Patent application number | Description | Published |
20110163695 | POWER SUPPLY UNIT AND METHOD FOR CONTROLLING A POWER SUPPLY UNIT - A power supply unit is provided which comprises an AC/DC conversion unit with an input to which an input voltage is coupled and an output to which a DC bus voltage is coupled. The power supply unit furthermore comprises a DC bus capacitor which is coupled to the output of the AC/DC conversion unit. The power supply unit furthermore comprises at least one sub-power supply unit receiving the DC bus voltage as input for providing at least one power supply. The power supply of the at least one sub-power supply unit or part of the load is at least reduced or switched off if the input voltage falls below a predetermined threshold value. | 07-07-2011 |
20110164339 | SURGE PROTECTION CIRCUIT - A surge protection circuit for a circuit having a rectification module. The surge protection circuit includes a first diode, a second diode, a capacitor and a discharge device. The anode of the first diode is connected to a first input of the rectification module, and the anode of the second diode is connected to a second input of the rectification module. The cathodes of the first and second diodes are both connected to the first plate of the capacitor. The second plate of the capacitor is connected to the negative output of the rectification module. The capacitor is configured such that it is consistently charged to substantially the peak value of a supply voltage during normal operation between surge events. The discharge device is connected to the first plate of the capacitor and is configured to discharge the capacitor when the voltage across the capacitor is in excess of the peak of the maximum value of the normal supply voltage and not discharge the capacitor when the voltage across the capacitor is not in excess of the peak of the maximum value of the normal supply voltage. | 07-07-2011 |
20110188270 | CIRCUIT - A circuit comprising a power factor correction stage having a DC input, a ground input, a DC output and a ground output; a capacitor; a diode; and discharge means. A first terminal of the diode is connected to an input of the power factor correction stage, a second terminal of the diode is connected to the first plate of the capacitor; and the second plate of the capacitor is connected to the other input of the PFC stage. The discharge means is connected to the capacitor and is configured to discharge the capacitor such that it contributes to the output of the PFC stage when the level of a signal at the input of the PFC stage falls below a threshold value. | 08-04-2011 |
20110188273 | POWER FACTOR CORRECTION STAGE - A power factor correction stage comprising: an input terminal configured to receive an input signal; an output terminal configured to provide an output signal; a first converter stage and one or more further converter stages, wherein each of the converter stages is connected to the input terminal and the output terminal, and each converter stage comprises a switch; and a controller configured to operate the switches of the converter stages. The controller is configured to operate the switch of the one or more further converter stages at a period of time after operation of the switch of the first converter stage for a current switching cycle, wherein the period of time corresponds to a proportion of the switching frequency for an earlier switching cycle that does not correspond to substantially the period of the earlier switching cycle divided by the number of converter stages. | 08-04-2011 |
20110193612 | METHODS OF CONTROLLING A SYNCHRONOUS RECTIFIER - Consistent with an example embodiment, there is a method of controlling a synchronous rectifier having an input signal having oscillations therein and a switch which is switchable between an open state and a closed state. The method comprises filtering the input signal to produce a filtered signal, comparing the filtered signal with a reference value, and opening the switch in response to the comparison, in which the filtering is active filtering. | 08-11-2011 |
20110255314 | SWITCHED POWER CONVERTER WITH EXTENDED HOLD-UP TIME - A power supply module having a PFC stage has a hold-up capacitor ( | 10-20-2011 |
20110261599 | CONTROLLER FOR A POWER CONVERSION CIRCUIT - A power conversion controller for controlling the operation of a switch in a power conversion circuit, wherein the power conversion controller is configured to operate the switch according to: a variable frequency mode of operation for switching frequencies greater than a minimum threshold value; and a fixed frequency mode of operation at a switching frequency equal to the minimum threshold value. | 10-27-2011 |
20110317459 | CONTROLLER FOR A POWER CONVERSION CIRCUIT - A power conversion controller for controlling the operation of a switch in a power conversion circuit. The switch having a “time-on” property and a “clamping frequency” property, in use. The power conversion controller comprises a detector configured to detect one or more operational parameter values of the power conversion circuit, and a clamping frequency adjuster configured to adjust the clamping frequency of the switch in accordance with the one or more detected parameter values in order to maintain the “time-on” property of the switch above a minimum threshold value. | 12-29-2011 |
20120008350 | METHOD OF CONTROLLING A PFC STAGE OPERATING IN BOUNDARY CONDUCTION MODE, A PFC STAGE, AND AN SMPS - For many applications an SMPS is designed to operate in boundary conduction mode. As the load decreases the switching frequency increases, and so the concept of valley skipping may be used in which the switching frequency is clamped, by delaying to turn on the time of the active switch, for an integral number of cycles of a resonant circuit in the SMPS. With further reduction of the load, additional valleys may be skipped. However, each change in the number of valleys skipped results in a step in the input current that is drawn, distorting the ideal mains sine wave, thereby increasing unwanted harmonics. | 01-12-2012 |