# US 12,114,409 B2 · Energy metering and surge current detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,114,409 B2 - Document ID: US12114409B2 - Status: Granted - Kind: B2 - Application number: 17/916,069 - Filed: 2021-03-26 - Published: 2023-05-18 - Granted: 2024-10-08 - Earliest claimed: 2020-04-09 - Assignees: Signify Holding B.V. - Applicants: Signify Holding B.V. - Inventors: Johannes Adrianus Cornelis Misdom - Web page: https://patentgrep.com/patent/US12114409B2 ## CPC - H05B 47/25: Circuit arrangements for protecting against overcurrent - G01R 19/16571: {comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52)} - G01R 22/065: {related to mechanical aspects} - H02H 1/0007: {concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445)} - G01R 15/183: {using transformers with a magnetic core} - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) ## Abstract A circuit is provided for energy metering and surge current detection. It uses a current transformer. A first current sensing arrangement is connected to the secondary side of the transformer for energy metering and a second current sensing arrangement is connected to the secondary side, with a high pass filter, for surge current detection. A single component is thus able to provide energy metering and surge detection. ## Claims ### Claim 1 A circuit for energy metering and surge current detection, comprising: a current transformer having a primary winding and a secondary winding (L2, L3); a first current sensing arrangement connected to the secondary winding, for energy metering; and a second current sensing arrangement connected to the secondary winding, for surge current detection, wherein the second current sensing arrangement comprises a high pass filter, wherein the secondary winding comprises first and second winding portions in series, wherein a virtual earth is defined at the junction between the first and second winding portions, and the ends of the first and second winding portions opposite the junction each connect to a transformer output through a respective forward diode, and wherein the first and second current sensing arrangement are each connected to the transformer output and to the virtual earth. ### Claim 2 (depends on 1) The circuit according to claim 1, wherein the high pass filter has a cutoff frequency above a frequency of normal operation of the current transformer. ### Claim 3 (depends on 2) The circuit according to claim 2, wherein the frequency of normal operation of the current transformer is a mains frequency. ### Claim 4 (depends on 1) The circuit according to claim 1, wherein the first current sensing arrangement comprises a first resistor across which an energy metering signal is measured. ### Claim 5 (depends on 4) The circuit according to claim 4, wherein the energy metering signal comprises a voltage across the first resistor. ### Claim 6 (depends on 4) The circuit according to claim 4, wherein the second current sensing arrangement comprises a second resistor across which a current surge signal is measured. ### Claim 7 (depends on 6) The circuit according to claim 6, wherein the current surge signal comprises a second voltage across the second resistor. ### Claim 8 (depends on 6) The circuit according to claim 6, wherein the first resistor has a larger resistance than the second resistor. ### Claim 9 (depends on 6) The circuit according to claim 6, wherein the high pass filter comprises a series capacitor between the secondary winding and the second resistor. ### Claim 10 (depends on 1) The circuit according to claim 1, wherein the first current sensing arrangement further comprises a low pass filter at an input of the first current sensing arrangement. ### Claim 11 (depends on 1) The circuit according to claim 1, wherein the second current sensing arrangement further comprises a sample and hold circuit at an output of the second current sensing arrangement. ### Claim 12 (depends on 11) The circuit according to claim 11, wherein the sample and hold circuit comprises a peak detector circuit. ### Claim 13 (depends on 1) A LED lighting circuit comprising: a LED unit; and the circuit for energy metering and surge current detection according to claim 1 for metering energy usage by the LED unit and surge current sensing and counting. ### Claim 14 (depends on 13) The LED lighting circuit according to claim 13, further comprising a LED driver, wherein the circuit for energy metering and surge current detection is connected with the primary winding of the current transformer in series along an input line to the LED driver.