Patent application number | Description | Published |
20090080223 | FORWARD CONVERTER WITH SELF-DRIVEN SYNCHRONOUS RECTIFIERS - The present invention relates to a forward converter with self-driven synchronous rectifiers, which utilizes a secondary driving winding and a secondary driving circuit to drive the synchronous rectifiers in the secondary power loop. The secondary driving circuit, which is composed of a level shifter and a signal distributor, can shift the voltage waveform across the secondary driving winding by a predetermined level and distribute proper driving signals to the synchronous rectifiers to reduce the rectifier conduction loss. Specially, the channel of the freewheeling synchronous rectifier still can be turned on during the dead interval to further reduce the body diode conduction loss. | 03-26-2009 |
20090244933 | HALF-BRIDGE LLC RESONANT CONVERTER WITH SELF-DRIVEN SYNCHRONOUS RECTIFIERS - The present invention discloses a half-bridge LLC resonant converter with self-driven synchronous rectifiers, which utilizes a primary IC controller and a gate driver to drive the secondary synchronous rectifiers. In correspondence with the gate drive output voltages of the primary IC controller to the primary switch transistors, the gate driver for the secondary synchronous rectifiers comprises a differential transformer if the primary IC controller outputs two ground-referenced gate drive voltages, which cannot directly drive the primary switch transistors but can be imposed on the differential transformer; or comprises a DC shifter, a DC restorer and a differential transformer if the primary IC controller outputs two gate-source voltages, which can directly drive the primary switch transistors but cannot be imposed on the differential transformer. The drive voltages of the primary switch transistors are unipolar; however the drive voltage of the secondary synchronous rectifiers can be bipolar or unipolar. Under the valid operation mode, this converter can decrease the rectifier conduction losses to increase the power converter efficiency. | 10-01-2009 |
20100067275 | UNIDIRECTIONAL MOSFET AND APPLICATIONS THEREOF - Owing to the property of bidirectional conduction under the saturation mode, synchronous rectifiers in conventional power converters usually suffer from a reverse current under light loads or a shoot-through current under heavy loads. The reverse current may degrade the converter efficiency and the shoot-through current may damage synchronous rectifiers. The present invention discloses a unidirectional metal oxide semiconductor field effect transistor (UMOS), which comprises a metal oxide semiconductor field effect transistor (MOS), a current detection circuit and a fast turn-off circuit. The current detection circuit detects the direction of the current flowing through the MOS. When a forward current is detected, the fast turn-off circuit is disabled and the channel of the MOS can be formed. When a reverse current is detected, the fast turn-off circuit is enabled and the channel of the MOS cannot be formed. This UMOS can be applied, but not limited, to synchronous rectifiers to detect the occurrence of a reverse current or a shoot-through current and fast turn off the channel of the MOSFET. | 03-18-2010 |
20100123517 | GATE-CONTROLLED RECTIFIER AND APPLICATION TO RECTIFICATION CIRCUITS THEREOF - Conventional diode rectifiers usually suffer from a higher conduction loss. The present invention discloses a gate-controlled rectifier, which comprises a line voltage polarity detection circuit, a constant voltage source, a driving circuit and a gate-controlled transistor. The line voltage polarity detection circuit detects the polarity of the line voltage and controls the driving circuit to turn on or turn off the gate-controlled transistor. The gate-controlled transistor may be a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) with a gate, a source and a drain or an Insulated Gate Bipolar Transistor (IGBT) with a gate, an emitter and a collector. The constant voltage source is provided or induced by external circuits and referred to the source of the MOSFET or the emitter of the IGBT. Thanks to a lower conduction loss, this gate-controlled rectifier can be applied to rectification circuits to increase the rectification efficiency. | 05-20-2010 |
20100289461 | BRIDGELESS POWER FACTOR CORRECTOR WITH LOGIC CONTROL - The present invention discloses a bridgeless active power factor corrector with a logic control comprising a high frequency switch controller, a boost inductor, an output filtering capacitor, two boost transistor modules, two boost diodes, two AC input voltage polarity detectors, and two low frequency switch drivers. With a coupling signal, the two AC input voltage polarity detectors respectively control the two low frequency switch drivers in conjunction with the high frequency switch controller to drive the two boost transistor modules with a logic control so that the inductor current releasing electric energy from the boost inductor can flow through the channels of the two boost transistor modules to effectively reduce the body diode conduction loss. | 11-18-2010 |
20110013424 | FORWARD CONVERTER WITH SECONDARY SIDE POST-REGULATION AND ZERO VOLTAGE SWITCHING - The present invention discloses a forward converter with secondary side post-regulation and zero voltage switching, where the primary side power loop may adopt a single or a dual transistor structure, driven by a primary side driving circuit with a constant duty ratio so that the voltage waveform across the secondary side power winding has a constant pulse width; the secondary side power loop uses a controllable switch, a magnetic amplifier (MA) or an N channel metal oxide semiconductor field transistor (NMOS), to blank the leading edge of the voltage waveform across the secondary side power winding, regulate the output voltage, and achieve zero voltage switching of primary side switch transistors. | 01-20-2011 |
20140210351 | ELECTRONIC CONTROL GEARS FOR LED LIGHT ENGINE AND APPLICATION THEREOF - Disclosed are electronic control gears for LED light engines able to improve power factor by way of gearing up or down the LED current and the AC input current in response to and in synchronization with the AC input voltage. Moreover, the disclosed electronic control gears could further reduce flicker phenomenon and total harmonic distortion when used in collocation with disclosed valley fillers, filling the LED current valleys only during the dead time, and in conjunction with disclosed dummy loads, ramping up or down the AC input current only during the dead time. | 07-31-2014 |
20150163869 | CONTROL CIRCUITS, INTEGRATED CIRCUITS AND ILLUMINATING APPARATUSES HAVING THE SAME - Disclosed are control circuits capable of auto-configuring two LED arrays either in parallel when the two LED arrays are operating off of 100±20% V AC voltage sources or in series when the two LED arrays are operating off of 200±20% V AC voltage sources according to the detection of the AC input voltage magnitude. The disclosed control circuits, ruling over the parallel or series configuration of the two LED arrays, could be implemented in discrete forms or as integrated circuits (IC). | 06-11-2015 |
20150163875 | AC-POWERED LED LIGHT ENGINES, INTEGRATED CIRCUITS AND ILLUMINATING APPARATUSES HAVING THE SAME - An ac-powered LED light engine coupled between a rectifier and a plurality of extrinsic LED sub-arrays is provided. The ac-powered LED light engine comprises a plurality of normally closed bypass switches, a normally closed current regulator, and a plurality of switch controllers. Each of the normally closed bypass switches is connected in parallel with a corresponding LED sub-array except for the topmost or the bottommost LED sub-array and shuttles between three switch states: ON, REGULATION, and OFF. The normally closed current regulator is coupled to the normally closed bypass switches and used to regulate the highest LED current level near the peak of an extrinsic mains voltage. Each of the switch controllers is coupled to a corresponding bypass switch as a feedback network and takes control of the three switch states according to a corresponding current sense signal. | 06-11-2015 |