Light emitting diode driving circuit

Abstract

A light emitting diode driving circuit is electrically connected to a light emitting diode matrix. The light emitting diode matrix comprises a plurality of light strings. The light emitting diode driving circuit comprises a constant current source, a plurality of resistors, a detection circuit and a judgment circuit. The constant current source is used for controlling the driving current provided for the plurality of lamp strings to be constant current. The first ends of the plurality of resistors are electrically connected to the plurality of lamp strings respectively, and the second ends of the plurality of resistors are electrically connected to a reference potential. The judgment circuit is used for outputting a fault judgment signal according to the potential of the first ends of the plurality of resistors. The lamp string and the resistors form a plurality of current branches, and the detection circuit switches off or switches on the electrical paths from the input end of the judgment circuit to the current branches according to the voltage drop of the plurality of resistors, so as to detect whether the light emitting diodes in the plurality of current branches have faults or not, thereby simplifying the design of the circuit and improving the reliability of the circuit. And the operation efficiency of the circuit is improved.

Description

Technical Field

[0001] This case relates to a light-emitting diode driving circuit, and particularly to a light-emitting diode driving circuit with a light-emitting diode fault detection function. Background Art

[0002] Currently, due to many advantages of light-emitting diodes, such as fast response speed, low cost, etc., light-emitting diodes are often used as the light source of vehicle headlights. For driving safety, the luminous intensity of vehicle headlights is usually regulated by regulations. However, the light source components of vehicle headlights are more likely to fail due to factors such as usage conditions and power supply voltage. In this case, if any one of the light-emitting diodes in the vehicle headlights fails and the driving method is not adjusted, the luminous intensity of the vehicle headlights may not comply with legal regulations or seriously affect driving safety.

[0003] Therefore, how to provide a light-emitting diode driving circuit capable of detecting faults in light-emitting diodes is an important issue in this field. Summary of the Invention

[0004] The present disclosure provides a light-emitting diode driving circuit. The light-emitting diode driving circuit is electrically connected to a light-emitting diode matrix. The light-emitting diode matrix includes a plurality of lamp strings. Each of the plurality of lamp strings includes a plurality of light-emitting diodes. The plurality of lamp strings are electrically connected to a first current terminal and receive a driving current from the first current terminal. The light-emitting diode driving circuit includes a constant current source, a plurality of resistors, a detection circuit, and a judgment circuit. The constant current source is electrically connected between the plurality of lamp strings and a second current terminal for controlling the driving current to be a constant current. The first ends of the plurality of resistors are respectively electrically connected to the plurality of lamp strings, and the second ends of the plurality of resistors are electrically connected to a reference potential. The detection circuit is electrically connected between the plurality of resistors and the plurality of lamp strings, and the detection circuit includes a plurality of diode units. Each of the plurality of diode units includes a first diode and a second diode connected in series. The judgment circuit includes a first comparator and a second comparator. The first comparator has a first first input terminal, a first second input terminal, and a first output terminal. The first first input terminal of the first comparator is electrically connected to the plurality of first diodes. The first second input terminal of the first comparator is used to receive a first floating potential. The first output terminal of the first comparator is used to output the first judgment signal. The second comparator has a second first input terminal, a second second input terminal, and a second output terminal. The second first input terminal of the second comparator is electrically connected to the plurality of second diodes. The second second input terminal of the second comparator is used to receive a second floating potential. The second output terminal of the second comparator is used to output the second judgment signal. The first floating potential and the second floating potential vary with the reference potential.

[0005] In some embodiments of the present disclosure, the light-emitting diode driving circuit further includes a first floating voltage source and a second floating voltage source. A first end of the first floating voltage source is electrically connected to the first input terminal of the first comparator, and a second end of the first floating voltage source is electrically connected to the reference potential, wherein the first floating voltage source is used to provide the first floating potential. A first end of the second floating voltage source is electrically connected to the second input terminal of the second comparator, and a second end of the second floating voltage source is electrically connected to the reference potential, wherein the second floating voltage source is used to provide the second floating potential.

[0006] In some embodiments of the present disclosure, the first input terminal of the first comparator is electrically connected to the anodes of the plurality of first diodes and a first bias current source. Cathodes of the plurality of first diodes are respectively electrically connected to first ends of the plurality of resistors, and the first determination signal is used to provide open-circuit information related to the plurality of light-emitting diodes.

[0007] In some embodiments of the present disclosure, the second input terminal of the second comparator is electrically connected to the cathodes of the plurality of second diodes and a second bias current source. Anodes of the plurality of second diodes are respectively electrically connected to first ends of the plurality of resistors, and the second determination signal is used to provide short-circuit information related to the plurality of light-emitting diodes.

[0008] In some embodiments of the present disclosure, the light-emitting diode driving circuit further includes an OR gate. The OR gate is electrically connected to the first output terminal of the first comparator and the second output terminal of the second comparator, and is used to generate a fault determination signal according to the first determination signal and the second determination signal.

[0009] In some embodiments of the present disclosure, the light-emitting diode driving circuit further includes a switching circuit. The switching circuit is electrically connected between the constant current source and the second current terminal, and when the fault determination signal is at a high logic level, the switching circuit turns off the current path of the driving current accordingly.

[0010] In some embodiments of the present disclosure, the light-emitting diode driving circuit further includes a driving power supply. A first pin of the driving power supply is electrically connected to the first current terminal, a second pin of the driving power supply is electrically connected to the second current terminal, and a third pin of the driving power supply is electrically connected to the output terminal of the OR gate. The driving power supply is used to provide a driving current to the plurality of lamp strings, and the driving power supply is further used to adjust the amplitude of the driving current according to the fault determination signal.

[0011] In some embodiments of the present disclosure, the light-emitting diode driving circuit further includes a light-emitting module and a control circuit. The control circuit is electrically connected to the output terminal of the OR gate and the light-emitting module, and is configured to instruct the light-emitting module to perform supplementary lighting according to the fault determination signal.

[0012] The present disclosure provides another light-emitting diode driving circuit. The light-emitting diode driving circuit is electrically connected to a light-emitting diode matrix. The light-emitting diode matrix includes a plurality of lamp strings, and each of the plurality of lamp strings includes a plurality of light-emitting diodes. The plurality of lamp strings are electrically connected to a first current terminal and receive driving current from the first current terminal. The light-emitting diode driving circuit includes a constant current source, a plurality of resistors, a detection circuit, and a comparator. The constant current source is electrically connected between the plurality of lamp strings and a second current terminal, and the constant current source is configured to control the driving current to be a constant current. First ends of the plurality of resistors are respectively electrically connected to the plurality of lamp strings, and second ends of the plurality of resistors are respectively electrically connected to a reference potential. The detection circuit is electrically connected between the plurality of resistors and the plurality of lamp strings. The detection circuit includes a plurality of diodes. Anodes of the plurality of diodes are configured to receive a bias direct current, and cathodes of the plurality of diodes are respectively electrically connected to the plurality of resistors. The comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the comparator is electrically connected to the anodes of the plurality of diodes. The second input terminal of the comparator is configured to receive a floating potential. The output terminal of the comparator is configured to output a first determination signal, wherein the floating potential varies with the reference potential.

[0013] The present disclosure provides yet another light-emitting diode driving circuit. The light-emitting diode driving circuit is electrically connected to a light-emitting diode matrix. The light-emitting diode matrix includes a plurality of lamp strings. Each of the plurality of lamp strings includes a plurality of light-emitting diodes, and the plurality of lamp strings are electrically connected to a first current terminal and receive driving current from the first current terminal. The light-emitting diode driving circuit includes a constant current source, a plurality of resistors, a detection circuit, and a comparator. The constant current source is electrically connected between the plurality of lamp strings and a second current terminal, and the constant current source is configured to control the driving current to be a constant current. First ends of the plurality of resistors are respectively electrically connected to the plurality of lamp strings, and second ends of the plurality of resistors are respectively electrically connected to a reference potential. The detection circuit is electrically connected between the plurality of resistors and the plurality of lamp strings, and the detection circuit includes a plurality of diodes. Anodes of the plurality of diodes are respectively electrically connected to the plurality of resistors. The comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the comparator is electrically connected to the cathodes of the plurality of diodes. The second input terminal of the comparator is configured to receive a floating potential. The output terminal of the comparator is configured to output a determination signal, wherein the floating potential varies with the reference potential.

[0014] In summary, the light-emitting diode driving circuit of the present disclosure includes a plurality of current branches, each branch including a lamp string and a resistor connected in series electrically, wherein a diode is electrically connected between the lamp string and the resistor of each current branch, and the diode turns off or conducts the electrical path from the input terminal of the comparator to the current branch according to the voltage drop of the resistor of each current branch, so as to output a fault determination signal for detecting whether a component in the lamp string fails through the comparator. Description of the Drawings

[0015] To make the above and other objects, features, advantages and embodiments of the present disclosure more obvious and understandable, the description of the accompanying drawings is as follows:

[0016] Figure 1A FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure under normal operation.

[0017] Figure 1B FIG. is a schematic diagram of the operation of a lighting system according to an embodiment of the present disclosure when a light-emitting diode in the lighting system fails open.

[0018] Figure 1C FIG. is a schematic diagram of the operation of a lighting system according to an embodiment of the present disclosure when a light-emitting diode in the lighting system fails short.

[0019] Figure 2 FIG. is a schematic diagram of the circuit of a constant current source according to an embodiment of the present disclosure.

[0020] Figure 3 FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure.

[0021] Figure 4 FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure.

[0022] Figure 5A FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure.

[0023] Figure 5B FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure.

[0024] Figure 6 FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure.

[0025] Figure 7 FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure.

[0026] Figure 8 FIG. is a schematic diagram of a lighting system according to an embodiment of the present disclosure. Detailed Embodiments

[0027] The following provides detailed descriptions of embodiments in conjunction with the accompanying drawings. However, the provided embodiments are not intended to limit the scope covered by the present disclosure, and the description of the structure and operation is not intended to limit the execution order. Any structure formed by recombining elements that produces an apparatus with equivalent functions is within the scope covered by the present disclosure. Additionally, the drawings are for illustrative purposes only and are not drawn to the original scale. For ease of understanding, the same or similar elements will be denoted by the same reference numerals in the following description.

[0028] As used throughout the specification and claims, unless otherwise specified, the terms generally have their ordinary meanings as used in this field, in the context of this disclosure, and in the context of the particular content. In addition, the terms "comprising," "including," "having," "containing," etc. used in this document are all open-ended terms, meaning "including but not limited to." In addition, the "and / or" used in this document includes any one of the one or more items in the related listed items and all combinations thereof.

[0029] Please refer to Figure 1A , Figure 1A FIG. is a schematic diagram of a lighting system 100 in normal operation according to an embodiment of the present disclosure. In some embodiments, the lighting system 100 may be a headlight module for a heavy motorcycle. In some other embodiments, the lighting system 100 may be a headlight module for an automobile, a headlight module for a light motorcycle, etc., and the present case is not limited thereto. In some embodiments, the lighting system 100 may be a brake light module. In some embodiments, the lighting system 100 may be a running light. In still some other embodiments, the lighting system 100 may be a headlight, a taillight, a turn signal, etc., and the present case is not limited thereto.

[0030] As shown in Figure 1A , the lighting system 100 includes a light-emitting diode matrix ARR and a light-emitting diode driving circuit 10. In some embodiments, the light-emitting diode matrix ARR includes light-emitting diodes L 11 ~L nn arranged in a matrix. Further, the light-emitting diode matrix ARR includes lamp strings LS1~LS n , and each of the lamp strings LS1~LS n includes a plurality of serially connected light-emitting diodes. Specifically, the light-emitting diodes L 11 ~L 1n are electrically connected in series to form the lamp string LS1, the light-emitting diodes L 21 ~L 2n are electrically connected in series to form the lamp string LS2, and so on. The light-emitting diodes L n1 ~L nn are electrically connected in series to form the lamp string LS n .

[0031] In some embodiments, the light-emitting diode matrix ARR is electrically connected to the light-emitting diode driving circuit 10. In some embodiments, the light-emitting diode driving circuit 10 includes a detection circuit DETa, a judgment circuit CL, and resistors R S1 ~R Sn . In some embodiments, the lamp strings LS1~LS n in the light-emitting diode matrix ARR are respectively connected in series with the corresponding resistors R S1 ~R Sn to form a plurality of current branches, and the plurality of current branches are electrically connected in parallel between the first current terminal I IN and the second current terminal I OUT . Specifically, the lamp string LS1 and the resistor R S1 are electrically connected in series between the first current terminal I IN and the second current terminal I OUT , the lamp string LS2 and the resistor R S2 are electrically connected in series between the first current terminal I IN and the second current terminal I OUT , and so on, the lamp string LS n and the resistor R Sn are electrically connected in series between the first current terminal I IN and the second current terminal I OUT . In some embodiments, the first current terminal I IN can be understood as the current input terminal of the lighting system 100, and the second current terminal I OUT can be understood as the current output terminal of the lighting system 100.

[0032] In some embodiments, the first ends of the lamp strings LS1~LS n are electrically connected to the first current terminal I IN and receive the driving current I (only marked at the second current terminal I IN ). In some embodiments, the first ends of the resistors R OUT ~R S1 are respectively electrically connected to the second ends of the lamp strings LS1~LS Sn , and the second ends of the resistors R n ~R S1 ~R Sn are electrically connected to the second current terminal I OUT via the constant current source 20. It should be noted that each of the lamp strings LS1~LS n of the present disclosure has two ends. If the first end (for example, the end close to the first current terminal I IN ) is the anode ( / cathode), then the second end (for example, the end close to the resistors R S1 ~R SnOne end thereof is the cathode / anode. In some embodiments, the driving current I flows from the first current terminal I IN through the lamp strings LS1 to LS n and the resistor R S1 to R Sn in the current branch formed and reaches the second current terminal I OUT . In other words, the driving current I is divided into multiple currents Is at the first current terminal I IN and respectively flows through the multiple lamp strings LS1 to LS n and the resistor R S1 to R Sn in the multiple current branches formed and the constant current source 20 to reach the second current terminal I OUT . Under ideal conditions, for example, the lamp strings LS1 to LS n have light-emitting diodes with the same specifications and quantities, and the currents Is in each branch are substantially the same as each other.

[0033] In some embodiments, the constant current source 20 is electrically connected between the lamp strings LS1 to LS n and the second current terminal I OUT . In some embodiments, the constant current source 20 is electrically connected on the current path of the driving current I. In some embodiments, the constant current source 20 is used to generate a constant output current, that is, the constant current source 20 is used to control the driving current I as a constant current.

[0034] In some embodiments, the detection circuit DETa is electrically connected between the resistor R S1 to R Sn and the lamp strings LS1 to LS n , for example, through the nodes N1 to N n . In some embodiments, the detection circuit DETa includes diode units DU1 to DU n . In some embodiments, each of the diode units DU1 to DU n includes two diodes. For example, the diode unit DU1 includes diodes D 1A and D 1B , and so on. The diode unit DU n includes diodes D nA and D nB . In some embodiments, the cathodes of the diodes D 1A to D nA are respectively electrically connected to the first ends of the resistors R S1 to R Sn (i.e., the nodes N1 to N n ), and the anodes of the diodes D 1A to D nA are electrically connected to the judgment circuit CL. In some embodiments, the diodes D 1B to DnB The anodes of n are electrically connected to resistors R S1 ~R Sn at their first ends, and the cathodes of diodes D 1B ~D nB are electrically connected to the judgment circuit CL. In some embodiments, diodes D 1A ~D nA and D 1B ~D nB can be implemented by PN junction diodes. In some embodiments, diodes D 1A ~D nA and D 1B ~D nB can be implemented by Zener diodes. In some embodiments, diodes D 1A ~D nA and D 1B ~D nB can be implemented by Schottky diodes. The voltage drop of Schottky diodes is about 0.2 volts or less. When applied, the voltage error is low, and it has the characteristic of small deviation values under high and low temperature conditions.

[0035] In some embodiments, the judgment circuit CL includes comparators 16~17 and an OR gate 18. In some embodiments, the first input terminal (for example, the inverting input terminal, indicated by "-" in the figure) of comparator 16 is electrically connected to the anodes of diodes D 1A ~D nA , and the second input terminal (for example, the non-inverting input terminal, indicated by "+" in the figure) of comparator 16 is used to receive the floating potential V ref_min . In some embodiments, the first input terminal (for example, the non-inverting input terminal) of comparator 17 is electrically connected to the cathodes of diodes D 1B ~D nB , and the second input terminal (for example, the inverting input terminal) of comparator 17 is used to receive the floating potential V ref_max .

[0036] In some embodiments, the second input terminal of comparator 16 is electrically connected to the floating voltage source 14 and is used to receive the floating potential V ref_min provided by the floating voltage source 14. In some embodiments, the second end (for example, the negative pole) of the floating voltage source 14 is electrically connected to the reference potential V ref . In some embodiments, since the drive current I is controlled to be a constant current, if the potential V IN of the first current terminal I IN floats, the potential on the current path of the drive current I will float accordingly. That is, the reference potential V ref will follow the first current terminal I INPotential V IN is floating / variable. Therefore, by coupling the second terminal of the floating voltage source 14 to the reference potential V ref , since the floating potential V ref_min will be equal to the reference potential V ref plus the fixed potential difference provided by the floating voltage source 14, the value of the floating potential V ref_min can fully respond to the change in the potential V IN of the first current terminal I IN . Therefore, for the comparator 16, the potential V IN of the first current terminal I IN will not cause the second terminal of the comparator 16 to receive an incorrect comparison reference, making the generated comparison result meaningless. On the contrary, in the related art, the second terminal of the floating voltage source 14 is grounded, so it is affected by the change in the input terminal potential. In comparison, the judgment result of the present disclosure is not affected by the factor of the change in the potential V IN of the first current terminal I IN .

[0037] In some embodiments, the second input terminal of the comparator 17 is electrically connected to the floating voltage source 15 and is used to receive the floating potential V ref_max provided by the floating voltage source 15. In some embodiments, the second terminal (e.g., the negative terminal) of the floating voltage source 15 is electrically connected to the reference potential V ref . In some embodiments, since the drive current I is controlled to be a constant current, if the potential V IN of the first current terminal I IN is floating, the potential on the current path of the drive current I will float accordingly. That is, the reference potential V ref will float / vary with the potential V IN of the first current terminal I IN . Therefore, by coupling the second terminal of the floating voltage source 15 to the reference potential V ref , since the floating potential V ref_max will be equal to the reference potential V ref plus the fixed potential difference provided by the floating voltage source 15, the value of the floating potential V ref_max can fully respond to the change in the potential V IN of the first current terminal I IN . Therefore, for the comparator 17, the potential V IN of the first current terminal I IN will not cause the second terminal of the comparator 17 to receive an incorrect comparison reference, making the generated comparison result meaningless. On the contrary, in the related art, the second terminal of the floating voltage source 15 is grounded, so it is affected by the change in the input terminal potential. In comparison, the judgment result of the present disclosure is not affected by the potential V IN of the first current terminal IIN Affected by varying factors.

[0038] In some embodiments, the bias current source 11 is electrically connected to the anodes of diodes D 1A ~D nA and the first input terminal of the comparator 16. In some embodiments, the bias current source 11 is used to provide a bias current I bias_min , such that the diodes D 1A ~D nA are at the operating point to maintain basic operation. In some embodiments, the bias current I bias_min is 0.5 to 1.5 mA. In other embodiments, the bias current I bias_min can be implemented by a larger or smaller current. In some embodiments, the diodes D 1A ~D nA , resistors R S1 ~R Sn and the comparator 16 form an open - circuit fault detection circuit, and how the open - circuit fault detection circuit operates will be described in detail in subsequent embodiments.

[0039] In some embodiments, the bias current source 12 is electrically connected to the cathodes of diodes D 1B ~D nB and the first input terminal of the comparator 17. In some embodiments, the bias current source 12 is used to provide a bias current I bias_max , such that the diodes D 1B ~D nB are at the operating point. In some embodiments, the bias current I bias_max is 0.5 to 1.5 mA. In other embodiments, the bias current I bias_max can be implemented by a larger or smaller current. In some embodiments, the diodes D 1B ~D nB , resistors R S1 ~R Sn and the comparator 17 form a short - circuit fault detection circuit, and how the short - circuit fault detection circuit operates will be described in detail in subsequent embodiments.

[0040] For a clear illustration of open - circuit fault detection under normal operation and open - circuit fault conditions, please refer to Figure 1A and Figure 1B . Figure 1B FIG. is a schematic diagram of the operation of the light - emitting diode L 22 in the light - emitting diode driving circuit 100 according to an embodiment of the present disclosure in the case of an open - circuit fault. In some embodiments, in the case of normal operation of the lamp string LS1~LS n and an open - circuit fault of the light - emitting diode L 22 therein, at nodes N1~Nn The potential V S1 ~V Sn and the potential V at the inverting input terminal of comparator 16 s_min can be shown in Table 1 below.

[0041] <![CDATA[V S1 > <![CDATA[V S2 > ... <![CDATA[V Sn > <![CDATA[V s min > Normal operation <![CDATA[I s *R S > <![CDATA[I s *R S > ... <![CDATA[I s *R S > <![CDATA[[I s *R S +V DA > <![CDATA[L 22 Open circuit due to fault]]> <![CDATA[I s ’*R S > 0 ... <![CDATA[I s ’*R S > <![CDATA[[0+V DA >

[0042] Table 1

[0043] In Table 1, the potential at the second terminal of resistor R S2 is assumed to be 0 volts. R S represents the resistance value of each of resistors R S1 ~R Sn and V DA represents the voltage drop of each of diodes D 1A ~D nA In some embodiments, when the light-emitting diodes L n in the lamp strings LS1~LS 11 ~L nn are all operating normally, each of the foregoing branch circuits has the same voltage drop, such that the magnitude of the current I s flowing through each branch circuit is the same as each other. In some embodiments, each of the lamp strings LS1~LS n has the same number of light-emitting diodes, and these light-emitting diodes have the same specifications. In some embodiments, the resistance values of resistors R S1 ~R Sn are the same as each other, and the diodes D 1A ~D nA have the same specifications. In some embodiments, when the lamp strings LS1~LS n are operating normally, the current flowing through each of the lamp strings LS1~LS n can be represented by (I / n), and the voltage V S1 ~V Sn is the voltage across resistors R S1 ~R Sn and can be represented by (I / n)*R Sn , where "I" represents the magnitude of the driving current, "n" represents the number of lamp strings of lamp strings LS1~LS n , and R Sn represents the resistance value of each of resistors R S1 ~R Sn As shown in Figure 1A , when the lamp strings LS1~LS n are operating normally, the magnitude of the current I n flowing through the lamp strings LS1~LS S is substantially the same as each other, and the diodes D 1A ~DnA Maintain the potential difference across its two ends at a certain voltage (the voltage drop of the diode, for example, 0.7 volts). The voltage V at the inverting input terminal of the comparator 16 s_min can be represented by [I s *R S +V DA , where R S represents the resistance value of each of the resistors R S1 ~R Sn , and V DA represents the voltage drop of each of the diodes D 1A ~D nA . In some embodiments, if the diodes D 1A ~D nA are implemented by Schottky diodes, whose voltage drop is very small, [I s *R S +V DA can be approximated as [I s *R S . In some embodiments, the signals coupled to the two endpoints of the comparator 16 can be swapped, that is, the first end is coupled to the floating potential V ref_min , and the second end is coupled to the potential V s_min , and it is determined that the lighting system 100 has a faulty open circuit according to the low logic level output at the output terminal of the comparator 16.

[0044] In some embodiments, the floating potentials V ref_min , V ref_max are set values, and these two set voltage values can be set to the upper and lower limit values centered on the cross-voltage value V S1 ~V Sn . When any of the floating potentials V ref_min , V ref_max exceeds this upper and lower value range, it means that one or more light-emitting diodes have short-circuited or open-circuited failures. The difference between this upper and lower limit value and the center value of the cross-voltage value V S1 ~V Sn needs to be determined according to the voltage drop value of a single light-emitting diode and its distribution range, and generally can be 0.4 volts to 2.6 volts.

[0045] As Figure 1B shown, when the light-emitting diode L in the lamp string LS2 22 has a faulty open circuit, the current flowing through the lamp string LS2 decreases to substantially no current flowing, and the current Is' flowing into other lamp strings increases slightly. At this time, the cross-voltage across the resistor R S2 is 0 volts, that is, the potential of the node N2 is zero, so that the diode D 2A conducts the current path from the inverting input terminal of the comparator 16 to the resistor RS2 (for example, if the diode D2A is a Zener diode with a conduction voltage of about 0.2 volts or less and a small deviation value under high and low temperature conditions. The bias current source 11 provides an I bias_min sufficient to turn on the diode D 2A ), and the diode D 2B is not turned on. Therefore, the non-inverting input terminal of the comparator 17 is not connected to the current path of the resistor R S2 , causing the potential V s_min at the inverting input terminal of the comparator 16 to be equal to the potential at the first end of the resistor R S2 (i.e., the potential of the node N2). Then, the potential V s_min will be compared with the floating potential V ref_min . When the potential V s_min is less than the floating potential V ref_min , the judgment signal V DET1 output by the comparator 16 is at a high logic level.

[0046] Continuing from the above, in at least one of the light strings LS1 to LS n (for example, the light-emitting diode L 22 ) fails open, the judgment signal V DET1 output by the comparator 16 is at a high logic level. Therefore, the judgment signal V DET1 at a high logic level indicates that at least one of the light-emitting diodes L 11 to L nn has failed open, and the judgment signal V DET1 at a low logic level indicates that the light-emitting diodes L 11 to L nn have not failed open. That is, the judgment signal V DET1 is used to provide open-circuit information related to the light-emitting diodes L 11 to L nn .

[0047] In some embodiments, when the light-emitting diode L 22 fails open, since the potential at the first end of the diodes D 1A and D nA is less than the potential at their second ends (for example, the potential at the first end of D nA is equal to the potential of the node N2, which is substantially 0), the diodes D 1A to D nA except for the diode D 2A will be in the off state. In some embodiments, when the light-emitting diode L22 fails open, since the potential at the first end of the diode D 2B (the potential of the node N2) is not greater than the potential of the diode D 2BThe potential of the second terminal of the diode D 2B is in the off state. In some embodiments, when the light-emitting diode L 22 fails open, since the diode D 1B ~D nB except for the diode D 2B will stabilize the potential across its two ends at a certain voltage (generally the voltage drop of a diode is 0.7 volts, or the voltage drop of a Zener diode is 0.1 volts), so that the potential V s_max at the non-inverting input terminal of the comparator 17 can be represented by [I s ’*R S -V DB , where V DB represents the voltage drop of each of the diodes D 1B ~D nB . In some embodiments, when at least one light-emitting diode (e.g., the light-emitting diode L n ) in the lamp strings LS1~LS 22 fails open, the determination signal V DET2 output by the comparator 17 is at a low logic level.

[0048] In some embodiments, when the lamp strings LS1~LS n are all operating normally, the OR gate 18 outputs a fault determination signal V DET1 and V DET2 is at a low logic level according to the determination signal V DET_OUT . On the other hand, when at least one light-emitting diode (e.g., the light-emitting diode L n ) in the lamp strings LS1~LS 22 fails open, the OR gate 18 outputs a fault determination signal V DET1 and V DET2 is at a high logic level according to the determination signal V DET_OUT .

[0049] To clearly illustrate the fault short-circuit detection under normal operation and fault short-circuit conditions, please refer to Figure 1A and Figure 1C . Figure 1C is a schematic diagram of the operation in the case of a fault short-circuit of the light-emitting diode L 22 in the light-emitting diode driving circuit 100 according to an embodiment of the present disclosure. In some embodiments, when the lamp strings LS1~LS n are operating normally and the light-emitting diode L 22 among them fails short-circuit, the potentials V n ~V S1 ~V Sn at the nodes N1~Ns_max It can be shown in Table II below.

[0050] <![CDATA[V S1 > <![CDATA[V S2 > ... <![CDATA[V Sn > <![CDATA[V s max > Normal operation <![CDATA[I s *R S > <![CDATA[I s *R S > ... <![CDATA[I s *R S > <![CDATA[[I s *R S -V DB > <![CDATA[L 22 Fault short circuit]]> <![CDATA[I s ”*R S > <![CDATA[I k *R S > ... <![CDATA[I s ”*R S > <![CDATA[[I k *R S -V DB >

[0051] Table II

[0052] In Table II, the potential at the second terminal of resistor R S2 is assumed to be 0 volts. R S represents the resistance value of each of resistors R S1 ~R Sn , and V DB represents the conduction voltage of each of diodes D 1B ~D nB In some embodiments, when the light-emitting diodes L n in the lamp strings LS1~LS 11 ~L nn are all operating normally, each of the foregoing branch lines has the same voltage drop, such that the magnitudes of the current I s flowing through each branch line are the same as each other. In some embodiments, each of the lamp strings LS1~LS n has the same number of light-emitting diodes, and these light-emitting diodes have the same specifications. In some embodiments, the resistance values of resistors R S1 ~R Sn are the same as each other, and diodes D 1B ~D nB have the same specifications.

[0053] As Figure 1A shown, when the lamp strings LS1~LS n are operating normally, the magnitudes of the current I n flowing through the lamp strings LS1~LS S are substantially the same as each other. Diodes D 1B ~D nB maintain the potential difference across their two ends at a certain voltage (the voltage drop of the diode, e.g., 0.7 volts), such that the voltage V s_max at the non-inverting input terminal of comparator 17 can be represented by [I s *R S -V DB , where R S represents the resistance value of each of resistors R S1 ~R Sn , and V DB represents the voltage drop of each of diodes D 1B ~D nB In some embodiments, the floating potential V ref_max is based on [I s *R S -V DBconfigured such that the comparator 17 outputs a low logic level when the lamp strings LS1 to LS n operate normally. For example, the floating potential V ref_max is set to be greater than [I s *R S -V DB , so that the potential V s_max at the non-inverting input terminal of the comparator 17 is less than the floating potential V n when the lamp strings LS1 to LS ref_max operate normally. In some embodiments, if the diodes D 1A to D nA are implemented by Schottky diodes, whose voltage drop is very small, [I s *R S -V DB can be regarded as [I s *R S . In some embodiments, the signals coupled to the two ends of the comparator 17 can be swapped, that is, the first end is coupled to the floating potential V ref_max , and the second end receives the potential V s_max , and it is determined that the lighting system 100 has a faulty short circuit according to the low logic level output from the output terminal of the comparator 17.

[0054] As Figure 1C shown, when the light-emitting diode L 22 in the lamp string LS2 has a faulty short circuit, the current I 22 flowing through the lamp string L k increases (because the equivalent resistance of the lamp string LS2 is less than that of other lamp strings), and the current I s flowing into other lamp strings decreases. At this time, the potential of the node N2 rises, and the diode D 2B conducts the current path from the first end of the on-resistance R S2 to the non-inverting input terminal of the comparator 17, while D 2A does not conduct R S2 to V S_min , so that the potential at the non-inverting input terminal of the comparator 17 rises to the potential at the first end of the resistor R S2 , which is greater than the floating potential V ref_max , and the judgment signal V DET2 output by the comparator 17 is at a high logic level. In some embodiments, when at least one light-emitting diode (for example, the light-emitting diode L n ) in the lamp strings LS1 to LS 22 has a faulty short circuit, the judgment signal V DET2 output by the comparator 17 is at a high logic level.

[0055] In some embodiments, the judgment signal V DET2At a high logic level, it represents that at least one of the light-emitting diodes L 11 ~L nn has a short-circuit failure, and the judgment signal V DET2 at a low logic level represents that the light-emitting diodes L 11 ~L nn do not have a short-circuit failure. That is, the judgment signal V DET1 is used to provide short-circuit information related to the light-emitting diodes L 11 ~L nn .

[0056] In some embodiments, when the light-emitting diode L 22 has a short-circuit failure, due to the potential of the first end of the diodes D 1B and D nB being less than the potential of their second ends, the diodes D 1B ~D nB except for the diode D 2B are in the off state. In some embodiments, when the light-emitting diode L 22 has an open-circuit failure, due to the potential of the second end of the diode D 2A (the potential of node N2) being higher than the potential of the first end of the diode D 2A , the diode D 2A is in the off state. In some embodiments, when the light-emitting diode L 22 has a short-circuit failure, due to the diodes D 1A ~D nA except for D 2A stabilizing the potential across their two ends at a certain voltage (the voltage drop of the diode, for example, 0.7 volts, or the zener diode has a voltage drop of 0.1V), the potential Vs_min at the inverting input terminal of the comparator 16 can be represented by [I s ”*R S +V DA , where V DA represents the voltage drop of each of the diodes D 1A ~D nA . In some embodiments, [I s ”*R S +V DA is greater than the floating potential V ref_min , and the judgment signal V 22 output by the comparator 16 when the light-emitting diode L DET1 has a short-circuit failure is at a low logic level. In some embodiments, when at least one light-emitting diode (for example, the light-emitting diode L n ~LS 22 ) in the lamp string LS1 has a short-circuit failure, the judgment signal V DET2is at a low logic level.

[0057] In some embodiments, when the lamp strings LS1 to LS n are all operating normally, OR gate 18 outputs a fault determination signal V DET1 and V DET2 The fault determination signal V output DET_OUT is at a low logic level. On the other hand, when at least one light-emitting diode (e.g., light-emitting diode L n ) of the lamp strings LS1 to LS 22 has a short-circuit fault, OR gate 18 outputs a fault determination signal V DET1 and V DET2 The fault determination signal V output DET_OUT is at a high logic level. In other words, the fault determination signal V output by OR gate 18 DET_OUT can be used to determine whether at least one of an open-circuit event or a short-circuit event occurs in ARR.

[0058] Please refer to Figure 2 . Figure 2 FIG. is a schematic diagram of a constant current source 20 according to an embodiment of the present disclosure. In some embodiments, the constant current source 20 is exemplified by a constant current source composed of an operational amplifier and a transistor. In other embodiments, the constant current source 20 can be implemented by other circuits capable of realizing the constant current function, and the present case is not limited thereto. As Figure 2 shown, the constant current source 20 includes an operational amplifier 21, transistors M1, Q1, and resistors R1 and R2. In some embodiments, the operational amplifier 21 is electrically connected to the positive power supply terminal V+ and the negative power supply terminal V-. In some embodiments, the output terminal of the operational amplifier 21 is electrically connected to the gate terminal of the transistor M1, and the transistor M1 is electrically connected between the first terminal of the transistor Q1 and the gate terminal of the transistor Q1. In some embodiments, when the driving current I changes, the operational amplifier 21 adjusts the output voltage according to the reference potential Vr and the potential at the first terminal of the resistor R2, and the transistor M1 adjusts the potential at the gate terminal of the transistor Q1 according to the output of the operational amplifier 21, so that the reference potential Vr is equal to the potential at the first terminal of the resistor R2, thereby controlling the driving current I to be a constant current. In other words, the reference potential Vr is fed back negatively (virtual ground) to the first terminal of the resistor R2, so that the driving current I flowing through the resistor R2 becomes a fixed current, and this circuit becomes a constant current source.

[0059] Please refer to Figure 3 . Figure 3 FIG. is a schematic diagram of an illumination system 300 according to an embodiment of the present disclosure. As Figure 3 shown, the illumination system 300 includes light-emitting diodes L arranged in a matrix 11 ~L nn and is electrically connected to the light-emitting diodes L 11 ~Lnn Light-emitting diode driving circuit 30. In some embodiments, the light-emitting diode driving circuit 30 includes diodes D 1A ~D nA and D 1B ~D nB , resistors R S1 ~R Sn , comparators 16 and 17, OR gate 18, constant current source 20, bias current sources 11 and 12, floating voltage sources 14 and 15, inverters 31 and switch circuit S3. In some embodiments, the output terminal of the OR gate 18 is electrically connected to the control terminal of the switch circuit S3 through the inverter 31. In some embodiments, the switch circuit S3 is electrically connected between the constant current source 20 and the second current terminal I OUT . In some embodiments, when the fault judgment signal V DET_OUT output by the OR gate 18 is at a low logic level, the switch circuit S3 is turned on to conduct the current path of the driving current I. On the other hand, when the fault judgment signal V DET_OUT output by the OR gate 18 is at a high logic level, the switch circuit S3 turns off the current path of the driving current I, causing the light-emitting diodes L 11 ~L nn to stop operating.

[0060] In some embodiments, the bias current source 11 can be implemented by a resistor electrically connected between the first current terminal I IN and the inverting input terminal of the comparator 16 to provide a bias current I bias_min to the diodes D 1A ~D nA , so that the diodes D 1A ~D nA are at the operating point to maintain basic operation. In some embodiments, the bias current source 12 can be implemented by a resistor electrically connected between the second current terminal I OUT and the non-inverting input terminal of the comparator 17 to provide a bias current I bias_max to the diodes D 1B ~D nB , so that the diodes D 1B ~D nB are at the operating point to maintain basic operation.

[0061] Please refer to Figure 4 . Figure 4 FIG. is a schematic diagram of a lighting system 400 according to an embodiment of the present disclosure. As Figure 4 shown, the lighting system 400 includes a light-emitting diode driving circuit 40 and light-emitting diodes L 11 ~L nn . In some embodiments, the light-emitting diode driving circuit 400 includes diodes D 1A~D nA and D 1B ~D nB , resistor R S1 ~R Sn , comparators 16 and 17, OR gate 18, constant current source 20, bias current sources 11 and 12, floating voltage sources 14 and 15, and drive power supply 41. Compared with Figures 1A to 1C the light-emitting diode driving circuit 10 in Figure 4 the light-emitting diode driving circuit 40 in also includes a drive power supply 41. In some embodiments, the first pin of the drive power supply 41 is electrically connected to the first current terminal I IN , and the second pin of the drive power supply 41 is electrically connected to the second current terminal I OUT . In some embodiments, the third pin of the drive power supply 41 is electrically connected to the output terminal of the OR gate 18 to adjust the amplitude of the drive current I according to the output of the OR gate 18. In some other embodiments, the third pin of the drive power supply 41 is electrically connected to the output terminal of the comparator 16 to adjust the amplitude of the drive current I according to the output of the comparator 16. In still some other embodiments, the third pin of the drive power supply 41 is electrically connected to the output terminal of the comparator 17 to adjust the amplitude of the drive current I according to the output of the comparator 17. In some embodiments, if the judgment signal V DET1 output by the comparator 16 is at a high logic level (indicating that the light-emitting diode in one of the current branches fails open), the drive power supply 41 increases the current flowing into the light-emitting elements in other paths, thereby performing supplementary lighting.

[0062] Please refer to Figure 5A , Figure 5A which is a schematic diagram of a lighting system 500a according to an embodiment of the present disclosure. As Figure 5A shown, the lighting system 500a includes a light-emitting diode matrix ARR and a light-emitting diode driving circuit 50a. In some embodiments, the light-emitting diode driving circuit 50a includes a detection circuit DET and a judgment circuit CL. In some embodiments, Figure 5A the light-emitting diode matrix ARR, the detection circuit DET, and the judgment circuit CL in respectively correspond to Figure 1A the light-emitting diode matrix ARR, the detection circuit DET, and the judgment circuit CL in, which will not be elaborated here. In some embodiments, the output terminal of the judgment circuit CL is electrically connected to the display module DISP, and the display module DISP is used to display a fault prompt of the light-emitting diode driving circuit 500 according to the fault judgment signal V DET_OUT output by the judgment circuit CL. The light-emitting diode driving circuit fault prompt includes a light-emitting diode short circuit prompt, a light-emitting diode open circuit prompt, a light-emitting diode driving circuit forced shutdown prompt, a drive current adjustment prompt. The foregoing prompts are only for illustrative purposes and are not intended to limit the present disclosure.

[0063] Please refer to Figure 5B , Figure 5B , which is a schematic diagram of a lighting system 500b according to an embodiment of the present disclosure. As Figure 5B shown, the lighting system 500b includes a light-emitting diode matrix ARR and a light-emitting diode driving circuit 50b. In some embodiments, the light-emitting diode driving circuit 50b includes a detection circuit DET, a judgment circuit CL, a control circuit CON, and a light-emitting module LEM. In some embodiments, Figure 5A the light-emitting diode matrix ARR, the detection circuit DET, and the judgment circuit CL of Figure 1A correspond to the light-emitting diode matrix ARR, the detection circuit DET, and the judgment circuit CL in Figure 1A respectively, and will not be described in detail herein. In some embodiments, the control circuit CON is electrically connected to the output terminal of the OR gate 18 in the judgment circuit CL to supplement light according to the fault judgment signal V DET_OUT to instruct the light-emitting module LEM to perform supplementary lighting.

[0064] Please refer to Figure 6 , Figure 6 , which is a schematic diagram of a lighting system 600 according to an embodiment of the present disclosure. As Figure 6 shown, the lighting system 600 includes light-emitting diodes L 11 ~L nn and a light-emitting diode driving circuit 60. In some embodiments, the light-emitting diode driving circuit 60 includes a detection circuit DETb, resistors R S1 ~R Sn , a comparator 16, a bias current source 11, and a floating voltage source 14. In some embodiments, the detection circuit DETb includes diodes D 1A ~D nA . In some embodiments, the detection circuit DETb in the light-emitting diode driving circuit 60 is an open-circuit detection circuit. Compared with Figure 1A the light-emitting diode driving circuit 10 in Figure 1A , the short-circuit detection architecture is omitted in the light-emitting diode driving circuit 60, and the light-emitting diode driving circuit 60 can still normally detect the open-circuit faults of the light-emitting diodes L 11 ~L nn . The relevant description has been detailed in the embodiments of the embodiments in Figure 1B and will not be described in detail herein.

[0065] Please refer to Figure 7 , Figure 7 , which is a schematic diagram of a lighting system 700 according to an embodiment of the present disclosure. As Figure 6 shown, the lighting system 700 includes light-emitting diodes L 11 ~L nnand a light emitting diode driving circuit 70. In some embodiments, the light emitting diode driving circuit 70 includes a detection circuit DETc, resistors R S1 ~R Sn , a comparator 17, a bias current source 12, and a floating voltage source 15. In some embodiments, the detection circuit DETc includes diodes D 1B ~D nB . In some embodiments, the detection circuit DETc in the light emitting diode driving circuit 70 is a short-circuit detection circuit. Compared with Figure 1A the light emitting diode driving circuit 10 therein, the light emitting diode driving circuit 70 omits the open-circuit detection architecture, and the light emitting diode driving circuit 70 can still detect the short-circuit fault of the light emitting diodes L 11 ~L nn normally. The relevant description has been detailed in the embodiments in Figure 1C and will not be repeated here.

[0066] Please refer to Figure 8 , Figure 8 which is a schematic diagram of an illumination system 800 according to an embodiment of the present disclosure. As Figure 8 shown, the illumination system 800 includes light emitting diodes L 11 ~L nn and a light emitting diode driving circuit 80. In some embodiments, the light emitting diode driving circuit 80 includes a detection circuit DETa, resistors R S1 ~R Sn , bias current sources 11-12, floating voltage sources 14-15, and a judgment circuit CL. In some embodiments, the operation modes of the detection circuit DETa, resistors R S1 ~R Sn , bias current sources 11-12, floating voltage sources 14-15, and the judgment circuit CL in the light emitting diode driving circuit 80 correspond to those of Figure 1A the detection circuit DETa, resistors R S1 ~R Sn , bias current sources 11-12, floating voltage sources 14-15, and the judgment circuit CL therein, and will not be repeated here. Compared with Figure 1A the light emitting diode driving circuit 10 therein, the light emitting diode driving circuit 80 is electrically connected between the first current terminal I IN and the anodes of the lamp strings LS1-LS n . In some embodiments, based on the first current terminal I IN and the second current terminal I OUTRegarding the potential relationship, the light-emitting diode driving circuit 80 is a high-voltage detection architecture configured at the high-voltage end. The internal component connection relationship corresponds to the light-emitting diode driving circuit 10 configured at the low-voltage end and can achieve the same / similar functions as the light-emitting diode driving circuit 10. Therefore, it will not be elaborated here.

[0067] In summary, the detection circuit DETa of the light-emitting diode driving circuit 10 of the present disclosure can detect whether there are faults in the light-emitting diodes L 11 ~L nn in multiple current branches, thereby simplifying the circuit design and further improving the operation efficiency of the circuit.

[0068] Although the present disclosure has been disclosed as above in embodiments, it is not intended to limit the content of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be determined by the appended claims.

[0069]

Symbol Description

[0070] To make the above and other purposes, features, advantages and embodiments of the present disclosure more obvious and understandable, the description of the appended symbols is as follows:

[0071] 10, 30, 40, 50a, 50b, 60, 70, 80: Light-emitting diode driving circuit

[0072] 11, 12: Bias current source

[0073] 14, 15: Floating voltage source

[0074] 16, 17: Comparator

[0075] 21: Operational amplifier

[0076] 18: OR gate

[0077] 20: Constant current source

[0078] 31: Inverter

[0079] 41: Drive power supply

[0080] 100, 300, 400, 500a, 500b, 600, 700, 800: Lighting system

[0081] ARR: Light-emitting diode matrix

[0082] CL: Judgment circuit

[0083] D 1A ~D nA ,D 1B ~DnB : Diode

[0084] DET, DETa, DETb, DETc: Detection Circuit

[0085] DU1~DU n : Diode Unit

[0086] DISP: Display Module

[0087] I: Drive Current

[0088] I bias_min , I bias_max : Bias Current

[0089] I IN : First Current Terminal

[0090] I OUT : Second Current Terminal

[0091] I s , I s ’, I s ”, I k : Current

[0092] L 11 ~L nn : Light Emitting Diode

[0093] LS1~LS n : Lamp String

[0094] N1~N n : Node

[0095] R S1 ~R Sn , R1, R2: Resistor

[0096] M1: Transistor

[0097] Q1: Transistor

[0098] S3: Switching Circuit

[0099] V+: Positive Power Supply Terminal

[0100] V-: Negative Power Supply Terminal

[0101] V DET_OUT : Fault Judgment Signal

[0102] V DET1 , V DET2 : Judgment Signal

[0103] V IN , V s_min , V s_max , V S1 ~VS : Potential

[0104] V ref , V r : Reference potential

[0105] V ref_min , V ref_max : Floating potential.

Claims

1. A light-emitting diode driving circuit, characterized in that Electrically connected to a light-emitting diode matrix, the light-emitting diode matrix including a plurality of lamp strings, each of the plurality of lamp strings including a plurality of light-emitting diodes, wherein the plurality of lamp strings are electrically connected to a first current terminal and receive driving current from the first current terminal, the light-emitting diode driving circuit comprising: A constant current source, electrically connected between the plurality of lamp strings and a second current terminal, for controlling the driving current to be a constant current; A plurality of resistors, the first ends of which are respectively electrically connected to the plurality of lamp strings, and the second ends of which are respectively electrically connected to a reference potential; A detection circuit, electrically connected between the plurality of resistors and the plurality of lamp strings, and including a plurality of diode units, each of the plurality of diode units including a first diode and a second diode connected in series; and A judgment circuit, comprising: A first comparator, having a first first input terminal electrically connected to the plurality of first diodes, a first second input terminal for receiving a first floating potential, and a first output terminal for outputting a first judgment signal; and A second comparator, having a second first input terminal electrically connected to the plurality of second diodes, a second second input terminal for receiving a second floating potential, and a second output terminal for outputting a second judgment signal, wherein the first floating potential and the second floating potential vary with the reference potential.

2. The light-emitting diode driving circuit according to claim 1, wherein Further comprising: A first floating voltage source, the first end of which is electrically connected to the first first input terminal of the first comparator, and the second end of which is electrically connected to the reference potential, wherein the first floating voltage source is used to provide the first floating potential; And A second floating voltage source, the first end of which is electrically connected to the second first input terminal of the second comparator, and the second end of which is electrically connected to the reference potential, wherein the second floating voltage source is used to provide the second floating potential.

3. The light-emitting diode driving circuit according to claim 1, wherein Wherein the first first input terminal of the first comparator is electrically connected to the anodes of the plurality of first diodes and a first bias current source, the cathodes of the plurality of first diodes are respectively electrically connected to the first ends of the plurality of resistors, and the first judgment signal is used to provide open-circuit information related to the plurality of light-emitting diodes.

4. The light-emitting diode driving circuit according to claim 1, characterized in that Wherein the second first input terminal of the second comparator is electrically connected to the cathodes of the plurality of second diodes and a second bias current source, the anodes of the plurality of second diodes are respectively electrically connected to the first ends of the plurality of resistors, and the second judgment signal is used to provide short-circuit information related to the plurality of light-emitting diodes.

5. The light-emitting diode driving circuit according to claim 1, wherein Further comprising an OR gate, electrically connected to the first output terminal of the first comparator and the second output terminal of the second comparator, for generating a fault judgment signal according to the first judgment signal and the second judgment signal.

6. The light-emitting diode driving circuit according to claim 5, wherein Further comprising: A switch circuit, electrically connected between the constant current source and the second current terminal, and wherein when the fault judgment signal is at a high logic level, the switch circuit accordingly turns off the current path of the driving current.

7. The light emitting diode driving circuit according to claim 5, wherein Further comprising: A driving power supply, whose first pin is electrically connected to the first current terminal, whose second pin is electrically connected to the second current terminal, and whose third pin is electrically connected to the output terminal of the OR gate, wherein the driving power supply is used to provide a driving current to the plurality of lamp strings, and wherein the driving power supply is further used to adjust the amplitude of the driving current according to the fault judgment signal.

8. The light-emitting diode driving circuit according to claim 5, wherein, Further comprising: A light-emitting module; And A control circuit, electrically connected to the output terminal of the OR gate and the light-emitting module, for indicating the light-emitting module to perform supplementary lighting according to the fault judgment signal.

9. A light-emitting diode driving circuit, characterized in that, Electrically connected to a light-emitting diode matrix, the light-emitting diode matrix includes a plurality of lamp strings, each of the plurality of lamp strings includes a plurality of light-emitting diodes, wherein the plurality of lamp strings are electrically connected to a first current terminal and receive a driving current from the first current terminal, and the light-emitting diode driving circuit includes: A constant current source, electrically connected between the plurality of lamp strings and the second current terminal, for controlling the driving current to be a constant current; A plurality of resistors, whose first ends are respectively electrically connected to the plurality of lamp strings, and whose second ends are respectively electrically connected to a reference potential; A detection circuit, electrically connected between the plurality of resistors and the plurality of lamp strings, and includes a plurality of diodes, wherein anodes of the plurality of diodes are used to receive a bias DC current, and wherein cathodes of the plurality of diodes are respectively electrically connected to the plurality of resistors; and A comparator, having a first input terminal electrically connected to the anodes of the plurality of diodes, a second input terminal for receiving a floating potential, and an output terminal for outputting a first judgment signal, wherein the floating potential varies with the reference potential.

10. A light-emitting diode driving circuit, characterized in that, Electrically connected to a light-emitting diode matrix, the light-emitting diode matrix includes a plurality of lamp strings, each of the plurality of lamp strings includes a plurality of light-emitting diodes, wherein the plurality of lamp strings are electrically connected to a first current terminal and receive a driving current from the first current terminal, and the light-emitting diode driving circuit includes: A constant current source, electrically connected between the plurality of lamp strings and the second current terminal, for controlling the driving current to be a constant current; A plurality of resistors, whose first ends are respectively electrically connected to the plurality of lamp strings, and whose second ends are respectively electrically connected to a reference potential; A detection circuit, electrically connected between the plurality of resistors and the plurality of lamp strings, and includes a plurality of diodes, wherein cathodes of the plurality of diodes are used to receive a bias DC current, and wherein anodes of the plurality of diodes are respectively electrically connected to the plurality of resistors; and A comparator, having a first input terminal electrically connected to the cathodes of the plurality of diodes, a second input terminal for receiving a floating potential, and a second output terminal for outputting a judgment signal, wherein the floating potential varies with the reference potential.

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