# US 10,874,009 B2 · Load driving apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,874,009 B2 - Document ID: US10874009B2 - Status: Granted - Kind: B2 - Application number: 16/207,159 - Filed: 2018-12-02 - Published: 2019-04-11 - Granted: 2020-12-22 - Earliest claimed: 2016-06-13 - Assignees: Koito Manufacturing Co., Ltd. - Applicants: Koito Manufacturing Co., Ltd. - Inventors: Tomoyuki Ichikawa; Toshiaki Tsuda - Web page: https://patentgrep.com/patent/US10874009B2 ## CPC - H05B 45/375: using buck topology - B60Q 1/04: the devices being headlights - B60Q 11/005: {for lighting devices, e.g. indicating if lamps are burning or not} - F21S 41/16: Laser light sources - F21S 41/176: Light sources where the light is generated by photoluminescent material spaced from a primary light generating element - H02M 3/155: using semiconductor devices only - H05B 45/3725: Switched mode power supply [SMPS] - H05B 45/50: responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits - H05B 47/17: Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations - Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] - 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 - F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A load driving apparatus receives an input voltage from a power supply, and supplies electric power to a load under processor control. The processor outputs first and second signals via first and second pins in a conjunction such that they are negated when the load is instructed to suspend operation. An output circuit supplies electric power to the load. A protection switch is provided on a driving path that extends from the power supply to the load and returns to the power supply. When the first signal is asserted (negated), a control circuit sets the output circuit to an operation state (suspension state). The control circuit turns on the protection switch on assertion of the second signal, and turns it off on negation of this signal. ## Claims ### Claim 1 A load driving apparatus structured to receive an input voltage from a power supply, and to supply an electric power to a load under a control operation of a processor, wherein the processor outputs a first signal and a second signal in conjunction via a first pin and a second pin such that the first signal and the second signal are negated when the load is instructed to suspend an operation thereof, and wherein the load driving apparatus comprises: an output circuit structured to supply an electric power to the load; a protection switch provided on a driving path that extends from the power supply to the load and returns to the power supply; and a control circuit structured to be set to an operation state when the first signal is asserted, to be set to a suspension state when the first signal is negated, to turn on the protection switch when the second signal is asserted, and to turn off the protection switch when the second signal is negated. ### Claim 2 (depends on 1) The load driving apparatus according to claim 1, wherein the output circuit comprises a transistor structured to adjust an electrical state of the load, wherein the control circuit is structured to control the transistor such that the electrical state of the load approaches a target value when the first signal is asserted, and structured to turn off the transistor when the first signal is negated. ### Claim 3 (depends on 2) The load driving apparatus according to claim 2, wherein the output circuit is configured as a switching converter, and wherein the transistor is configured as a switching transistor. ### Claim 4 (depends on 1) The load driving apparatus according to claim 1, wherein the load comprises a light-emitting element structured to emit an excitation light and a fluorescent member structured to be excited by the excitation light and to emit a fluorescence light, and is structured to output a white output light having spectrum of the excitation light and the fluorescence light, and wherein, when a light leakage abnormality is detected in the light source, the processor negates the first signal and the second signal. ### Claim 5 (depends on 1) The load driving apparatus according to claim 1, wherein at least one from among the first signal and the second signal is generated as a pulse signal in an asserted state, and is generated as a DC signal in a negated state. ### Claim 6 (depends on 1) An automotive lamp comprising: a light source; the load driving apparatus according to claim 1, structured to drive the light source; and a processor structured to control the load driving apparatus. ### Claim 7 A lighting circuit employed in an automotive lamp, the lighting circuit comprising: a driving circuit structured to supply a driving current to a light-emitting element of a light source; and an abnormality detector structured to detect an abnormality that can occur in the light source, wherein the lighting circuit is structured to be switchable between a first mode in which the driving current is raised with a first slope when lighting is started up and a second mode in which the driving current is raised with a second slope that is smaller than the first slope when lighting is started up. ### Claim 8 (depends on 7) The lighting circuit according to claim 7, wherein a target value of the driving current in the second mode is substantially the same as the target value of the driving current in the first mode. ### Claim 9 (depends on 7) The lighting circuit according to claim 7, wherein the light source comprises: a laser diode structured as a light-emitting element; and a fluorescent member structured to be excited by an excitation light emitted from the laser diode, and to emit a fluorescence light, so as to generate a white output light including the excitation light and a fluorescence spectrum, and wherein the abnormality detector detects an abnormality which is leakage of the excitation light. ### Claim 10 (depends on 7) The lighting circuit according to claim 7, wherein, when the automotive lamp is to be tested, the second mode is selected. ### Claim 11 (depends on 7) The lighting circuit according to claim 7, wherein, when a speed of a vehicle is lower than a predetermined threshold value, the second mode is selected. ### Claim 12 (depends on 7) An automotive lamp comprising: a light source comprising a light-emitting element; and the lighting circuit according to claim 7, structured to supply a driving current to the light-emitting element. ### Claim 13 A lighting circuit employed in an automotive lamp, the lighting circuit comprising: a driving circuit structured to supply a driving current to a light-emitting element of a light source; and an abnormality detector structured to detect an abnormality that can occur in the light source, wherein the lighting circuit is structured to be switchable between a first mode in which the driving current is raised up to a predetermined value in a first start-up time when lighting is started up and a second mode in which the driving current is raised up to the predetermined value in a second start-up time that is longer than the first start-up time when lighting is started up. ### Claim 14 (depends on 13) The lighting circuit according to claim 13, wherein the light-emitting element comprises a laser diode, and wherein the predetermined value is determined to be higher than an oscillation threshold value of the laser diode.