TW201707509A - Method for LED fault tolerance and circuit thereof - Google Patents

Abstract

Using a bypass circuit connected in parallel with a LED, the bypass circuit can alternate the LED in the event of the LED failure. Also when the LED is working, the bypass circuit presents a high impedance cut-off state. Moreover, when the amount of an operating current flowing through the bypass circuit is equal to the amount of a set current, the amount of the operating voltage associated with the operating current of the bypass circuit is equal to the amount of the total forward voltage associated with the operating current of the LED. When the amount of the operating current flowing through the bypass circuit is greater than the amount of the set current, the amount of the operating voltage associated with the operating current of the bypass circuit is greater than the amount of the total forward voltage associated with the operating current of the LED. When the amount of the operating current flowing through the bypass circuit is smaller than the amount of the set current, the amount of the operating voltage associated with the operating current of the bypass circuit is less than the amount of the total forward voltage associated with the operating current of the LED.

Description

LED fault tolerance method and circuit thereof

The present invention relates to a method for fault tolerance of LEDs and a circuit thereof, and more particularly to an LED open circuit fault in a circuit, in which the fault LED is replaced by a bypass circuit in parallel with the fault LED.

When LED (Light Emitting Diode) is used as illumination, it is necessary to pass a forward current on the LED. However, the characteristic of the voltage V-current I on the LED is essentially that the forward operating voltage on the LED is related in an exponential relationship to the forward operating current through the LED. Moreover, the forward operating voltage on the LED is below a threshold and the LED does not illuminate. For example, the characteristic curve A, which is illustrated in the fourth figure, is a forward cross on a white LED (a white LED with a total forward voltage value between 2.5 and 3.3 volts) rated at 0.02A, 3.2V. The relationship between the voltage and the forward current. The voltage 2.5 volts illustrated by curve A in the figure is the threshold value of the total forward voltage value of the exemplary LED element, and the actual value of the total forward voltage value VSET corresponding to the rated current of 20 mA through the rated LED current is shown. 3.07 volts. Because, even if the same type of LEDs of the same batch are produced, the actual characteristics of each LED component are hardly the same. Therefore, when each of the LED elements actually flows through the rated current, the corresponding actual total forward voltage values are difficult to be the same.

Because the luminous intensity of the LED is positively correlated with the working current flowing through the LED, the operating current of the LED is too small, which is not conducive to the brightness of the LED, and is not conducive to cost reduction. low. In addition, the efficiency of the LED operating at the rated operating current must not be low. In order to improve the operating efficiency and cost of the LED, the operating current flowing through the LED is often expected to be close to its rated value. However, in the situation that the rated operating current flows through an LED, a slight increase in the operating voltage on the LED will cause a relatively large increase in the operating current flowing through it, which may cause an excessive operating current to flow through the LED, and thus may It raises its temperature too high, shortens its life, and even burns the LED.

As is well known, LEDs are often used in series to form a series of LEDs that provide a relatively uniform brightness by flowing the same current across each of the LED strings. However, an LED in an LED string has an open circuit failure, which will cause all the LEDs in the LED string to be off, which will be detrimental to the stability of the LED illumination source.

In order to solve the above problem, an architecture of a bypass short circuit as an LED fault tolerant circuit is proposed in U.S. Patent No. 8,410,705. Wherein each of the LED strings is configured in parallel with a fault-tolerant circuit; and each of the fault-tolerant circuits is flown through an operating current flowing through the LED string. In an open state; and after an open fault occurs in an LED in the LED string, the fault tolerant circuit in parallel with the open fault LED provides a short circuit voltage to allow the operating current flowing through the LED string to flow through The fault tolerant circuit, which is a bypass short circuit, continues to maintain the operating current circulating over the remaining LEDs in the LED string.

The above technique provides a short-circuit voltage bypass current path by a fault-tolerant short-circuit circuit in parallel with the fault LED after an open-circuit fault occurs in an LED of a LED string to continue to maintain the remaining current of the operating current in the LED string. Circulating on the LED. However, because the operating voltage before an LED fault is substantially different from the short-circuit voltage provided by the fault-tolerant short-circuit circuit after an LED fault, it may affect the electrical power of other working LEDs in the entire LED string. Pressure distribution.

For example, a white LED rated at 0.02A, 3.2V is connected in parallel with NUD4 700, a product manufactured by On Semiconductor, which is a fault-tolerant short circuit. Among them, the current of the NUD4700 when it is not turned on is less than 25 0μA, the voltage at the time of conduction is about 1V, and the current when the conduction is maintained is greater than 12mA. Therefore, when the current of 0.02A flows through the LED, the voltage of the parallel circuit is about 3.2V, and when the current of 0.02A after the LED failure flows through the NUD4700 which is a fault-tolerant short-circuit circuit, the voltage of the parallel circuit is about 1V.

In the worst case, if the total forward operating voltage applied to the LED string remains the same, the voltage distributed across each of the other LEDs in the LED string will be further increased. In addition, generally, in order to obtain higher operating efficiency and lower cost, the operating current flowing through the LED is often expected to be close to its rated value. Therefore, before the LED open circuit fault occurs, when the operating current flowing through the LED is close to its rated value, after the LED open circuit fault occurs, the fault-tolerant short-circuit circuit acts to replace the faulty LED. In this case, since the current on the LED increases with the increase of the voltage, the operating current flowing through the remaining LEDs in the LED string may be greater than the rated current of the LED, which is unfavorable for the safe operation of the remaining LEDs. In particular, after two or more LEDs have an open-circuit fault, a bypass short-circuit circuit is used as a fault-tolerant circuit to continue to maintain the operating current flowing through the remaining LEDs.

Different from the above technology, in the prior art of U.S. Patent No. 6,650,064, an alternative circuit structure for LED fault-tolerant bypass is disclosed, which is characterized in that each group of LEDs in a LED string is respectively configured with a Zener diode. The body is connected in parallel, and the clamping threshold voltage of the Zener diode is required to be equal to or slightly larger than the total forward voltage value of the maximum current of the group of LEDs, so that in the normal operation of the LED string, the Zener diode is connected in parallel with each group of LEDs. There is almost no current flowing through the body. Each of these groups The LED can be a LED element or a series of LED elements above two LED elements. The prior art "hopes" that when a group of LEDs in parallel with a Zener diode fails, the Zener diode is turned on to provide an alternate voltage for the Zener diode to fail in the corresponding set of LEDs. After that, there is almost no need to increase the applied voltage to provide an alternate current path for the bypass, and to maintain the other groups of LEDs in series in the circuit continue to illuminate without affecting other components in the circuit.

Ideally, in the general case of continuous conduction of the LED, although the breakdown voltage of the Zener diode can be selected to be greater than or equal to the sum of the total forward voltage values of all LED operating currents in its corresponding set of LEDs. However, in actual work, even if the same type of LEDs of the same batch are produced, the characteristics of each LED are not exactly the same. Therefore, according to this requirement, the breakdown voltage of the Zener diode corresponding to the LEDs of different groups must first measure the sum of the total forward voltage values of the operating currents of all the LEDs in a group of LEDs before determining the The set of LEDs corresponds to the value of the breakdown voltage of the Zener diode, and then finds a suitable corresponding Zener diode. This situation will complicate the circuit manufacturing process and is difficult to implement.

Therefore, in the above prior art, considering the imperfection of the actual circuit components, and in order to ensure that the Zener diode as a fault-tolerant replacement does not work during normal operation of the LED, the breakdown voltage of the Zener diode , selected to be equal to or slightly greater than the sum of the total forward voltage values of the maximum currents of all of the LEDs in its corresponding set of LEDs. In this case, after the LED open circuit failure, when the Zener diode is replaced by the Zener diode, the voltage distribution on the unfaulted component in the circuit powered by the voltage source will be affected.

Therefore, when a group of LEDs in a LED string fails, the voltage of the power supply circuit that supplies power to the LED string remains unchanged, because of the Zener diode corresponding to a group of LEDs. The breakdown voltage, selected to be equal to or slightly larger than the sum of the total forward voltage values of all of the LEDs in the corresponding set of LEDs, will cause the current flowing through the LED string to drop, thereby further reducing the illumination.

Alternatively, as mentioned in the prior art, when the set of LEDs in parallel with a Zener diode fails, the voltage of the power supply circuit is increased to the LED string so that the Zener diode provides a bypass current. At the same time as the path, the circuit maintains the current flowing through the LED string with the same magnitude of current before the LED string failure. In this case, it is not suitable to use the voltage supplied by the power supply circuit to a certain voltage value, or the power supply circuit is a constant voltage source such as a battery.

The first figure is a circuit overview of a conventional LED fault tolerant circuit to illustrate the prior art described above. In the first figure, a resistor R and four sets of LED devices L1-L4 are connected in series to the two ends of a circuit (not shown) ("+" positive terminal and "-" negative terminal), and each group The LED devices L1-L4 are each connected in parallel with a Zener diode Z1-Z4. The forward biasing direction of the Zener diodes Z1-Z4 is opposite to the corresponding set of LED devices L1-L4. Moreover, each set of LED devices can be an LED component or a series of LED components of a selected number of LED components. Moreover, the breakdown voltage of the Zener diode is preferably equal to or slightly larger than the total forward voltage value of the LED device at the maximum forward current to ensure that Zener is connected in parallel with the LED device in normal operation. The polar body can pass almost no current.

For example, the example values of the relevant components described in the circuit diagram of the first figure are: each of the LED devices L1-L4 is a white LED rated at 0.02A, 3.2V each (having a range of 2.5-3.3 volts) The white LED between the total forward voltage values); the breakdown voltage of each of the Zener diodes Z1-Z4 is approximately 3.3 volts; the resistance R is 100 ohms; and the circuit (not shown) is at both ends (" The +" positive terminal and the "-" negative terminal) provide a supply voltage.

For the example values exemplified in the first figure above, the actual value measured once under normal operation, when the current flowing through the resistor R is 20 mA, the supply voltage is supplied at a voltage of about 13.92 volts at both ends of the circuit (not shown), and the LED device L1 The voltage is approximately 3 volts, the voltage of L2 is approximately 2.94 volts, the voltage of L3 is approximately 3 volts, and the voltage of L4 is approximately 2.97 volts.

Then, when the LED device L1 is faulty, under the condition that the power supply voltage supplied to the conventional LED fault-tolerant circuit and the power supply voltage before the failure of the LED device remain unchanged, the actual value is measured as follows: the power supply voltage is approximately 13.92 volts, The voltage of the nano-polar body Z1 is about 3.47 volts, the voltage of the LED device L2 is about 2.9 volts, the voltage of L3 is about 2.96 volts, the voltage of L4 is about 2.93 volts, and the current flowing through the resistor R is about 16.6 mA. .

In this case, the characteristic curve of the voltage V-current I on the LED is exponential when the LED is turned on. Among them, the current on the LED increases as the voltage increases. Thus, when the voltage on an LED drops, the current flowing through the LED will drop. For the prior art, the illumination of the entire LED string is reduced in a group of LED faults, and after the Zener diode replaces the corresponding group of fault LEDs as a conduction path, the Zener diode is replaced as a fault tolerant replacement. The breakdown voltage, which is not equal to and greater than the operating voltage of the respective group of LEDs prior to the fault, affects the voltage distribution of the entire LED string in a circuit supplied by the voltage source. Therefore, under the condition that the voltage supply of the circuit is maintained, the current flowing through the LED string is lowered, and the illuminance is further lowered.

Alternatively, as in the prior art, when the LED device L1 is faulty and the sustain circuit is 20 mA, the actual value is measured as follows: the supply voltage is increased to 14.47 volts, the current flowing through the resistor R is 20 mA, the Zener diode The voltage of Z1 is approximately 3.55 volts, the voltage of LED device L2 is approximately 2.94 volts, the voltage of L3 is approximately 3 volts, and the voltage of L4 is approximately 2.97 volts.

In this case, although the current flowing through the circuit-powered LED string is maintained and the LED is mounted The current flowing before the L1 fault has the same size, which can prevent the illuminance output from further decreasing. However, it is necessary to add additional voltage to the power supply circuit, which causes additional power consumption in the power supply circuit. Moreover, such a condition is not suitable for a condition in which the power supply voltage supplied from the power supply circuit is a certain voltage value, or a constant voltage source such as a battery.

In the prior art, after a LED fault is replaced by a bypass circuit in parallel with the fault LED, the operating voltage of the fault LED before the LED fault cannot be equal to the substitute voltage provided by the bypass circuit after the LED fault And keep the current flowing through the bypass circuit the same size.

Therefore, there is a need to develop a fault-tolerant replacement circuit in parallel with the LED, and when the LED is in operation, the replacement circuit connected in parallel with the LED exhibits a high impedance cut-off state. After the LED fault, the replacement circuit acts as a bypass electrical path, and the current and voltage on the alternate circuit as a bypass electrical path can be the same as the current and voltage before the LED fault. Thus, for a circuit that supplies power to the LED, after the LED fails, the replacement circuit can be used to make the circuit itself completely unaffected, thereby eliminating the need to change the voltage of the power supply circuit after the LED failure.

Moreover, for LED fault-tolerant technology, a technology is needed to develop a fault-tolerant replacement circuit in parallel with the LED for a constant voltage source such as a battery or a supply voltage of a commonly used power supply circuit to a certain voltage value. Moreover, when the LED is in operation, the replacement circuit connected in parallel with the LED exhibits a high impedance cutoff state. When the operating current flowing through the LED is relatively large, causing an LED failure, the replacement circuit can be used as a bypass electrical path after the LED failure, and the voltage on the replacement circuit when the electrical path is a bypass is greater than the LED. The LED voltage before the fault, and thus the operating current after the LED fault, as an LED Protection after failure.

Alternatively, a technique is needed for a constant voltage source such as a battery or a supply voltage of a commonly used power supply circuit to have a certain voltage value, and a fault-tolerant replacement circuit is connected in parallel with the LED, and when the LED is in operation The replacement circuit connected in parallel with the LED exhibits a high impedance cutoff state. When the operating current flowing through the LED is less than a certain value, the alternative circuit can be used as a bypass electrical path after the LED fault, and the voltage on the substitute circuit when the electrical path is bypassed is less than the LED fault. The front voltage, and thus the operating current after the LED fault, compensates for the illuminance drop after the LED fault.

In view of this, the present invention discloses an LED fault tolerant technology, which proposes to use a bypass circuit to be connected in parallel with an LED, so that after the LED open circuit failure, the bypass circuit connected in parallel with the fault LED is used as an alternative to the fault LED. And when the LED is in operation, the bypass circuit connected in parallel with the LED exhibits a high impedance off state. Wherein, unlike the prior art, the current and voltage on the bypass circuit, which is fault tolerant after the failure of the LED, can be equal to the current and voltage on the LED before the LED failure. Thus, for the power supply circuit that supplies power to the LED, the power supply circuit can be unaffected when the bypass circuit in parallel with the fault LED is replaced with fault tolerance after the LED failure.

It is an object of the present invention to provide an LED fault tolerant circuit in a circuit that is arranged in response to a fault and continuation of the corresponding LED device by an arrangement of a corresponding LED device connected in parallel with a bypass circuit When the condition of the operating current flowing through the bypass circuit is allowed to occur, the operation of the bypass circuit may not affect the voltage and current on other un-faulted components in the circuit, so that the energy consumption of other un-faulted components may be unaffected. .

Another object of the present invention is to provide an LED fault tolerant circuit in a circuit that is responsive to a fault and continuation of the corresponding LED device by an arrangement of a corresponding LED device connected in parallel with a bypass circuit When the condition of the operating current flowing through the bypass circuit is allowed to occur, the operating current value flowing through the bypass circuit is greater than the value of the operating current flowing before the corresponding LED failure is relatively large. Setting a current value such that a voltage value of the bypass circuit obtained by circulating the working current on the bypass circuit is greater than a voltage value of the corresponding LED before the corresponding LED failure, and thus reducing the operation after the corresponding LED failure Current value.

It is a further object of the present invention to provide an LED fault tolerant circuit in a circuit that is arranged in response to a fault and continuation of the corresponding LED device by an arrangement of a corresponding LED device connected in parallel with a bypass circuit When the condition of the operating current flowing through the bypass circuit is allowed to occur, the operating current value flowing through the bypass circuit is smaller than the operating current value flowing before the corresponding LED failure is relatively small. Setting a current value such that a voltage value of the bypass circuit obtained by circulating the working current on the bypass circuit is smaller than a voltage value of the corresponding LED before the corresponding LED failure, and thus improving the operation of the corresponding LED failure Current value.

The main technical idea of the method of the present invention is to make the bypass circuit respond to a fault of the corresponding LED device and continue to allow the circuit to circulate the operating current by the arrangement of a corresponding LED device connected in parallel with a bypass circuit. On the circuit, and when the operating current flowing on the bypass circuit is equal to a set current value, the bypass circuit has a corresponding set voltage value corresponding to the set current value, wherein the corresponding set voltage value is equal to the corresponding LED The total forward voltage value at which the set current value in the forward direction flows through the device. Thus, when replaced as a fault LED When the bypass circuit of the circuit of the present invention is operated, the current value and the voltage value of the bypass circuit may be the same as the current value and the voltage value before the failure of the LED device. When the bypass circuit of the circuit of the present invention responds to the failure of the corresponding LED device and continues to allow the circulating operating current to be on the bypass circuit, the operation of the bypass circuit may not affect the voltage and current on other un-faulted components in the circuit. .

Secondly, the operating current on the bypass circuit is further operated when the operating current value flowing through the bypass circuit is greater than the set current value by the bypass circuit of the circuit of the present invention replaced by the fault LED. A corresponding operating voltage value is greater than a corresponding set voltage value of the pair of set current values that the bypass circuit circulates through the set current. Therefore, in the case where the power supply circuit for supplying power to the LED has a relatively large operating current value before the corresponding LED failure, the operating current value of the power supply circuit can be reduced after the LED failure.

Alternatively, in the case where the bypass circuit of the circuit of the present invention, which is replaced by the fault LED, operates, the operating current value on the bypass circuit is obtained when the operating current value flowing through the bypass circuit is less than the set current value. A corresponding operating voltage value is less than a corresponding set voltage value of the pair of set current values that the bypass circuit circulates through the set current. Therefore, for the power supply circuit that supplies power to the LED, under the condition that the operating current value flowing before the corresponding LED failure is relatively small, the operating current value of the power supply circuit can be increased after the LED failure.

In another aspect, the present invention also provides an LED illumination system employing the method of the present invention, the system combining a plurality of the above-described circuits of the present invention using the method of the present invention to obtain a string formed by the circuit of the present invention; and, in the present invention In the system, a circuit is used to supply a series of operating currents through the circuit of the present invention.

Therefore, when the operating current value circulating on the fault-tolerant circuit is greater than a set current value, the current of the LED lighting device can be reduced to prevent the excessive current from continuing to deteriorate; When the operating current value on the wrong circuit is less than a set current value, the current of the LED lighting device can be increased to prevent further reduction of the luminous intensity and illumination of the LED lighting device.

To achieve the above object, the present invention provides a fault tolerance method for an LED fault tolerant circuit, comprising: providing a circuit to supply an LED device, and circulating an operating current in a forward direction on the LED device; and connecting the LED device in parallel a bypass circuit as a bypass electrical path for responding to a fault of the LED device and continuing to allow the circuit to circulate the operating current on the bypass circuit; and wherein the bypass circuit supplies power to the LED In the device, a high-impedance cut-off state is presented; wherein, for the bypass circuit as an electrical path condition of the bypass, when the current value flowing through the bypass circuit is equal to a set current value, the bypass circuit has a Corresponding to the set voltage value corresponding to the current value, and the corresponding set voltage value is equal to the total forward voltage value when the set current value in the forward direction flows through the LED device, and the set current value is smaller than the LED device Maximum forward current; wherein for the bypass circuit as the electrical path condition of the bypass, when the operating current value flowing through the bypass circuit is greater than the setting At a current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is greater than a total forward voltage value corresponding to the operating current of the LED device; wherein the bypass circuit serves as an electrical path condition of the bypass, When the operating current value flowing through the bypass circuit is less than the set current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is less than the total forward voltage value corresponding to the operating current of the LED device.

Further, wherein the LED device is an LED component or a series of LED components of a selected number of LED components.

Alternatively, wherein the set current value is less than or equal to the rated current of the LED device.

Further, the method of the present invention includes: the bypass circuit monitors performance of the LED device; and, in response to the failure of the LED device, turns on a switch in the bypass circuit and allows the operating current to pass through a current limiting unit To become the electrical path of the bypass.

Further, the method of the present invention includes: supplying, by the circuit, a plurality of LED device series connected in series by the LED devices, and circulating an operating current in a forward direction on the LED device string; wherein each of the LEDs Each of the devices is coupled in parallel with a bypass circuit that is an electrical path of a bypass such that the bypass circuit is responsive to a failure of the LED device in parallel and continues to allow the circuit to circulate the operating current The bypass circuit; and wherein the bypass circuit exhibits a high impedance off state when the circuit supplies power to the paralleled LED device.

In addition, in order to achieve the above object, the present invention provides an LED fault tolerant circuit, comprising: an LED device configured to supply a working current through a circuit through a LED device, the operating current flowing through the LED a forward direction of the LED component of the device, and the LED device is an LED component or a series of LED components of a selected number of LED components; a bypass circuit configured to be connected in parallel with the LED device to serve as a side An electrical path of the circuit for responding to a fault of the LED device and continuing to allow the circuit to circulate the operating current on the bypass circuit; and further, the bypass circuit exhibits a high voltage when the circuit supplies power to the LED device An off state of the impedance; wherein, for the bypass circuit as an electrical path condition of the bypass, when the current value flowing through the bypass circuit is equal to a set current value, the bypass circuit has a pair of current values that should be set Corresponding to a set voltage value, and the corresponding set voltage value is equal to a total forward voltage value when the set current value in a forward direction flows through the LED device, and the setting Means the current value is less than the maximum LED forward current; wherein the bypass circuit for the bypass electrically as a path condition, when the operating current value flowing through the bypass circuit is greater than the set current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is greater than a total direction corresponding to the working current of the LED device a voltage value; wherein, for the bypass circuit as an electrical path condition of the bypass, when the operating current value flowing through the bypass circuit is less than the set current value, the bypass circuit corresponds to the working current The voltage value is less than a total forward voltage value corresponding to the operating current of the LED device.

Further, wherein the set current value is less than or equal to a rated current of the LED device.

Further, the bypass circuit further includes: a sensing component configured to sense a fault of the LED device and to provide a control signal in response to the fault; a switching component configured to provide the side The circuit circuit is responsive to the control signal; and a current limiting unit at both ends is configured to allow the operating current to pass through the current limiting unit when the switching element responsive to the control signal is turned on, so that the bypass circuit acts as the The electrical path of the bypass.

Further, wherein the current limiting unit is a resistor at both ends or a circuit having a current limiting component characteristic at both ends; wherein the circuit having the characteristics of the current limiting component at both ends may be A circuit having a single element at both ends, or a circuit of a plurality of elements at both ends, provides electrical characteristics such as a current limiting diode.

Further, to achieve the above object, the present invention proposes a system employing the method of the present invention to complete the implementation of the method of the present invention. The present invention provides an LED illumination system having an LED fault tolerant circuit, the system comprising: a selected number of LED devices configured to be connected in series in a forward direction to form a series of LED devices, and the LED device is an LED a component or a series of LED elements of a selected number of LED elements; a circuit configured to supply an operating current When the LED device is serially arranged, the operating current flows in a forward direction of the LED elements of the LED device series; and each of the LED devices is connected in parallel with a bypass circuit; wherein the bypass circuit is configured to Actuating as a bypass electrical path for responding to a fault in the parallel connected LED device and continuing to allow the circuit to circulate the operating current on the bypass circuit, and the bypass circuit supplies power to the parallel circuit in the circuit The LED device exhibits a high impedance off state; wherein the bypass circuit acts as an electrical path condition of the bypass, and the bypass circuit is when a current value flowing through the bypass circuit is equal to a set current value Having a pair of corresponding set voltage values that should set a current value, and the corresponding set voltage value is equal to a total forward voltage value when the set current value in a forward direction flows through the LED device, and the set current value is smaller than the a maximum forward current of the LED device; wherein, for the bypass circuit as an electrical path condition of the bypass, when the operating current value flowing through the bypass circuit is greater than the set current value The corresponding operating voltage value corresponding to the operating current of the bypass circuit is greater than a total forward voltage value corresponding to the operating current of the LED device; wherein the bypass circuit acts as an electrical path condition of the bypass when flowing through the When the operating current value of the bypass circuit is less than the set current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is smaller than the total forward voltage value corresponding to the operating current of the LED device.

The present invention may have various other and not identical physicalization measures as far as the present invention is actually carried out, together with the consideration and description of the following figures; it is possible to modify only the details of the present invention without departing from the present invention. The present invention has been described with respect to the technical matters described in the claims. The description and drawings of the present invention are intended to be regarded as merely illustrative in nature and not limitation.

+, 1‧‧‧ positive endpoint

-, 2‧‧‧ negative endpoint

10, L1, L2, L3, L4‧‧‧ LED devices

10a, 10b, 10c, 10d‧‧‧ LED components

20, 21, 22, 23, 23a, 23b, 23c, 23d‧‧‧ bypass circuit

31‧‧‧ Current limiting unit

41, 42, 43‧‧‧ Control signals

51‧‧‧SCR (one-way thyristor)

61, Z1, Z2, Z3, Z4‧‧‧ Zener diode

62, 63, 64, 100‧‧‧ resistance

71, 72, 73, 74, 75‧‧‧ nodes of the circuit

90, 91, 92‧ ‧ div.

A‧‧‧The relationship between forward voltage and current on a specific LED device

B‧‧‧Partial relationship between forward voltage and current of a bypass circuit of the invention as a bypass electrical path

The relationship between the forward voltage and current on the C, E‧‧‧ LED components

D, F‧‧‧ The relationship between the forward voltage and current of a bypass circuit of the invention as a bypass electrical path

ISET‧‧‧Set current

I1‧‧‧ is greater than the operating current of the set current ISET

I2‧‧‧ is less than the operating current of the set current ISET

VSET‧‧‧Set voltage

V1A‧‧‧ Total forward voltage value when operating current value I1 is distributed on a specific LED device

V2A‧‧‧ Total forward voltage value when operating current value I2 on a particular LED device

Total forward voltage value when operating current value I1 flows on V1C, V1E‧‧‧ an LED component

Total forward voltage value when operating current value I2 is distributed on V2C, V2E‧‧‧ LED devices

A corresponding operating voltage value of the operating current value I1 on the V1B, V1D, V1F‧‧‧ bypass circuit

A corresponding operating voltage value of the operating current value I2 on the V2B, V2D, V2F‧‧‧ bypass circuit

The illustration of the invention is illustrated by way of example and not of limitation. Similar in the figure The components are denoted by like reference numerals, and a few embodiments of the invention are illustrated by the following figures, which are illustrated as follows:

The first figure is a circuit outline of a conventional LED fault tolerant circuit.

The characteristic curve A of the second figure is an illustration of the relationship between the forward voltage and the current on a particular LED device; the characteristic curve B is a bypass circuit used in the present invention connected in parallel with the specific LED device as a bypass In the electrical path, the bypass circuit crosses the voltage and current in part.

The third through third figures D are circuit diagrams of several LED fault tolerant circuits of the present invention, each illustrating an embodiment of the inventive circuit embodying the method of the present invention.

The fourth to fourth C diagrams illustrate some of the existing circuits having current limiting element characteristics at both ends.

The characteristic curve C of the fifth figure is the relationship between the forward voltage and the current on an LED element, wherein the LED element is a white LED element having a total forward voltage value ranging between 2.5-3.3 volts; D is a bypass path of the present invention connected in parallel with the LED element as a bypass electrical path, the bypass circuit bypassing the relationship between voltage and current, wherein the bypass circuit is in the third A diagram The circuit outline is shown as a practical embodiment of the embodiment, and the current limiting unit in this illustration is a resistor at both ends.

The sixth through sixth C diagrams are each an outline of a circuit containing four LED fault tolerant circuits of the present invention.

The characteristic curve E of the seventh figure is the relationship between the forward voltage and the current on an LED element, wherein the LED element is a white LED having a total forward voltage value ranging between 2.5 and 3.3 volts. The characteristic curve F is a forward bypass voltage and current relationship of the bypass circuit when the bypass circuit of the present invention is connected in parallel with the LED element as a bypass electrical path, wherein the bypass circuit is The circuit outline of the three A diagram is shown as another practical embodiment of the embodiment, and the current limiting unit in this illustration is a current limiting element exemplifying one of the two end points in the fourth C diagram.

The prior art of U.S. Patent No. 6,650,064 discloses that a Zener diode as a bypass circuit is configured in parallel with a group of LEDs (light-emitting diodes), and the collapse threshold voltage of the Zener diode is selected to be equal to or slightly The total forward voltage value is greater than the maximum current of the group of LEDs, so that after the group of LEDs fails, the Zener diode is turned on as a bypass of the set of LEDs to replace the current path. The Zener diode after the turn-on provides a breakdown voltage. And in the normal operation of the group of LEDs, the Zener diode connected in parallel with the set of LEDs has almost no current passing, so that the Zener diode as a bypass circuit exhibits a high impedance off state.

However, with the prior art described above, after a set of LED faults, when a Zener diode is substituted for the set of fault LEDs, the Zener diode provides a breakdown voltage as a substitute voltage, which is impossible to be equal to the set of LEDs. The operating voltage of the set of LEDs in normal operation, and maintaining the same amount of operating current flowing through the Zener diode. Also, in normal operation of the set of LEDs, the Zener diode exhibits a high impedance cutoff state. In particular, in the actual work, the same type of LED produced in the same batch, the characteristics of each LED are often inconsistent.

To improve the above problems, the method of the present invention is similar to the prior art in that a bypass circuit is connected in parallel with a group of LEDs, and after the group of LEDs fails, the bypass circuit operates. Unlike prior art bypass circuits that essentially provide a voltage as an alternative to LED failure, the present invention provides a fault tolerant method in which a bypass circuit of the circuit of the present invention is required to operate in parallel with a set of faulty LEDs. The current value and voltage value of the bypass circuit may be the same as the current value and voltage value before the group of LED faults.

In the following, the present invention will be described with reference to the accompanying drawings.

To illustrate the means of the method of the present invention, a fault-tolerant method in accordance with the present invention is illustrated by exemplifying a relative comparison of characteristic curve A and characteristic curve B of the second figure. The characteristic curve A of the second figure is an illustration of the relationship between the forward voltage and the current on a particular LED device; the characteristic curve B is a bypass circuit of the invention connected in parallel with the specific LED device as a bypass In the case of an electrical path, the forward path of the bypass circuit is a partial relationship between voltage and current. Wherein, the specific LED device is an LED component or a series of LED components of a selected number of LED components. Moreover, the bypass circuit used in the present invention in parallel with the particular LED device exhibits a high impedance off state when the particular LED device is in operation.

In the second figure, according to the method of the present invention, for the bypass circuit as the electrical path condition of the bypass, when the current value flowing through the bypass circuit is equal to a set current value ISET, the bypass circuit has a Corresponding set voltage value VSET corresponding to the current value is set, and the corresponding set voltage value VSET is equal to the total forward voltage value VSET when the set current value ISET in a forward direction flows through the specific LED device, and the set current is The value ISET is less than the maximum forward current of the particular LED device; wherein the operating current value I1 on the bypass circuit when the operating current value I1 flowing through the bypass circuit is greater than the set current value ISET a corresponding operating voltage value V1B is greater than a total forward voltage value V1A when the operating current value I1 flows through the particular LED device; and wherein the operating current value I2 flowing through the bypass circuit is less than the set current When the value is ISET, a corresponding operating voltage value V2B of the operating current value I2 on the bypass circuit is smaller than a total forward voltage value V2A when the operating current value I2 flows through the specific LED device.

In order to practice the method of the present invention, the present invention provides a circuit outline of the LED fault tolerant circuit of the present invention using the method of the present invention as an illustration of an embodiment of the method of the present invention.

The third through third figures D are circuit diagrams of several LED fault tolerant circuits of the present invention, each illustrating an embodiment of the method of the present invention.

The third A is a circuit outline of an embodiment of the LED fault tolerant circuit of the present invention. A positive terminal 1 and a negative terminal 2 of the two ends of a bypass circuit 20 are connected in parallel to the ends of an LED device 10. The LED device 10 can be an LED component or a series of LED components of a selected number of LED components; and the LED device 10 is configured such that when a circuit (not shown) supplies an operating current through the positive terminal 1 When the LED device 10 flows to the negative terminal 2, the operating current flows in a forward direction of the LED elements of the LED device 10.

The bypass circuit 20 of the third embodiment A includes a Zener diode 61 at both ends, a current limiting unit 31 at both ends, and an SCR (one-way thyristor) 51 as a switching element, wherein the Zener The cathode and anode of the diode 61 are connected in parallel to the anode and gate of the SCR 51 between the node 71 and the node 72. Thus, the Zener diode 61 forms a voltage dividing circuit 90 with the gate and cathode of the SCR 51. Also in the bypass circuit 20, the first terminal of the current limiting unit 31 is connected to the positive terminal 1, the second terminal of the current limiting unit 31 is connected to the node 71, and the cathode of the SCR 51 is connected to The negative endpoint 2.

The operation of the above circuit 20 is described as follows: When a circuit (not shown) supplies an operating current to the LED device 10, the bypass circuit 20 assumes a high impedance off state. The LED device 10 connected in parallel with the bypass circuit 20 fails, causing current to flow from the positive terminal 1 to the Zener Diode 61. When the voltage across the Zener diode 61 increases, a control signal 41 is provided to the gate of the SCR 51. The Zener diode 61 is selected such that the voltage at the node 72 as the control signal 41 is sufficient to turn on the SCR 51 as a switching element. Once the SCR 51 is turned on, the operating current flows from the positive terminal 1 through the current limiting unit 31, through the SCR 51, to the negative terminal 2, thereby making the bypass circuit 20 a bypass electrical path. .

Further, as the current through the current limiting unit 31 increases, the voltage across the current limiting unit 31 will increase. Moreover, the current limiting unit 31 is appropriately selected so that the bypass circuit 20 serves as an electrical path condition of the bypass, and when the current flowing through the bypass circuit 20 is equal to a set current, the bypass circuit 20 Having a pair of corresponding set voltage values that should set a current value, and the corresponding set voltage value is equal to a total forward voltage value when the set current in a forward direction flows through the LED device 10, and the set current value is smaller than the The maximum forward current of the LED device 10.

In circuit 20, the voltage divider circuit 90 acts as a sensing component to sense a fault in the LED device 10 and as a control signal 41 in response to the fault; the SCR 51 acts as a switching component to provide The bypass circuit 20 is responsive to the control signal 41; and the current limiting unit 31 acts as a current limiting unit at both ends to allow the operating current to pass through the current limiting when the switching element 51 in response to the control signal 41 is turned on. Unit 31 causes the bypass circuit 20 to act as an electrical path for the bypass.

Thus, as further described above, the operation of the method of the present invention with the bypass circuit 20 can be described as follows: the bypass circuit 20 monitors the performance of the LED device 10; and, in response to the failure of the LED device 10, conducts A switch 51 in the bypass circuit 20 allows the operating current to pass through a current limiting unit 31 to become an electrical path for the bypass.

Figure 3B is a circuit diagram of a variation of an embodiment of the LED fault tolerant circuit of the present invention. A positive terminal 1 and a negative terminal 2 of the two ends of a bypass circuit 21 are connected in parallel to the ends of an LED device 10. The LED device 10 can be an LED component or a series of LED components of a selected number of LED components; and the LED device 10 is configured such that when a circuit (not shown) supplies an operating current through the positive terminal 1 When the LED device 10 flows to the negative terminal 2, the operating current flows in a forward direction of the LED elements of the LED device 10.

The bypass circuit 21 of the third B diagram includes a Zener diode 61 at both ends, a current limiting unit 31 at both ends, and an SCR 51, wherein the first end of the current limiting unit 31 is connected to the At the positive end point 1, the second end of the current limiting unit 31 is coupled to the anode of the SCR 51 to the node 73. Also in the bypass circuit 21, the cathode of the Zener diode 61 is connected to the positive terminal 1, and the anode of the Zener diode 61 and the gate of the SCR 51 are connected to the node 72, the SCR The cathode of 51 is connected to the negative terminal 2. Thus, the Zener diode 61 forms a voltage dividing circuit 90 with the gate and cathode of the SCR 51.

The operation of the above circuit 21 is described as follows: When a circuit (not shown) supplies an operating current to the LED device 10, the bypass circuit 21 assumes a high impedance off state. The LED device 10 connected in parallel with the bypass circuit 21 fails, causing current to flow from the positive terminal 1 to the Zener diode 61. When the voltage across the Zener diode 61 increases, a control signal 41 is provided to the gate of the SCR 51. The Zener diode 61 is selected such that the voltage at the node 72 as the control signal 41 is sufficient to turn on the SCR 51 as a switching element. Once the SCR 51 is turned on, the operating current flows from the positive terminal 1 through the current limiting unit 31, through the SCR 51, to the negative terminal 2, thereby making the bypass circuit 21 a bypass electrical path. .

Further, as the current through the current limiting unit 31 increases, the current limit will be made The jumper voltage on element 31 increases until the jumper voltage is limited by the reverse collapse threshold voltage of the Zener diode 61. Moreover, the current limiting unit 31 is appropriately selected so that the bypass circuit 21 serves as an electrical path condition of the bypass, and when the current flowing through the bypass circuit 21 is equal to a set current, the bypass circuit 21 Having a pair of corresponding set voltage values that should set a current value, and the corresponding set voltage value is equal to a total forward voltage value when the set current in a forward direction flows through the LED device 10, and the set current value is smaller than the The maximum forward current of the LED device 10.

Although, unlike circuit 20, the voltage across the circuit 21 will have a critical limit. However, by appropriately selecting the reverse collapse threshold voltage of the Zener diode 61, the limit on the jumper voltage on the circuit 21 can be selected to be greater than the maximum allowable voltage on the particular LED device 10, so in actual use, It can be said that the operating condition of the circuit 21 is substantially similar to the operating condition of the circuit 20.

In the circuit 21, the voltage dividing circuit 90 functions as a sensing element for sensing a fault of the LED device 10, and as a control signal 41 for providing a response to the fault; the SCR 51 acts as a switching element to provide The bypass circuit 21 is responsive to the control signal 41; and the current limiting unit 31 acts as a current limiting unit at both ends to allow the operating current to pass through the current limiting when the switching element 51 in response to the control signal 41 is turned on. Unit 31 causes the bypass circuit 21 to act as an electrical path for the bypass.

Third C is a circuit outline of one other embodiment of the LED fault tolerant circuit of the present invention. A positive terminal 1 and a negative terminal 2 of the two ends of a bypass circuit 22 are connected in parallel to the ends of a light emitting diode (LED) device 10. The LED device 10 can be an LED component or a series of LED components of a selected number of LED components; and the LED device 10 is configured such that when a circuit (not shown) supplies an operating current through the positive terminal 1 The LED device 10 flows At the negative terminal 2, the operating current flows in a forward direction of the LED elements of the LED device 10.

The bypass circuit 22 of the third C diagram includes a voltage dividing circuit 91, a current limiting unit 31 at both ends, and an SCR 51. The voltage dividing circuit 91 includes a resistor 62 and a resistor 63. The two ends of the resistor 62 are connected in parallel to the anode and the gate of the SCR 51 between the node 74 and the node 75; the two ends of the resistor 63 are connected in parallel to the gate and cathode of the SCR 51. Between node 75 and the negative endpoint 2. Also in the bypass circuit 22, the first terminal of the current limiting unit 31 is connected to the positive terminal 1, the second terminal of the current limiting unit 31 is connected to the node 74, and the cathode of the SCR 51 is connected to The negative endpoint 2. Therefore, the resistor 62 and the resistor 63 form a voltage dividing circuit 91.

The operation of the above circuit 22 is described as follows: When a circuit (not shown) supplies an operating current to the LED device 10, the bypass circuit 22 assumes a high impedance off state. The failure of the LED device 10 connected in parallel with the bypass circuit 22 causes the voltage on the voltage dividing circuit 91 to increase. When the voltage across the voltage dividing circuit 91 at node 75 increases until it is large enough to provide a control signal 42 to the gate of the SCR 51. The resistor 62 and the resistor 63 of the voltage dividing circuit 91 are selected such that after the LED device 10 fails, the voltage at the node 75 is sufficient to turn on the SCR 51 as a switching element. Once the SCR 51 is turned on, the operating current flows from the positive terminal 1 through the current limiting unit 31, through the SCR 51, to the negative terminal 2, thereby making the bypass circuit 22 a bypass electrical path. .

Further, as the current through the current limiting unit 31 increases, the voltage across the current limiting unit 31 will increase. Moreover, the current limiting unit 31 is appropriately selected so that the bypass circuit 22 serves as an electrical path condition of the bypass, and when the current flowing through the bypass circuit 22 is equal to a set current, the bypass circuit 22 Having a pair of corresponding set voltage values that should set a current value, and the corresponding set voltage value is equal to the setting in the forward direction of the LED device 10 The total forward voltage value at a constant current, and the set current value is less than the maximum forward current of the LED device 10.

In circuit 22, the voltage dividing circuit 91 acts as a sensing element to sense a fault in the LED device 10 and as a control signal 42 in response to the fault; the SCR 51 acts as a switching element to provide The bypass circuit 22 is responsive to the control signal 42; and the current limiting unit 31 acts as a current limiting unit at both ends to allow the operating current to pass through the current limiting when the switching element 51 in response to the control signal 42 is turned on. Unit 31 causes the bypass circuit 22 to act as an electrical path for the bypass.

The third D diagram is a circuit outline of another embodiment of the LED fault tolerant circuit of the present invention. With respect to the third A diagram, the third D diagram is primarily connected in parallel with the gate and cathode of the SCR 51 by adding an additional resistor 64 in the bypass circuit 23 between the node 72 and the negative terminal 2.

The embodiment of the circuit 23 of the third D diagram is substantially similar to the embodiment of the third A diagram. In the circuit 23, the Zener diode 61 and the resistor 64 form a voltage dividing circuit 92.

The operation of the above circuit 23 is described as follows: When a circuit (not shown) supplies an operating current to the LED device 10, the bypass circuit 23 assumes a high impedance off state. The LED device 10 connected in parallel with the bypass circuit 23 fails, and current flows from the positive terminal 1 to the Zener diode 61, causing the voltage on the voltage dividing circuit 92 to increase. When the voltage across the voltage dividing circuit 92 at node 72 increases until it is large enough to provide a control signal 43 to the gate of the SCR 51. The Zener diode 61 is selected such that the voltage at the node 72 as the control signal 43 is sufficient to turn on the SCR 51 as a switching element. Once the SCR 51 is turned on, the operating current flows from the positive terminal 1 through the current limiting unit 31, through the SCR 51, to the negative terminal 2, thereby making the bypass circuit 23 A bypass electrical path.

Further, as the current through the current limiting unit 31 increases, the voltage across the current limiting unit 31 will increase. Moreover, the current limiting unit 31 is appropriately selected so that the bypass circuit 23 serves as an electrical path condition of the bypass, and when the current flowing through the bypass circuit 23 is equal to a set current, the bypass circuit 23 Having a pair of corresponding set voltage values that should set a current value, and the corresponding set voltage value is equal to a total forward voltage value when the set current in a forward direction flows through the LED device 10, and the set current value is smaller than the The maximum forward current of the LED device 10.

In circuit 23, the voltage dividing circuit 92 acts as a sensing element to sense a fault in the LED device 10 and as a control signal 43 in response to the fault; the SCR 51 acts as a switching element to provide The bypass circuit 23 is responsive to the control signal 43; and the current limiting unit 31 acts as a current limiting unit at both ends to allow the operating current to pass through the current limiting when the switching element 51 in response to the control signal 43 is turned on. Unit 31 causes the bypass circuit 23 to act as an electrical path for the bypass.

As described above, the circuit outlines of the various circuits of the present invention in the third to third D-drawings, and various combinations of the circuit elements in the drawings can be exemplified as an embodiment of the method of the present invention. Moreover, the various circuit schematics illustrated in the third through third figures are merely illustrative and not limiting.

Further, the current limiting unit 31 of the bypass circuit in the above circuit outline may be a resistor at both ends, or a Current Regulating Diode at both ends, or a point at both ends a two-terminal circuit formed by connecting two ends of the resistor to a point of a current regulating diode at both ends, or a terminal having a characteristic of a current limiting unit such as a terminal Point circuit. Wherein, the two-point circuit having the characteristics of the current limiting unit such as the two ends may be a circuit of a single component at both ends, or a circuit of a plurality of components, providing a point such as a terminal point. Electrical characteristics such as a current limiting circuit are exemplified in the fourth to fourth C diagrams.

4A to 4C, each of which exemplifies some existing two-point circuit having an electrical characteristic such as a current limiting circuit, has the characteristics required by the present invention, and can be used as a current limiting unit in the circuit of the present invention. in. The various combinations of elements provided in the above figures are provided by way of illustration and not limitation. Wherein, the fourth A picture is a current regulating diode (CRD) composed of a junction field effect transistor (JFET) as a terminal limiting unit; the fourth B picture is a junction field The utility transistor is connected in parallel with an electric group device as a terminal limiting unit; the fourth C picture is composed of two npn-bipolar junction type transistors (npn-BJT) and two electric groups A conventional two-point point current limiting circuit is formed as a two-point point current limiting unit.

Although, for a short-time working LED, the operating current value flowing on it can be used to be greater than its rated current; however, for an LED operating under normal continuous time, the operating current flowing on it is substantially smaller than its rated current. . Thus, for LEDs that operate in general continuous time, the set current value of the bypass circuit in the method and circuit of the present invention is substantially less than or equal to the rated current of the LED device connected in parallel with the bypass circuit.

The characteristic curve C of the fifth figure is the relationship between the forward voltage and the current on an LED element, wherein the LED element is a white LED element having a forward voltage value ranging between 2.5-3.3 volts; characteristic curve D When the bypass circuit of the present invention connected in parallel with the LED element serves as a bypass electrical path, the bypass circuit bypasses the relationship between voltage and current, wherein the bypass circuit has a third D diagram. The circuit outline is shown as a practical embodiment of the embodiment, and the current limiting unit 31 in this illustration is a resistor at both ends.

To illustrate the fifth diagram, the circuit outline of the third D diagram is taken as an embodiment of the embodiment of the bypass circuit of the present invention, and the current limiting unit 31 in this illustration is a resistor at both ends. Example values of the relevant elements described as a circuit outline in an embodiment of the practical embodiment are: LED device 10 is a white LED rated at 0.02 amps, 3.2 volts (having a forward voltage ranging between 2.5-3.3 volts) Value white LED) component. The relationship between the total forward voltage between the positive terminal 1 and the negative terminal 2 and the forward current of the white LED element 10 is exemplified by the voltage-current characteristic curve C of the fifth diagram. In the bypass circuit 23, the breakdown voltage on the Zener diode 61 is approximately 4.3 volts; the resistance 64 is 1000 ohms; the resistance 31 as a current limiting unit is 115 ohms; and the SCR 51 as a switching element The current at the time of non-conduction is less than 100 mA, the voltage at turn-on is greater than 0.7 volts, and the current at the time of conduction is greater than 0.2 mA. Thus, when the bypass circuit 23 acts as a bypass electrical path, the voltage between the positive terminal 1 and the negative terminal 2 of the bypass circuit 23 flows toward the positive terminal 1 of the bypass circuit 23. The current between the negative terminals 2, the relationship between the two, is exemplified in the voltage-current characteristic curve D of the fifth figure.

The current 0.37 mA exemplified on the curve D of the fifth graph is the current required to maintain the SCR 51 conducting, and the current required to maintain conduction is 0.37 mA at the bypass circuit 23 at the positive terminal 1 and the negative terminal The corresponding voltage between 2 is 0.71 volts. Moreover, the current value ISET exemplified on the curve D of the fifth graph is 20 mA, and the current value ISET is at the corresponding voltage value VSET between the positive terminal 1 and the negative terminal 2 of the bypass circuit 23. It is 3.07 volts.

Therefore, the circuit of the present invention having the fifth graph characteristic curve D, when the bypass circuit 23 is in the electrical path condition of the bypass, when the current flowing through the bypass circuit 23 is equal to a set current value ISET, The bypass circuit has a pair of corresponding set voltage values VSET that should set the current value ISET, and the corresponding set voltage value VSET is equal to the circulation on the LED device 10. a total forward voltage value VSET when the current value ISET is set in a forward direction, and the set current value ISET is smaller than a maximum forward current of the LED device 10; wherein, when the operating current flows on the bypass circuit When the value I1 is greater than the set current value ISET, a corresponding operating voltage value V1D of the operating current value I1 on the bypass circuit is greater than a total forward voltage value when the operating current value I1 flows through the LED device 10. V1C; and wherein, when the operating current value I2 flowing on the bypass circuit is less than the set current value ISET, a corresponding operating voltage value V2D of the operating current value I2 on the bypass circuit is smaller than The total forward voltage value V2C when the operating current value I2 flows through the LED device 10. Among the example values of the actual measurements in this example, I1 is 23 mA, V1C is 3.11 volts, V1D is 3.41 volts, I2 is 17 mA, V2C is 3.01 volts, and V2D is 2.72 volts.

Moreover, for the circuit outlines of the various sample invention circuits exemplified in the third to third D diagrams, each can be described as follows: an LED device configured to supply a working current through the LED device with a circuit, The operating current flows in a forward direction of the LED component of the LED device, and the LED device is an LED component or a series of LED components of a selected number of LED components; a bypass circuit configured to be associated with the LED The devices are connected in parallel as a bypass electrical path for responding to a fault of the LED device and continuing to allow the circuit to circulate the operating current on the bypass circuit; and wherein the bypass circuit supplies power to the circuit In the case of the LED device, a high impedance off state is present; wherein, for the bypass circuit as an electrical path condition of the bypass, when the current value flowing through the bypass circuit is equal to a set current value, the bypass circuit has a pair of corresponding set voltage values that should set a current value, and the corresponding set voltage value is equal to a total forward voltage value when the set current value in a forward direction flows through the LED device, and The set current value is less than the maximum LED forward current means; wherein the operating current value as the bypass circuit for the bypass electrical path conditions, when the flow through the bypass circuit is greater than the set current a value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is greater than a total forward voltage value corresponding to the operating current of the LED device; wherein, for the bypass circuit, the electrical path condition of the bypass is When the operating current value flowing through the bypass circuit is less than the set current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is smaller than the total forward voltage value corresponding to the operating current of the LED device.

Thus, in the case of one of the circuits of the third to third D diagrams as an embodiment of the fault-tolerant method according to the present invention, the operation is to provide a circuit (not shown) for supplying an LED device 10 and circulating the LED device. 10 a working current in a forward direction; a bypass circuit connected in parallel with the LED device 10 as a bypass electrical path for allowing the circuit to circulate the operating current in response to a fault of the LED device 10 On the bypass circuit; further, the bypass circuit exhibits a high impedance off state when the circuit (not shown) supplies power to the LED device 10; wherein the bypass circuit serves as an electrical path for the bypass a condition, when a current value flowing through the bypass circuit is equal to a set current value, the bypass circuit has a pair of corresponding set voltage values that should set a current value, and the corresponding set voltage value is equal to being circulated on the LED device 10. a total forward voltage value at the set current in a forward direction, and the set current value is smaller than a maximum forward current of the LED device 10; wherein the bypass circuit serves as an electrical path of the bypass When the operating current value flowing through the bypass circuit is greater than the set current value, the bypass circuit has a corresponding operating voltage value corresponding to the operating current greater than a total forward direction when the operating current is distributed on the LED device 10. a voltage value; wherein, for the bypass circuit as an electrical path condition of the bypass, when the operating current value flowing through the bypass circuit is less than the set current value, the bypass circuit corresponds to the working current The voltage value is less than the total forward voltage value when the operating current is flowing through the LED device 10.

6A through 6C are each a circuit outline containing four LED fault tolerant circuits of the present invention to illustrate an embodiment of the LED lighting system with LED fault tolerant circuitry of the present invention embodying the method of the present invention.

Figure 6A is a schematic diagram of a circuit with a resistor 100 connected in series with a set of four inventive circuits in series to the ends of a circuit (not shown) ("+" positive terminal and "-" negative terminal) . In the sixth picture B, the sixth A picture is powered at the two ends of the circuit (not shown) (the "+" positive terminal and the "-" negative terminal), and the current path for supplying an operating current contains normal operation. All four LED components. In the sixth C picture, the sixth picture A is powered at the two ends of the circuit (not shown) ("+" positive terminal and "-" negative terminal), and when one LED element fails, the circuit is powered. The current path of the operating current passes through the corresponding bypass circuit of the faulty LED component.

For an embodiment of the embodiment of the system of the present invention, in the respective figures of the sixth through sixth embodiments, four LED elements 10a, 10b, 10c, 10d are connected in series in the forward direction to form an LED. Device string. Moreover, the LED device series is connected in series via a resistor 100 to the two end points of a power supply circuit (not shown) ("+" positive terminal and "-" negative terminal). Each of the LED elements 10a, 10b, 10c, 10d serves as an LED device, and each of the LED elements 10a, 10b, 10c, 10d is connected in parallel with a bypass circuit 23a, 23b, 23c, 23d. Moreover, the bypass circuits 23a, 23b, 23c, 23d in this embodiment are represented by the circuit outline of the third D diagram as an embodiment of the above-described embodiment of the bypass circuit of the system of the present invention, and the current limiting unit in this illustration 31 is a resistor at both ends.

For example, example values of the relevant elements in the circuits of the sixth to sixth C diagrams as an embodiment of the practical embodiment are: the resistance 100 is 100 ohms; the LED elements 10a, 10b, 10c, 10d are each rated at 0.02. Ampere, 3.2 volt white LED (with a range between 2.5-3.3 volts) a white LED of a forward voltage value; in the above bypass circuits 23a, 23b, 23c, 23d, the breakdown voltage on the Zener diode is about 4.3 volts; the resistance is 1000 ohms; the resistance as a current limiting unit It is 115 ohms; and the current when the SCR 51 is not turned on as a switching element is less than 100 mA, the voltage at the time of conduction is greater than 0.7 volts, and the current at the time of conduction is greater than 0.2 mA. Therefore, as an embodiment of the practical embodiment, for the condition that the bypass circuits 23a, 23b, 23c, and 23d are used as a bypass electrical path, the bypass circuits each have a forward voltage and current across the circuit. The relationship, as exemplified in the characteristic curve D of the fifth graph, is an example value of an actual measurement, I1 is 23 mA, V1C is 3.11 volts, V1D is 3.41 volts, I2 is 17 mA, V2C is 3.01 volts. V2D is 2.72 volts. Further, the set currents of the bypass circuits 23a, 23b, 23c, and 23d are set to 20 mA, and the corresponding set voltage VSET corresponding to the set current ISET of 20 mA is 3.07 volts.

For the circuit in Figure 6B, the supply point voltage ("+" positive terminal and "-" negative terminal) of the circuit (not shown) is approximately 14.48 volts, and the current flowing through resistor 100 is At 20 mAh, the actual measured value under normal operation, the voltage of the LED element 10a is about 3.08 volts, the voltage of the LED element 10b is about 3.07 volts, the voltage of the LED element 10c is about 3.2 volts, and the voltage of the LED element 10d is about At 3.12 volts, the voltage of resistor 100 is approximately 2 volts.

Then, when the LED element 10b fails, the current path of the operating current supplied by the circuit is shown in the sixth C diagram, the supply voltage of the circuit (not shown) is maintained at 14.48 volts, and the actual value of one measurement in this case, the LED element 10a The voltage is approximately 3.08 volts, the voltage of the bypass circuit 23b is approximately 3.07 volts, the voltage of the LED element 10c is approximately 3.2 volts, and the voltage of the LED element 10d is approximately 3.12 volts. Moreover, the voltage of the resistor 100 is maintained at 2 volts, and the current across the resistor 100 remains unchanged at 20 mA.

Thus, as exemplified by the above-described practical embodiments, unlike the prior art providing a specific voltage as an alternative to a faulty LED, the embodiment provided by the method of the present invention operates by the bypass circuit 23b of the circuit of the present invention as an alternative to the faulty LED 10b. It is possible to obtain the current value and the voltage value of the bypass circuit 23b, and have the same current value and voltage value before the failure of the group of LEDs 10b.

In this case, in the above-described example, for the LED fault-tolerant circuit of the present invention in which the bypass circuit 23b is connected in parallel with the LED element 10b, when an operating current is supplied by a circuit through the LED fault-tolerant circuit of the present invention, When the bypass circuit 23b of the inventive circuit responds to the failure of a corresponding LED 10b and continues to allow the circulating operating current to be on the bypass circuit 23b, the operation of the bypass circuit 23b may not affect the voltage and current on other un-faulted components in the circuit. So that the energy consumption on other unbroken components can be unaffected.

Further, in the circuit of FIG. B, the power supply voltages of the two ends of the circuit (not shown) ("+" positive terminal and "-" negative terminal) are approximately 15.04 volts, and flow through the resistor 100. When the current is 23 mA, the actual measured value under normal operation, the voltage of the LED element 10a is about 3.15 volts, the voltage of the LED element 10b is about 3.11 volts, the voltage of the LED element 10c is about 3.29 volts, and the LED element 10d The voltage is approximately 3.17 volts and the voltage of resistor 100 is approximately 2.3 volts.

Then, when the LED element 10b fails, the current path of the operating current supplied by the circuit (not shown) is shown in the sixth C diagram, and the supply voltage of the circuit (not shown) is maintained at 15.04 volts, and the actual value measured once in this case, The voltage of the LED element 10a is approximately 3.1 volts, the voltage of the bypass circuit 23b is approximately 3.31 volts, the voltage of the LED element 10c is approximately 3.27 volts, and the voltage of the LED element 10d is approximately 3.16 volts. Moreover, the voltage of the resistor 100 is 2.18 volts, and the resistor 100 The current on the current is 21.8 mA, so that the operating current of the power supply can approach the set current ISET of the bypass circuit 23b under the condition that the power supply voltage remains unchanged.

Alternatively, for the circuit of Figure B, the supply point voltage ("+" positive terminal and "-" negative terminal) of the circuit (not shown) is approximately 14 volts, and the current flowing through resistor 100 is At 17 mAh, the actual measured value under normal operation, the voltage of the LED element 10a is about 3.03 volts, the voltage of the LED element 10b is about 3.03 volts, the voltage of the LED element 10c is about 3.14 volts, and the voltage of the LED element 10d is about At 3.06 volts, the voltage of resistor 100 is approximately 1.7 volts.

Then, when the LED element 10b fails, the current path of the operating current supplied by the circuit (not shown) is shown in the sixth C diagram, the supply voltage of the circuit (not shown) is maintained at 14 volts, and the actual value measured once in this case, The voltage of the LED element 10a is approximately 3.05 volts, the voltage of the bypass circuit 23b is approximately 2.83 volts, the voltage of the LED element 10c is approximately 3.18 volts, and the voltage of the LED element 10d is approximately 3.09 volts. Moreover, the voltage of the resistor 100 is 1.78 volts, and the current on the resistor 100 is 17.8 mA, so that the operating current of the power supply can approach the set current ISET of the bypass circuit 23b under the condition that the power supply voltage remains unchanged.

The above situation, unlike the prior art providing a specific voltage as an alternative to a faulty LED, can achieve the object of the present invention by implementing the method of the present invention with the circuit of the present invention. Wherein, when the LED is faulty and the fault-tolerant circuit is used as the bypass circuit, the operating current flowing through the bypass circuit is greater than the operating current flowing on the LED before the LED failure is relatively large. A current value ISET is set such that the voltage of the bypass circuit obtained by circulating the operating current on the bypass circuit is greater than the LED voltage before the LED failure, and thus the operating current after the LED failure is reduced. Therefore, the operating current flowing in the LED of the present invention is relatively large, and when the LED is faulty, the operating current after the LED fault can be reduced to protect the LED after the fault.

Further, when the LED is faulty and the fault-tolerant circuit is operated as the bypass circuit, the operating current value of the circuit of the present invention flowing through the bypass circuit is less than one when the operating current flowing before the LED failure is relatively small. The current value ISET is set such that the voltage of the bypass circuit obtained by circulating the operating current on the bypass circuit is smaller than the LED voltage before the LED failure, and thus the operating current after the LED failure can be increased. Therefore, in the present invention, when the operating current flowing through the LED is less than a certain value, the operating current after the LED failure can be increased to compensate for the decrease in illumination after the LED failure.

Further, for an embodiment of the inventive LED illumination system illustrated in Figures 6A through 6C, it can be described as follows: A selected number of LED devices 10a, 10b, 10c, 10d are configured to be connected in series Connecting to form a LED device string, and the LED device 10a, 10b, 10c, 10d is an LED component; a circuit configured to supply a working current through the LED device string when the operating current flows therethrough a forward direction of the LED elements of the LED device; and each of the LED devices 10a, 10b, 10c, 10d is connected in parallel with a bypass circuit 23a, 23b, 23c, 23d; wherein the bypass circuits 23a, 23b , 23c, 23d are configured as a bypass electrical path for responding to a fault in the parallel connected LED devices 10a, 10b, 10c, 10d and continuing to allow the circuit to circulate the operating current in the bypass circuit 23a And 23b, 23c, 23d, and the bypass circuits 23a, 23b, 23c, 23d exhibit a high impedance off state when the circuit supplies power to the parallel LED devices 10a, 10b, 10c, 10d; For the bypass circuits 23a, 23b, 23c, 23 d is the electrical path condition of the bypass, and when the current flowing through the bypass circuits 23a, 23b, 23c, 23d is equal to a set current value, the bypass circuits 23a, 23b, 23c, 23d have a pair to be set. a corresponding set voltage value of the current value, and the corresponding set voltage value is equal to the total forward direction when the set current value in the forward direction flows through the LED devices 10a, 10b, 10c, 10d a voltage value, and the set current value is less than a maximum forward current of the LED devices 10a, 10b, 10c, 10d; wherein the bypass circuit 23a, 23b, 23c, 23d serves as an electrical path condition of the bypass when circulating When the operating current value of the bypass circuits 23a, 23b, 23c, 23d is greater than the set current value, a corresponding operating voltage value of the operating current on the bypass circuits 23a, 23b, 23c, 23d is greater than a total forward voltage value when the operating current flows through the LED devices 10a, 10b, 10c, and 10d; wherein the bypass circuits 23a, 23b, 23c, and 23d serve as electrical paths of the bypass when they are distributed When the operating current value of the bypass circuits 23a, 23b, 23c, 23d is less than the set current value, a corresponding operating voltage value of the operating current on the bypass circuits 23a, 23b, 23c, 23d is smaller than the LED The total forward voltage value at which the operating current flows through the devices 10a, 10b, 10c, and 10d.

Therefore, when the circuit outline of FIG. 6A is taken as an embodiment of the fault-tolerant method according to the present invention, the working process is: a series of LED devices formed by connecting a plurality of LED devices 10a, 10b, 10c, and 10d in series by a circuit. And circulating an operating current in a forward direction on the LED device string; wherein each of the LED devices 10a, 10b, 10c, 10d and a bypass circuit 23a, 23b, 23c as an electrical path of a bypass And 23d are connected in parallel such that the bypass circuit 23a, 23b, 23c, 23d responds to a failure of the LED devices 10a, 10b, 10c, 10d connected in parallel and continues to allow the circuit to circulate the operating current in the bypass circuit 23a And 23b, 23c, 23d; and wherein the bypass circuit exhibits a high impedance off state when the circuit supplies power to the paralleled LED devices 10a, 10b, 10c, 10d. Moreover, as previously described, during its operation, the bypass circuits 23a, 23b, 23c, 23d serve as electrical paths for the bypass, when currents flowing through the bypass circuits 23a, 23b, 23c, 23d When the value is equal to a set current value, the bypass circuits 23a, 23b, 23c, and 23d have a pair of corresponding set voltage values that should set a current value. And the corresponding set voltage value is equal to the total forward voltage value when the LED device 10a, 10b, 10c, 10d flows the set current value in a forward direction, and the set current value is smaller than the LED device 10a, 10b, 10c Maximum forward current of 10d; during operation, the bypass circuits 23a, 23b, 23c, 23d serve as electrical paths of the bypass when circulating in the bypass circuits 23a, 23b, 23c, 23d When the operating current value is greater than the set current value, a corresponding operating voltage value of the operating current in the bypass circuits 23a, 23b, 23c, 23d is greater than the operating current flowing through the LED devices 10a, 10b, 10c, 10d. The total forward voltage value of the time; during operation, the bypass circuit 23a, 23b, 23c, 23d serves as an electrical path condition of the bypass when flowing through the bypass circuits 23a, 23b, 23c, 23d When the operating current value is less than the set current value, a corresponding operating voltage value of the operating current on the bypass circuits 23a, 23b, 23c, 23d is smaller than the circulating current in the LED devices 10a, 10b, 10c, 10d. The total forward voltage value at current.

Although the implementation of the present invention has been exemplified as in the above example, the current limiting unit 31 such as the bypass circuit is a resistor at both ends; however, the current limiting unit 31 of the bypass circuit can also be exemplified in the fourth A. A fourth-end point current limiting unit having the characteristics of the current limiting circuit at both ends is shown in FIG.

Similar to the fifth figure, the characteristic curve E of the seventh figure is the relationship between the forward voltage and the current on an LED element, wherein the LED element has a forward voltage value ranging between 2.5 and 3.3 volts. The white LED component; the characteristic curve F is a forward bypass voltage and current relationship of the bypass circuit when the bypass circuit of the invention connected in parallel with the LED component is used as a bypass electrical path, wherein the bypass The circuit is shown as another practical embodiment of the third D diagram, and the current limiting unit 31 in this illustration is a current limiting circuit illustrating a two-point point in the fourth C diagram. Wherein, the fourth C picture is composed of two npn-bipolar junction type transistors (npn-BJT) and two A conventional current limiting circuit composed of a power packer serves as a current limiting unit 31 at both ends.

To illustrate the seventh diagram, the circuit outline of the third D diagram is taken as another practical embodiment of the implementation of the bypass circuit of the present invention, and the current limiting unit 31 in this illustration is exemplified in the fourth C diagram. Two terminal current limiting circuits. An exemplary value of a related component described as a circuit outline of another embodiment is that the LED device 10 is a white LED rated at 0.02 amps and 3.2 volts (having a forward voltage value ranging between 2.5 and 3.3 volts). White LED) component. The relationship between the total forward voltage between the positive terminal 1 and the negative terminal 2 and the forward current of the white LED element 10 is exemplified by the voltage-current characteristic curve E of the fifth diagram. Wherein, in the bypass circuit 23, the breakdown voltage on the Zener diode 61 is about 4.3 volts; the resistance 64 is 1000 ohms; using a two-terminal point current limiting circuit of the fourth C diagram as a two-point point The current limiting unit 31, the two npn-BJTs in the fourth C diagram are 2N5088BU, the resistance connected to the emitters of the two npn-BJTs is 30 ohms, and the resistance connected to the collectors of the two npn-BJTs is 3300 ohms. And the current when the SCR 51 is not turned on as a switching element is less than 100 microamperes, the voltage at the turn-on is greater than 0.7 volts, and the current at the time of maintaining conduction is greater than 0.2 milliamperes. Thus, when the bypass circuit 23 acts as a bypass electrical path, the voltage between the positive terminal 1 and the negative terminal 2 of the bypass circuit 23 flows toward the positive terminal 1 of the bypass circuit 23. The current between the negative terminals 2, the relationship between the two, is exemplified in the voltage-current characteristic curve F of the seventh figure.

The current exemplified on the curve F of the seventh graph is 1.49 mA to maintain the minimum current required for the SCR 51 to be turned on, and the current required to maintain conduction is 1.49 mA at the bypass circuit 23 at the positive terminal 1 and the negative terminal. The corresponding voltage between points 2 is 1.4 volts. Moreover, a set current value ISET exemplified on the curve F of the fifth figure is 19.79 milliamperes, and the current value ISET corresponds to a corresponding voltage between the positive terminal 1 and the negative terminal 2 of the bypass circuit 23. The value VSET is 3.07 volts.

Thus, for this other practical embodiment, the circuit of the present invention having the seventh characteristic curve F, when the bypass circuit 23 is in the electrical path condition of the bypass, when the current flowing through the bypass circuit 23 When the value is equal to a set current value ISET, the bypass circuit has a pair of corresponding set voltage values VSET that should be set to a current value, and the corresponding set voltage value VSET is equal to the set current flowing in the forward direction of the LED device 10. a total forward voltage value VSET at a value of ISET, and the set current value ISET is less than a maximum forward current of the LED device 10; wherein, when the operating current value I1 flowing on the bypass circuit is greater than the set current value ISET a corresponding operating voltage value V1F of the operating current value I1 on the bypass circuit is greater than a total forward voltage value V1E when the operating current value I1 flows through the LED device 10; and wherein, when When the operating current value I2 on the bypass circuit is less than the set current value ISET, a corresponding operating voltage value V2F of the operating current value I2 on the bypass circuit is smaller than the circulating current on the LED device 10. The total forward voltage value V2E at the current value I2. For example, in the example values of the actual measurements shown in this example, I1 is 22 mA, V1E is 3.10 volts, V1F is 6.09 volts, I2 is 18 mA, V2E is 3.03 volts, and V2F is 2.312 volts.

In any event, unlike prior art bypass circuits which essentially provide a voltage as an alternative to LED failure, the present invention provides a fault tolerant method by providing an implementation of a bypass circuit of the present invention having a second characteristic curve B Solution, the method of the invention is completed. Wherein, when the bypass circuit of the present invention is required to operate, the current value and voltage value of the bypass circuit in parallel with a set of fault LEDs may be the same as the current value and voltage value before the group of LED faults.

This improvement allows the method of the present invention to maintain the same amount of operating current before the LED failure after the LED failure, as compared to the prior art, without the need to change the voltage of the power supply circuit. Or, the operating current flowing in the LED of the present invention is relatively large, causing LED failure. When the LED is faulty, the operating current can be reduced to protect the LED after the fault. Alternatively, in the present invention, when the operating current flowing through the LED is less than a certain value, the operating current after the LED failure may be increased to compensate for the decrease in illumination after the LED failure.

In an actual implementation, the LED in the LED fault-tolerant circuit of the present invention and the bypass circuit of the present invention may be a single component; or the bypass circuit of the present invention may be an integrated circuit; or the bypass circuit of the present invention Can be composed of discrete components.

The content described in the embodiments of the present specification is merely an enumeration of the implementation forms of the inventive concept, and the scope of the present invention should not be construed as being limited to the specific forms stated in the embodiments. Equivalent technical means that a person can think of in accordance with the inventive concept.

A‧‧‧The relationship between forward voltage and current on a specific LED device

B‧‧‧Partial relationship between forward voltage and current of a bypass circuit of the invention as a bypass electrical path

VSET‧‧‧Set voltage

I1‧‧‧ is greater than the operating current of the set current ISET

V1A‧‧‧ Total forward voltage value when operating current value I1 is distributed on a specific LED device

V1B‧‧‧ A corresponding operating voltage value of the operating current value I1 on a bypass circuit

I2‧‧‧ is less than the operating current of the set current ISET

V2A‧‧‧ Total forward voltage value when operating current value I2 on a particular LED device

V2B‧‧‧ A corresponding operating voltage value of the operating current value I2 on a bypass circuit

Claims (10)

A fault-tolerant method for an LED fault-tolerant circuit includes: providing a circuit to supply an LED device, and circulating a working current in a forward direction on the LED device; and a bypass circuit connected in parallel with the LED device as a bypass An electrical path for responding to a fault of the LED device and continuing to allow the circuit to circulate the operating current on the bypass circuit; further, the bypass circuit exhibits a high impedance when the circuit supplies power to the LED device An off state; wherein, for the bypass circuit as an electrical path condition of the bypass, when the current value flowing through the bypass circuit is equal to a set current value, the bypass circuit has a corresponding setting of a set current value a voltage value, and the corresponding set voltage value is equal to a total forward voltage value when the set current value in a forward direction flows through the LED device, and the set current value is less than a maximum forward current of the LED device; The bypass circuit is used as an electrical path condition of the bypass. When the operating current value flowing through the bypass circuit is greater than the set current value, the bypass circuit is in the The corresponding operating voltage value corresponding to the current is greater than the total forward voltage value corresponding to the operating current of the LED device; wherein the bypass circuit acts as the electrical path condition of the bypass when the operation of the bypass circuit flows When the current value is less than the set current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is smaller than the total forward voltage value corresponding to the operating current of the LED device. The method of claim 1, wherein the LED device is an LED component or a series of LED components of a selected number of LED components. The method of claim 1, wherein the set current value is less than or equal to the LED package Set the rated current. The method of claim 1-3, further comprising: the bypass circuit monitoring performance of the LED device; and, in response to the failure of the LED device, turning on a switch in the bypass circuit, and The operating current is allowed to pass through a current limiting unit to become an electrical path for the bypass. The method of claim 4, further comprising: supplying, by the circuit, a plurality of LED device series connected in series by the LED devices, and circulating an operating current in a forward direction on the LED device string; Each of the LED devices is each connected in parallel with a bypass circuit as an electrical path of a bypass, such that the bypass circuit allows the circuit to respond to a fault and continue to be connected to the LED device in parallel Circulating the operating current on the bypass circuit; and wherein the bypass circuit exhibits a high impedance off state when the circuit supplies power to the paralleled LED device. An LED fault tolerant circuit comprising: an LED device configured to supply a working current through a circuit through a LED device, the operating current flowing in a forward direction of the LED component of the LED device, and the LED device is An LED component or a series of LED components of a selected number of LED components; a bypass circuit configured to be connected in parallel with the LED device to serve as a bypass electrical path for responding to a fault in the LED device And continuing to allow the circuit to circulate the operating current on the bypass circuit; further, the bypass circuit exhibits a high impedance off state when the circuit supplies power to the LED device; wherein the bypass circuit acts as the bypass Electrical path condition when flowing through the bypass circuit When the current value is equal to a set current value, the bypass circuit has a pair of corresponding set voltage values that should be set to a current value, and the corresponding set voltage value is equal to the set current value flowing in a forward direction on the LED device. a total forward voltage value, and the set current value is less than a maximum forward current of the LED device; wherein, for the bypass circuit as an electrical path condition of the bypass, when the operating current value flowing through the bypass circuit is greater than When the current value is set, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is greater than a total forward voltage value corresponding to the operating current of the LED device; wherein the bypass circuit serves as an electrical path of the bypass a condition, when the operating current value flowing through the bypass circuit is less than the set current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is smaller than a total forward voltage value corresponding to the operating current of the LED device. . The LED fault tolerance as described in claim 6 wherein the set current value is less than or equal to a rated current of the LED device. The LED fault tolerance as claimed in claim 6-7, wherein the bypass circuit further comprises: a sensing component configured to sense a fault of the LED device and to provide a control in response to the fault a switching element configured to provide the bypass circuit in response to the control signal; and a current limiting unit at both ends configured to allow the operating current when the switching element responsive to the control signal is turned on The bypass circuit is used as an electrical path of the bypass by the current limiting unit. The LED fault tolerance as claimed in claim 8 wherein the current limiting unit is a resistor at both ends. An LED illumination system having an LED fault tolerant circuit, comprising: a selected number of LED devices configured to be connected in series in a forward direction to form a series of LED devices, and wherein the LED device is an LED component or a a plurality of LED elements in a selected number of LED elements; a circuit configured to supply a working current through the LED device in series, the operating current flowing in a forward direction of the LED elements of the LED device series; Each of the LED devices is each coupled in parallel with a bypass circuit; wherein the bypass circuit is configured to act as a bypass electrical path for allowing the circuit to circulate the operation in response to a failure of the LED device in parallel a current is on the bypass circuit, and the bypass circuit exhibits a high impedance off state when the circuit supplies power to the paralleled LED device; wherein the bypass circuit serves as an electrical path condition of the bypass When the current value flowing through the bypass circuit is equal to a set current value, the bypass circuit has a pair of corresponding set voltage values that should be set to a current value, and the corresponding set voltage is a value equal to a total forward voltage value when the set current value in a forward direction flows through the LED device, and the set current value is less than a maximum forward current of the LED device; wherein the bypass circuit is used as the bypass The electrical path condition, when the operating current value flowing through the bypass circuit is greater than the set current value, the corresponding operating voltage value corresponding to the operating current of the bypass circuit is greater than the total corresponding to the operating current of the LED device. a forward voltage value; wherein, for the bypass circuit as an electrical path condition of the bypass, when the operating current value flowing through the bypass circuit is less than the set current value, the bypass circuit corresponds to the operating current The corresponding working voltage value is less than the total forward voltage value corresponding to the operating current of the LED device.