# US 9,049,764 B2 · LED drive circuit with a programmable input for LED lighting > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,049,764 B2 - Document ID: US9049764B2 - Status: Granted - Kind: B2 - Application number: 14/261,613 - Filed: 2014-04-25 - Published: 2014-08-21 - Granted: 2015-06-02 - Earliest claimed: 2010-12-27 - Assignees: System General Corp. - Applicants: System General Corp. - Inventors: Ta-Yung Yang; Chuh-Ching Li; Ming-Chieh Lee; Kuo-Hsien Huang - Web page: https://patentgrep.com/patent/US9049764B2 ## CPC - H05B 45/382: with galvanic isolation between input and output - H05B 45/37: Converter circuits - 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 LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal. ## Claims ### Claim 1 A LED drive circuit comprising: a controller generating a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs; and a programmable signal coupled to regulate a current-control signal of the controller; wherein the switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal. ### Claim 2 (depends on 1) The LED drive circuit as claimed in claim 1, wherein the switching signal is coupled to control a switching current of the magnetic device; the magnetic device is an offline transformer. ### Claim 3 (depends on 1) The LED drive circuit as claimed in claim 1, wherein the programmable signal is generated in response to an AC input of the LED drive circuit. ### Claim 4 (depends on 1) The LED drive circuit as claimed in claim 1, wherein the controller is a primary-side controller that is coupled to switch a primary winding of the magnetic device. ### Claim 5 (depends on 1) The LED drive circuit as claimed in claim 1, wherein the controller comprises a sample-and-hold circuit to sample a current feedback signal for generating the current-control signal; the current feedback signal is correlated to a switching current of the magnetic device; wherein the sample-and-hold circuit stops sampling the current feedback signal once an AC input of the LED drive circuit is lower than a low-voltage threshold. ### Claim 6 A LED circuit comprising: a controller generating a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs; and a programmable signal coupled to control a reference signal of the controller; wherein the switching signal is modulated in response to the reference signal, and the level of the output current is correlated to the reference signal. ### Claim 7 (depends on 6) The LED circuit as claimed in claim 6, wherein the magnetic device is an offline transformer. ### Claim 8 (depends on 6) The LED circuit as claimed in claim 6, wherein the programmable signal is generated in response to an AC input of the LED circuit. ### Claim 9 (depends on 6) The LED circuit as claimed in claim 6, wherein the controller comprises a sample-and-hold circuit to sample a current feedback signal: the current feedback signal is correlated to a switching current of the magnetic device; wherein the sample-and-hold circuit stops sampling the current feedback signal once an input voltage of the LED circuit is lower than a low-voltage threshold. ### Claim 10 A LED driver comprising: a controller generating a switching signal coupled to switch a transformer for generating an output current connected to drive a plurality of LEDs; and a programmable signal coupled to modulate a current input signal; wherein the switching signal is controlled in response to the current input signal for regulating the output current. ### Claim 11 (depends on 10) The LED driver as claimed in claim 10, wherein the controller is a primary-side controller that is coupled to switch a primary winding of the transformer. ### Claim 12 (depends on 10) The LED driver as claimed in claim 10, wherein the controller comprises a sample-and-hold circuit coupled to sample the current input signal; the sample-and-hold circuit stops sampling the current input signal once an input voltage of the LED driver is lower than a low-voltage threshold. ### Claim 13 A LED drive circuit comprising: a controller generating a switching signal coupled to switch a transformer for generating an output current to drive a plurality of LEDs; and a programmable signal generated in response to an input of the LED drive circuit; wherein the switching signal is modulated in response to the programmable signal for controlling the output current. ### Claim 14 (depends on 13) The LED drive circuit as claimed in claim 13, wherein the controller is for providing a feed-forward control to control the output current. ### Claim 15 (depends on 13) The LED drive circuit as claimed in claim 13, wherein the controller is a primary-side controller that is coupled to switch a primary winding of the transformer. ### Claim 16 A LED drive circuit comprising: a controller, generating a switching signal coupled to switch a magnetic device for generating an output current to drive at least a LED (Light Emitting Diode); an input circuit, receiving a programmable signal correlated to an input of the LED drive circuit to generate a programmable current; wherein the programmable current is coupled to control a current input signal which is correlated to a switching current of the magnetic device; and a comparison circuit, comparing a signal sourced from an oscillator and a voltage potential generated by a current-control loop for generating a current-control signal; wherein the switching signal is controlled in response to the current-control signal for regulating the output current, and a level of the output current is correlated to the current-control signal. ### Claim 17 (depends on 16) The LED drive circuit as claimed in claim 16, wherein the voltage potential is generated in response to the programmable current. ### Claim 18 (depends on 16) The LED drive circuit as claimed in claim 16, wherein the voltage potential is generated in response to the current input signal. ### Claim 19 (depends on 16) The LED drive circuit as claimed in claim 16, wherein the input of the LED drive circuit is a DC (Direct Current) signal. ### Claim 20 (depends on 16) The LED drive circuit as claimed in claim 16, wherein the input of the LED drive circuit is a rectified AC (Alternating Current) signal. ### Claim 21 (depends on 16) The LED drive circuit as claimed in claim 16, wherein the controller is a primary-side controller that is coupled to switch a primary winding of the magnetic device. ### Claim 22 A LED drive circuit comprising: A primary-side controller configured for coupling to a switch, a magnetic device, and an input source to generate a switching signal to drive the switch to generate an output current to drive at least one LED; wherein the primary side controller is configured to generate a programmable signal in response to a signal received from the input source and the switching signal is controlled in response to the programmable signal to regulate the output current that drives the at least one LED. ### Claim 23 (depends on 22) The LED drive circuit of claim 22, wherein the primary side controller further comprises a comparator configured to compare a oscillator signal to a current-control signal to control the switching signal, wherein the current-control signal is correlated to the programmable signal.