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EP-4739002-A1 - LED SHORT DETECTION CIRCUIT AND LED SYSTEM INCLUDING THE SAME

EP4739002A1EP 4739002 A1EP4739002 A1EP 4739002A1EP-4739002-A1

Abstract

A light-emitting diode (LED) short detection circuit includes a first smoothing circuit configured to receive a first LED driving voltage applied to a first end of an LED string and perform smoothing on the first LED driving voltage; a second smoothing circuit configured to receive a second LED driving voltage applied to a second end of the LED string and perform smoothing on the second LED driving voltage; an amplifier configured to amplify a 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 configured to compare the detection voltage with a predetermined reference voltage to output a short-circuit signal indicating whether a short-circuit has occurred.

Inventors

  • PARK, JEONG HYUN

Assignees

  • Samsung Electro-Mechanics Co., Ltd.

Dates

Publication Date
20260506
Application Date
20250923

Claims (12)

  1. A light-emitting diode (LED) short detection circuit, comprising: a first smoothing circuit configured to receive a first LED driving voltage applied to a first end of an LED string and perform smoothing on the first LED driving voltage; a second smoothing circuit configured to receive a second LED driving voltage applied to a second end of the LED string and perform smoothing on the second LED driving voltage; an amplifier configured to amplify a 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 configured to compare the detection voltage with a predetermined reference voltage to output a short-circuit signal indicating whether a short-circuit has occurred.
  2. The LED short detection circuit of claim 1, further comprising a buffer configured to receive the second smoothing voltage and output the second smoothing voltage to the amplifier.
  3. The LED short detection circuit of claim 1, wherein the first smoothing circuit comprises a first resistor having a first end connected to the first end of the LED string, and a first capacitor connected between a second end of the first resistor and ground, and the second smoothing circuit comprises a second resistor having a first end connected to the second end of the LED string, and a second capacitor connected between a second end of the second resistor and ground.
  4. The LED short detection circuit of claim 3, further comprising a buffer configured to have an input terminal connected to the second end of the second resistor, and an output terminal outputting the second smoothing voltage to the amplifier.
  5. The LED short detection circuit of claim 1, wherein the short-circuit signal indicates a short circuit in response to the detection voltage being lower than the reference voltage.
  6. The LED short detection circuit of claim 5, wherein the short-circuit determination circuit comprises a comparator that receives each of the detection voltage and the reference voltage and outputs the short-circuit signal.
  7. An LED system comprising: an LED driving circuit configured to supply the first LED driving voltage and the second LED driving voltage; and the LED short detection circuit of claim 1 configured to receive the first LED driving voltage and the second LED driving voltage.
  8. A light-emitting diode (LED) system comprising: an LED string configured to comprise a plurality of LEDs; an LED driving circuit configured to supply a first LED driving voltage to a first end of the LED string and a second LED driving voltage to a second end of the LED string; and an LED short detection circuit configured to receive the first LED driving voltage and the second LED driving voltage, and generate a short-circuit signal indicating whether a short-circuit has occurred in the LED string, wherein the LED short detection circuit comprises: a first smoothing circuit configured to perform smoothing on the first LED driving voltage to output a first smoothing voltage; a second smoothing circuit configured to perform smoothing on the second LED driving voltage to output a second smoothing voltage; an amplifier configured to amplify a difference between the first smoothing voltage and the second smoothing voltage to output a detection voltage; and a short-circuit determination circuit configured to compare the detection voltage with a predetermined reference voltage to output a short-circuit signal.
  9. The LED system of claim 8, wherein the LED short detection circuit further comprises a buffer configured to receive the second smoothing voltage and output the second smoothing voltage to the amplifier.
  10. The LED system of claim 8, wherein the first smoothing circuit is an RC smoothing circuit configured to generate the first smoothing voltage corresponding to an average value of the first LED driving voltage, and the second smoothing circuit is an RC smoothing circuit configured to generate the second smoothing voltage corresponding to an average value of the second LED driving voltage.
  11. The LED system of claim 8, wherein the short-circuit signal indicates a short circuit in response to the detection voltage being lower than the reference voltage.
  12. The LED system of claim 11, wherein the short-circuit determination circuit comprises a comparator that receives each of the detection voltage and the reference voltage, and outputs the short-circuit signal.

Description

BACKGROUND 1. Field The present disclosure relates to an LED short detection circuit and an LED system including the same. 2. Description of the Background A light-emitting diode (LED) is a semiconductor device that emits light when a current is applied. LEDs are used for a variety of purposes, including lighting and backlighting of displays, and recently, LEDs are also being used in battlefield cameras. A vehicle-mounted camera is installed inside a vehicle and used to monitor a driver, a passenger, etc. An infrared camera is used to monitor drivers and passengers. In an infrared camera, an infrared LED may be used as a light source. In the infrared LED used as light sources, multiple LEDs are connected in series with each other. A circuit may be desired to detect even when a problem (short circuit) occurs in at least one LED among the LEDs. The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure. SUMMARY This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. In one general aspect, a light-emitting diode (LED) short detection circuit includes a first smoothing circuit configured to receive a first LED driving voltage applied to a first end of an LED string and perform smoothing on the first LED driving voltage; a second smoothing circuit configured to receive a second LED driving voltage applied to a second end of the LED string and perform smoothing on the second LED driving voltage; an amplifier configured to amplify a 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 configured to compare the detection voltage with a predetermined reference voltage to output a short-circuit signal indicating whether a short-circuit has occurred. The LED short detection circuit may further include a buffer configured to receive the second smoothing voltage and output the second smoothing voltage to the amplifier. The first smoothing circuit may include a first resistor having a first end connected to the first end of the LED string, and a first capacitor connected between a second end of the first resistor and ground, and the second smoothing circuit may include a second resistor having a first end connected to the second end of the LED string, and a second capacitor connected between a second end of the second resistor and ground. The LED short detection circuit may further include a buffer configured to have an input terminal connected to the second end of the second resistor, and an output terminal outputting the second smoothing voltage to the amplifier. The short-circuit signal may indicate a short circuit in response to the detection voltage being lower than the reference voltage. The short-circuit determination circuit may include a comparator that receives each of the detection voltage and the reference voltage and outputs the short-circuit signal. An LED system may include an LED driving circuit configured to supply the first LED driving voltage and the second LED driving voltage, and the LED short detection circuit described herein may be configured to receive the first LED driving voltage and the second LED driving voltage. In another general aspect, light-emitting diode (LED) includes an LED string configured to include a plurality of LEDs, an LED driving circuit configured to supply a first LED driving voltage to a first end of the LED string and a second LED driving voltage to a second end of the LED string, and an LED short detection circuit configured to receive the first LED driving voltage and the second LED driving voltage and generate a short-circuit signal indicating whether a short-circuit has occurred in the LED string, and the LED short detection circuit may include a first smoothing circuit configured to perform smoothing on the first LED driving voltage to output a first smoothing voltage, a second smoothing circuit configured to perform smoothing on the second LED driving voltage to output a second smoothing voltage, an amplifier configured to amplify a difference between the first smoothing voltage and the second smoothing voltage to output a detection voltage, and a short-circuit determination circuit configured to compare the detected voltage with a predetermined reference voltage to output a short-circuit signal. The LED short detection circuit may further include a buffer configured to receive the second smoo