TWI542247B - Applicable for different voltage source of the light-emitting diode device - Google Patents

Description

Light-emitting diode device for different voltage sources

The invention relates to a light-emitting diode device, in particular to a light-emitting diode device suitable for different voltage sources.

With the rise of energy conservation, carbon reduction and environmental awareness in recent years, large-scale public buildings around the world, such as highway lighting, traffic signs, and large billboards, have gradually replaced the light-emitting diode components with better luminous efficiency and power saving. Some incandescent bulbs and fluorescent tubes not only have a long service life, but also have better luminous efficiency, so as to save energy and expenses for maintenance of lighting, and European and American countries have further developed an incandescent bulb prohibition order. Lighting equipment such as home lighting, decorative lighting, and ceremonial celebrations are further advanced towards full-light LED components. Therefore, lighting manufacturers around the world are committed to the development of lighting diode components.

The driving circuit structure of the prior art single-voltage light-emitting diode lamp adopts a linear power supply design, and the circuit is simple, small in size and low in cost, but as the name suggests, it can only be used under unique specific voltage conditions for consumers. In addition, it is necessary to pay attention to the purchase. If you accidentally purchase the wrong specifications, it will not only waste money, but if you install it on the socket with the wrong voltage without knowing it, it will also cause danger in use. In order to cope with the current domestic power supply 110 volts and 220 volts two voltage specifications, each need to manufacture a certain amount of storage, not only increase the cost of production, but also increase storage management expenses. For consumers, the traditional lamp holder adopts the design of the starter. If the traditional lamp holder is to be equipped with the light-emitting diode lamp, the working principle and tradition of the light-emitting diode lamp Different lamps have different direction of connection. Therefore, in general, the manufacturer must manually remove the starter to avoid the burning of the LED lamp. However, the method is obviously too complicated and inconvenient.

The light-emitting diode lamp of the prior art has a driving circuit structure of a full-voltage LED lamp, which adopts a series-parallel switching between two light-emitting diode strings to apply to a full-voltage power supply. At high voltages, two LED strings are connected in series, and two LEDs are connected in parallel at low voltage. The prior art full-voltage LED lamp is only designed for the 110 volts and 220 volts provided by the current domestic utility standard, and the voltages of the two specifications coincide with a multiple relationship. Therefore, the same two light-emitting diodes can be directly connected in series at a high voltage, and the power supply of 220 volts is shared by two times of the light-emitting diode strings, and the light-emitting diodes are connected in parallel at a low voltage. The strings are for a 110 volt power supply.

However, the power supply standards in other countries are not necessarily twice as good as, for example, 115 volts and 240 volts. Under such conditions, if the cross-voltage of two LED strings is 115 volts. At the time of the power supply of 115 volts, the two light-emitting diode strings can be normally used by parallel connection, but if the two light-emitting diode strings are connected in series under the power supply of 240 volts, It can withstand twice the pressure of 115 volts, or 230 volts, and cannot withstand a voltage of 240 volts, resulting in excessive over-pressure and damage. Therefore, when the two voltage values of the power supply are not in a multiple relationship, the prior art full-voltage LED driving circuit structure cannot be used, and further improvement is necessary.

In view of this, the main object of the present invention is to provide a Light-Emitting Diode (LED) device suitable for different voltage sources, which is applicable to two different voltage sources, and the voltage sources are not multiplied. relationship.

In order to achieve the above object, the main technical means adopted by the present invention is that the LED device for different voltage sources includes: a first LED light string, which is formed by a first number of LEDs connected in series; The LED light string is formed by connecting the first number of LEDs in series; a voltage detecting circuit is connected to a power terminal, and when the voltage value of the power terminal is a first voltage value, outputting a first detection signal And outputting a second detection signal when the voltage value of the power terminal is a second voltage value; wherein the second voltage value is greater than the first voltage value; and a series of parallel control circuits having a third LED light a string, the series-parallel control circuit is connected to the voltage detecting circuit, the first LED string and the second LED string, and when the first detecting signal is received, controlling the first LED string and the first The second LED string is connected in parallel to the power terminal, and when the second detection signal is received, controlling the first LED string, the third LED string and the second LED string are connected in series to the power terminal; The third LED string is constructed by a second number of LEDs connected in series .

In the LED device of the present invention, when the voltage of the power supply terminal is the first voltage value, the first and second LED lights are connected in parallel, so that the first and second LED light strings respectively accept the The power source provided by the voltage source emits light. And the first and second LED light strings respectively have the same number of series LEDs to be applied to the same voltage source.

And when the voltage value of the power terminal is the second voltage value, even if the second voltage value is not twice the first voltage value, the present invention connects the first, third, and second LED light strings in series to A greater number of series LEDs are provided, and the voltage output by the power terminals can still drive the present invention normally. In addition, the third LED light string is additionally provided by the present invention. When the third LED light string is activated, the overall LED device can have stronger brightness than when only the first and second light strings are activated.

10‧‧‧First LED light string

11‧‧‧ first input

12‧‧‧ first output

20‧‧‧Second LED light string

21‧‧‧second input

22‧‧‧second output

30‧‧‧Voltage detection circuit

31‧‧‧Detection

32‧‧‧Signal output

40‧‧‧Serial and parallel control circuit

41‧‧‧Signal receiving end

42‧‧‧ Third LED string

421‧‧‧ third input

422‧‧‧ third output

50‧‧‧Constant current drive circuit

51‧‧‧current control terminal

52‧‧‧Detection

60‧‧‧Return circuit

70‧‧‧First rectification unit

80‧‧‧Secondary rectifier unit

90‧‧‧LED tube

1 is a block diagram of a first preferred embodiment of the present invention.

2 is a circuit diagram of a first preferred embodiment of the present invention.

Figure 3 is a block diagram showing a second preferred embodiment of the present invention.

Figure 4 is a schematic view showing the appearance of a second preferred embodiment of the present invention.

Figure 5 is a circuit diagram showing a second preferred embodiment of the present invention.

FIG. 6 is a schematic diagram of current flow when the second preferred embodiment of the present invention is applied to a power source having a first voltage value.

FIG. 7 is a schematic diagram showing current flow when the second preferred embodiment of the present invention is applied to a power source having a second voltage value.

The technical means adopted by the present invention for achieving the intended purpose of the invention are further described below in conjunction with the preferred embodiments of the invention.

Referring to FIG. 1 , a first preferred embodiment of a light emitting diode (LED) device for applying different voltage sources according to the present invention includes a first LED light string 10 , a second LED light string 20 , and a voltage detection. Circuit 30 and a series of parallel control circuits 40.

The first LED string 10 is formed by connecting a first number of LEDs in series, and has a first input terminal 11 and a first output terminal 12, and the first input terminal 11 is connected to a power terminal Vcc. The second LED string 20 is formed by connecting the first number of LEDs in series, and has a second input terminal 21 and a second output terminal 22, and the second output terminal 22 is connected to a ground terminal GND.

The voltage detecting circuit 30 has a voltage detecting end 31 and a signal output end 32. The voltage detecting end 31 is connected to the power terminal Vcc to detect the voltage value of the power terminal Vcc. The voltage detecting circuit 30 outputs a first detection signal from the signal output terminal 32 when the voltage value of the power supply terminal Vcc is a first voltage value, and the voltage value of the power supply terminal Vcc is a second voltage. The news The output terminal 32 outputs a second detection signal. The second voltage value is greater than the first voltage value, and the second voltage value is greater than twice the first voltage value.

The serial-parallel control circuit 40 has a signal receiving end 41 and a third LED string 42. The signal receiving end 41 is connected to the signal output end 32 of the voltage detecting circuit 30 to receive the first detecting signal or the second. Detection signal. The third LED string 42 is formed by connecting a second number of LEDs in series, and has a third input terminal 421 and a third output terminal 422.

When the serial-parallel control circuit 40 receives the first detection signal, the first input end 11 of the first LED string 10 is connected to the second input end 21 of the second LED string 20, and the The first output 12 of the first LED string 10 is coupled to the second output 22 of the second LED string 20 such that the first LED string 10 is in parallel with the second LED string 20.

When the serial-parallel control circuit 40 receives the second detection signal, the first output terminal 12 of the first LED string 10 is connected to the third input terminal 421 of the third LED string 42, and the The third output end 422 of the third LED string 42 is connected to the second input end 21 of the second LED string 20, so that the first LED string 10, the third LED string 42 and the second LED string 20 series.

The first preferred embodiment of the LED device for different voltage sources detects the voltage value of the power terminal Vcc and controls the first LED string 10 and the second LED according to the voltage value of the power terminal Vcc. The strings 20 are connected in series and in parallel to supply power supplies of different voltages. And the first LED light string 10 and the second LED light string 20 are respectively formed by connecting the same number of LEDs in series, and when the normal light is emitted, the first LED light string 10 and the second LED light string 20 have The same cross pressure. Therefore, when the voltage value of the power terminal Vcc is a relatively small first voltage value, the first LED string 10 is connected in parallel with the second LED string 20, so that the first LED string 10 and the first The voltage across the two LED strings 20 is the first voltage value provided by the power terminal Vcc for normal power-on illumination at a low voltage power supply.

And when the voltage value of the power terminal Vcc is a relatively large second voltage value, and the second voltage value is greater than twice the first voltage value. If only the first LED string 10 and the second LED string 20 are directly connected in series, the power source having the second voltage value is passed, because the first LED string 10 is connected in series with the second LED string 20 , which is composed of twice the first number of LEDs connected in series, and the span voltage that can be withstood is twice the first voltage value, but the second voltage value is greater than twice the first voltage value, so The voltage across the first LED string 10 and the second LED string 20 is too large to cause damage and cannot be normally illuminated. Therefore, when the voltage value of the power terminal Vcc is the second voltage value, the first LED string 10, the third LED string 42 and the second LED string 20 are connected in series by the third LED lamp. The string 42 is arranged such that the first LED string 10, the third LED string 42 and the second LED string 20 in series have twice the first number plus twice the second number of series LEDs, so A voltage source that is greater than twice the first voltage value, that is, a power source having the second voltage value, is capable of normally emitting light, and because the number of series LEDs is increased, the overall LED device can provide greater brightness.

Referring to FIG. 2, the voltage detecting circuit 30 has a Zener diode D1, a first resistor R1, a second resistor R2, a third resistor R3, and a first transistor Q1. The anode of the Zener diode D1 is connected to the ground GND, and the cathode thereof is connected to the source of the first transistor Q1. The first resistor R1 is connected between the gate of the first transistor Q1 and the power terminal Vcc, and the second resistor R2 is connected between the gate of the first transistor Q1 and the ground GND. . The drain of the first transistor Q1 is connected to the power terminal Vcc through the third resistor R3. In the preferred embodiment, one end of the first resistor R1 connected to the power terminal Vcc is the voltage detecting terminal 31, and the drain of the first transistor Q1 is the signal output terminal 32.

The series-parallel control circuit 40 further has a second transistor Q2, a second diode D2, a third diode D3, a fourth diode D4, a fourth resistor R4 and a third battery. Crystal Q3. The drain of the second transistor Q2 is connected to the power supply terminal Vcc, and the gate thereof is connected to the signal output terminal 32 of the voltage detecting circuit 30, that is, the drain of the first transistor Q1. And the second transistor Q2 The source is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the second input 21 of the second LED string 20. The drain of the third transistor Q3 is connected to the first output terminal 12 of the first LED string 10, and the gate thereof is connected to the anode of the fourth diode D4 through the fourth resistor R4. The cathode of the fourth diode D4 is connected to the source of the second transistor Q2, and the source of the third transistor Q3 is connected to the anode of the third diode D3, the third diode The cathode of D3 is coupled to the second output 22 of the second LED string 20. The third input end 421 of the third LED string 42 is connected to the first output end 12 of the first LED string 10, and the third output end 422 of the third LED string 42 is connected to the second The second input 21 of the LED string 20.

Referring to FIG. 3, the second preferred embodiment of the present invention is further provided with a certain current driving circuit 50 and a feedback circuit 60 as compared with the first preferred embodiment. The constant current driving circuit 50 has a current control terminal 51 and a detecting terminal 52. The current control terminal 51 is directly connected to the second output terminal 22 of the second LED string 20. The feedback circuit 60 is connected to the gate of the third transistor Q3 in the series-parallel control circuit 40, and the feedback circuit 60 adjusts the feedback circuit 60 according to the gate voltage of the third transistor Q3. Equivalent resistance value. The detecting end 52 of the constant current driving circuit 50 is connected to the feedback circuit, and detects the magnitude of the equivalent resistance value of the feedback circuit 60 according to the detecting end 52, and controls the magnitude of the current flowing into the current control terminal 51. In the preferred embodiment, the constant current driving circuit 50 is an integrated circuit of the type AT7315.

The LED device for different voltage sources is further provided with a first rectifying unit 70 and a second rectifying unit 80. The first rectifying unit 70 has two AC power terminals P1 and P2 and two DC output terminals. The two DC output terminals are respectively connected to the power terminal Vcc and the ground terminal GND to provide DC power. The second rectifying unit 80 has two AC power terminals P3 and P4 and two DC output terminals. The two DC output terminals are respectively connected to the power terminal Vcc and the ground terminal GND to provide DC power.

As shown in FIG. 4, the LED device for different voltage sources may be an LED tube 90, and the four power pins of the LED tube 90 are the first rectifying unit 70 and the second rectifying unit. AC power terminals P1~P4 of unit 80. When the LED lamp 90 is used, no matter which pin the external AC power source flows in, it can flow out from any of the remaining three pins and pass through the first rectifying unit 70 or the second rectifying unit. The AC power is rectified and supplied to the internal circuit for use. The direction in which the LED tube is used during use is not limited, and the occurrence of damage or inability to use due to the wrong direction of the power supply is avoided. In the preferred embodiment, the first rectifying unit 70 and the second rectifying unit 80 are both bridge rectifiers.

As shown in FIG. 5, the feedback circuit 60 has a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a fourth transistor Q4. The fifth resistor R5 is connected between the detecting end 52 of the constant current driving circuit 50 and the ground GND. The drain of the fourth transistor Q4 is connected to the detecting end 52 of the constant current driving circuit 50 through the sixth resistor R6, and the gate thereof is connected to the gate of the third transistor Q3 of the series-parallel control circuit 40. The source of the fourth transistor Q4 is connected to the ground GND. The seventh resistor R7 is connected between the gate of the fourth transistor Q4 and the source of the fourth transistor Q4.

The operation of the circuit will be described by way of example only and is not intended to limit any numerical size of the invention.

The breakdown voltage of the Zener diode D1 of the voltage detecting circuit 30 is 13V, and the first resistor R1 and the second resistor R2 divide the voltage of the power terminal Vcc to provide a partial voltage of 1/10. To the gate of the first transistor Q1.

Referring to FIG. 6, when the voltage value of the power terminal Vcc is 100 volts (V), the gate voltage of the first transistor Q1 is 1/10 of the voltage value of the power terminal Vcc, which is 10V, but The Zener diode D1 has a breakdown voltage of 13 V. When the Zener diode D1 collapses in the reverse direction, it supplies 13 V to the source of the first transistor Q1. Therefore, the gate-source voltage of the first transistor Q1 is a negative value, so the first transistor Q1 is not turned on, so that the gate voltage of the second transistor Q2 is the voltage of the power terminal Vcc, which is 100V. .

The source voltage of the second transistor Q2 is 100V of the voltage of the power supply terminal Vcc, because the gate and drain voltages of the second transistor Q2 are both 100V, and the source of the second transistor Q2 is transmitted through The fourth diode D4, the fourth resistor R4 and the seventh resistor R7 are grounded, so that the initial state of the source of the second transistor Q2 is 0V, and the second transistor Q2 is turned on, allowing current to flow through the The drain and source of the second transistor Q2. At the same time, because the second transistor Q2 has a drain current, and then the breakdown of the fourth diode D4, and the fourth resistor R4 and the seventh resistor R7 pull the source of the second crystal Q2 Voltage, and the source voltage of the second transistor Q2 is only slightly smaller than the gate voltage of the second transistor Q2, which is approximately less than 100V, so that the second transistor Q2 acts on the conductive state (Linear region) .

The first LED string 10 and the second LED string 20 have a voltage across the normal operation of 70V. The voltages of the first output terminal 12 of the first LED string 10 and the second output terminal of the second LED string 20 are both 30V, so that the source voltage of the third transistor Q3 is 30V. The gate voltage of the third transistor Q3 is a partial voltage generated by the source voltage of the second transistor Q2 through the fourth resistor R4 and the seventh resistor R7. In the illustrated example, the fourth diode The breakdown voltage of the body D4 is 14V, and the resistance value of the fourth resistor R4 and the seventh resistor R7 is the same, so that the generated partial pressure is (100-14)/2=43V. Therefore, the gate voltage of the third transistor Q3 is greater than its source voltage and is turned on, allowing current to flow through the drain and source of the third transistor Q3.

In addition, the gate voltage of the fourth transistor Q4 is the same as the gate voltage of the third transistor Q3, which is 43V, and the source of the fourth transistor Q4 is grounded, so the fourth transistor Q4 is turned on. The fifth resistor R5 is connected in parallel with the sixth resistor R6. Therefore, the equivalent resistance value of the feedback circuit 60 detected by the detection terminal of the constant current driving circuit 50 is the equivalent resistance of the fifth resistor R5 and the sixth resistor R6 in parallel, and the control flows into the The current of the current control terminal 51 is 2I. Because the first LED string 10 is connected in parallel with the second LED string 20, the current flowing into the current terminal 51 is the sum of the current flowing through the first LED string 10 and the second LED string 20. Flowing through the first LED string 10 and the first The currents of the two LED strings 20 are respectively I, so the total current flowing into the current control terminal 51 must be controlled to 2I to avoid the large current generation and damage the first LED string 10 and the second LED string 20.

The first input end 11 of the first LED string 10 is transmitted through the second transistor Q2 and the second LED string 20 in a state in which both the second transistor Q2 and the third transistor Q3 are turned on. The second input end 21 is connected, and the first output end 12 of the first LED string 10 is connected to the second output end 22 of the second LED string 20 through the third transistor Q3, so the first LED lamp The string 10 is connected in parallel with the second LED string 20, so that the LED device for different voltage sources can be applied to a 100V power source.

Referring to FIG. 7, when the voltage value of the power terminal Vcc is 220V, the gate voltage of the first transistor Q1 is 1/10 of 220V, which is 22V, and the breakdown voltage of the Zener diode D1. It is 13V. Therefore, the gate voltage of the first transistor Q1 is greater than the source voltage thereof, so that the first transistor Q1 is turned on, so that the gate voltage of the second transistor Q2 is the cathode voltage of the polar diode D1. It is 13V.

The drain voltage of the second transistor Q2 is the voltage of the power supply terminal Vcc 220V, because the source of the second transistor Q2 is transmitted through the fourth diode D4, the fourth resistor R4 and the seventh resistor. R7 is grounded, so the initial state of the source of the second transistor Q2 is 0V, and the second transistor Q2 is turned on to allow current to flow through the drain and source of the second transistor Q2. At the same time, because the second transistor Q2 has a drain current, and then the breakdown of the fourth diode D4, and the fourth resistor R4 and the seventh resistor R7 pull the source of the second crystal Q2 Voltage, but the source voltage of the second transistor Q2 is only slightly smaller than the gate voltage of the second transistor Q2, which is slightly less than 13V, so that the second transistor Q2 acts on the conduction state (Saturation region) . At this time, since the source voltage of the second transistor Q2 is slightly less than 13V, the fourth diode D4 is not collapsed and turned on, so the fourth diode D4 is not turned on.

The first LED string 10 and the second LED string 20 have a voltage across the normal operation of 70V, and the third LED string 42 has a voltage across the normal operation of 50V. Therefore, the voltage of the first output terminal 12 of the first LED string 10 is the voltage of the power terminal Vcc minus the consumption of the first LED string 10. The voltage is obtained, and the voltage of the first output terminal 12 is 150V. The voltage of the third output terminal 422 of the third LED string 42 is the voltage of the first output terminal 12 of the first LED string 10 minus the voltage consumed by the third LED string 42 to obtain the third output. The voltage at terminal 422 is 100V. With the second diode D2 disposed, the voltage of the third output terminal 422 of the third LED string 42 is the cathode voltage of the second diode D2, which is 100V, and the second transistor Q2 The source voltage is the anode voltage of the second diode D2, which is 13V, so that the second diode D2 is not turned on due to the reverse bias, so that the current flowing out of the third LED string 42 flows directly into the source. The second input 21 of the second LED string 20.

The voltage of the second output terminal 22 of the second LED string 20 is the voltage of the third LED 422 of the third LED string 42 minus the voltage consumed by the second LED string 20, and the second output is obtained. The voltage at terminal 22 is 30V. The source voltage of the third transistor Q3 is the same as the voltage of the second output terminal 22, which is 30V, but the gate voltage of the third transistor Q3 is not turned on because the fourth diode D4 is not The third transistor Q3 is grounded through the fourth resistor R4 and the seventh resistor R7, so that the gate voltage of the third transistor Q3 is 0V, so that the gate voltage of the third transistor Q3 is less than the source voltage thereof. The third transistor Q3 is not turned on.

In addition, the gate voltage of the fourth transistor Q4 is the same as the gate voltage of the third transistor Q3, both of which are 0V, and the source of the fourth transistor Q4 is grounded, so the fourth transistor Q4 is not turned on. The magnitude of the equivalent resistance of the feedback circuit 60 detected by the detection terminal of the constant current driving circuit 50 is the resistance value of the fifth resistor R5 to control the magnitude of the current flowing into the current control terminal 51. . Because the first LED string 10, the third LED string 42 and the second LED string 20 are connected in series, the current flowing into the current terminal 51 flows through the first LED string 10 and the third LED. The current of the light string 42 and the second LED light string 20, so the total current flowing into the current control terminal 51 must be controlled to I to avoid large current generation and damage the first LED light string 10, the third LED light string 42 and the second LED string 20.

In summary, when the voltage of the power terminal Vcc is 220V, the current I flowing through the first LED string 10 further flows through the third LED string 42 and the second LED string 20, so that The purpose of connecting the first, second, and third LED strings 10, 20, and 42 in series is to enable the LED device for different voltage sources to be applied to a 220V power supply. The LED device for different voltage sources can be applied to two different power sources of 100V and 220V, which are not in multiple relationship, and can normally emit light, and when applied to a 220V power supply, the third LED string 42 is together. Illuminate to provide a light source with better brightness.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention. A person skilled in the art can make some modifications or modifications to equivalent embodiments by using the above-disclosed technical contents without departing from the technical scope of the present invention. It is still within the scope of the technical solution of the present invention to make any simple modifications, equivalent changes and modifications to the above embodiments.

10 first LED string 11 first input 12 first output 20 second LED string 21 second input 22 second output 30 voltage detection circuit 31 detection terminal 32 signal output 40 series-parallel control circuit 41 signal Receiver 42 third LED string 421 third input 422 third output

Claims (14)

A light-emitting diode device suitable for different voltage sources includes: a first light-emitting diode (LED) light string, which is formed by a first number of LEDs connected in series; a second LED light string is The first number of LEDs are connected in series; a voltage detecting circuit is connected to a power terminal, and when the voltage value of the power terminal is a first voltage value, a first detection signal is output, and at the power terminal When the voltage value is a second voltage value, a second detection signal is output; wherein the second voltage value is greater than the first voltage value; a series of parallel control circuits having a third LED string, the series-parallel control circuit Connecting to the voltage detecting circuit, the first LED light string and the second LED light string, and when receiving the first detecting signal, controlling the first LED light string and the second LED light string to be connected in parallel to the power source End, and when receiving the second detection signal, controlling the first LED string, the third LED string and the second LED string are connected in series to the power terminal; wherein the third LED string is The second number of LEDs are connected in series. The illuminating diode device of the different voltage source is as described in claim 1, wherein: the first LED string has a first input end and a first output end, and the first input end is connected to the power end The second LED string has a second input end and a second output end, the second output end is connected to a ground end; the voltage detecting circuit has a voltage detecting end and a signal output end, The voltage detecting end is connected to the power terminal to detect the voltage value of the power terminal, and the signal output terminal outputs the first detecting signal or the second detecting signal; the series-parallel control circuit further has a signal receiving end. The signal receiving end is connected to the signal output end of the voltage detecting circuit; the third LED light string has a third input end and a third output end; When the serial-parallel control circuit receives the first detection signal, the first input end of the first LED string is connected to the second input end of the second LED string, and the first LED string is The first output end is connected to the second output end of the second LED light string, so that the first LED light string is connected in parallel with the second LED light string; when the serial-parallel control circuit receives the second detection signal Controlling that the first output end of the first LED string is connected to the third input of the third LED string, and the third output of the third LED string is connected to the second LED string The two input terminals are arranged in series with the first, third and second LED light strings. The illuminating diode device of claim 2, wherein the voltage detecting circuit comprises: a Zener diode having an anode connected to the ground; a first transistor, a source thereof Is connected to the cathode of the Zener diode; a first resistor is connected between the gate of the first transistor and the power terminal; and a second resistor is connected to the gate of the first transistor And a third resistor is connected between the drain of the first transistor and the power terminal; wherein one end of the first resistor and the power terminal is the voltage detecting end, The drain of the first transistor is the signal output terminal of the voltage detecting circuit. The LED device of claim 2, wherein the series-parallel control circuit further comprises: a second transistor having a drain connected to the power terminal and a gate connected to the voltage a signal output end of the detecting circuit; a second diode having an anode connected to the source of the second transistor, a cathode connected to the second input end of the second LED string; a third diode The cathode is connected to the second output end of the second LED string; a third transistor having a source connected to the anode of the third diode, a drain connected to the first output of the first LED string; a fourth diode having a cathode connected to the second a source of the transistor; and a fourth resistor connected between the gate of the third transistor and the anode of the fourth diode; wherein the third input of the third LED string is connected to the a first output of an LED string, the third output being coupled to a second input of the second LED string. The illuminating diode device of the different voltage source is as described in claim 3, wherein the series-parallel control circuit further comprises: a second transistor having a drain connected to the power terminal and a gate connected to the voltage a signal output end of the detecting circuit; a second diode having an anode connected to the source of the second transistor, a cathode connected to the second input end of the second LED string; a third diode The cathode is connected to the second output end of the second LED string; a third transistor has a source connected to the anode of the third diode, and a drain connected to the first output of the first LED string a fourth diode, the cathode of which is connected to the source of the second transistor; and a fourth resistor connected between the gate of the third transistor and the anode of the fourth diode; The third input end of the third LED string is connected to the first output end of the first LED string, and the third output is connected to the second input end of the second LED string. The illuminating diode device for applying different voltage sources according to claim 4, further comprising: a feedback circuit connected to the gate of the third transistor, and adjusting according to the gate voltage of the third transistor The equivalent resistance value of the feedback circuit; The constant current driving circuit has a current control end and a detecting end, the current control end is connected to the second output end of the second LED string, and the detecting end is connected to the feedback circuit, and the constant current driving The circuit detects the equivalent resistance value of the feedback circuit and controls the amount of current flowing into the current control terminal. The illuminating diode device for applying different voltage sources according to claim 5, further comprising: a feedback circuit connected to the gate of the third transistor, and adjusting according to the gate voltage of the third transistor The equivalent resistance value of the feedback circuit; the constant current driving circuit has a current control end and a detecting end, the current control end is connected to the second output end of the second LED string, and the detecting end is connected to The feedback circuit, and the constant current driving circuit detects the magnitude of the equivalent resistance of the feedback circuit and controls the magnitude of the current flowing into the current control terminal. The light-emitting diode device of different voltage sources is applied as described in claim 6 or 7, wherein the constant current driving circuit is an integrated circuit of the type AT7315. The light-emitting diode device of claim 6 or 7, wherein the feedback circuit includes: a fifth resistor connected between the detecting end of the constant current driving circuit and the grounding end a fourth transistor having a gate connected to the gate of the third transistor, a source connected to the ground; a sixth resistor connected to the drain of the fourth transistor and the constant current driving circuit Between the detecting ends; a seventh resistor connected between the gate of the fourth transistor and the source of the fourth transistor. The illuminating diode device for applying different voltage sources according to any one of claims 1 to 7, further comprising: a first rectifying unit having two AC power terminals and two DC power terminals, wherein the two DC power terminals are respectively connected to the power terminal and the ground terminal; and a second rectifying unit has two AC power terminals and two DC power terminals, Two DC power terminals are respectively connected to the power terminal and the ground terminal. The light emitting diode device of claim 10, wherein the first rectifying unit and the second rectifying unit are respectively a bridge rectifier. The light emitting diode device of claim 1, wherein the second voltage value is greater than twice the first voltage value. The light emitting diode device of the different voltage source is applied as described in claim 9, wherein the second voltage value is greater than twice the first voltage value. The light emitting diode device of the different voltage source is applied as described in claim 10, wherein the second voltage value is greater than twice the first voltage value.