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 |
20100141170 | AC/DC MODULATION CONVERSION SYSTEM AND APPLICATION THEREOF - This invention discloses an AC/DC modulation conversion system, which comprises a control signal transmitter, a control signal receiver and a control signal/modulation signal converter. The control signal transmitter transmits a control signal, the control signal receiver receives the control signal, the control signal/modulation signal converter converts the control signal into a pulse width modulation signal or a DC level modulation signal. Therefore, this AC/DC modulation conversion system can be applied to controllable DC load circuits such as a controllable DC heater, a controllable DC motor or a controllable DC lamp etc for respectively controlling the temperature, speed or brightness etc. | 06-10-2010 |
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 |