# US 8,786,129 B2 · Control device for lighting LED and detecting breakage thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,129 B2 - Document ID: US8786129B2 - Status: Granted - Kind: B2 - Application number: 13/800,137 - Filed: 2013-03-13 - Published: 2013-09-19 - Granted: 2014-07-22 - Earliest claimed: 2012-03-13 - Assignees: Omron Automotive Electronics Co., Ltd. - Applicants: Yoichi Sakuma - Inventors: Yoichi Sakuma - Web page: https://patentgrep.com/patent/US8786129B2 ## CPC - H05B 45/46: having LEDs disposed in parallel lines - H05B 45/50: responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A control device includes a plurality of LED arrays connected in parallel to one another, each of the plurality of LED arrays including one or more LEDs connected in series and a resistance element connected in series to the LEDs, a voltage application circuit that applies a voltage to the plurality of LED arrays, a switching element disposed between the plurality of LED arrays and a ground, a voltage detection circuit having an end connected between the switching element and the plurality of LED arrays, a capacitor having an end connected between the switching element and the plurality of LED arrays, and another end connected to the ground, and a control circuit that controls the voltage outputted from the voltage application circuit and switching of conduction states of the switching element, and reads a voltage from the voltage detection circuit. ## Claims ### Claim 1 A control device that controls lighting of a plurality of LEDs and detects a breakage of each LED, the control device comprising: a plurality of LED arrays connected in parallel to one another, each of the plurality of LED arrays including one or more LEDs connected in series and a resistance element connected in series to the LEDs; a voltage application circuit that applies a voltage to the plurality of LED arrays; a switching element disposed between the plurality of LED arrays and a ground; a voltage detection circuit having an end connected between the switching element and the plurality of LED arrays; a capacitor having an end connected between the switching element and the plurality of LED arrays, and another end connected to the ground; and a control circuit that controls the voltage outputted from the voltage application circuit and switching of conduction states of the switching element, and reads a voltage from the voltage detection circuit, wherein the resistance elements connected in series to the corresponding LEDs have different resistances from one another, the control circuit renders the switching element be in a connection state, and outputs a command signal to the voltage application circuit to apply the voltage for lighting the LEDs, and the control circuit renders the switching element in a disconnection state, and outputs a command signal to the voltage application circuit to apply a rectangular wave pulse voltage having a pulse duration that does not cause the LEDs to be lighted, to detect presence or absence of breakages of the LEDs in each LED array based on the voltage read from the voltage detection circuit and determine which of the LED arrays is broken. ### Claim 2 (depends on 1) The control device according to claim 1, wherein the control circuit brings the switching element into conduction after reading the voltage from the voltage detection circuit. ### Claim 3 (depends on 2) The control device according to claim 2, wherein the control circuit reads the voltage from the voltage detection circuit after the rectangular wave pulse voltage having the pulse duration that does not cause the LEDs to be lighted becomes 0 V. ### Claim 4 (depends on 3) The control device according to claim 3, wherein the control device detects presence or absence of breakages of the LEDs in each LED array and determines which of LED arrays is broken by comparing the voltage read from the voltage detection circuit with a voltage threshold determined in advance based on respective resistances of the resistance elements. ### Claim 5 (depends on 3) The control device according to claim 3, wherein the control device detects presence or absence of breakages of the LEDs in each LED array based on a change in the voltage read from the voltage detection circuit. ### Claim 6 (depends on 3) The control device according to claim 3, wherein during a period over which the control device outputs a command signal to the voltage application circuit to continuously apply a rectangular pulse wave voltage having a pulse duration that causes the LEDs to be lighted, when the rectangular pulse wave voltage becomes 0 V, the control device outputs the command signal to the voltage application circuit to apply the rectangular pulse wave voltage having the pulse duration that does not cause the LEDs to be lighted. ### Claim 7 (depends on 3) The control device according to claim 3, wherein in the case where the plurality of LED arrays constitute a single lamp, when detecting a breakage of one of the plurality of LED arrays in the single lamp, the control circuit increases luminance of the LEDs constituting the LED arrays other than the broken one in the single lamp. ### Claim 8 (depends on 2) The control device according to claim 2, wherein the control device detects presence or absence of breakages of the LEDs in each LED array and determines which of LED arrays is broken by comparing the voltage read from the voltage detection circuit with a voltage threshold determined in advance based on respective resistances of the resistance elements. ### Claim 9 (depends on 2) The control device according to claim 2, wherein the control device detects presence or absence of breakages of the LEDs in each LED array based on a change in the voltage read from the voltage detection circuit. ### Claim 10 (depends on 2) The control device according to claim 2, wherein during a period over which the control device outputs a command signal to the voltage application circuit to continuously apply a rectangular pulse wave voltage having a pulse duration that causes the LEDs to be lighted, when the rectangular pulse wave voltage becomes 0 V, the control device outputs the command signal to the voltage application circuit to apply the rectangular pulse wave voltage having the pulse duration that does not cause the LEDs to be lighted. ### Claim 11 (depends on 2) The control device according to claim 2, wherein in the case where the plurality of LED arrays constitute a single lamp, when detecting a breakage of one of the plurality of LED arrays in the single lamp, the control circuit increases luminance of the LEDs constituting the LED arrays other than the broken one in the single lamp. ### Claim 12 (depends on 1) The control device according to claim 1, wherein the control device detects presence or absence of breakages of the LEDs in each LED array and determines which of LED arrays is broken by comparing the voltage read from the voltage detection circuit with a voltage threshold determined in advance based on respective resistances of the resistance elements. ### Claim 13 (depends on 12) The control device according to claim 12, wherein during a period over which the control device outputs a command signal to the voltage application circuit to continuously apply a rectangular pulse wave voltage having a pulse duration that causes the LEDs to be lighted, when the rectangular pulse wave voltage becomes 0 V, the control device outputs the command signal to the voltage application circuit to apply the rectangular pulse wave voltage having the pulse duration that does not cause the LEDs to be lighted. ### Claim 14 (depends on 12) The control device according to claim 12, wherein in the case where the plurality of LED arrays constitute a single lamp, when detecting a breakage of one of the plurality of LED arrays in the single lamp, the control circuit increases luminance of the LEDs constituting the LED arrays other than the broken one in the single lamp. ### Claim 15 (depends on 1) The control device according to claim 1, wherein the control device detects presence or absence of breakages of the LEDs in each LED array based on a change in the voltage read from the voltage detection circuit. ### Claim 16 (depends on 15) The control device according to claim 15, wherein during a period over which the control device outputs a command signal to the voltage application circuit to continuously apply a rectangular pulse wave voltage having a pulse duration that causes the LEDs to be lighted, when the rectangular pulse wave voltage becomes 0 V, the control device outputs the command signal to the voltage application circuit to apply the rectangular pulse wave voltage having the pulse duration that does not cause the LEDs to be lighted. ### Claim 17 (depends on 15) The control device according to claim 15, wherein in the case where the plurality of LED arrays constitute a single lamp, when detecting a breakage of one of the plurality of LED arrays in the single lamp, the control circuit increases luminance of the LEDs constituting the LED arrays other than the broken one in the single lamp. ### Claim 18 (depends on 1) The control device according to claim 1, wherein during a period over which the control device outputs a command signal to the voltage application circuit to continuously apply a rectangular pulse wave voltage having a pulse duration that causes the LEDs to be lighted, when the rectangular pulse wave voltage becomes 0 V, the control device outputs the command signal to the voltage application circuit to apply the rectangular pulse wave voltage having the pulse duration that does not cause the LEDs to be lighted. ### Claim 19 (depends on 1) The control device according to claim 1, wherein in the case where the plurality of LED arrays constitute a single lamp, when detecting a breakage of one of the plurality of LED arrays in the single lamp, the control circuit increases luminance of the LEDs constituting the LED arrays other than the broken one in the single lamp. ### Claim 20 (depends on 1) The control device according to claim 1, wherein the LEDs are provided in a vehicle.