Patent application number | Description | Published |
20090187925 | Driver that efficiently regulates current in a plurality of LED strings - A light-emitting diode (LED) driver according to the present invention consists of a voltage pre-regulator and multiple linear current regulators with an adaptively-controlled drive voltage. In this LED driver, the efficiency maximization is achieved by eliminating the sensing of the voltage drops across the linear regulators, i.e., by removing the external voltage feedback for the adjustment of the output voltage of the pre-regulator. In the LED driver of the present invention, the self-adjustment of drive voltage is achieved by relying on a relatively strong dependence between the gate-to-source and drain-to-source voltages of a current-regulating transistor, e.g., a MOSFET, operating in the linear region. The driver powers all LEDs in a string with a constant current and provides consistent illumination and optimum operating efficiency at low cost over a wide range of input/output voltage and temperature. | 07-23-2009 |
20100253234 | POWER SUPPLY HAVING AN AUXILIARY POWER STAGE FOR SUSTAINING SUFFICIENT POST IGNITION CURRENT IN A DC LAMP - The current invention provides a power supply that includes an igniter that generates an ignition voltage for igniting a DC lamp; an auxiliary power stage that outputs an auxiliary voltage for sustaining sufficient current in the DC lamp after the DC lamp is ignited; a voltage conversion stage coupled to the auxiliary power stage and generating a voltage at a level that is higher than the auxiliary voltage; and a switch that couples the auxiliary voltage to the DC lamp and the voltage conversion stage for a predefined period of time. | 10-07-2010 |
20110248812 | CURRENT-CONTROLLED VARIABLE INDUCTOR - A variable inductor comprises one or more magnetic cores providing magnetic flux paths. An inductor coil is wound around one or more inductor sections of the one or more magnetic cores. An inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core. A control coil is wound around one or more control sections of the one or more magnetic cores. A control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core. Under this arrangement, the inductor magnetic flux substantially does not flow through the control sections of the magnetic core and the control magnetic flux substantially does not flow through the inductor sections of the magnetic core. The closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core not including the control sections and inductor sections. The inductance of said variable inductor is varied by varying said control magnetic flux. | 10-13-2011 |
20120146546 | LOAD CURRENT BALANCING CIRCUIT - A load current balancing circuit that operates with a direct current (DC) power supply includes at least one transformer having a first inductive element adapted to couple in series with a first load and a second inductive element adapted to couple in series with a second load. The first load is parallel to the second load. The load balancing circuit further includes at least one switch adapted to operate at one or more switching frequencies associated with at least one driving signal. The switch is configured to periodically interrupt respective current flows through the first inductive element and second inductive element substantially simultaneously. | 06-14-2012 |
20130300310 | LIGHT EMITTING DIODE DRIVER WITH ISOLATED CONTROL CIRCUITS - A light emitting diode (LED) driver circuit that generates current for driving an LED load includes a voltage converter circuit configured to supply a drive current to the LED load in response to a control signal, a control circuit that generates the control signal, and a bias voltage generating circuit that generates the bias voltage for the control circuit. The bias voltage generating circuit is galvanically isolated from a power supply voltage and from the LED load. The voltage converter circuit regulates a level of the drive current supplied to the LED load in response to the control signal. | 11-14-2013 |
20140125248 | LIGHTING APPARATUS AND METHODS USING OSCILLATOR-BASED DIMMING CONTROL - An apparatus includes a driver circuit configured to control a current through at least one LED responsive to a control signal. The apparatus further includes a modulated oscillator circuit configured to modulate an oscillating signal responsive to a dimming signal and to generate the control signal responsive to the modulated oscillating signal. | 05-08-2014 |
20140218987 | POWER SUPPLY WITH LOW ELECTRO-MAGNETIC INTERFERENCE AND INDUCTOR FOR POWER SUPPLY WITH LOW ELECTRO-MAGNETIC INTERFERENCE - A power supply circuit includes an input configured to receive an input voltage, an output configured to supply an output voltage, at least one inductor, at least one diode, and at least one switch. The inductor may have a parasitic capacitance less than about 100 pF. Related inductors are also disclosed. | 08-07-2014 |
20140252965 | Methods of Operating Switched Mode Power Supply Circuits Using Adaptive Filtering and Related Controller Circuits - A method of operating a switched mode power supply circuit can be provided by determining an error in a control signal for the switched mode power supply circuit. The error can be compared to an error threshold value to provide a filtering selection. The error can be adaptively filtered of based on the filtering selection to provide a selected filtering and the error can be filtered using the selected filtering. | 09-11-2014 |
20140253056 | Power Supply with Adaptive-Controlled Output Voltage - A power supply circuit includes a pre-regulator configured to receive an input voltage and to generate an output voltage, and a switching current regulator coupled to an output of the pre-regulator and configured to regulate a level of current supplied to an output load. The switching current regulator is controlled by a switching signal having a duty cycle. The circuit further includes a controller that generates the switching signal. The controller monitors the duty cycle of the switching signal and controls a level of the output voltage generated by the pre-regulator by providing a control signal in response to the duty cycle of the switching signal. | 09-11-2014 |