# US 11,441,742 B2 · LED tube lamp > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,742 B2 - Document ID: US11441742B2 - Status: Granted - Kind: B2 - Application number: 17/344,542 - Filed: 2021-06-10 - Published: 2021-10-07 - Granted: 2022-09-13 - Earliest claimed: 2015-12-09 - Assignees: Jiaxing Super Lighting Electric Appliance Co., Ltd - Applicants: Jiaxing Super Lighting Electric Appliance Co., Ltd - Inventors: Aiming Xiong; Xintong Liu; Junren Chen; Hechen Hu; Hao Zhang - Web page: https://patentgrep.com/patent/US11441742B2 ## CPC - F21K 9/278: Arrangement or mounting of circuit elements integrated in the light source - H05B 45/3578: Emulating the electrical or functional characteristics of discharge lamps - F21K 9/272: Details of end parts, i.e. the parts that connect the light source to a fitting; Arrangement of components within end parts (F21K9/278 takes precedence) - F21K 9/275: Details of bases or housings, i.e. the parts between the light-generating element and the end caps; Arrangement of components within bases or housings (F21K9/278 takes precedence) - F21V 3/061: {the material being glass} - F21V 15/015: Devices for covering joints between adjacent lighting devices; End coverings - F21V 23/003: {the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array} - F21V 23/005: {the substrate is supporting also the light source} - F21V 23/023: {Power supplies in a casing (F21V23/003 takes precedence)} - F21V 25/02: coming into action when lighting device is disturbed, dismounted, or broken - F21V 29/70: characterised by passive heat-dissipating elements, e.g. heat-sinks - H05B 45/00: Circuit arrangements for operating light-emitting diodes [LED] - H05B 45/10: Controlling the intensity of the light - H05B 45/20: Controlling the colour of the light - H05B 45/37: Converter circuits - H05B 45/59: for reducing or suppressing flicker or glow effects - H05K 1/00: Printed circuits - F21V 23/02: the elements being transformers, impedances {or power supply units, e.g. a transformer with a rectifier} - F21V 29/83: the elements having apertures, ducts or channels, e.g. heat radiation holes - F21Y 2103/10: comprising a linear array of point-like light-generating elements - F21Y 2115/10: Light-emitting diodes [LED] - H05B 45/50: responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits - H05K 1/14: Structural association of two or more printed circuits (providing electric connection to or between printed circuits H05K1/11, H01R12/00) - H05K 1/147: {at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit (H05K1/148 takes precedence)} - H05K 1/181: associated with surface mounted components - H05K 1/189: characterised by the use of flexible or folded printed circuits - H05K 2201/09027: Non-rectangular flat PCB, e.g. circular - H05K 2201/10106: Light emitting diode [LED] - H05K 2201/10151: Sensor - Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] - F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract An LED tube lamp and an impedance detection method thereof are provided. The LED tube lamp includes a power supply module comprising an impedance detection controller, configured to perform, before the LED tube lamp being lighted up, an impedance detection to determine whether the LED tube lamp is electrically connected to a foreign external impedance in series. When the LED tube lamp is connected to the foreign external impedance in series, the impedance detection controller causes at least two transient variations to an operating current of the LED tube lamp and limits the operating current of the LED tube lamp to not exceed 5 MIU in root-mean-square (RMS), in which a duration of each transient variation does not exceed 1 millisecond when the impedance detection controller performs the impedance detection. ## Claims ### Claim 1 An LED tube lamp comprising: an LED module, configured to emit light in response to a driving current; and a power supply module, electrically connected to the LED module to provide the driving current based on an external driving signal, wherein the power supply module comprises: an impedance detection controller, configured to perform, before the LED tube lamp is lighted up, an impedance detection to determine whether the LED tube lamp is electrically connected to a foreign external impedance in series, wherein when the LED tube lamp is connected to the foreign external impedance in series, the impedance detection controller causes at least two transient variations to an operating current of the LED tube lamp and limits the operating current of the LED tube lamp to not exceed 5 MIU in root-mean-square (RMS), and wherein a duration of each transient variation does not exceed 1 millisecond when the impedance detection controller performs the impedance detection. ### Claim 2 (depends on 1) The LED tube lamp according to claim 1, wherein the time difference between adjacent transient variations is in a range of between plus and minus 15% of 75 ms. ### Claim 3 (depends on 1) The LED tube lamp according to claim 1, wherein at least one of the transient variations occurs within a first detection period and at least another one of the transient variations occurs within a second detection period, and wherein the time interval between the first detection period and the second detection period is in a range of 0.5 seconds to 2 seconds. ### Claim 4 (depends on 1) The LED tube lamp according to claim 1, wherein the impedance detection controller is activated to perform the impedance detection when the LED tube lamp receives an external driving signal, and triggers the transient variations during a falling time of the external driving signal. ### Claim 5 (depends on 4) The LED tube lamp according to claim 4, wherein the impedance detection controller triggers the transient variations when the external driving signal reaches a first voltage level or a first phase during the falling time. ### Claim 6 (depends on 1) The LED tube lamp according to claim 1, wherein the impedance detection controller is activated to perform the impedance detection when the LED tube lamp receives an external driving signal, and triggers the transient variations during a rising time of the external driving signal. ### Claim 7 (depends on 6) The LED tube lamp according to claim 6, wherein the impedance detection controller triggers the transient variations when the external driving signal reaches a first voltage level or a first phase during the rising time. ### Claim 8 (depends on 1) The LED tube lamp according to claim 1, wherein the power supply module further comprises: a rectifying circuit, configured to rectify an external driving signal received by the LED tube lamp; and a filtering circuit, configured to filter a signal received from the rectifying circuit, wherein the impedance detection controller has a first terminal electrically connected to an output of the rectifying circuit and a second terminal electrically connected to an input of the filtering circuit. ### Claim 9 (depends on 8) The LED tube lamp according to claim 8, wherein the impedance detection controller receives a first signal indicating a voltage level of the external driving signal by a third terminal. ### Claim 10 (depends on 9) The LED tube lamp according to claim 9, wherein the third terminal is electrically connected to the output of the rectifying circuit. ### Claim 11 (depends on 9) The LED tube lamp according to claim 9, wherein the power supply module further comprises: a first diode, having an anode electrically connected to a first input of the rectifying circuit, and a cathode electrically connected to the third terminal of the impedance detection controller; and a second diode, having an anode electrically connected to a second input of the rectifying circuit, and a cathode electrically connected to the cathode of the first diode. ### Claim 12 (depends on 1) The LED tube lamp according to claim 1, wherein the power supply module further comprises: a ballast detection circuit, electrically connected to the impedance detection controller, and configured to detect a signal feature of an external driving signal received by the LED tube lamp and determine whether the external driving signal is provided by an electronic ballast or directly by a power grid. ### Claim 13 (depends on 12) The LED tube lamp according to claim 12, wherein when the external driving signal is provided by an electronic ballast, the ballast detection circuit bypasses at least one component of the impedance detection controller to block the impedance detection. ### Claim 14 An impedance detection method for detecting whether an LED tube lamp is electrically connected to a foreign external impedance before lighting up, comprising: causing at least one transient variation to an operating current of the LED tube lamp; receiving a first signal indicating a voltage level of an external driving signal received by the LED tube lamp; receiving a second signal indicating an amount of the operating current; generating a detection result according to the first signal and the second signal; when the detection result indicates the LED tube lamp is electrically connected to the foreign external impedance, repeatedly performing the above steps; and when the detection result indicates the LED tube lamp is not electrically connected to the foreign external impedance, allowing the conduction of the operating current by not blocking a power loop of the LED tube lamp. ### Claim 15 (depends on 14) The impedance detection method according to claim 14, wherein the step of causing the at least one transient variation to the operating current comprises: causing the at least one transient variation with a duration not exceeding 1 millisecond. ### Claim 16 (depends on 14) The impedance detection method according to claim 14, wherein the LED tube lamp comprises a rectifying circuit configured to rectify the external driving signal and the step of receiving the first signal indicating the voltage level of an external driving signal received by the LED tube lamp comprises: receiving the first signal from an output of the rectifying circuit. ### Claim 17 (depends on 14) The impedance detection method according to claim 14, wherein the LED tube lamp comprises a rectifying circuit configured to rectify the external driving signal and the step of receiving the first signal indicating the voltage level of an external driving signal received by the LED tube lamp comprises: receiving the first signal from an input of the rectifying circuit through at least one diode. ### Claim 18 (depends on 14) The impedance detection method according to claim 14, further comprising: receiving a third signal indicating a frequency of the external driving signal; and when the third signal indicates the frequency exceeds a threshold, allowing the conduction of the operating current without referring to the detection result. ### Claim 19 (depends on 14) The impedance detection method according to claim 14, wherein the step of causing the at least one transient variation to the operating current comprises: triggering the transient variation during a falling time of the external driving signal. ### Claim 20 (depends on 19) The impedance detection method according to claim 19, wherein the step of triggering the transient variation during the falling time of the external driving signal comprises: determining, according to the first signal, whether the external driving signal reaches a first voltage level or a first phase during the falling time; and triggering the transient variation when it is determined that the external driving signal reaches the first voltage level or the first phase. ### Claim 21 (depends on 14) The impedance detection method according to claim 14, wherein the step of causing the at least one transient variation to the operating current comprises: triggering the transient variation during a rising time of the external driving signal. ### Claim 22 (depends on 21) The impedance detection method according to claim 21, wherein the step of triggering the transient variation during the rising time of the external driving signal comprises: determining, according to the first signal, whether the external driving signal reaches a first voltage level or a first phase during the rising time; and triggering the transient variation when it is determined the external driving signal reaches the first voltage level or the first phase. ### Claim 23 (depends on 14) The impedance detection method according to claim 14, wherein the step of causing the at least one transient variation to the operating current comprises: triggering a first transient variation and a second transient variation, wherein the time difference between the first and the second transient variations is in a range of between plus and minus 15% of 75 ms. ### Claim 24 (depends on 14) The impedance detection method according to claim 14, wherein the step of causing the at least one transient variation to the operating current comprises: triggering at least two first transient variations during a first detection period and at least two second transient variations during a second detection period, wherein the time interval between the first detection period and the second detection period is in a range of 0.5 second to 2 second. ### Claim 25 (depends on 24) The impedance detection method according to claim 24, wherein the time difference between the first transient variations is in a range of between plus and minus 15% of 75 ms. ### Claim 26 (depends on 25) The impedance detection method according to claim 25, wherein the time difference between the second transient variations is in a range of between plus and minus 15% of 75 ms.