# US 4,395,660 A · Lamp dimmer circuit utilizing opto-isolators > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,395,660 A - Document ID: US4395660A - Status: Granted - Kind: A - Application number: 06/221,708 - Filed: 1980-12-31 - Granted: 1983-07-26 - Earliest claimed: 1980-12-31 - Inventors: Edward P. Waszkiewicz - Web page: https://patentgrep.com/patent/US4395660A ## CPC - H02M 5/2573: {with control circuit} - G05F 1/455: with phase control - H02M 1/092: the control signals being transmitted optically - Y10S 315/04: Dimming circuit for fluorescent lamps - Y10S 323/902: Optical coupling to semiconductor - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A solid-state dimmer control circuit using opto-isolators, whereby the effective power to be supplied to a load is selectively varied. The opto-isolators couple a variable pulse switching circuit to a full-wave switching circuit which includes back-to-back silicon-controlled rectifiers. The variable pulse switching circuit is connected to means for generating a selectively variable control signal that is proportional to the power to be supplied to the load. A single a.c. power source is provided both switching circuits. ## Claims ### Claim 1 An electrical load control circuit for selectively varying the effective power to be supplied to a load, comprising means for generating a selectively variable control signal proportional to the power to be supplied to the load, means responsive to said control signal generating means and to the occurrence of initiating signals for producing cyclical light output pulses, means optically coupled to said light pulse producing means and adapted for electrical connection to a power source, and responsive to such pulses, for switching power from such power source to the electrical load, and means responsive to said power switching means for generating such initiating signals. ### Claim 2 (depends on 1) The circuit of claim 1 including means for connecting a load in series between said full-wave power switching circuit means and such power source. ### Claim 3 (depends on 1, 2) The load control circuit defined in claim 1 or claim 2 wherein the control signal generated by said control signal generating means comprises a direct current having a selected voltage amplitude. ### Claim 4 (depends on 1, 2) The load control circuit defined in claim 1 or claim 2 wherein said light output pulse producing means comprises a voltage comparator for generating one of such output pulses whenever the amplitude of such control signal equals or exceeds the amplitude of a corresponding initiating signal. ### Claim 5 (depends on 4) The load control circuit defined in claim 4 including a light emitting diode energized by said voltage comparator. ### Claim 6 (depends on 1, 2) The load control circuit defined in claim 1 or claim 2 wherein said power switching means includes a pair of silicon-controlled-rectifiers each having an anode and a cathode and each adapted to be in series between the alternating-current power source and the electrical load, each of said rectifiers having a gate electrode controlled by said means responsive to such pulses. ### Claim 7 (depends on 6) The load control circuit defined in claim 6 wherein said means for generating initiating signals comprises a fixed reference voltage means and a light emitting diode that is energized whenever the potential at an anode of one of said rectifiers is greater than the potential of the anode of the other of said rectifiers, and a phototransistor optically coupled to said light output pulse producing means. ### Claim 8 (depends on 1, 2) The load controlled circuit defined in claim 1 or claim 2 wherein said means responsive to such pulses comprises a phototransistor optically coupled to said light output pulse producing means. ### Claim 9 (depends on 1, 2) The circuit of claim 1 or claim 2 including an alternating-current power source and an electrical load. ### Claim 10 (depends on 9) The load control circuit defined in claim 9 wherein said power switching means includes a pair of silicon-controlled-rectifiers each having an anode and a cathode, each of said rectifiers in series between said alternating-current power source and said electrical load, each of said rectifiers having a gate electrode controlled by said means responsive to such pulses. ### Claim 11 (depends on 10) The load control circuit defined in claim 10 wherein said means for generating initiating signals comprises a fixed reference voltage means and a light emitting diode that is energized whenever the potential at an anode of one of said rectifiers is greater than the potential of the anode of the other of said rectifiers, and a phototransistor optically coupled to said light output pulse producing means. ### Claim 12 (depends on 9) The load control circuit defined in claim 9 wherein said means responsive to such pulses comprises a phototransistor optically coupled to said light output pulse producing means. ### Claim 13 (depends on 9) The load control circuit defined in claim 9 wherein the control signal generated by said control signal generating means comprises a direct current having a selected voltage amplitude. ### Claim 14 (depends on 9) The load control circuit defined in claim 9 wherein said light output pulse producing means comprises a voltage comparator for generating one of such output pulses whenever the amplitude of such control signal equals or exceeds the amplitude of a corresponding initiating signal. ### Claim 15 (depends on 9) The load control circuit defined in claim 9 including a light emitting diode energized by said voltage comparator. ### Claim 16 In a load control circuit for selectively varying the effective power to be supplied to a load, the improvement comprising means for generating a selectively variable control signal proportional to the power to be supplied to the load, means responsive to said control signal generating means and to the occurrence of initiating signals for producing cyclical light output pulses, means optically coupled to said light pulse producing means, and responsive to such pulses, for switching power from such power source to the electrical load, and means responsive to said power switching means for generating such initiating signals. ### Claim 17 (depends on 16) In the circuit of claim 16, said control signal generating means generating a control signal comprising a direct current having a selected voltage amplitude. ### Claim 18 (depends on 16, 17) In the circuit of claim 16 or claim 17, said light output pulse producing means comprising a voltage comparator for generating one of such output pulses whenever the amplitude of such control signal equals or exceeds the amplitude of a corresponding initiating signal. ### Claim 19 (depends on 18) In the circuit of claim 18, a light emitting diode energized by said voltage comparator. ### Claim 20 (depends on 19) In the circuit of claim 19, said means responsive to such pulses comprising a phototransistor optically coupled to said light output producing means. ### Claim 21 (depends on 16, 17) In the circuit of claim 16 or claim 17, said power-switching means comprising a pair of silicon-controlled rectifiers each having an anode and a cathode, each of said rectifiers having a gate electrode controlled by said means responsive to such pulses. ### Claim 22 (depends on 21) In the circuit of claim 21, said means for generating initiating signals comprising a fixed reference voltage means and a light emitting diode that is energized whenever the potential at an anode of one of said rectifiers is greater than the potential at the anode of the other of said rectifiers, and a phototransistor optically coupled to said light output pulse producing means. ### Claim 23 (depends on 21) In the circuit of claim 21, said means responsive to such pulses comprising a phototransistor optically coupled to said light output producing means. ### Claim 24 (depends on 23) In the circuit of claim 23, said means for generating initiating signals comprising a fixed reference voltage means and a light emitting diode that is energized whenever the potential at an anode of one of said rectifiers is greater than the potential at the anode of the other of said rectifiers, and a phototransistor optically coupled to said light output pulse producing means.