CN111083856B - Failure detection circuit and detection method for LED lamp - Google Patents
Failure detection circuit and detection method for LED lamp Download PDFInfo
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Abstract
The invention discloses a failure detection circuit for an LED lamp, which comprises the LED lamp, a negative feedback module, a reference voltage module and a failure detection module, wherein the reference voltage module controls the current flowing through the LED lamp through the negative feedback module to adjust the brightness of the LED lamp; the failure detection module comprises a sixth diode D6 and a second diode D2 which are connected in parallel, wherein the sixth diode D6 is arranged close to the LED lamp, and the second diode D2 is arranged at the ambient temperature; the invention also discloses a method for detecting the failure of the LED lamp. The failure detection module can detect the failure state of the LED lamp, and corresponding measures are taken according to the failure state to prevent the LED lamp from being damaged; meanwhile, the invention adopts an external reference voltage module and a negative feedback module to realize the dynamic regulation of the current of the LED lamp.
Description
Technical Field
The invention belongs to the technical field of LED lamp failure detection, and particularly relates to a failure detection circuit and a failure detection method for an LED lamp.
Background
An LED lamp, i.e., a light emitting diode, is a solid-state semiconductor device that can convert electrical energy into visible light, and can directly convert electricity into light, thus having a wide application market.
However, the LED lamp may fail due to the change of the usage time or the surrounding environment, such as: due to the fact that current is excessive, the PN junction temperature is too high and fails; due to the fact that the PN junction temperature is overhigh due to the fact that the working condition environment temperature is excessive, the LED current is in positive feedback and finally fails.
Currently, an NTC sampling circuit is generally adopted for detecting the failure of an LED lamp circuit in real time, and the defects of high cost of NTC hardware, excessive MCU detection ports and unclear theoretical support are caused; in addition, the circuits of the existing LED lamps are generally LED constant current circuits based on a switching power supply, and the circuits are used in high-power occasions and have the defects of poor EMI effect, prominent switching spike signals, high circuit cost and the like.
Disclosure of Invention
In order to solve the above problems, the present invention provides a failure detection circuit for an LED lamp, which abandons the traditional LED constant current circuit based on a switching power supply, and adopts an external reference voltage module and a negative feedback module to realize dynamic adjustment of the current of the LED lamp; and the failure detection module realizes the detection of the failure state of the LED lamp.
The invention further aims to provide a method for detecting the failure of the LED lamp.
The technical scheme adopted by the invention is as follows:
a failure detection circuit for an LED lamp comprises the LED lamp, a negative feedback module, a reference voltage module and a failure detection module, wherein the reference voltage module controls current flowing through the LED lamp through the negative feedback module to adjust the brightness of the LED lamp, the input end of the failure detection module is connected with the LED lamp and used for detecting the failure state of the LED lamp, and the output end of the failure detection module is connected with the negative feedback module through a single chip microcomputer; the failure detection module comprises a sixth diode D6 and a second diode D2 connected in parallel, the sixth diode D6 is arranged close to the LED lamp, and the second diode D2 is arranged at the ambient temperature.
Preferably, the failure states of the LED lamp include an open circuit failure, a short circuit failure, and an over-temperature failure.
Preferably, the negative feedback module includes a first transistor TR1 and a second transistor TR2 which are symmetrically arranged, a base of the first transistor TR1 is connected with a base of the second transistor TR2, one path of an emitter of the first transistor TR1 is connected with the reference voltage module, the other path is connected with a ninth capacitor C9, an emitter of the second transistor TR2 is connected with a tenth capacitor C10, the ninth capacitor C9 and the tenth capacitor C10 are commonly grounded, the tenth capacitor C10 is connected with a seventh resistor R7 in parallel, a collector of the first transistor TR1 is connected with VCC _ SW through a fifth resistor R5, and a collector of the second transistor TR2 is connected with VCC _ SW through a sixth resistor R6; the LED lamp further comprises a third field effect transistor Q3, the grid electrode of the third field effect transistor Q3 is connected with the collector electrode of the first transistor TR1, the drain electrode of the third field effect transistor Q3 is connected with the cathode of the LED lamp, and the source electrode of the third field effect transistor Q3 is connected with a seventh resistor R7.
Preferably, the first transistor TR1 and the second transistor TR2 form a symmetrical transistor Q4, and the signal of the transistor Q4 is BCV 61C.
Preferably, the reference voltage module includes a first transistor Q1, a base of the first transistor Q1 is connected to the CMD _ PL port, an emitter of the first transistor Q1 is connected to a base of the first transistor Q1 through a fourth capacitor C4 in one path, and the other path is connected to a third resistor R3, the third resistor R3 is connected to a collector of the first transistor Q1 through a fourth resistor R4 in one path, and the other path is connected to a second resistor R2, the second resistor R2 is connected to ground through a thirtieth capacitor C30 in one path, and the other path is connected to the negative feedback module; the port CMD _ PL is used to generate a high level or a low level.
Preferably, the failure detection module further includes a thirty-fourth capacitor C34 connected in parallel with a sixth diode D6, and a second capacitor C2 connected in parallel with a second diode D2, where the sixth diode D6 and the thirty-fourth capacitor C34 are connected in parallel and then connected to VCC through a twentieth resistor R20, and the second diode D2 and the second capacitor C2 are connected in parallel and then form an output terminal of the failure detection module.
The failure detection method for the LED lamp applies the failure detection circuit for the LED lamp, and specifically comprises the following steps:
judging the electrical failure state of the LED lamp according to the voltage at the output end of the failure detection module; the states of electrical failure include open circuit failure and short circuit failure;
and judging whether the LED lamp is in an over-temperature failure mode or not according to the relation between the voltage difference of the output end of the failure detection module and the negative feedback module and the voltage difference of the sixth diode D6 and the second diode D2.
Preferably, the method further comprises: when the LED lamp is in an electrical failure state, the singlechip turns off a power supply VCC _ SW of the negative feedback module;
when the LED lamp is in an over-temperature failure mode, the current flowing through the LED lamp is reduced through the negative feedback module and the reference voltage module, so that the temperature of the LED lamp is reduced.
Preferably, the state of electrical failure of the LED lamp is judged by the voltage at the output end of the failure detection module, which specifically includes:
if the formula (1) is established, judging that the failure state of the LED lamp is open circuit failure;
VFAILURE≈(VD6+VR7)-VD2 (1)
wherein, VFAILUREVoltage, V, at the output of the failure detection moduleD6、VR7And VD2The voltages at the sixth diode D6, the seventh resistor R7, and the second diode D2, respectively;
if the formula (2) is established, judging that the failure state of the LED lamp is short-circuit failure;
VFAILURE≈VCC_SW (2)
VCC _ SW is the power supply voltage of the negative feedback module;
and if the formulas (1) and (2) are not true, judging that the LED lamp is in non-electrical failure.
Preferably, the determining whether the LED lamp is in the over-temperature failure mode according to a relationship between a voltage difference between the output end of the failure detection module and the negative feedback module and a voltage difference between the sixth diode D6 and the second diode D2 includes:
if the formula (3) does not hold, the LED lamp is judged to be in an over-temperature failure state, otherwise, the LED lamp is in a non-over-temperature failure state:
VFAILURE-(VQ3_ds+VR7)≈VD6-VD2 (3)
wherein, VQ3_dsIs the voltage of the third field effect transistor Q3.
Compared with the prior art, when the LED lamp failure detection device is used, the failure state of the LED lamp can be detected through the failure detection module, and corresponding measures are taken according to the failure state to prevent the LED lamp from being damaged; meanwhile, the invention adopts an external reference voltage module and a negative feedback module to realize the dynamic regulation of the current of the LED lamp.
Drawings
Fig. 1 is a circuit diagram of a failure detection circuit for an LED lamp according to embodiment 1 of the present invention;
fig. 2 is a temperature profile of a sixth diode in a failure detection circuit for an LED lamp according to embodiment 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be understood that the terms "vertical", "lateral", "longitudinal", "front", "rear", "left", "right", "upper", "lower", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description of the present invention, and do not mean that the device or member to which the present invention is directed must have a specific orientation or position, and thus, cannot be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1
The embodiment 1 of the invention provides a failure detection circuit for an LED lamp, which comprises an LED lamp 1, a negative feedback module 2, a reference voltage module 3 and a failure detection module 4, wherein the reference voltage module 3 controls current flowing through the LED lamp 1 through the negative feedback module 2 to adjust the brightness of the LED lamp 1, the input end of the failure detection module 4 is connected with the LED lamp 1 and used for detecting the failure state of the LED lamp 1, and the output end of the failure detection module 4 is connected with the negative feedback module 2 through a single chip microcomputer;
the failure detection module 4 comprises a sixth diode D6 and a second diode D2 which are connected in parallel, the sixth diode D6 is arranged close to the LED lamp 1, and the second diode D2 is arranged at the ambient temperature, wherein the temperature environment ranges from 24 ℃ to 26 ℃, and is preferably 25 ℃;
thus, by adopting the structure, the failure state of the LED lamp 1 is judged by the mutual cooperation of the negative feedback module 2, the reference voltage module 3, the failure detection module 4 and the singlechip;
and the power supply voltage of the negative feedback module 2 is adjusted through the singlechip according to the failure state so as to realize the protection of the LED lamp 1.
The model of the sixth diode D6 is BAS21, the model of the second diode D2 is BAW56W, and the temperature curve is shown in fig. 2;
the failure states of the LED lamp 1 include open circuit failure, short circuit failure, and over-temperature failure.
The negative feedback module 2 comprises a first triode TR1 and a second triode TR2 which are symmetrically arranged, the base of the first triode TR1 is connected with the base of the second triode TR2, one path of the emitter of the first triode TR1 is connected with the reference voltage module 3, the other path of the emitter of the first triode TR1 is connected with a ninth capacitor C9, the emitter of the second triode TR2 is connected with a tenth capacitor C10, the ninth capacitor C9 and the tenth capacitor C10 are grounded in common, the tenth capacitor C10 is connected with a seventh resistor R7 in parallel, the collector of the first triode TR1 is connected with VCC _ SW through a fifth resistor R5, and the collector of the second triode TR2 is connected with VCC _ SW through a sixth resistor R6; the LED lamp further comprises a third field effect transistor Q3, the grid electrode of the third field effect transistor Q3 is connected with the collector electrode of the first transistor TR1, the drain electrode of the third field effect transistor Q3 is connected with the cathode electrode of the LED lamp 1, and the source electrode of the third field effect transistor Q3 is connected with a seventh resistor R7;
the first transistor TR1 and the second transistor TR2 form a symmetrical transistor Q4, and the signal of the transistor Q4 is BCV 61C;
thus, the implementation process of the constant current circuit function of the negative feedback module 2 is as follows: since the bases of the first transistor TR1 and the second transistor TR2 are connected to each other and are at the same potential, and the first transistor TR1 and the second transistor TR2 are symmetrical BJT transistors, V is formedbe_TR1≈Vbe_TR2，VR7≈VR3Since R7 is smaller than the resistance of R3, the current IR7Is greater than IR3So far, the negative feedback module 2 generates the current imbalance effect and makes the gate voltage V of the third field effect transistor Q3gs_Q3>Vgs(th)_Q3(threshold voltage) so that the thirdThe field effect transistor Q3 is turned on as a pure switch to achieve the purpose of turning on the LED lamp 1.
The process of carrying out constant-current negative feedback stable control on the LED lamp 1 through the negative feedback module 2 comprises the following steps: current (I) of the LED lamp 1R7) Enlargement → VR7Enlargement → Vb_TR1/TR2Enlargement → Ib_TR1/TR2Enlargement → Ic_TR1Enlargement → VR5Enlargement → Vgs_Q3Descent → Ids_Q3Descending; the capacitance values of the ninth capacitor C9, the tenth capacitor C10 and the twenty-fourth capacitor C24 are increased to increase the LED lamp current (I)R7) And the offset of the phase margin, thereby improving the stability of the feedback loop.
The reference voltage module 3 comprises a first triode Q1, the base of the first triode Q1 is connected with the port CMD _ PL, one path of the emitter of the first triode Q1 is connected with the base of the first triode Q1 through a fourth capacitor C4, the other path is connected with a third resistor R3, one path of the third resistor R3 is connected with the collector of the first triode Q1 through a fourth resistor R4, the other path is connected with a second resistor R2, one path of the second resistor R2 is grounded through a thirtieth capacitor C30, and the other path is connected with the negative feedback module 2; the port CMD _ PL is used for generating a high level or a low level;
thus, the implementation process of dynamically adjusting the current of the LED lamp 1 through the reference voltage module 3 is as follows: since VR7 ≈ VR3, there are: ILED ═ IR7 ═ V (V)R7/R7)＝(VR3/R7) from which V is knownR3The current of the LED lamp 1 can be controlled to dynamically change by the value of the ILED, and the ILED is the current of the LED lamp 1;
high-light current mode: when the CMD _ PL is at a low level, the first transistor Q1 is turned off, and there are: ILED ═ IR7＝(VR7/R7)＝(VCC_SW*R3)/(R2+R3)；
Over-temperature current mode: when the CMD _ PL is at a high level, the first transistor Q1 is turned on in saturation, and the fourth resistor R4 is connected in parallel with the third resistor R3, so that:
ILED＝(VR7/R7)＝(VCC_SW*(R3//R4))/(R2+(R3//R4))。
the failure detection module 4 further includes a thirty-fourth capacitor C34 connected in parallel with the sixth diode D6, and a second capacitor C2 connected in parallel with the second diode D2, the sixth diode D6 and the thirty-fourth capacitor C34 are connected in parallel and then connected to VCC through a twentieth resistor R20, and the second diode D2 and the second capacitor C2 are connected in parallel and then form an output terminal of the failure detection module 4.
The working process is as follows:
whether the LED lamp 1 is open-circuit failure or not is judged, and the method specifically comprises the following steps:
according to the law of superposition, has VFAILURE＝(VD6+VQ3_ds+VR7)-VD2If the LED lamp 1 is open at this time, the third fet Q3 is a pure switch, and its drain-source current Ids is 0, then VQ3_dsIs about zero;
thus when V isFAILURE≈(VD6+VR7)-VD2When the LED lamp 1 is in the open circuit state, the LED lamp 1 is judged to be in the open circuit failure state.
Whether the LED lamp 1 is short-circuit failure is judged, and the method specifically comprises the following steps:
according to the law of superposition, has VFAILURE＝(VD6+VQ3_ds+VR7)-VD2If the LED lamp 1 is short-circuited at this time, the drain voltage of the third fet Q3 approaches the power supply voltage VCC _ SW of the negative feedback module 2;
thus when V isFAILUREWhen VCC _ SW is satisfied, it is determined that the LED lamp 1 is short-circuited and failed.
Whether the LED lamp 1 fails due to over-temperature is judged, and the method specifically comprises the following steps:
the specification given by most LED lamp manufacturers on the market indicates that the working temperature of 125 ℃ is the service life guarantee point of the LED lamp; when the sixth diode D6 (pair tube) is placed nearest to the LED lamp 1, the operating temperatures are approximately the same, and V is obtained in the normal operating temperature range with reference to fig. twoD6(ii) this data should actually be obtained according to the chosen diode specification, the present invention obtains 0.5-0.7V with reference to the S1G diode);
according to the law of superposition, has VFAILURE＝(VD6+VQ3_ds+VR7)-VD2If the LED lamp 1 fails due to over-temperature, the third fet Q3 is a pure switch, the drain-source current Ids is the current ILED of the LED lamp 1, and the third fet is a pure switchField effect transistor Q3 voltage VQ3_ds：
Then there are: vQ3_ds≈(ILED^2)*Rds(on)；
Rds (on) is a resistance between the drain and the source of the third fet Q3, which is a constant value, and ILED current is also a constant value, so VQ3_ ds is a constant value;
therefore, the method comprises the following steps: vFAILURE-(VQ3_ds+VR7)≈VD6-VD2；
From this, it can be seen that (V)FAILURE-(VQ3_ds+VR7) Herein (V)D6-VD2) Outside the range is an over-temperature failure mode of the LED lamp 1.
According to the embodiment, the failure detection module can detect the failure state of the LED lamp, and corresponding measures are taken according to the failure state to prevent the LED lamp from being damaged; meanwhile, the invention adopts an external reference voltage module and a negative feedback module to realize the dynamic regulation of the current of the LED lamp.
Example 2
the state of electrical failure of the LED lamp 1 is judged through the voltage at the output end of the failure detection module 4; the electrical failure state comprises an open circuit failure and a short circuit failure, and specifically comprises the following steps:
if the formula (1) is established, judging that the failure state of the LED lamp 1 is open-circuit failure;
VFAILURE≈(VD6+VR7)-VD2 (1)
wherein, VFAILUREFor the voltage at the output of the failure detection module 4, VD6、VR7And VD2The voltages at the sixth diode D6, the seventh resistor R7, and the second diode D2, respectively;
if the formula (2) is established, judging that the failure state of the LED lamp 1 is short-circuit failure;
VFAILURE≈VCC_SW (2)
VCC _ SW is the power supply voltage of the negative feedback module 2;
if the formulas (1) and (2) are not true, judging that the LED lamp 1 is in non-electrical failure;
whether the LED lamp 1 is in the over-temperature failure mode is judged through the relationship between the voltage difference between the output end of the failure detection module 4 and the negative feedback module 2 and the voltage difference between the sixth diode D6 and the second diode D2, which specifically includes:
if the formula (3) does not hold, the LED lamp 1 is judged to be in an over-temperature failure state, otherwise, the LED lamp is in a non-over-temperature failure state:
VFAILURE-(VQ3_ds+VR7)≈VD6-VD2 (3)
wherein, VQ3_dsIs the voltage of the third field effect transistor Q3.
The method further comprises the following steps: when the LED lamp 1 is in an electrical failure state, the singlechip turns off a power supply VCC _ SW of the negative feedback module 2;
when the LED lamp 1 is in an over-temperature failure mode, the current flowing through the LED lamp 1 is reduced through the negative feedback module 2 and the reference voltage module 3, so that the temperature of the LED lamp 1 is reduced.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. The failure detection circuit for the LED lamp is characterized by comprising the LED lamp (1), a negative feedback module (2), a reference voltage module (3) and a failure detection module (4), wherein the reference voltage module (3) controls current flowing through the LED lamp (1) through the negative feedback module (2) to adjust the brightness of the LED lamp (1), the input end of the failure detection module (4) is connected with the LED lamp (1) and used for detecting the failure state of the LED lamp (1), and the output end of the failure detection module (4) is connected with the negative feedback module (2) through a single chip microcomputer; the failure detection module (4) comprises a sixth diode D6 and a second diode D2 connected in parallel, the sixth diode D6 is arranged close to the LED lamp (1), and the second diode D2 is arranged at the ambient temperature;
the failure detection module (4) further comprises a thirty-fourth capacitor C34 connected with a sixth diode D6 in parallel and a second capacitor C2 connected with a second diode D2 in parallel, the sixth diode D6 and the thirty-fourth capacitor C34 are connected in parallel, one circuit of the sixth diode D6 and the thirty-fourth capacitor C34 is connected with VCC through a twentieth resistor R20, the other circuit of the sixth diode D6 and the thirty-fourth capacitor C34 is connected with one end of a parallel circuit of the second diode D2 and the second capacitor C2, and the other end of the parallel circuit of the second diode D2 and the second capacitor C2 forms an output end of the failure detection module (4).
2. The failure detection circuit for an LED lamp according to claim 1, wherein the failure states of the LED lamp (1) include open circuit failure, short circuit failure, and over temperature failure.
3. The failure detection circuit for the LED lamp according to claim 2, wherein the negative feedback module (2) comprises a first transistor TR1 and a second transistor TR2 which are symmetrically arranged, the base of the first transistor TR1 is connected with the base of the second transistor TR2, one path of the emitter of the first transistor TR1 is connected with the reference voltage module (3), the other path of the emitter of the first transistor TR1 is connected with a ninth capacitor C9, the emitter of the second transistor TR2 is connected with a tenth capacitor C10, the ninth capacitor C9 and the tenth capacitor C10 are connected with the ground in common, the tenth capacitor C10 is connected with a seventh resistor R7 in parallel, the collector of the first transistor TR1 is connected with VCC _ SW through a fifth resistor R5, and the collector of the second transistor TR2 is connected with VCC _ SW through a sixth resistor R6; the LED lamp further comprises a third field effect triode Q3, the grid electrode of the third field effect triode Q3 is connected with the collector electrode of the first triode TR1, the drain electrode of the third field effect triode Q3 is connected with the cathode of the LED lamp (1), and the source electrode of the third field effect triode Q3 is connected with a seventh resistor R7.
4. The failure detection circuit for the LED lamp as claimed in claim 3, wherein the first transistor TR1 and the second transistor TR2 form a symmetrical transistor Q4, and the signal of the transistor Q4 is BCV 61C.
5. A failure detection circuit for LED lamp according to any of claims 1-4, characterized in that the reference voltage module (3) comprises a first transistor Q1, the base of the first transistor Q1 is connected with the CMD _ PL port, the emitter of the first transistor Q1 is connected with the base of the first transistor Q1 through a fourth capacitor C4 and the other is connected with a third resistor R3, the third resistor R3 is connected with the collector of the first transistor Q1 through a fourth resistor R4 and the other is connected with a second resistor R2, the second resistor R2 is connected with the ground through a thirty capacitor C30 and the other is connected with the negative feedback module (2); the port CMD _ PL is used to generate a high level or a low level.
6. A method for detecting failure of an LED lamp, which applies the failure detection circuit for an LED lamp according to any one of claims 3 to 5, the method comprising:
the state of electrical failure of the LED lamp (1) is judged through the voltage at the output end of the failure detection module (4); the states of electrical failure include open circuit failure and short circuit failure;
whether the LED lamp (1) is in an over-temperature failure mode or not is judged according to the relation between the voltage difference between the output end of the failure detection module (4) and the negative feedback module (2) and the voltage difference between the sixth diode D6 and the second diode D2;
the state of electrical failure of the LED lamp (1) is judged by the voltage at the output end of the failure detection module (4), and the method specifically comprises the following steps:
if the formula (1) is established, judging that the failure state of the LED lamp (1) is open-circuit failure;
VFAILURE≈(VD6+VR7)-VD2 (1)
wherein, VFAILUREFor the voltage, V, at the output of the failure detection module (4)D6、VR7And VD2The voltages at the sixth diode D6, the seventh resistor R7, and the second diode D2, respectively;
if the formula (2) is established, judging that the failure state of the LED lamp (1) is short-circuit failure;
VFAILURE≈VCC_SW (2)
VCC _ SW is the power supply voltage of the negative feedback module (2);
and if the formulas (1) and (2) are not true, judging that the LED lamp (1) is in non-electrical failure.
7. The method of claim 6, further comprising: when the LED lamp (1) is in an electrical failure state, the singlechip turns off a power supply VCC _ SW of the negative feedback module (2);
when the LED lamp (1) is in an over-temperature failure mode, the current flowing through the LED lamp (1) is reduced through the negative feedback module (2) and the reference voltage module (3), so that the temperature of the LED lamp (1) is reduced.
8. The method for detecting the failure of the LED lamp according to claim 7, wherein the relationship between the voltage difference between the output end of the failure detection module (4) and the negative feedback module (2) and the voltage difference between the sixth diode D6 and the second diode D2 is used to determine whether the LED lamp (1) is in the over-temperature failure mode, specifically:
if the formula (3) does not hold, the LED lamp (1) is judged to be in an over-temperature failure state, otherwise, the LED lamp is in a non-over-temperature failure state:
VFAILURE-(VQ3_ds+VR7)≈VD6-VD2 (3)
wherein, VQ3_dsIs the voltage of the third field effect transistor Q3.
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| CN109688677A (en) * | 2015-01-29 | 2019-04-26 | 技术消费产品股份有限公司 | With light emitting diode (LED) driver for directly replacing ability |
| EP3089555B1 (en) * | 2015-04-29 | 2020-05-27 | Valeo Vision | Device and method for detecting a short-circuited light-emitting diode in a motor vehicle lighting device |
| CN204598411U (en) * | 2015-05-13 | 2015-08-26 | 深圳市垅运照明电器有限公司 | A kind of LED drove temperature drop current circuit |
| CN204968177U (en) * | 2015-08-26 | 2016-01-13 | 深圳市源拓光电技术有限公司 | Protection circuit based on diode temperature test |
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