Patent application number | Description | Published |
20080278973 | Apparatus and method for providing multiple functions and protections for a power converter - A power converter has a transformer including a primary winding connected between a power input and a power switch, the power switch is switched to deliver power from the power input to a power output, an auxiliary winding provides an induced voltage in such a manner that when the power switch is at a first switch state, the induced voltage reflects an input information of the power converter, and when the power switch is at a second switch state, the induced voltage reflects an output information of the power converter. Two detection signals are generated from the input and output information, respectively, to implement multiple functions and protections. | 11-13-2008 |
20080279324 | Frequency jittering control for varying the switching frequency of a power supply - A frequency jittering circuit modulates a hysteretic band of an oscillator such that the clock generated by the oscillator has a jitter frequency, and thus a switching mode power supply operative on the clock will have a jittering switching frequency. | 11-13-2008 |
20090073725 | Apparatus and method for regulating constant output voltage and current on primary side in a flyback converter - A voltage detector circuitry extracts a signal on primary side of a transformer in a flyback converter, which is proportional to the output voltage of the converter without voltage drop on the rectifier diode and leakage inductance effect on the transformer, and good output regulation is achieved without opto-coupler. To accurately detect the output voltage on the primary side, the knee point of the voltage on an auxiliary winding of the transformer is detected. A current limit proportional to the input voltage of the converter is produced from the voltage on an auxiliary winding for stabilizing the output current in constant current mode. | 03-19-2009 |
20090279214 | PROTECTION APPARATUS AND METHOD FOR A POWER CONVERTER - A power converter uses a PWM controller to provide a driver output to modulate the duty of the power converter. A protection apparatus and method compare a current sense input of the PWM controller with a reference voltage to assert a signal representing failure, count the number of cycles where the signal representing failure is asserted, and reset an enable signal to inhibit the driver output if the signal representing failure is asserted in several cycles. | 11-12-2009 |
20090284994 | Control circuit and method for a flyback converter - A control circuit and method are provided for a flyback converter converting an input voltage to an output voltage, to compensate for an entry point of a burst mode of the flyback converter, so that the entry point is not affected by the input voltage, and audible noise resulted from a higher input voltage is reduced without impacting the light load efficiency of the flyback converter. | 11-19-2009 |
20100008110 | CONTROL CIRCUIT AND METHOD FOR A FLYBACK POWER CONVERTER - A flyback power converter includes a power switch connected to a primary side of a transformer, and a sensing signal is provided for a control circuit to switch the power switch so as for the transformer to convert an input voltage into an output voltage. The sensing signal is a function of the input voltage, and the control circuit extracts a variation of the sensing signal during a preset time period. The variation of the sensing signal is used to prevent the output ripple and the green mode entry point of the flyback power converter from varying with the input voltage. | 01-14-2010 |
20110012554 | APPARATUS AND METHOD FOR IMPROVING THE STANDBY EFFICIENCY OF A CHARGER, AND ULTRA LOW STANDBY POWER CHARGER - A charger has two pins for connecting with a battery therebetween, and an apparatus and method are proposed to determine to wake up or turn off the charger according to a voltage or a current detected from the two pins, to reduce the standby power consumption of the charger. | 01-20-2011 |
20110018590 | FEEDBACK CIRCUIT AND CONTROL METHOD FOR AN ISOLATED POWER CONVERTER - A feedback circuit for an isolated power converter includes an opto-coupler and a reversed polarity regulator. The opto-coupler provides a current related to an output voltage of the isolated power converter. When the isolated power converter enters light load, the output voltage rises and the reversed polarity regulator reduces the current to decrease the power consumption and thus improve the light load efficiency of the isolated power converter. | 01-27-2011 |
20110051463 | APPARATUS AND METHOD FOR STANDBY POWER REDUCTION OF A FLYBACK POWER CONVERTER - An apparatus and method for a flyback power converter reduce the standby output voltage of the flyback power converter by switching the reference voltage provided by a shunt regulator of the flyback power converter or the ratio of voltage divider resistors of the shunt regulator, to reduce the standby power consumption by an output feedback circuit of the flyback power converter, the shunt regulator, and the voltage divider resistors, and thereby the power loss of the flyback power converter in standby mode. | 03-03-2011 |
20110095735 | CIRCUIT AND METHOD FOR PREDICTING A VALLEY TIMING FOR A VOLTAGE ACROSS A SWITCHING DEVICE - Disclosed are circuits and methods for use in a control circuit of a switching mode power supply for turning on a switching device in the switching mode power supply when the voltage across the switching device is at a minimum. A voltage detector is provided for detecting the voltage across the switching device to produce a detection voltage which is a function of the voltage across the switching device, and circuit arrangement is used to predict a valley timing for the voltage across the switching device by evaluating the time period that the detection voltage falls down from a first threshold to a second threshold. | 04-28-2011 |
20120194162 | PULSE WIDTH MODULATION CONTROLLER AND METHOD FOR OUTPUT RIPPLE REDUCTION OF A JITTERING FREQUENCY SWITCHING POWER SUPPLY - A pulse width modulation controller and method for output ripple reduction of a jittering frequency switching power supply detect the current of a power switch of the switching power supply to generate a current sense signal, and adjust the gain or the level of the current sense signal according to the switching frequency of the power switch to adjust the on time of the power switch, to reduce the output ripple of the switching power supply caused by the jittering frequency of the switching power supply. | 08-02-2012 |
20130194837 | CONTROL CIRCUIT AND METHOD FOR A FLYBACK CONVERTER TO COMPENSATE FOR AN ENTRY POINT OF A BURST MODE - A control circuit and method are provided for a flyback converter converting an input voltage to an output voltage, to compensate for an entry point of a burst mode of the flyback converter, so that the entry point is not affected by the input voltage, and audible noise resulted from a higher input voltage is reduced without impacting the light load efficiency of the flyback converter. | 08-01-2013 |
20130229833 | FEEDBACK CIRCUIT AND CONTROL METHOD FOR AN ISOLATED POWER CONVERTER - A feedback circuit for an isolated power converter includes an opto-coupler and a reversed polarity regulator. The opto-coupler provides a current related to an output voltage of the isolated power converter. When the isolated power converter enters light load, the output voltage rises and the reversed polarity regulator reduces the current to decrease the power consumption and thus improve the light load efficiency of the isolated power converter. | 09-05-2013 |