# US 2025/0167680 A1 · Synchronous buck converter for supplying a led load > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0167680 A1 - Document ID: US20250167680A1 - Status: Published application - Kind: A1 - Application number: 18/834,052 - Filed: 2023-03-16 - Published: 2025-05-22 - Earliest claimed: 2022-03-17 - Assignees: Tridonic GmbH & Co KG - Applicants: Tridonic GmbH & Co KG - Inventors: Jakob Maldoner; Patrick Matre; Nikola Dimic - Web page: https://patentgrep.com/patent/US20250167680A1 ## CPC - H05B 45/375: using buck topology - H02M 1/0025: {Arrangements for modifying reference values, feedback values or error values in the control loop of a converter} - H02M 3/157: with digital control - H02M 3/1588: {comprising at least one synchronous rectifier element (H02M3/1582, H02M3/1584 take precedence)} - H02M 1/0058: {by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826)} - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - 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) ## Abstract A synchronous buck converter for supplying a LED load has a high side switch and a low side switch connected in series. An inductor is connected to the midpoint of these switches, and control circuitry controls the alternate switching operation of the two switches. The switches are controlled such that there are time periods in which a negative current is flowing through the low side switch, and a feedback signal indicating the level of the negative current is supplied to the control circuitry. A switching-off command is issued to the low side switch as soon as the feedback signal reaches or crosses a threshold value. A feedback signal from the LED load is fed back to the control circuitry, the control circuitry adapts its threshold value depending on the feedback signal. ## Claims ### Claim 1 A synchronous buck converter for supplying a LED load comprising: a high side switch and a low side switch connected in series, an inductor connected to the midpoint of these switches, and a control circuitry controlling the alternate switching operation of the two switches, wherein the switches are controlled such that there are time periods in which a negative current is flowing through said low side switch, wherein the control circuitry is supplied with a feedback signal indicating the level of the negative current and is arranged to issue a switching-off command to the low side switch as soon as the feedback signal reaches or crosses a threshold value, wherein a least one feedback from the LED load is fed back to the control circuitry, wherein the at least one feedback signal comprises at least one of LED voltage and LED current, wherein the control circuitry is arranged to adapt its threshold value depending on the at least one feedback signal. ### Claim 2 (depends on 1) The converter of claim 1, wherein the adaptation is limited within a preset adaptation range. ### Claim 3 (depends on 1) The converter of claim 1, wherein the adaptation of the threshold value is only performed in case there is a variation of the feedback back signal exceeding a preset hysteresis value. ### Claim 4 (depends on 1) The converter of claim 1, wherein the adaptation is effected such that the negative current value at the time point where the switching-off command is actually performed by the low side switch is essentially constant even at varying LED voltage and/or LED current. ### Claim 5 (depends on 1) The converter of claim 1, wherein the threshold value is the more reduced the higher the LED voltage. ### Claim 6 (depends on 1) The converter of claim 1, wherein the threshold value is the more reduced the higher the LED current. ### Claim 7 (depends on 1) The converter according to claim 1, wherein the threshold value is adapted by deducing an LED current and/or LED voltage dependent adaptation value from a preset threshold value. ### Claim 8 (depends on 1) The converter according to claim 1, wherein the threshold value is adapted only if the LED current exceeds a given LED current threshold value. ### Claim 9 (depends on 1) The converter according to claim 1, wherein the threshold value is adapted in discrete time increments, where a maximum adaptation step size is given. ### Claim 10 (depends on 1) The converter of claim 1, wherein the control circuitry comprises a plurality of ICs, such as e.g. an ASIC and a microcontroller. ### Claim 11 (depends on 10) The converter of claim 10, wherein the adaptation of the threshold value is performed by the microcontroller communicating adapted threshold values to the ASIC and being supplied with one or more feedback signals indicating e.g. the LED current and/or the LED voltage. ### Claim 12 (depends on 1) A LED lighting unit comprising a LED converter according to claim 1 and a LED load supplied by such converter. ### Claim 13 A method of operation of a synchronous buck converter for supplying a LED load comprising: a high side switch and a low side switch connected in series, and a control circuitry controlling the alternate switching operation of the two switches, wherein the switches are controlled such that there are time periods in which a negative current is flowing through said low side switch, wherein the control circuitry is supplied with a feedback signal indicating the level of the negative current and is arranged to issue a switching-off command to the low side switch as soon as the feedback signal reaches or crosses a threshold value, wherein a least one feedback from the LED load is fed back to the control circuitry, wherein the at least one feedback signal comprises at least one of LED voltage and LED current, wherein the control circuitry adapts its threshold value depending on the at least one feedback signal. ### Claim 14 (depends on 13) An integrated circuit, such as e.g. a microcontroller, arranged to implement the adaptation step of the method of claim 13. ### Claim 15 (depends on 13) An integrated circuit system, such as e.g. an ASIC and a microcontroller, arranged to together implement the control circuit functions of the method of claim 13.