Patent application number | Description | Published |
20090306914 | SYSTEM AND METHOD FOR MEASURING INPUT POWER OF POWER SUPPLIES - A system and method is provided to determine input power of a power supply using an input section by dividing input section output power by an efficiency value of the input section. Measurements of operating parameters are obtained through sensing devices that may be previously provided to avoid increased expense and complexity associated with the addition of a current sensing device. The input section maybe a rectifier or PFC stage. Input section output power can be determined by measuring current in a downstream DC/DC converter or converters. The current drawn by the DC/DC converter(s) is used as the output current of the input section to determine output power of the input section. The efficiency value is obtained for an operating point of the input section based on operating parameter values, as indicated in a lookup table or algorithm providing the efficiency values. The calculated input power may also be used to determine input RMS current for the power supply. | 12-10-2009 |
20100027298 | System and method for synchronous rectifier drive that enables converters to operate in transition and discontinuous mode - A synchronous rectifier is switched in accordance with a primary switch transition and a reference signal representing current in a current storage device to which the synchronous rectifier is coupled. A current emulator provides a signal representing current in the current storage device as a volt-second product so that current stored in the current storage device while the primary switch is on is discharged by the synchronous rectifier. The use of a current emulator provides an inexpensive solution for controlling synchronous rectifier transitions without resorting to more expensive current sensing solutions that are commercially impracticable. Blanking intervals are provided for avoiding false transitions of the synchronous rectifier when the primary switch turns on and after the synchronous rectifier turns off. The disclosed system and method can be applied to flyback converters for a synchronous rectifier on the secondary side of a transformer, or the inductor of buck converters. | 02-04-2010 |
20100052568 | Light emitting diode array driver - A device and method for controlling current output to current driven loads such as active light emitting diodes (LEDs) and, more particularly, a device and method for controlling current to an array of active LED strings that are disposed in series. The device generates a square wave AC current that flows through primary windings of plural isolation transformers whose primary windings are electrically connected in series. The device includes a current regulator that produces a regulated DC current that is proportional to a current reference; a free running inverter that converts the DC current to square wave AC current; and plural isolation transformers whose secondary windings are electrically connected to LED strings. | 03-04-2010 |
20100195254 | OVERCURRENT AND BROWN OUT PROTECTION APPARATUS - A discontinuous conduction mode (DCM) converter is provided. The converter comprises a transformer having a primary and a secondary side, an RCD network, a rectifier, a switch, and a controller. The transformer has primary side with a first primary winding and a second primary winding and has a secondary side with a secondary winding. The RCD network is coupled to the first primary winding and is adapted to receive energy from the leakage inductance of the first primary winding. The rectifier is coupled to the second primary winding. The switch is coupled between the RCD network and ground. The controller receives indicia of a rectified voltage from the rectifier, indicia of current from the switch, indicia of transformer magnetization and controls the actuation of the switch. Preferably, the controller provides an actuation signal to the switch with actuation periods that are separated from one another by an interval that allows energy within the transformer to substantially dissipate. Average output current of this converter is generally limited from the peak switch current level that is allowed by the controller and a switching frequency that the controller allows the converter to operate. | 08-05-2010 |
20100315840 | SYSTEM AND METHOD FOR INDIRECT CONTROL OF A CONVERTER OUTPUT - One embodiment of the invention relates to a power apparatus. The power apparatus includes a power converter configured to convert an input voltage to an output voltage for providing power at an output thereof to which a load is connectable. The converter can include an isolation barrier configured to electrically isolate the output and the load from an input source that provides the input voltage. The system also includes a control loop that includes indirect sense circuitry configured to indirectly derive an indication of at least one of output current and output power of the converter. The control loop is configured to control output current or output power based on the indirectly derived indication of output current or output power, respectively. | 12-16-2010 |
20110266970 | SYSTEM AND METHODS FOR PROVIDING EQUAL CURRENTS TO CURRENT DRIVEN LOADS - Systems and methods are provided for providing a substantially constant and equal current to a plurality of current driven loads. In one embodiment, a system is provided that comprises a plurality of current regulated outputs and a plurality of current driven loads. The plurality of current regulated outputs and the plurality of current driven loads are arranged in a single current loop configuration with a respective current regulated output providing an output voltage to a respective current driven load of the plurality of current driven loads. | 11-03-2011 |
20110316430 | MULTI-TRANSFORMER LLC RESONANT CONVERTER CIRCUITS AND METHODS - In a first aspect, an LLC resonant converter is provided for driving a plurality of output circuits from a DC input signal. The LLC resonant converter includes: (a) an inverter circuit for converting the DC input signal to a square-wave signal; (b) an inductor network coupled to the inverter circuit; and (c) a plurality of transformers, each transformer including a primary winding and a secondary winding. The primary windings of the transformers are coupled in series, and the series-coupled primary windings are coupled in parallel with the inductor network. The secondary winding of each transformer is coupled to and provides a current to a corresponding one of the output circuits. The secondary winding currents are substantially equal, and power is processed by a single transformer between the DC input signal and each output circuit. Numerous other aspects are also provided. | 12-29-2011 |
20120153920 | SYSTEMS FOR INDIRECT AVERAGE CURRENT MEASUREMENT - One example of the invention relates to a power system. The power system can include a power converter configured to convert an input voltage to an output voltage for providing power at an output thereof to which a load is connectable. A measurement system can include measurement circuitry configured to measure an average of an accessible current in the power converter and derive an average measurement of another current in the power converter based on timing control signals used to control operation of the power converter. | 06-21-2012 |
20120275198 | TRANSITION MODE CHARGE CONTROL FOR A POWER CONVERTER - One embodiment relates to power conversion system. The system includes a converter configured to convert an input voltage to an output voltage, the converter comprising at least one switch that is controlled in response to an activation signal to provide current through an inductor. A transition mode controller is configured to provide the activation signal based on a measure of charge derived from current through the switch and based on the current through the inductor. | 11-01-2012 |
20130077356 | DC-DC CONVERTERS - A DC-DC converter includes a waveform generator that generates an output waveform for the DC-DC converter based on a DC input voltage. A rectifier rectifies the output waveform from the waveform generator to generate a rectified voltage for the DC-DC converter. A tank circuit having an inductor and a capacitor can be configured to have a resonant frequency that is correlated with a frequency of the output waveform, wherein the capacitor of the tank circuit also functions as a filter for the DC-DC converter. | 03-28-2013 |
20130082611 | FEED FORWARD CONTROLLED VOLTAGE TO CURRENT SOURCE FOR LED DRIVER - A DC to DC converter receives a DC input voltage and generates an output DC voltage. A current sensor measures a DC input current. A control circuit is coupled to the current sensor for controlling the DC to DC converter to have a constant DC input current. | 04-04-2013 |
20130163295 | POWER SUPPLY CONVERTER WITH A PRE-REGULATOR - A power supply converter with a pre-regulator is provided. In one embodiment, the power supply converter comprises a rectifier that receives an AC input voltage and provides a rectified AC input voltage, a filter that receives the rectified AC input voltage and provides a filtered DC input voltage and a pre-regulator that connects the rectified AC input voltage for allowing for providing current and voltage to the filter from the rectified AC input voltage upon a measurement that indicates that the AC input voltage or the rectified AC input voltage crosses a predetermined turn on threshold. | 06-27-2013 |
20130307512 | SYSTEMS FOR INDIRECT AVERAGE CURRENT MEASUREMENT - One example of the invention relates to a power system. The power system can include a switching power converter configured to convert an input voltage to an output voltage for providing power at an output thereof to which a load is connectable. A measurement system can include measurement circuitry configured to measure an average of an accessible current in the power converter during both continuous and discontinuous modes of operation and derive an average measurement of another current in the power converter based on timing control signals used to control operation of the power converter. | 11-21-2013 |
20140145634 | CIRCUIT AND METHOD FOR GENERATING A REFERENCE VOLTAGE FOR A POWER CONVERTER - Circuits and methods for generating a reference voltage for a power converter control are disclosed herein. The power converter control providing a signal on an output for aligning the voltage and current on a power line so that they are in phase. An embodiment of a circuit includes a voltage detector that detects the voltage on the power line. A signal generator generates a wave that is in phase with voltage on the power line, the wave being generated independent of the voltage on the power line. The output of the signal generator is the reference voltage. | 05-29-2014 |
20140355319 | AC-DC CONVERTER HAVING SOFT-SWITCHED TOTEM-POLE OUTPUT - An AC-DC converter has a totem-pole output circuit having first and second semiconductor switches, each having a channel coupled to a switching node and having a parasitic capacitance associated with the channel. An inductor has one terminal thereof connected to a switching node. First and second bypass devices are coupled to a second terminal of the inductor and operable during at least a portion of an input voltage to allow reverse current from an output of the converter to generate soft-switching of the first semiconductor switch. An asymmetrical shunt for measuring current in a first direction and bypassing current in a second direction opposite the first direction allows accurate measurement of reverse current. | 12-04-2014 |
20150061521 | METHOD AND APPARATUS FOR CALCULATING AN AVERAGE VALUE OF AN INACCESSIBLE CURRENT FROM AN ACESSIBLE CURRENT - In a power converter, a circuit determines an average value of an inaccessible current from an average value of an accessible current and a value of the operating duty cycle of the converter. A method of measuring an average value of an inaccessible current from a measured value of a current in a power converter by a duty cycle of a pulse width modulation (PWM) signal representing a duty cycle of the power converter. Coupling a voltage representing the measured value to an input of a low pass filter during a time period (D) and coupling the input of the low pass filter to a reference voltage during a time period (1−D). | 03-05-2015 |
20150061522 | METHOD AND APPARATUS FOR CALCULATING AN AVERAGE VALUE OF AN INACCESSIBLE CURRENT FROM AN ACESSIBLE CURRENT - In a power converter, a circuit determines an average value of an inaccessible current from an average value of an accessible current and a value of the operating duty cycle of the converter. A method of measuring an average value of an inaccessible current from a measured value of a current in a power converter by a duty cycle of a pulse width modulation (PWM) signal representing a duty cycle of the power converter. Coupling a voltage representing the measured value to an input of a low pass filter during a time period (D) and coupling the input of the low pass filter to a reference voltage during a time period (1−D). | 03-05-2015 |
20150061614 | METHOD AND APPARATUS FOR CALCULATING AN AVERAGE VALUE OF AN INACCESSIBLE CURRENT FROM AN ACESSIBLE CURRENT - In a power converter, a circuit determines an average value of an inaccessible current from an average value of an accessible current and a value of the operating duty cycle of the converter. A method of measuring an average value of an inaccessible current from a measured value of a current in a power converter by a duty cycle of a pulse width modulated (PWM) signal representing a duty cycle of the power converter. Coupling a voltage representing the measured value to an input of a low pass filter during a time period (D) and coupling the input of the low pass filter to a reference voltage during a time period (1−D). | 03-05-2015 |