# US 12,604,386 B2 · LED controller, LED drive system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,604,386 B2 - Document ID: US12604386B2 - Status: Granted - Kind: B2 - Application number: 17/292,711 - Filed: 2021-05-10 - Published: 2025-09-04 - Granted: 2026-04-14 - Earliest claimed: 2021-04-15 - Assignees: Infineon Technologies AG - Applicants: Infineon Technologies AG - Inventors: Xing Su; Fausto Borghetti; Enrico Tonazzo - Web page: https://patentgrep.com/patent/US12604386B2 ## CPC - H05B 45/48: having LEDs organised in strings and incorporating parallel shunting devices - H05B 47/25: Circuit arrangements for protecting against overcurrent - H05B 45/345: Current stabilisation; Maintaining constant current - H05B 45/375: using buck topology - H05B 45/54: in a series array of LEDs - H05B 47/14: by determining electrical parameters of the light source - H05B 47/155: Coordinated control of two or more light sources - H05B 47/16: by timing means - H05B 47/165: following a pre-assigned programmed sequence; Logic control [LC] - H05B 47/17: Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations - B60Q 1/1415: {Dimming circuits} - H05B 45/20: Controlling the colour of the light - 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 ## Abstract Light emitting diode, LED, controllers (110), light-emitting diode drive systems (10) and corresponding methods are provided. A LED arrangement (14) is switchable between a first set of active LEDs (15) and a second set of active LEDS (16). Upon switching, a series switch (13) between a power supply and the LED arrangement is switched off and on repeatedly during a transition period. ## Claims ### Claim 1 A light emitting diode (LED) controller, comprising: a control terminal to be coupled to a series switch between a power supply and an LED arrangement switchable between a first set of active LEDs and a second set of active LEDs, an input terminal configured to receive a measure of a current through the series switch, and a control circuit configured to, upon switching of a number of active LEDs from the first set to the second set, output a control signal at the control terminal to repeatedly switch the series switch off and on during a transition period, wherein the control circuit is configured such that the transition period ends when the measure indicates that the current remains below a predefined threshold. ### Claim 2 (depends on 1) The controller of claim 1, wherein the control circuit, for repeatedly switching the series switch off and on, is configured to switch the series switch off when the measure indicates that the current exceeds an upper threshold. ### Claim 3 (depends on 2) The controller of claim 2, wherein the control circuit, for repeatedly switching the series switch off and on, is configured to switch the series switch on when the measure indicates that the current falls below a lower threshold. ### Claim 4 (depends on 1) The controller of claim 1, wherein the control circuit, for repeatedly switching the series switch off and on, is configured to switch the series switch on a predefined time after switching the series switch off. ### Claim 5 (depends on 4) The controller of claim 4, wherein the predefined time is adjustable. ### Claim 6 A light emitting diode (LED) drive system, comprising: an LED arrangement, a power supply configured to supply the LED arrangement with power, a series switch coupled between the LED arrangement and the power supply, and a controller comprising: a control terminal to be coupled to the series switch between the power supply and the LED arrangement, wherein the LED arrangement is switchable between a first set of active LEDs and a second set of active LEDs, an input terminal configured to receive a measure of a current through the series switch, and a control circuit configured to, upon switching of a number of active LEDs from the first set to the second set, output a control signal at the control terminal to repeatedly switch the series switch off and on during a transition period, wherein the control circuit is configured such that the transition period ends when the measure indicates that the current remains below a predefined threshold. ### Claim 7 (depends on 6) The system of claim 6, further comprising a further switch configured to bridge a part of the LEDs of the LED arrangement to switch the LED arrangement between a first number of active LEDs and a second number of active LEDs. ### Claim 8 (depends on 6) The system of claim 6, wherein the power supply comprises an output capacitor, wherein the repeatedly switching the series switch off and on during the transition period discharges the output capacitor. ### Claim 9 (depends on 6) The system of claim 6, wherein the controller is configured to control the power supply to provide a regulated output current. ### Claim 10 A method of supplying a light emitting diode (LED) arrangement with power, the method comprising: operating the LED arrangement with a first set of active LEDs, switching the LED arrangement from the first set of active LEDs to a second set of active LEDs, in response to the switching of the LED arrangement, repeatedly switching a series switch between a power supply and the LED arrangement off and on during a transition period, measuring a current through the series switch, ending the transition period when the current remains below a predefined threshold, and operating the LED arrangement with the second set of active LEDs after the transition period. ### Claim 11 (depends on 10) The method of claim 10, wherein repeatedly switching the series switch off and on comprises switching the series switch off when the measuring indicates that the current exceeds an upper threshold. ### Claim 12 (depends on 11) The method of claim 11, wherein repeatedly switching the series switch off and on comprises switching the series switch on when the measuring indicates that the current falls below a lower threshold. ### Claim 13 (depends on 10) The method of claim 10, wherein repeatedly switching the series switch off and on comprises switching the series switch on a predefined time after switching the series switch off. ### Claim 14 (depends on 13) The method of claim 13, wherein the predefined time is adjustable. ### Claim 15 (depends on 10) The method of claim 10, wherein repeatedly switching the series switch off and on discharges an output capacitor of the power supply. ### Claim 16 (depends on 10) The method of claim 10, wherein switching the LED arrangement from the first set of active LEDs to the second set of active LEDs comprises bridging a part of LEDs of the LED arrangement.