# US 9,253,843 B2 · Driving circuit with dimming controller for driving light sources > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,253,843 B2 - Document ID: US9253843B2 - Status: Granted - Kind: B2 - Application number: 14/509,711 - Filed: 2014-10-08 - Published: 2015-01-22 - Granted: 2016-02-02 - Earliest claimed: 2008-12-12 - Assignees: 02Micro, Inc. - Applicants: O2Micro Inc. - Inventors: Sheng-Tai Lee; Ching-Chuan Kuo; Yung-Lin Lin - Web page: https://patentgrep.com/patent/US9253843B2 ## CPC - H05B 45/395: Linear regulators - H05B 45/10: Controlling the intensity of the light - H05B 45/375: using buck topology - H05B 45/14: using electrical feedback from LEDs or from LED modules - Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A driving circuit includes a power converter, a dimming controller and a current path coupled to the dimming controller. The power converter receives input power from a rectifier and provides output power to a light source. A power switch transfers power from an AC power source to the rectifier when the power switch is on. The dimming controller receives a switch monitoring signal indicative of the state of the power switch. An average current flowing through the light source has a first value if the power switch is on. The dimming controller is operable for adjusting the average current based on the switch monitoring signal. A current flows from the AC power source through the current path to ground when the power switch is off. ## Claims ### Claim 1 A dimming controller for a light source, said dimming controller comprising: a monitoring terminal operable for receiving a switch monitoring signal indicative of an on/off state of a power switch, wherein said power switch transfers power from an AC power source to a rectifier and wherein a power converter receives input power from said rectifier and provides output power to said light source if said power switch is on, and wherein an average current flowing through said light source has a first value when said power switch is on; a control terminal operable for providing a control signal to adjust said average current based on said switch monitoring signal and control dimming of said light source; a power terminal operable for receiving power from said AC power source through said power switch when said power switch is on, and operable for receiving power from said AC power source through an illuminated indicator when said power switch is off; a trigger monitoring unit operable for receiving said switch monitoring signal and for generating a driving signal in response to operation of said power switch; a timer, coupled to said trigger monitoring unit and controlled by said driving signal, operable for measuring the period of time between when said power switch is turned off and when said power switch is next turned on; and a reference signal generator coupled to said timer and operable for generating a reference signal based on an output of said timer. ### Claim 2 (depends on 1) The dimming controller of claim 1, wherein said control terminal is operable for providing said control signal to adjust said average current from said first value to a second value if said switch monitoring signal indicates that said power switch is turned on within a predetermined time period after said power switch was turned off. ### Claim 3 (depends on 1) The dimming controller of claim 1, wherein said control terminal is operable for providing said control signal to maintain said average current at said first value if said switch monitoring signal indicates that said power switch is turned on after expiration of a predetermined time period that began when said power switch was turned off. ### Claim 4 (depends on 1) The dimming controller of claim 1, wherein said reference signal generator is operable for adjusting said reference signal from a first level to a second level if said period of time is less than a predetermined time period, and wherein said reference signal generator is operable for maintaining said reference signal at said first level if said period of time is greater than a predetermined time period. ### Claim 5 (depends on 1) The dimming controller of claim 1, further comprising: an amplifier operable for generating an error signal by comparing said reference signal and a sensing signal indicating said average current flowing through said light source, wherein said control signal is determined based on said error signal. ### Claim 6 (depends on 5) The dimming controller of claim 5, further comprising: a current monitoring terminal operable for receiving a current monitoring signal indicating a current flowing through said light source; and a filter coupled to said current monitoring terminal and operable for generating said sensing signal based on said current monitoring signal. ### Claim 7 A driving circuit comprising: a power converter operable for receiving input power from a rectifier and providing output power to a light source, wherein a power switch transfers power from an AC power source to said rectifier when said power switch is on; a dimming controller, coupled to said power converter, and operable for receiving a switch monitoring signal indicative of an on/off state of said power switch, wherein an average current flowing through said light source has a first value if said power switch is on, and wherein said dimming controller is operable for adjusting said average current based on said switch monitoring signal and controlling dimming of said light source; a current path coupled to said dimming controller, wherein a current flows from said AC power source through said current path to ground when said power switch is off; a trigger monitoring unit operable for receiving said switch monitoring signal and for generating a driving signal in response to operation of said power switch; a timer, coupled to said trigger monitoring unit and controlled by said driving signal, operable for measuring the period of time between when said power switch is turned off and when said power switch is next turned on; and a reference signal generator coupled to said timer and operable for generating a reference signal based on an output of said timer. ### Claim 8 (depends on 7) The driving circuit of claim 7, further comprising: a control switch coupled to said light source, wherein said dimming controller is operable for adjusting said average current flowing through said light source by controlling said control switch according to said switch monitoring signal, and wherein said dimming controller is operable for adjusting said average current from said first value to a second value if said switch monitoring signal indicates that said power switch is turned on within a predetermined time period after said power switch was turned off. ### Claim 9 (depends on 7) The driving circuit of claim 7, further comprising: a control switch coupled to said light source, wherein said dimming controller is operable for adjusting said average current flowing through said light source by controlling said control switch according to said switch monitoring signal, and wherein said dimming controller is operable for maintaining said average current at said first value if said switch monitoring signal indicates that said power switch is turned on after expiration of a predetermined time period that began when said power switch was turned off. ### Claim 10 (depends on 7) The driving circuit of claim 7, wherein said reference signal generator is operable for adjusting said reference signal from a first level to a second level if said period of time is less than a predetermined time period, and wherein said reference signal generator is operable for maintaining said reference signal at said first level if said period of time is greater than a predetermined time period. ### Claim 11 (depends on 7) The driving circuit of claim 7, wherein said dimming controller further comprises: an amplifier operable for generating an error signal by comparing said reference signal and a sensing signal indicating said average current flowing through said light source, wherein said control signal is determined based on said error signal. ### Claim 12 (depends on 11) The driving circuit of claim 11, further comprising: a current sensor operable for providing a current monitoring signal indicating a current flowing through said light source; and a filter coupled to said current sensor and operable for generating said sensing signal based on said current monitoring signal.