TW201608928A - AC driving device of LED - Google Patents

Abstract

The present invention relates to an LED driving device which can be directly driven by an AC power source. By adjusting the series connection and parallel connection types of plural sets of LED light strings with plural kinds of total conduction voltages, the plural sets of LED light strings can be simultaneously turned on at high and low voltage parts of the AC power source. Such a design not only increases the utilization rate of LED when being directly driven by the AC power source and promotes the use efficiency of power source, but also allows the plural sets of LED light strings to have identical period, so as to reduce the complexity of circuit layout.

Description

Light-emitting diode AC drive

The device is a light-emitting diode driving device capable of directly driving an AC power source, and is configured to adjust a series and a parallel connection manner of a complex array light-emitting diode lamp string having a plurality of kinds of total conduction voltages, so that the complex array light-emitting diode lamp string At the same time, the high and low parts of the AC power supply voltage can be turned on at the same time. This design not only enhances the use of the LED when driven directly by AC voltage, but also improves the performance of the power supply. It also allows the LED arrays of the entire array to have the same period. More importantly, it can reduce the complexity of circuit layout, and is more convenient for circuit layout design and product production.

The high-voltage AC power supply of the commercial power supply is not stepped down to a stable low-voltage DC power supply to drive the light-emitting diodes, but the light-emitting diode device directly driven by the AC power supply voltage of the commercial power is the most direct method. Figure 1 shows. The input AC voltage is converted into a pulsating DC voltage ( V ) through a bridge rectifier, and then the LED string is connected in series with the constant current circuit, and then the positive and negative (+/-) of the bridge rectifier The output is connected.

This design requires a string in order to absorb most of the voltage. A considerable number of light-emitting diodes are connected. Therefore, this LED string requires a relatively high voltage to allow the LED to conduct. In other words, this will make the duty cycle of the LED string become lower. In addition to the low duty cycle of the LED string, this connection has another serious problem: the total amount of illumination is also susceptible to changes in the AC supply voltage, as shown in Figure 2.

The current waveform in Fig. 2 is generated by the circuit shown in Fig. 1 when a light-emitting diode string having a high total on-voltage is used, wherein I is a current of a constant current circuit for driving the light-emitting diode. Waveform, V is the pulsating DC waveform after the AC power supply voltage passes through the bridge rectifier, and V _LED is the total turn-on voltage of the LED string.

When the AC power supply voltage changes, the peak value of the voltage waveform V also changes, but the value of the V _LED does not change. In the second voltage waveform V starting from the left of the first, second and third half cycles, each half cycle represents a waveform of the AC power source voltage at the highest, medium and lowest. Although the ratio of the peak values of the three waveforms is not much different, the difference in the conduction period in which the constant current circuit generates the steady current I is very large, and thus the total luminescence amount of the device is greatly different. That is to say, when the AC power source voltage fluctuates, the LED light-emitting device generates a flicker phenomenon.

In order to improve the duty cycle of the LED string and to stabilize the illumination of the LED string from the fluctuation of the AC power supply voltage, the simplest method is to reduce the total conduction voltage of the LED string. The current waveform of the method is shown in Figure 3. Similarly to Fig. 2, the first, second, and third half cycles of the voltage waveform V from the left indicate the highest, medium, and lowest half cycle waveforms of the AC power supply voltage, respectively. The ratio of the peaks of the three waveforms is also the same as in Fig. 2, but the difference in the conduction period of the steady current I generated by the current circuit is much smaller than the amount of change shown in Fig. 2. In other words, the lower the total on-voltage of the light-emitting diode string, the smaller the total amount of illumination is affected by the change in the AC supply voltage.

The opposite problem arises from the fact that the lower the total on-voltage of the LED string, the lower the power efficiency. In Figures 2 and 3, as long as the voltage is above the V _LED , it will fall on the constant current circuit instead of falling on the LED string, so the power consumption in these areas is redundant. of. Comparison of FIG. 2 and FIG. 3 can be found when the light emitting diode string turn-on voltage V always lower _{the LED,} the more will increase the area V _LED. In other words, the reactive power that is not generated in the LED string will increase, so the power efficiency will also decrease.

In order to simultaneously reduce the excess power consumption and improve the conduction period of the LED string, in order to improve the power efficiency and increase the usage rate of the LED string, there are such as the Republic of China Patent Publication No. 201037213 and the invention patent I397198. The practice was put forward. This type of design is to divide a single string of light-emitting diodes shown in FIG. 1 into a plurality of small light-emitting diode strings having the same total on-voltage. When the pulsating DC voltage values at the output of the bridge rectifier are different, the corresponding number of LED segments are respectively turned on. In order to obtain a suitable total on-voltage of the LED, thereby reducing the power consumption on the constant current circuit to improve the power efficiency.

Figure 4 is a simple example of this type of practice, only shown in Figure 1. A single string of light emitting diodes is divided into three fewer light emitting diode strings having the same total turn-on voltage. When the voltage is at the lowest range, the first switching circuit will be in the on state, directly grounding the lower group of the first group of LED strings, so only the first group of LED strings will be turned on, and the second The group of LED light strings and the third group of LED strings are not turned on. When the voltage is in the middle range, the first switching circuit will be in a non-conducting state, and the second switching circuit will be in the conducting state, directly grounding the second group of LED strings below, so only the first group The LED string is electrically connected to the second group of LED strings, and the third group of LED strings is not turned on. When the voltage is at the highest range value, the first and second switching circuits are in a non-conducting state, so that the three LED strings are turned on.

The waveform in Fig. 5 is the corresponding waveform generated in Fig. 4, where I is the current waveform of the constant current circuit driving the LED string, and V is the ripple DC waveform after the AC power voltage passes through the bridge rectifier. The V _LED is the total turn-on voltage of the LED string. Since the conduction state of the plurality of light-emitting diode strings varies with the change of the voltage, the value of the V _LED changes with the number of the light-emitting diode strings that are turned on. As can be seen from this waveform, the on-period of the light-emitting diode string can be greatly increased, and the voltage region above the V _LED becomes small. In other words, this type of practice not only improves the efficiency of the LED string, but also improves the efficiency of the power supply.

Although this type of method can improve the usage rate of the LED string and the power efficiency, different sections have different conduction periods. This will make the light-emitting diode strings of different passages have different illuminating conditions. This will cause the illuminator to have uneven illumination. In order to solve this problem, it is necessary to arrange all the light-emitting diodes in a complicated manner, so that the light-emitting diodes in the light-emitting diode strings of different passages are evenly distributed, so as to avoid illumination due to different conduction periods of different paragraphs. Uniform problems, such as the practice of the Republic of China invention patent I397198.

Therefore, if a variation of the pulsating direct current after the bridge rectifier is used, a series and parallel connection manner of the complex array light-emitting diode string conduction time having a plurality of total on-voltages can be proposed to allow the complex array of light-emitting diodes. The string can be turned on at the same time in the high and low voltage parts of the AC power supply voltage. This design not only improves the usage of the LED when driven directly by AC voltage, but also improves the performance of the power supply. It also allows the LED arrays of the entire array to have the same period. The complexity of the circuit layout can be reduced, thereby making the AC LED device more suitable for use in lighting applications.

The main purpose of the present invention is to provide a light-emitting diode string driving device that can be directly driven by an AC power source voltage, and to provide a series and parallel configuration of a plurality of LED strings having a plurality of total conduction voltages. In order to simultaneously improve the life cycle and power efficiency of the LED string.

To this end, the main purpose of this creation is to provide a series and parallel configuration of a light-emitting diode string that can be determined according to the instantaneous voltage level of the pulsating DC output from the AC power source after passing through the bridge rectifier. When the instantaneous voltage of the pulsating direct current is in the lower potential interval, the plurality of the plurality of total on-voltages are The series and parallel configuration of the LED strings is at a lower total on-voltage state, and each group has the same total on-voltage as the LED strings connected in series with the constant current circuit. When the instantaneous voltage of the pulsating DC is in the higher potential interval, the series and parallel configuration of the plurality of LED strings having a plurality of total on-voltages is in a state of a high total on-voltage, and also allows each A set of LED strings connected in series with a constant current circuit have the same total turn-on voltage.

Because the decision of the series and parallel configuration of the LED strings is based on the instantaneous voltage level of the pulsating DC output after passing through the bridge rectifier, it is independent of the operating frequency. Therefore, the LED driving device designed by using this technology can operate normally under the condition of 50 Hz, 60 Hz or a higher frequency power source generated by an electronic ballast or the like.

To achieve the above functions, the LED driving device of the present invention comprises the following parts:

1. Providing a light-emitting diode for illumination.

Second, the bridge rectifier, the purpose is to rectify the positive and negative alternating current into a pulsating direct current, in order to pass the same light-emitting diode string in both positive and negative half cycles, so that the use efficiency of the light-emitting diode string is improved.

Third, the constant current circuit, the purpose of which is to provide a stable driving current to the light emitting diode when the light emitting diode string is turned on.

Fourth, the switch circuit, its purpose is to determine the series and parallel configuration of a plurality of light-emitting diode strings.

5. Voltage detection circuit, monitoring the instantaneous voltage value of the AC power supply, in the instantaneous voltage value When the set voltage value condition is met, the "on" and "non-conducting" states of all the switch circuits are adjusted to adjust the series and parallel configuration of the plurality of LED strings. In order to obtain a suitable total on-voltage of the LED, thereby reducing the power consumption on the constant current circuit to improve the power efficiency.

100‧‧‧Lighting diode AC drive

101‧‧‧Bridge rectifier

102‧‧‧Lighting diode string

103‧‧‧Constant current circuit

104‧‧‧Switch circuit

105‧‧‧Voltage detection circuit

SW ₁ ‧‧‧first switch circuit

SW ₂ ‧‧‧Second switch circuit

SW ₃ ‧‧‧third switch circuit

SW ₄ ‧‧‧fourth switch circuit

SW ₅ ‧‧‧ fifth switch circuit

SW ₆ ‧‧‧ sixth switch circuit

SW ₇ ‧‧‧ seventh switch circuit

CC‧‧‧ constant current circuit

CC ₁ ‧‧‧First set of constant current circuits

CC ₂ ‧‧‧Second set of constant current circuits

CC ₃ ‧‧‧The third set of constant current circuits

CC ₄ ‧‧‧Fourth set of constant current circuits

LED _S1 ‧‧‧The first group of LED strings

LED _S2 ‧‧‧Second Group of Light-emitting Diode Light Strings

LED _S3 ‧‧‧The third group of LED light strings

LED _S4 ‧‧‧Fourth Group of Light-emitting Diode Light Strings

LED _S5 ‧‧‧Fifth Group LED Light String

LED _S6 ‧‧‧Sixth Group LED Light String

The first figure is a design in which the light-emitting diode string is connected in series with the constant current circuit and directly connected to the positive and negative ends of the rectifier output of the bridge rectifier.

The second figure is a voltage waveform V and a constant current circuit which are rectified and outputted via a bridge rectifier when the input AC power supply voltage is unstable when the LED light string having a high total on-voltage is connected in series with the constant current circuit. Generated drive current waveform I.

Figure 3 is a diagram showing a voltage waveform V and a constant current circuit that are rectified and outputted via a bridge rectifier when the input AC power supply voltage is unstable when a light-emitting diode string having a lower total on-voltage is connected in series with a constant current circuit. Generated drive current waveform I.

Figure 4 shows a three-stage LED with the same total on-voltage as a segmented conduction circuit.

Figure 5 is a diagram showing a voltage waveform V of a rectified output via a bridge rectifier and a voltage waveform V _LED on a light-emitting diode string in a circuit in which three LEDs of the same total on-voltage are used as a segmented conduction. The drive current waveform I generated by the constant current circuit.

Figure 6 is a first embodiment of the present invention.

Among the embodiments of FIG. 7 via the line voltage waveform V rectified output of the bridge rectifier and the voltage waveform V _LED on the light emitting diode lamp strings according to a first embodiment Creation.

Figure 8 is a second embodiment of the present invention.

Figure 9 is a third embodiment of the present creation.

Some exemplary embodiments for achieving the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different aspects without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used as the description of the case, rather than limiting the case. .

The circuit shown in FIG. 6 is the first embodiment of the creation. The LED driving device 100 of the embodiment includes a bridge rectifier 101, three constant current circuits 103, five switching circuits 104, and a circuit. The voltage detecting circuit 105, two sets of LED strings 102 having a small number of serial connections, and two sets of LED strings 102 having a plurality of serial numbers. The second group and the third group of LED strings 102 have fewer identical serial numbers, and the first group and the fourth group of LED strings 102 have more identical serial numbers. Moreover, the number of serial connections of the first group and the fourth group of LED strings 102 is twice that of the second group and the third group. In other words, the total turn-on voltage of the first and fourth sets of light-emitting diode strings 102 is twice that of the second and third groups.

Four sets of circuits are connected in parallel between the positive terminal and the negative terminal of the bridge rectifier 101, and the first group is the voltage detecting circuit 105. The second group is connected in series from top to bottom, which is a first group of LED strings 102, a first switching circuit 104, and a first constant current circuit 103. The third group is connected in series from top to bottom, which is a second group of LED strings 102, a third switching circuit 104, a third group of LED strings 102, and a second constant current circuit 103. The fourth group is connected in series from top to bottom in sequence, which is a fifth switch circuit, 104 fourth group of light-emitting diode strings 102 and third constant current circuit 103.

Between the first group of LED strings 102 in the second group and the third group of LED strings 102 in the third group of circuits, the second switch 104 is transmitted through the second switch 104. connected. As for the fourth switching circuit 104, there are two points above the second group of LED strings 102 in the third group of circuits and the fourth group of LED strings 102 in the fourth group of circuits. between. There are different control line connections between the voltage detecting circuit 105 and the five switching circuits 104.

After the LED driving device 100 is activated, the voltage detecting circuit 105 detects the pulsating DC voltage rectified by the AC power source via the bridge rectifier 101 regardless of the change of the AC power voltage.

When the pulsating DC voltage rises from 0V, since the voltage at this time falls within the lower voltage range, the voltage detecting circuit 105 sends a non-conducting control signal to the second and fourth switching circuits 104, and simultaneously A conduction control signal is also sent to the first, third, and fifth switching circuits 104. At this time, the first constant current circuit 103 is only connected in series with the first group of LED strings 102, and the third constant current circuit 103 is only connected in series with the fourth group of LED strings 102. The second constant current circuit 103 is connected through the turned-on third switching circuit 104 after the second group of LED strings 102 and the third group of LED strings 102 are connected in series. Since the total on-voltage of the first group and the fourth group of LED strings 102 is twice that of the second group and the third group, the light rays respectively connected to the first, second, and third constant current circuits 103 are respectively connected. The total turn-on voltage of the diode string 102 is the same. Therefore, the three constant current circuits 103 can start at the same voltage, so the four groups of LED strings 102 have the same on period.

When the pulsating DC voltage rises to a higher voltage range, the voltage detecting circuit 105 sends a conduction control signal to the second and fourth switching circuits 104, and also sends the first, third, and fifth switching circuits 104. The control signal that is turned on. At this time, the first constant current circuit 103 is not connected to any of the light-emitting diode strings 102 because the first switching circuit 104 is not turned on. Moreover, between the second group of LED strings 102 and the third group of LED strings 102, the third switch circuit 104 is also not connected due to non-conduction. As for the fifth switch circuit 104 above the fourth group of LED strings 102 is also in a non-conducting state, the fourth group of LED strings 102 are not connected to the positive terminal of the bridge rectifier 101. .

At this time, the second constant current circuit 103 is connected through the second switch circuit 104 that is turned on after the first group of LED strings 102 and the third group of LED strings 102 are connected in series. The third constant current circuit 103 is connected through the fourth switch circuit 104 that is turned on after the second group of LED strings 102 and the fourth group of LED strings 102 are connected in series.

Because the total turn-on voltage of the first group and the fourth group of LED strings 102 are the same, and the total on-voltage of the second group and the third group of LED strings 102 are also the same. Therefore, the total on-voltage of the light-emitting diode string 102 connected in series with the second and third constant current circuits 103 is also the same. Therefore, the two constant current circuits 103 can start at the same voltage, so the four groups of LED strings 102 have the same on period.

As can be seen from the above description, the conduction detection circuit 105 sets the guidance of the five switching circuits 104 in the circuit, whether it is below the lower or higher voltage range. In the state of conduction or non-conduction, the series and parallel states of the four groups of LED strings 102 can be changed, so that the four groups of LED strings 102 have the same conduction period. As long as the current values set by the three sets of constant current circuits 103 are the same, the four sets of light-emitting diode strings 102 will have the same light-emitting brightness. Therefore, this design can not only improve the LED usage rate, but also improve the efficiency of the power supply.

The waveform of Fig. 7 is obtained according to the above working principle. At a lower voltage, the total on-voltage of the LED string 102 connected in series with the fixed current circuit 103 is relatively low. At a higher voltage, since the total on-voltage of the LED string 102 connected in series with the fixed current circuit 103 is relatively high, the V _LED change as shown in FIG. 7 can be obtained. Waveform. Therefore, it is known that the design can detect the instantaneous value of the pulsating DC voltage after rectification by the bridge rectifier 101, thereby adjusting the series and parallel configuration of the LED string 102, thereby simultaneously improving the LED string 102 of the LED. Use efficiency and power efficiency.

Compared to the waveform in Figure 5, the waveform in Figure 7 shows that the power efficiency used in this design is only less than the area "1" and "5" in Figure 5, but the area of these two areas is small. , so the power efficiency is not much reduced. However, the design of Figure 5, such as the Republic of China invention patent I397198, has a slightly higher power efficiency, but this design has the problem that the LED string 102 has different conduction periods, resulting in circuit layout. difficult. Compared with the method of invention patent I397198 of the Republic of China, although this creation has a slightly lower power efficiency, all the LED strings 102 have the same conduction period, but it is very helpful for product design and design. Production, so for mass-produced products, it will be more competitive Potential.

The circuit shown in FIG. 8 is a second embodiment of the present invention. The LED driving device 100 of the present embodiment includes a bridge rectifier 101, four constant current circuits 103, seven switch circuits 104, and a circuit. Voltage detecting circuit 105 and two sets of light-emitting diode strings 102 having a minimum number of serial connections, two sets of light-emitting diode strings 102 having a medium serial number, and two sets of light-emitting diodes having the maximum number of serial connections Light string 102. The third group and the fourth group of LED strings 102 have the least number of serial connections, and the second group and the fifth group of LED strings 102 have a medium number of serial connections, and the first group and the first group The six sets of light-emitting diode strings 102 have the largest number of series connections. Moreover, the number of serial connections of the first group and the sixth group of LED strings 102 is three times that of the third group and the fourth group, and the number of serial connections of the second group and the fifth group of LED strings 102 is The third group is twice as large as the fourth group. In other words, the total turn-on voltage of the first and sixth sets of light-emitting diode strings 102 is three times that of the third and fourth groups, and the total of the second and fifth groups of light-emitting diode strings 102 The turn-on voltage is twice that of the third and fourth groups.

Five sets of circuits are connected in parallel between the positive terminal and the negative terminal of the bridge rectifier 101, and the first group is the voltage detecting circuit 105. The second group is connected in series from top to bottom, which is a first group of LED strings 102, a first switching circuit 104, and a first constant current circuit 103. The third group is connected in series from top to bottom, which is a second group of LED strings 102, a third switching circuit 104, a third group of LED strings 102, and a second constant current circuit 103. The fourth group is connected in series from top to bottom, which is a fourth group of LED strings 102, a fifth switching circuit 104, a fifth group of LED strings 102, and a third constant current circuit 103. The fifth group is connected in series from top to bottom in sequence. The circuit 104, the sixth group of LED strings 102 and the fourth constant current circuit 103.

Between the first group of LED strings 102 in the second group of circuits and the two points above the third group of LED strings 102 in the third group of circuits, connected through the second switch 104 together. As for the fourth switch circuit 104, there are two points above the second group of LED strings 102 in the third group of circuits and the fifth group of LED strings 102 in the fourth group of circuits. between. Between the fourth group of light-emitting diode strings 102 in the fourth group of circuits and the two points above the sixth group of LED strings 102 in the fifth group of circuits, the second switch 104 is connected. There are different control line connections between the voltage detecting circuit 105 and the seven switching circuits 104.

The six groups of LED strings 102 in FIG. 8 are controlled by the voltage detecting circuit 105 to control the conduction and non-conduction states of all the switching circuits 104, so that the AC power supply voltage is rectified by the bridge rectifier 101. Among the two voltage region ranges, different configurations are constructed in different series and parallel manners, thereby simultaneously improving the duty cycle and power efficiency of the LED string 102. Under the appropriate selection of the voltages of the six groups of LED strings 102, the six groups of LED strings 102 can have the same conduction period, and the six groups of LED strings 102 can be made. Have the same amount of luminescence.

In order to perform the above functions, when the instantaneous voltage is in the lower voltage range, the first, third, fifth, and seventh switching circuits are all in the on state, and the second, fourth, and sixth switching circuits are not conducting. status. Conversely, in the higher voltage range, the first, third, fifth, and seventh switching circuits are in a non-conducting state, and The second, fourth and sixth switching circuits are all in a conducting state.

The circuit shown in FIG. 9 is a third embodiment of the present invention. The LED driving device 100 of the present embodiment includes a bridge rectifier 101, a constant current circuit 103, five switching circuits 104, and a voltage. The detection circuit 105, two sets of LED arrays 102 having a small number of serial connections, and two sets of LED arrays 102 having a greater number of serial connections. The ratio of the number of series connection of the first group, the second group, the third group and the fourth group of LED strings 102 is the same as that of FIG. 6.

The structure of this embodiment is the same except that it is changed from three constant current circuits 103 to one constant current circuit 103. Since there is only one constant current circuit 103, the first switching circuit 104, the third group of LED strings 102, and the fourth group of LED strings 102 are connected to a single constant current circuit.

Similarly, after the LED driving device 100 is activated, the voltage detecting circuit 105 detects the pulsating DC voltage rectified by the AC power source via the bridge rectifier 101 regardless of the change of the AC power voltage.

When the pulsating DC voltage rises from 0V, since the voltage at this time falls within a lower voltage range, the voltage detecting circuit 105 sends a non-conducting control signal to the second and fourth switching circuits 104, and also A conduction control signal is sent to the first, third, and fifth switching circuits 104. At this time, the second group and the third group of LED strings 102 are connected in series through the third switching circuit 104 that is turned on, and then the first group of LED strings 102 and the fourth group of LED lamps. The strings 102 are connected in parallel. Because the total turn-on voltage of the first and fourth sets of LED strings 102 is the second group and The third group is twice, so the total conduction voltage after the second group and the third group of LED strings 102 are connected in series through the turned-on third switching circuit 104, and the first group and the fourth group of LEDs The total turn-on voltage of the string 102 is the same. Therefore, the three sets of parallel LED strings 102 can be connected together in the same constant current circuit 103. At this time, the three sets of LED strings 102 will equally divide the current supplied by the constant current circuit 103. In other words, each set of LED strings 102 will each have one third of the current supplied by the constant current circuit 103. Therefore, the first group to the fourth group of LED strings 102 will have the same on-current except for the same on-period. That is to say, each of the first to fourth sets of light-emitting diode strings 102 has the same amount of light at this lower voltage range.

When the pulsating DC voltage rises to a higher voltage range, the voltage detecting circuit 105 sends a conduction control signal to the second and fourth switching circuits 104, and also sends the first, third, and fifth switching circuits 104. The control signal that is turned on. At this time, the non-conduction state of the first switch circuit 104 is such that the first group of LED strings 102 are not directly connected to the constant current circuit 103. Moreover, between the second group of LED strings 102 and the third group of LED strings 102, the third switch circuit 104 is also not connected due to non-conduction. As for the fifth switch circuit 104 above the fourth group of LED strings 102, the non-conducting state is also in a non-conducting state, and the fourth group of LED strings 102 are not connected to the positive terminal of the bridge rectifier 101.

The first group of LED strings 102 are connected in series with the third group of LED strings 102 through the second switching circuit 104 that is turned on, and then connected to the constant current circuit 103. The second group of LED strings 102 is a fourth switching circuit that is turned on. After being connected in series with the fourth group of light-emitting diode strings 102, 104 is connected to the constant current circuit 103.

Because the total turn-on voltage of the first group and the fourth group of LED strings 102 are the same, and the total on-voltage of the second group and the third group of LED strings 102 are also the same. Therefore, the total on-voltage of the two series of LED strings 102 is also the same, so they can be connected together and then connected to the same constant current circuit 103.

In other words, each group of LED strings 102 will each have half of the current supplied by the constant current circuit 103. Therefore, the first group to the fourth group of LED strings 102 will have the same on-current except for the same on-period. That is to say, each of the first to fourth sets of light-emitting diode strings 102 has the same amount of light at this higher voltage range.

As can be seen from the above description, the four sets of light-emitting diodes can be changed by setting the state of the five switch circuits 104 to be turned on or off by the voltage detecting circuit 105 in the lower or higher voltage range. The series and parallel states of the body light strings 102 allow the four groups of light-emitting diode strings 102 to have the same conduction period, and the four groups of light-emitting diode strings 102 all have the same amount of light. Therefore, this design can not only improve the LED usage rate, but also improve the efficiency of the power supply.

In the sixth and eighth figures, the light-emitting diode string 102 is divided into four groups and six groups of light-emitting diode strings 102 having different total on-voltages respectively composed of different serial numbers, and Other segmentation methods are used to meet the design requirements.

In the sixth and ninth figures, the same number and structure of the light-emitting diode string 102 are provided. The difference is that three constant current circuits 103 are used in Fig. 6, and only one constant current circuit 103 is used in Fig. 9. In addition, a different number of different current circuit circuits 103 can be used to meet the design requirements.

In summary, the present invention provides a direct AC driven LED driving circuit, which has the effect of reducing production cost because it does not need to be provided with a transformer and a large capacitor with high withstand voltage. In addition, by segmenting the LED array 102 into a complex array of LEDs 102 having different series connection voltages and different total on-voltages, the use of the constant current circuit 103 can be used not only The working cycle of the LED string 102 can be improved, and the power efficiency can be improved. Therefore, the light-emitting diode driving circuit of this case is of great industrial value, and the application is filed according to law.

This case has been modified by people who are familiar with the technology, but it is not intended to be protected by the scope of the patent application.

100‧‧‧Lighting diode AC drive

101‧‧‧Bridge rectifier

102‧‧‧Lighting diode string

103‧‧‧Constant current circuit

104‧‧‧Switch circuit

105‧‧‧Voltage detection circuit

SW ₁ ‧‧‧first switch circuit

SW ₂ ‧‧‧Second switch circuit

SW ₃ ‧‧‧third switch circuit

SW ₄ ‧‧‧fourth switch circuit

SW ₅ ‧‧‧ fifth switch circuit

CC ₁ ‧‧‧First set of constant current circuits

CC ₂ ‧‧‧Second set of constant current circuits

CC ₃ ‧‧‧The third set of constant current circuits

LED _S1 ‧‧‧The first group of LED strings

LED _S2 ‧‧‧Second Group of Light-emitting Diode Light Strings

LED _S3 ‧‧‧The third group of LED light strings

LED _S4 ‧‧‧Fourth Group of Light-emitting Diode Light Strings

Claims (12)

A light-emitting diode AC driving device is used for driving a complex array of light-emitting diode strings having a plurality of total on-voltages composed of a plurality of light-emitting diodes, comprising: a rectifier circuit for receiving an alternating current Voltage, and converting the alternating voltage into a pulsating DC voltage; a voltage detecting circuit is connected to the rectifying circuit and all the switching circuits, and how many kinds of connection configurations are in the complex array of the LED strings; How many preset voltage range values are there in the voltage detection circuit; a plurality of switching circuits are respectively used between the positive (+) end of the rectifier circuit and the upper side of the LED string, and below the LED string The connection between the corresponding constant current circuit and the adjacent two adjacent light-emitting diode strings is controlled by the voltage detecting circuit to determine the series connection of the light-emitting diode strings of the complex array And a parallel configuration; and a plurality of constant current circuits are connected to the corresponding LED string through the switch circuit to provide a stable current when the LED string is turned on; wherein, the voltage detection According to the voltage range in which the instantaneous voltage of the pulsating DC voltage value obtained by the rectifier circuit is located, the signal is sent to control the conduction and non-conduction of all the switching circuits, and the series and parallel configuration of all the LED strings are set, thereby improving the illumination. The working cycle of the polar body and the power efficiency. The illuminating diode AC driving device according to claim 1, wherein the rectifying circuit is a bridge rectifier. The illuminating diode AC driving device according to claim 1, wherein the illuminating device is directly connected to the positive (+) end of the rectifying circuit except the first group of the illuminating diode strings. The switching circuit between the diode string and the positive (+) terminal of the rectifier circuit provides a positive power supply to the LED string connection for a particular configuration. The light-emitting diode AC driving device according to claim 1, wherein the light-emitting diode string is connected in series with the constant current circuit except the last group of light-emitting diode strings. The switching circuit between the lower and the corresponding constant current circuit provides a connection between the LED string and the constant current circuit in a specific configuration. The light-emitting diode AC driving device according to claim 1, wherein the two groups of adjacent LED light strings are connected to the latter group of light-emitting diodes under the light-emitting diode string The switching circuit above the string provides a series connection of two adjacent LED strings in a particular configuration. For example, in the light-emitting diode AC driving device described in claim 1, the switch circuit connected in series between different light-emitting diode strings in the same group is provided for connecting the upper and lower phase in a specific configuration. A series connection of diode strings. The light-emitting diode AC driving device according to claim 1, wherein the voltage detecting circuit is configured to be configured to turn on the light-emitting diode string when the instantaneous pulsating DC voltage value is in the lowest voltage range. The total on-voltage of the LED strings of all the LEDs connected in series with the constant current circuit is connected to have the lowest total on-voltage for improving the duty cycle of the LED strings. The light-emitting diode AC driving device according to claim 1, wherein the voltage detecting circuit is configured to be configured to turn on the light-emitting diode string when the instantaneous pulsating DC voltage value is in the highest voltage range. It is the highest total on-voltage of the LEDs of all the LED strings connected in series with the constant current circuit to improve the maximum efficiency of the power supply. The illuminating diode AC driving device according to claim 1, wherein the voltage detecting circuit sets a voltage range value of more than two, and when the instantaneous pulsating DC voltage value is not in the minimum and maximum voltage ranges, Set all the LED strings to be sent to the set series and parallel configuration. The illuminating diode AC driving device according to claim 1, wherein the switching circuit is composed of a double junction transistor, a field effect transistor, a photocoupler circuit, a solid state relay, and a solid unidirectional conductive element. The illuminating diode AC driving device according to claim 1, wherein the voltage detecting circuit is a comparator formed by a double junction transistor, a field effect transistor and an operational amplifier combined with a resistor, a diode and a capacitor. The circuit is composed of a microprocessor or a monitoring program. The illuminating diode AC driving device according to claim 1, wherein the constant current circuit is composed of a double junction transistor, a field effect transistor, a diode, and an operational amplifier combined with a resistor and a capacitor. .