CN201654157U - A fault detection device for LED driving circuit - Google Patents

Abstract

The utility model relates to a fault detection device for an LED drive circuit. The fault detection device includes a voltage detection module and a logic circuit, and the voltage detection module respectively inputs a detection output from each group of LEDs The difference between the signal and a reference voltage signal output by the driving device is compared with the set value input externally, and an identification signal is output; the logic circuit performs logical operation on the identification signal output by the voltage detection module, and outputs an Judgment signal. The utility model can detect open-circuit and/or short-circuit faults of LEDs in real time when one or more groups of LEDs are working, and facilitates users to accurately locate the faults to take measures to prevent LED faults from expanding, thereby making the entire LED The drive circuit can work continuously and stably for a long time.

Description

A fault detection device for LED driving circuit

technical field

The utility model relates to an integrated circuit, in particular to a fault detection device for an LED (light emitting diode) drive circuit.

Background technique

As we all know, in the driving circuit and its application for multiple groups of LEDs, when one or more groups of LEDs work at the same time, and some LEDs have open circuit or short circuit faults for some reason, if they cannot be detected or cannot be detected in time. If the location of the fault is detected, the fault may be expanded, causing damage to more LEDs or the entire LED driving circuit. Therefore, in order to avoid this situation and make the LED work stably for a longer period of time, it is necessary to perform real-time fault detection on multiple groups of LEDs in the LED driving circuit.

Utility model content

In order to solve the above problems, the utility model aims to provide a fault detection device for the LED drive circuit, so that the open circuit and short circuit fault detection of the LED network in the LED drive circuit can be reliably realized, and the entire LED drive circuit can continue to work .

The utility model relates to a fault detection device for an LED driving circuit, the LED driving circuit includes an LED network and a power supply device and a driving device respectively connected to the LED network, and the LED network includes N group of LEDs, and N is a natural number, the fault detection device includes a voltage detection module and a logic circuit,

The voltage detection module compares the difference between a detection input signal output from each group of LEDs and a reference voltage signal output by the driving device with an externally input set value, and outputs an identification signal;

The logic circuit performs logical operation on the identification signal output by the voltage detection module, and outputs a judgment signal.

In the above fault detection device for LED driving circuit, the voltage detection module includes an overvoltage detection circuit connected with the logic circuit.

In the above fault detection device for LED driving circuit, the voltage detection module includes an undervoltage detection circuit connected with the logic circuit.

In the above fault detection device for LED driving circuit, the under-voltage detection circuit and the over-voltage detection circuit are respectively a comparison circuit with different thresholds.

Due to the adoption of the above-mentioned technical solution, the utility model realizes the real-time detection of the LED network in the LED driving circuit through the voltage detection module and the logic circuit, and adopts the undervoltage detection circuit or the overvoltage detection circuit or the overvoltage detection circuit in the voltage detection module. At the same time, two under-voltage detection circuits and over-voltage detection circuits with different thresholds are used, so that the utility model can detect open circuit and/or short circuit faults of LEDs in real time when one or more groups of LEDs are working, and it is convenient for users to correct The fault is accurately located to take measures to prevent the expansion of the LED fault, so that the entire LED drive circuit can continue to work stably for a long time.

Description of drawings

Fig. 1 is a working principle diagram of a preferred embodiment of a fault detection device for an LED drive circuit of the present invention.

Detailed ways

As shown in Figure 1, the LED driving circuit includes an LED network 3 (such as a plurality of LED strings) and a power supply device 1 (such as LED power supply) and a driving device 2 (such as LED constant current) connected to the LED network 3 respectively. driving circuit), wherein the LED network 3 includes N groups of LED30, where N is a natural number. The utility model, that is, a fault detection device 8 for an LED drive circuit includes a voltage detection module 45 and a logic circuit 6, wherein:

The voltage detection module 45 is respectively the difference between a detection input signal 31 output from each group of LED30 and a reference voltage signal 31 provided by the driving device 2 and the set value of the external input (this set value can also be determined by the voltage detection module. 45 internally generated) comparison, and output a corresponding identification signal; specifically, the voltage detection module 45 includes an overvoltage detection circuit 4 and an undervoltage detection circuit 5 respectively connected to the logic circuit 6, wherein the overvoltage detection circuit 4 is used for To detect whether the difference between each detection input signal 32 and the reference voltage signal 31 is higher than the first set value Vt1 input externally, the undervoltage detection circuit 5 is used to detect the difference between each detection input signal 32 and the reference voltage signal 31 Whether the value is lower than the second set value Vt2 of the external input; in the utility model, the undervoltage detection circuit 5 and the overvoltage detection circuit 4 respectively adopt comparison circuits with different thresholds;

The logic circuit 6 performs logical operation on the identification signal output by the voltage detection module 45, and outputs a/group judgment signal 7, which is used to indicate whether each group of LEDs 30 in the LED network 3 is in a fault state.

In this embodiment, the working principle of a fault detection device for an LED driving circuit of the present invention is described in detail.

First, a sampling step is performed, that is, the voltage detection module 45 collects a detection input signal 32 output by each group of LEDs 30 and a reference voltage signal 31 provided by the driving device 2 .

Secondly, the detection step is carried out, that is, the voltage detection module 45 compares the difference between each detection input signal 32 and the reference voltage signal 31 in the sampling step with the set value of the external input, and generates a corresponding identification signal; specifically, The detection step includes an overvoltage detection step and an undervoltage detection step, wherein the overvoltage detection step is to detect whether the difference between each detection input signal 32 and the reference voltage signal 31 is higher than The first set value Vt1 of external input, when the difference between a certain detection input signal 32 and the reference voltage signal 31 rises to exceed the first set value Vt1, while the difference between other detection signals 32 and the reference voltage signal 31 remains When it remains unchanged, it means that a group of LED30 corresponding to the detection input signal 32 in the LED network 3 has a short-circuit fault; the undervoltage detection step is to detect each detection input signal by the undervoltage detection circuit 5 in the voltage detection module 45 Whether the difference between 32 and the reference voltage signal 31 is lower than the second set value Vt2 of the external input, when the difference between a certain detection input signal 32 and the reference voltage signal 31 is lower than the second set value Vt2, while other When the difference between the detection signal 32 and the reference voltage signal 31 rises to exceed the first set value Vt1 or remains unchanged, it means that a group of LEDs 30 corresponding to the detection input signal 32 in the LED network 3 has an open-circuit fault. , that is, the group of LED30 loses the driving current.

Finally, the judging step is performed, that is, the logic circuit 6 performs logic operations on the identification signals output by the overvoltage detection circuit 4 and the undervoltage detection circuit 5 in the detection step, thereby judging the position of one or more groups of LED30 that have failed, and generating The corresponding judgment signal 7 is convenient for the user to accurately and timely locate the faulty LED.

To sum up, the utility model of a fault detection device and detection method for LED drive circuit can reliably realize the open circuit and short circuit fault detection of the LED network in the LED drive circuit, and make the entire LED drive circuit sustainable work steadily.

The utility model has been described in detail above in conjunction with the embodiments of the accompanying drawings, and those skilled in the art can make various changes to the utility model according to the above description. Therefore, some details in the embodiments should not constitute a limitation to the utility model, and the utility model shall take the scope defined by the appended claims as the protection scope of the utility model.

Claims (4)

1. A fault detection device for an LED driving circuit, the LED driving circuit comprising an LED network and a power supply device and a driving device respectively connected to the LED network, the LED network comprising N groups of LEDs, and N is a natural number, characterized in that the fault detection device includes a voltage detection module and a logic circuit, The voltage detection module compares the difference between a detection input signal output from each group of LEDs and a reference voltage signal output by the driving device with an externally input set value, and outputs an identification signal; The logic circuit performs logical operation on the identification signal output by the voltage detection module, and outputs a judgment signal. 2. The fault detection device for LED driving circuit according to claim 1, wherein said voltage detection module comprises an overvoltage detection circuit connected with said logic circuit. 3. The fault detection device for LED driving circuit according to claim 1 or 2, characterized in that, the voltage detection module comprises an undervoltage detection circuit connected with the logic circuit. 4 . The fault detection device for LED driving circuit according to claim 3 , wherein the undervoltage detection circuit and the overvoltage detection circuit are respectively a comparison circuit with different thresholds.

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