# US 2017/0229269 A1 · Systems and methods for controlling relay activation timing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0229269 A1 - Document ID: US20170229269A1 - Status: Published application - Kind: A1 - Application number: 15/018,679 - Filed: 2016-02-08 - Published: 2017-08-10 - Earliest claimed: 2016-02-08 - Assignees: Control4 Corporation - Applicants: Control4 Corporation - Inventors: Gregory Scott Smith; Sidney Lyle King - Web page: https://patentgrep.com/patent/US20170229269A1 ## CPC - H01H 47/20: for producing frequency-selective operation of the relay - H01H 47/002: {Monitoring or fail-safe circuits} - H01H 47/325: {by switching regulator} - H01H 47/18: for introducing delay in the operation of the relay (short-circuited conducting sleeves, bands or discs H01H50/46) - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) ## Abstract Circuitry for controlling relay activation timing is described. The circuitry includes voltage zero cross detection circuitry configured to produce a zero cross detection signal indicating a zero cross time of an alternating current (AC) signal. The circuitry also includes current measuring circuitry coupled to voltage zero cross detection circuitry. The current measuring circuitry is configured to produce a current flow detection signal indicating a current flow start time of the AC signal. The circuitry further includes relay circuitry coupled to the current measuring circuitry. The circuitry additionally includes a processor coupled to the voltage zero cross detection circuitry, to the current measuring circuitry, and to the relay circuitry. The processor is configured to determine a relay time error based on the zero cross time and the current flow start time. The processor is also configured to control relay activation signal timing to reduce the relay time error. ## Claims ### Claim 1 Circuitry for controlling relay activation timing, comprising: voltage zero cross detection circuitry configured to produce a zero cross detection signal indicating a zero cross time of an alternating current (AC) signal; current measuring circuitry coupled to voltage zero cross detection circuitry, wherein the current measuring circuitry is configured to produce a current flow detection signal indicating a current flow start time of the AC signal; relay circuitry coupled to the current measuring circuitry; and a processor coupled to the voltage zero cross detection circuitry, to the current measuring circuitry, and to the relay circuitry, wherein the processor is configured to determine a relay time error based on the zero cross time and the current flow start time, and wherein the processor is configured to control relay activation signal timing to reduce the relay time error. ### Claim 2 (depends on 1) The circuitry of claim 1, wherein the processor is configured to determine the relay time error as a time difference between the current flow start time and the zero cross time. ### Claim 3 (depends on 1) The circuitry of claim 1, wherein the processor is configured to adjust the activation signal timing by increasing or decreasing a timing delay by an amount of the relay time error. ### Claim 4 (depends on 1) The circuitry of claim 1, wherein the processor is configured to activate the relay based on adjusted relay activation signal timing for a next switching cycle. ### Claim 5 (depends on 1) The circuitry of claim 1, wherein the processor is configured to start utilizing the current flow detection signal upon detection of a relay activation instruction. ### Claim 6 (depends on 1) The circuitry of claim 1, wherein the processor is configured to determine whether the current flow detection signal is greater than a current threshold. ### Claim 7 (depends on 6) The circuitry of claim 6, wherein the processor is configured to determine the current flow start time by stepping back from a time at which the current flow detection signal crossed the current threshold. ### Claim 8 (depends on 1) The circuitry of claim 1, wherein the current measuring circuitry is coupled between an alternating current supply and an input to the relay circuitry. ### Claim 9 (depends on 1) The circuitry of claim 1, wherein the voltage zero cross circuitry is coupled between an alternating current supply and the processor. ### Claim 10 A method for controlling relay activation timing, comprising: producing a zero cross detection signal indicating a zero cross time of an alternating current (AC) signal; producing a current flow detection signal indicating a current flow start time of the AC signal; determining a relay time error based on the zero cross time and the current flow start time; and controlling relay activation signal timing to reduce the relay time error. ### Claim 11 (depends on 10) The method of claim 10, further comprising determining the relay time error as a time difference between the current flow start time and the zero cross time. ### Claim 12 (depends on 10) The method of claim 10, wherein controlling the relay activation signal timing comprises adjusting the activation signal timing by increasing or decreasing a timing delay by an amount of the relay time error. ### Claim 13 (depends on 10) The method of claim 10, further comprising activating the relay based on adjusted relay activation signal timing for a next switching cycle. ### Claim 14 (depends on 10) The method of claim 10, further comprising starting to utilize the current flow detection signal upon detection of a relay activation instruction. ### Claim 15 (depends on 10) The method of claim 10, further comprising determining whether the current flow detection signal is greater than a current threshold. ### Claim 16 (depends on 15) The method of claim 15, wherein determining the current flow start time comprises stepping back from a time at which the current flow detection signal crossed the current threshold. ### Claim 17 A non-transitory tangible computer-readable medium for controlling relay activation timing, the computer-readable medium comprising executable instructions for: determining a relay time error based on a zero cross time and a current flow start time; and controlling relay activation signal timing to reduce the relay time error. ### Claim 18 (depends on 17) The computer-readable medium of claim 17, further comprising executable instructions for determining the relay time error as a time difference between the current flow start time and the zero cross time. ### Claim 19 (depends on 17) The computer-readable medium of claim 17, further comprising executable instructions for adjusting the activation signal timing by increasing or decreasing a timing delay by an amount of the relay time error. ### Claim 20 (depends on 17) The computer-readable medium of claim 17, further comprising executable instructions for activating the relay based on adjusted relay activation signal timing for a next switching cycle.