧ Third circuit

Claims (10)

An AC LED lamp includes: a first circuit, the first circuit includes at least one LED, and the LED is connected in series with a switching element, and the first circuit includes a voltage detecting circuit connected in parallel with the LED and the switching element, The first circuit is connected in series with a control unit, and the control unit is a control circuit or a protection circuit, thereby controlling the amount of current of the first circuit, and further comprising a second circuit in parallel with the first circuit, the second circuit system Included in the at least one LED, and the LED is connected in series with a switching element, the second circuit includes an LED and a switching element having a voltage detecting circuit connected in parallel on the second circuit, and the polarity of the LED in the first circuit is opposite to the second The LEDs in the circuit are of opposite polarity; an AC power source is electrically connected to the first circuit to provide a power source for the first circuit. The AC LED lamp of claim 1, wherein the first circuit and the second circuit respectively comprise N LEDs, wherein the first circuit includes at least two intervals. One of the sections includes M LEDs, the other section includes NM LEDs, and the second circuit includes at least two sections, one section including M LEDs and the other section including NM LEDs. The light intensity of the LED output is increased by setting the voltage drop of the switching element. The AC LED lamp of claim 1, comprising at least two or more combinations of the first circuit and the second circuit in parallel. The AC LED lamp of claim 3, wherein the first circuit and the second circuit are respectively connected in series with one of the control units, and each of the control units is a control unit. A circuit or a protection circuit for controlling the amount of current of the first circuit and the second circuit, respectively. The AC LED lamp of claim 1, wherein the switching element is an electronic switching element or an electromechanical switching element. An AC LED lamp includes: four first circuits and an AC power source, wherein the AC power source is electrically connected to the four first circuits to form a bridge rectifier, and in any two adjacent firsts The circuit is not connected to the AC power source to form two nodes, the first circuit is respectively provided with at least one LED, and the LEDs of each of the first circuits are respectively connected in series with a switching element, and each of the first circuits respectively includes a voltage detecting circuit The LEDs and the switching elements of the first circuit are connected in parallel; a load end is electrically connected to the two nodes. The AC LED lamp of claim 6, wherein the load end includes at least one third circuit, the third circuit includes at least one LED, the polarity of the LED and the polarity of the LED in the first circuit In contrast, the LED is connected in series with a switching element, and the third circuit includes an LED and a switching element having a voltage detecting circuit connected in parallel to the third circuit. The AC LED lamp of claim 7, wherein the third circuit is connected in series with a control unit, and the control unit is a control circuit or a protection circuit for controlling the amount of current of the third circuit. The AC LED lamp of claim 7, wherein the first circuit and the third circuit respectively comprise N LEDs, wherein the first circuit includes at least two intervals. One of the sections includes M LEDs, the other section includes NM LEDs, and the second circuit includes at least two sections, one section including M LEDs and the other section including NM LEDs. By setting the switching element The voltage drop increases the intensity of the light output by the LED. The AC LED lamp of claim 6, wherein the switching element is an electronic switching element or an electromechanical switching element.