# US 12,193,129 B2 · Light emitting element driving device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,193,129 B2 - Document ID: US12193129B2 - Status: Granted - Kind: B2 - Application number: 17/781,836 - Filed: 2020-08-26 - Published: 2023-01-05 - Granted: 2025-01-07 - Earliest claimed: 2019-12-06 - Assignees: Rohm Co., Ltd. - Applicants: Rohm Co., Ltd. - Inventors: Kei Nagao - Web page: https://patentgrep.com/patent/US12193129B2 ## CPC - H05B 45/10: Controlling the intensity of the light - H05B 45/58: involving end of life detection of LEDs - H05B 47/18: via data-bus transmission - B60Q 1/2607: {comprising at least two indicating lamps} - B60Q 1/30: for indicating rear of vehicle, e.g. by means of reflecting surfaces - Y02B 20/40: Control techniques providing energy savings, e.g. smart controller or presence detection - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - B60Q: ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A light emitting element driving device includes a receiver that receives a predetermined communication signal transmitted across a communication line, a generator that generates a reference signal based on the start time point of a start bit in the predetermined communication signal, and a determiner that determines, based on the reference signal, the timing of switching a light emitting element from extinction to lighting. The predetermined communication signal is a signal in which the start bit with a first logic level is transmitted at a prescribed period from a transmitter and in which the data bits succeeding each start bit do not have a second logic level a predetermined number of times or more consecutively. ## Claims ### Claim 1 A light emitting element driving device comprising: a receiver configured to receive a predetermined communication signal transmitted across a communication line; a generator configured to generate a reference signal based on a start time point of a start bit in the predetermined communication signal; and a determiner configured to determine, based on the reference signal, timing of switching a light emitting element from an OFF state to an ON state, wherein the predetermined communication signal is a signal in which the start bit with a first logic level is transmitted at a prescribed period from a transmitter and in which data bits succeeding each start bit do not have a second logic level a predetermined number of times or more consecutively, wherein the generator includes a first detector configured to detect that a period during which the communication line is at the second logic level has continued for a first predetermined time, and a second detector configured to detect, as the start time point of the start bit, a first logic appearance time point at which the first logic level appears on the communication line for a first time after the period in which the communication line is at the second logic level has continued for the first predetermined time, wherein the second detector is configured such that, if the period in which the communication line is at the first logic level does not continue for a second predetermined time after the first logic appearance time point, the second detector exceptionally does not detect the first logic appearance time point as the start time point of the start bit. ### Claim 2 (depends on 1) The light emitting element driving device according to claim 1, wherein the second predetermined time is shorter than the first predetermined time. ### Claim 3 (depends on 1) The light emitting element driving device according to claim 1, wherein the predetermined communication signal includes dimming information for the light emitting element. ### Claim 4 (depends on 1) The light emitting element driving device according to claim 1, wherein the predetermined communication signal is a UART (universal asynchronous receiver-transmitter) communication signal. ### Claim 5 (depends on 1) A light emitting system comprising a plurality of the light emitting element driving devices according to claim 1, the light emitting system further comprising: the communication line; the transmitter; and at least as many of the light emitting elements as there are the light emitting element driving devices. ### Claim 6 (depends on 5) A vehicle comprising the light emitting system according to claim 5. ### Claim 7 An LED dimming control device comprising a receiver configured to receive a predetermined communication signal transmitted across a communication line, the LED dimming control device being configured to perform programmable PWM dimming on individual LEDs using an internal PWM clock signal, wherein the predetermined communication signal is a UART communication signal, with each UART frame in a serial interface composed of one start bit and data bits, the internal PWM clock signal is adjusted by the predetermined communication signal, the predetermined communication signal is a signal in which a start bit with a first logic level is transmitted at a prescribed period from a transmitter and, as data bits succeeding each start bit, a signal with a second logic level is transmitted a predetermined number of times consecutively. ### Claim 8 (depends on 7) The LED dimming control device according to claim 7, further comprising: a first terminal configured to have a cathode of a first LED externally connected thereto; a second terminal configured to have a cathode of a second LED externally connected thereto; and a third terminal configured to have a cathode of a third LED externally connected thereto. ### Claim 9 (depends on 8) The LED dimming control device according to claim 8, wherein the first, second, and third LEDs are individually subjected to dimming control. ### Claim 10 (depends on 8) The LED dimming control device according to claim 8, further comprising a register configured to set an on-duty of the LEDs. ### Claim 11 (depends on 7) The LED dimming control device according to claim 7, wherein an on-timing of the internal PWM clock signal is changed every prescribed period. ### Claim 12 (depends on 7) The LED dimming control device according to claim 7, wherein the communication line is a CAN, and the LED dimming control device includes a terminal configured to have a bus of the CAN connected thereto. ### Claim 13 (depends on 9) An LED system comprising: the LED dimming control device according to claim 9; and the LEDs. ### Claim 14 (depends on 13) A vehicle comprising the LED system according to claim 13. ### Claim 15 A light emitting element driving device comprising: a receiver configured to receive a predetermined communication signal transmitted across a communication line; a generator configured to generate a reference signal based on a start time point of a start bit in the predetermined communication signal; and a determiner configured to determine, based on the reference signal, timing of switching a light emitting element from OFF state to ON state, wherein the predetermined communication signal is a signal in which the start bit with a first logic level is transmitted at a prescribed period from a transmitter and in which data bits succeeding each start bit do not have a second logic level a predetermined number of times or more consecutively, wherein the generator includes: a detector configured to detect, as the start time point of the start bit, a first logic appearance time point at which the first logic level appears on the communication line for a first time after the period in which the communication line is at the second logic level has continued for a first predetermined time, wherein the detector is configured such that, if the period in which the communication line is at the first logic level does not continue for a second predetermined time after the first logic appearance time point, the detector exceptionally does not detect the first logic appearance time point as the start time point of the start bit.