Patent application number | Description | Published |
20090184668 | HIGH EFFICIENCY BOOST LED DRIVER WITH OUTPUT - A current driver for powering a string of LEDs has a boost converter coupled to an input voltage source. A voltage multiplier circuit is coupled to the boost converter and to the string of LEDs. A latch is provided having an output coupled to the boost converter. A current sense element is coupled to the boost converter. A current comparator is provided having an output coupled to a first input of the latch, a first input coupled to the current sense element, and a second input coupled to a reference current. A zero-volt detector circuit is provided having an output coupled to a second input of the latch and an input coupled to the boost converter and the voltage multiplier circuit. | 07-23-2009 |
20090302774 | CONTROL CIRCUIT AND METHOD FOR REGULATING AVERAGE INDUCTOR CURRENT IN A SWITCHING CONVERTER - A switching power converter has an input voltage source. An output load is coupled to the input voltage source. An inductive element is coupled to the load. A switch is coupled to the inductive element. A current reference input is provided. A control circuit is coupled to the switch and the current reference input for activating and deactivating the switch. The inductive element receives power from the input voltage source when the switch is activated and conducting continuous current. The control circuit deactivates the switch after a controlled delay time when the current in the inductive element and the switch exceeds the current reference input so that an average current in the inductive element is determined by a magnitude of the current reference input. | 12-10-2009 |
20100118572 | LED DRIVER WITH LOW HARMONIC DISTORTION OF INPUT AC CURRENT AND METHODS OF CONTROLLING THE SAME - A power supply circuit for powering a load at constant current has a rectifier stage for receiving an AC voltage input and for producing a first substantially DC voltage. A first capacitor is attached to the load. A charge-pump is attached to an output of the rectifier stage and to the load for providing power factor correction and for converting the first substantially DC voltage to a second substantially DC voltage at the first capacitor. The charge pump is prevented from conducting energy back into the output of the rectifier stage. The charge pump delivers energy to a charge pump output, the energy being delivered directly instead of being stored. A converter stage is attached to the load and the first capacitor. The converter stage is used for converting voltages at the first capacitor and the charge pump to an output DC current. The converter stage has a switch for periodically connecting a first series-coupled circuit of the charge pump to the output of the rectifier stage. | 05-13-2010 |
20100259177 | LED DRIVER WITH EXTENDED DIMMING RANGE AND METHOD FOR ACHIEVING THE SAME - A circuit for powering of a Light Emitting Diode (LED) string has a switching power converter. A brightness control circuit is coupled to the switching power converter to allow a duration of a conductive state of the power converter to exceed a duration of a conductive state of the LED string for maintaining a current magnitude in the LED string constant. | 10-14-2010 |
20130207567 | BOOST CONVERTER ASSISTED VALLEY-FILL POWER FACTOR CORRECTION CIRCUIT - A Light Emitting Diode (LED) lighting circuit has a passive valley-fill type power factor correction (PFC) circuit. A boost converter stage is coupled to the PFC circuit. | 08-15-2013 |
20140210360 | LED DRIVER WITH EXTENDED DIMMING RANGE AND METHOD FOR ACHIEVING THE SAME - A circuit for powering of a Light Emitting Diode (LED) string has a switching power converter. A brightness control circuit is coupled to the switching power converter to allow a duration of a conductive state of the power converter to exceed a duration of a conductive state of the LED string for maintaining a current magnitude in the LED string constant. | 07-31-2014 |
20140217911 | CIRCUIT AND METHOD FOR FLICKER SUPPRESSION IN LIGHT EMITTING DIODES (LEDS) - A circuit for flicker suppression in a Light Emitting Diode (LED) has a latch. The latch has a first state set with a trailing edge of Pulse Width Modulated Dimming (PWMD) pulse, and a second state set delayed with respect to the PWMD trailing edge. A trigger circuit is coupled to the latch. The trigger circuit sends a signal to the latch to change to the second state when a decision point occurs during a time following a duty limit D | 08-07-2014 |
20140320037 | LOW DROPOUT LIGHT EMITTING DIODE (LED) BALLAST CIRCUIT AND METHOD THEREFOR - A ballast circuit for a Light Emitting Diode (LED) has a regulator element coupled to the LED and to an input voltage source. A control circuit is coupled to the LED and to an input voltage source. A first switching device is coupled in series with the regulator element. A second switching device is coupled to the input voltage and the control circuit. | 10-30-2014 |
20140347021 | SAMPLING NEGATIVE COIL CURRENT IN A SWITCHING POWER CONVERTER AND METHOD THEREOF - An electronic circuit and method for sampling negative coil current in a power converter includes a zero crossing detector and a sample-and-hold circuit. A switch determines whether a charging or discharging current is flowing through a coil. | 11-27-2014 |
20140376285 | Auxiliary Power Supplies - The invention relates to auxiliary power supplies. | 12-25-2014 |
20150022168 | OUTPUT CURRENT CONTROL IN A BOUNDARY CONDUCTION MODE BUCK CONVERTER - A switching power converter has an input voltage source. An output load is coupled to the input voltage source. An inductive element is coupled to the load. A switch is coupled to the inductive element. A control circuit is coupled to the switch and the inductive element for activating and deactivating the switch, the control circuit activating and deactivating the switch based on a negative voltage drop across a resistive element of the control circuit. | 01-22-2015 |