Patent application number | Description | Published |
20130342129 | FLICKER PREVENTION WITH SWITCHED BULK CAPACITOR - This relates to an apparatus and method for selectively adding a capacitance to an input of a power converter of a power conversion system. A power conversion system may selectively introduce additional input capacitance in response to an input voltage. In one example, a power conversion system operates in a first mode (dimming mode) and engages a selective capacitor circuit to introduce additional capacitance to an input of a power converter. In a second mode (non-dimming mode), the power conversion system disengages the selective capacitor circuit from the input of the power converter. | 12-26-2013 |
20150200599 | VARIABLE FEEDBACK SIGNAL BASED ON CONDUCTION TIME - A controller for a power converter includes conduction detection circuitry and a variable reference generator. The conduction detection circuitry is coupled to generate a conduction signal representative of conduction times that an input signal is above a threshold value. The variable reference generator is coupled to receive the conduction signal and configured to generate a count value in response to a first conduction time of the conduction signal. The variable reference generator is coupled to output a reference signal in response to the count value and in response to prior count values stored in the variable reference generator. | 07-16-2015 |
20150295500 | SAMPLING FOR DIMMER EDGE DETECTION IN POWER CONVERTER - A controller and a method for controlling a power converter includes a sample block coupled to generate a first, second, and third sample by sampling an input sense signal that is representative of an input voltage of the power converter. An enable signal is asserted when a first difference between the first sample and the second sample exceeds a first threshold. An edge signal is asserted when both the enable signal is asserted and a second difference between the first sample and the third sample exceeds a second threshold. A drive circuit is coupled to output a drive signal in response to the edge signal. The drive signal is for controlling a switch coupled to regulate an output of the power converter. | 10-15-2015 |
20150312978 | MULTI-BLEEDER MODE CONTROL FOR IMPROVED LED DRIVER PERFORMANCE - Various examples directed to phase-dimming LED driver input circuitry having multiple bleeder circuits activated by a controller with multi-bleeder mode control are disclosed. In one example, the input circuitry may include multiple bleeder circuits controlled by the controller in an open-loop or closed-loop configuration. The controller may selectively activate or deactivate the multiple bleeder circuits based on the input line voltage, the dimming state, and the type of dimming being implemented to improve performance of the LED driver by preventing or reducing shimmering/blinking and by reducing bleeder loss. | 10-29-2015 |
20150333630 | MULTI-PACE CONTROLLER - A controller for controlling a power supply includes a feedback signal generator to generate a feedback signal representative of an output current in response to an output sense signal. A state selector circuit receives the feedback signal and outputs a digital state signal to set an operational state of a switch of the power supply. The state selector circuit adjusts the digital state signal in response to feedback information at an end of a feedback period. A driver circuit receives the digital state signal and generates a drive signal in response to the digital state signal. The drive signal drives switching of the switch in accordance with the operational state of the switch. | 11-19-2015 |
20150333764 | DIGITAL-TO-ANALOG CONVERTER CIRCUIT FOR USE IN A POWER CONVERTER - A digital-to-analog converter circuit includes an input to receive a digital input signal having multiple bits. A modulation circuit is coupled to respond to less significant bits of the digital input signal by outputting a modulation signal that alternates between a logic low level and a logic high level. A digital-to-analog circuit is configured to convert more significant bits of the digital input signal to a first analog level. The digital-to-analog circuit is configured to alternate an analog output between the first analog level corresponding to a value of the more significant bits and a second analog level corresponding to one of adjacent values of the more significant bits in response to the modulation signal. | 11-19-2015 |
20150366010 | LINE RIPPLE COMPENSATION FOR SHIMMERLESS LED DRIVER - A power converter controller includes an oscillator, a drive circuit, and a frequency modulator. The drive circuit receives a clock signal from the oscillator and generates a drive signal in response thereto to control switching of a switch of the power converter. The frequency modulator controls the frequency of the clock signal in response to an inductor voltage across an inductor of the energy transfer element to reduce a peak-to-peak ripple value in an output current of the power converter. The frequency modulator controls the frequency of the clock signal during each line half cycle to be a fixed frequency when the inductor voltage is less than or equal to a threshold voltage. When the inductor voltage is greater than the threshold voltage the frequency modulator varies the frequency to be less than the fixed frequency to adjust a shape of an input current of the power converter. | 12-17-2015 |
20160095174 | LED DRIVER CIRCUIT WITH OPEN LOAD DETECTION - Various examples directed to LED driver circuits capable of detecting the removal of an LED load are disclosed. In one example, the LED driver circuit may include a bleeder and load disconnect detection circuit having a bleeder circuit and a bleeder controller coupled to control the bleeder circuit. The bleeder controller may cause the bleeder circuit to draw a bleeder current that functions to supplement a load current drawn by an LED load to cause an input current of the LED driver circuit to be greater than a minimum holding current of a dimmer circuit. The bleeder controller may be further configured to detect a disconnect of the LED load based on the input current of the LED driver circuit, the bleeder control signal, and/or the bleeder current. In response to detecting a disconnect of the LED load, the bleeder controller may disable operation of the bleeder circuit. | 03-31-2016 |