KR-20260064444-A - LED SHORT DETECTION CIRCUIT AND LED SYSTEM INCLUDING THE SAME

KR20260064444AKR 20260064444 AKR20260064444 AKR 20260064444AKR-20260064444-A

Abstract

An LED short circuit detection circuit may be provided to detect whether a short circuit has occurred in an LED string. The LED short circuit detection circuit may include: a first smoothing circuit that receives a first LED driving voltage applied to one end of the LED string and performs smoothing on the first LED driving voltage; a second smoothing circuit that receives a second LED driving voltage applied to the other end of the LED string and performs smoothing on the second LED driving voltage; an amplifier that amplifies the difference between the first smoothing voltage output from the first smoothing circuit and the second smoothing voltage output from the second smoothing circuit and outputs a detection voltage; and a short circuit determination circuit that compares the detection voltage with a predetermined reference voltage and outputs a short circuit signal indicating whether a short circuit has occurred.

Inventors

박정현

Assignees

삼성전기주식회사

Dates

Publication Date: 20260507
Application Date: 20250324
Priority Date: 20241031

Claims (11)

As an LED short-circuit detection circuit for detecting whether a short circuit has occurred in an LED string, A first smoothing circuit that receives a first LED driving voltage applied to one end of the above LED row and performs smoothing on the first LED driving voltage, A second smoothing circuit that receives a second LED driving voltage applied to the other end of the LED row and performs smoothing on the second LED driving voltage, An amplifier that amplifies the difference between a first smoothing voltage output from the first smoothing circuit and a second smoothing voltage output from the second smoothing circuit to output a detection voltage, and A short-circuit determination circuit comprising comparing the above-mentioned detection voltage with a predetermined reference voltage and outputting a short-circuit signal indicating whether a short circuit exists. LED short-circuit detection circuit.
In paragraph 1, A buffer further comprising receiving the second smoothing voltage and outputting the second smoothing voltage to the amplifier LED short-circuit detection circuit.
In paragraph 1, The first smoothing circuit comprises a first resistor having one end connected to one end of the LED row, and a first capacitor connected between the other end of the first resistor and ground. The second smoothing circuit comprises a second resistor having one end connected to the other end of the LED column, and a second capacitor connected between the other end of the second resistor and ground. LED short-circuit detection circuit.
In paragraph 3, A buffer further comprising an input terminal connected to the other end of the second resistor and an output terminal that outputs the second smoothing voltage to the amplifier LED short-circuit detection circuit.
In paragraph 1, The above short-circuit detection circuit outputs a short-circuit signal indicating a short circuit when the detection voltage is lower than the reference voltage. LED short-circuit detection circuit.
In paragraph 5, The above short-circuit determination circuit includes a comparator that receives the detection voltage and the reference voltage, respectively, and outputs the short-circuit signal. LED short-circuit detection circuit.
LED string containing multiple LEDs An LED driving circuit that supplies a first LED driving voltage to one end of the LED column and supplies a second LED driving voltage to the other end of the LED column, and It includes an LED short-circuit detection circuit that receives the first LED driving voltage and the second LED driving voltage and generates a short-circuit signal indicating whether a short circuit has occurred in the LED row. The above LED short-circuit detection circuit is, A first smoothing circuit that performs smoothing on the first LED driving voltage and outputs a first smoothed voltage, A second smoothing circuit that performs smoothing on the second LED driving voltage and outputs a second smoothed voltage, An amplifier that amplifies the difference between the first smoothed voltage and the second smoothed voltage to output a detection voltage, and A short-circuit determination circuit that outputs the short-circuit signal by comparing the above-mentioned detection voltage with a predetermined reference voltage. LED system.
In Paragraph 7, The above LED short-circuit detection circuit is, A buffer further comprising receiving the second smoothing voltage and outputting the second smoothing voltage to the amplifier LED system.
In Paragraph 7, The first smoothing circuit is an RC smoothing circuit that generates the first smoothing voltage corresponding to the average value of the first LED driving voltage, and The second smoothing circuit is an RC smoothing circuit that generates the second smoothing voltage corresponding to the average value of the second LED driving voltage. LED system.
In Paragraph 7, The above short-circuit detection circuit outputs a short-circuit signal indicating a short circuit when the detection voltage is lower than the reference voltage. LED system.
In Paragraph 10, The above short-circuit determination circuit includes a comparator that receives the detection voltage and the reference voltage, respectively, and outputs the short-circuit signal. LED system.

Description

LED Short Circuit Detection Circuit and LED System Including the Same This invention relates to an LED short-circuit detection circuit and an LED system including the same. An LED (Light Emitting Diode) is a semiconductor device that emits light when an electric current is applied. LEDs are used for various purposes, such as lighting and backlights for displays, and recently, they are also being adopted in automotive cameras. Automotive cameras are installed inside vehicles and are used to monitor drivers and passengers. Infrared cameras are used to monitor drivers and passengers. Infrared LEDs can be used as the light source for infrared cameras. In infrared LEDs used as light sources, multiple LEDs are connected in series. A circuit is required to detect a problem (short circuit) even when it occurs in at least one of the multiple LEDs. FIG. 1 is a drawing showing an LED system according to one embodiment. Figure 2 is a graph showing an example of LED driving voltage (V LED+ , V LED- ), LED driving current (I LED ), and on/off of LED column (300). Figure 3 is a block diagram showing the simplified internal configuration of an LED short-circuit detection circuit. Figure 4 is a circuit diagram showing the detailed internal configuration of an LED short-circuit detection circuit. Figure 5 is a graph conceptually showing the LED driving voltage (V LED+ , V LED- ) and smoothing voltage (V SM+ , V SM- ). Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals. The attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification is not limited by the attached drawings; it should be understood that all modifications, equivalents, and substitutions included within the concept and technical scope of the present invention are included. Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. Furthermore, when it is said that a part, such as a layer, membrane, region, or plate, is "on" or "on" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when it is said that a part is "directly above" another part, it means that there is no other part in between. Also, saying that a part is "on" or "on" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "on" or "on" in the direction opposite to gravity. Throughout the specification, terms such as “comprising” or “having” are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Accordingly, when a part is said to “comprising” a certain component, unless specifically stated otherwise, this means that it may include additional components rather than excluding other components. Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side. Throughout the specification, when a part is described as being "coupled" with another part, this includes not only cases where they are "directly or physically coupled," but also cases where they are "indirectly or non-contact coupled" with another element in between. Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly or physically connected," but also cases where they are "indirectly or non-contactually connected" with other elements in between, or cases where they are "electrically connected." FIG. 1 is a drawing showing an LED system (1000) according to one embodiment. As shown in FIG. 1, the LED system (1000) may include an LED driving circuit (100), an LED string (200), and an LED short circuit detection circuit (300). The LED system (1000) of FIG. 1 may be mounted on an electric camera and emit infrared light. The LED driving circuit (100) generates an LED driving voltage (V LED+ , V LED- ), and the ge