Transformerless LED driving circuit
Patent 5917779 Issued on June 29, 1999. Estimated Expiration Date: 
April 16, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 16, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3602795 3869641 Numerical display using plural light sources and having a reduced and substantially constant current requirement Light indicating system having light emitting diodes and power reduction circuit Transformerless clock circuit with duplex optoelectronic display Transformerless line powdered digital AC voltmeter Power factor corrected electrical power converter Patent #: 5600549 InventorsAssigneeApplicationNo. 842636 filed on 04/16/1997US Classes:368/83, Solid body light emitter (e.g., LED)345/211, Display power source368/204, Electrical368/241With solid body light emitter (e.g., LED)ExaminersPrimary: Miska, Vit W.Attorney, Agent or FirmInternational ClassesG04C 019/00G04B 037/12 G09G 005/00 AbstractA transformerless oven timer which uses a 20 pin microcontroller connected to light emitting diodes. The microcontroller has 2 Kbytes of 8 bit read only memory and has software etched therein. The microcontroller can transfer power and voltage to the light emitting diodes when the oven is connected to, and powered by, an electrical outlet. The software etched into the microcontroller detects whether a resistor is connected to the microcontroller and converts a pin on the microcontroller from an input into an output. The software also synchronizes the microcontroller with the frequency of the electrical outlet to provide that the microcontroller keeps track of time. The transformerless oven timer also includes electrical circuitry connected to the microcontroller, where the electrical circuitry reduces the voltage and current provided to the microcontroller and to the light emitting diodes without using a transformer. The electrical circuitry also provides real resistance to reject noise from the electrical outlet.Field of SearchWith auxiliary illumination for displayWith electro-optical display Solid body light emitter (e.g., LED) Liquid crystal display (i.e., LCD) Optical With circular pattern of light sources With solid body light emitter (e.g., LED) With liquid crystal display (i.e., LCD) REGULATION OF THE CONTROL CURRENT AND/OR POTENTIAL APPLIED TO DISCHARGE CONTROL DISCHARGE DEVICE LOADS BY PHASE SHIFTING MEANS Inverse parallel connected asymmetric load devices Plural load device systems Discharge device and/or rectifier in the primary circuit of the supply transformer Discharge device and/or rectifier in shunt to the load device Rectifier and/or discharge device in the control circuit With condenser in the control circuit Solid body light emitter (e.g., LED) Tri-linear Display power source | |
