Abstract:
A power system utilizing a method and apparatus to cost-effectively and efficiently supply power to an electrical system requiring a switchable main power source and a continuous auxiliary power source. Specifically, the power system utilizes an improved power converter having a main output circuit and an auxiliary output circuit coupled to a common input circuit. Primary switching circuitry in the input circuit, secondary switching circuitry in the main output circuit, and capacitance in the auxiliary output circuit allow for the systematic control of the main output from the power converter to the electrical system. In particular, the main output circuit can be switched on and off without interrupting the auxiliary output circuits supply of electrical power to the electrical system. Moreover, switching at a zero current state allows for the use of more cost-effective and efficient circuitry. The power system method and apparatus of the present invention produces functionality and operating characteristics similar to using two separate and independent power systems to supply an electrical system but with increased efficiency as well as reduced cost and complexity.
Abstract:
A filter for an inrush relay, the relay having a relay coil having first and second leads includes a common-mode inductor connected to the relay coil leads across the relay coil. A first capacitor is connected to the first relay coil lead and a chassis ground potential. A second capacitor is connected to the second relay coil lead and the chassis ground potential. A third capacitor is connected to the relay coil leads across the relay coil. A first resistor is connected to the first relay lead, and a second resistor is connected to the second relay coil lead. The inductor and first and second capacitors form a high frequency common-mode filter. The third capacitor and first and second resistors form a high frequency differential mode filter.
Abstract:
A circuit for, and method of, reducing a preload current required to maintain a duty cycle of an asymmetrical DC/DC converter and a DC/DC converter incorporating the circuit or the method. In one embodiment, the circuit includes an auxiliary inductor, coupled in series with an output capacitor of the converter in an output current doubler thereof, that reduces ripple current in the output current doubler and thereby maintains the duty cycle.
Abstract:
Various systems and methods for providing soft-start and soft-stop to an asymmetrical half-bridge converter and a power supply employing such systems or methods. The power supply includes a power train including an asymmetrical half-bridge converter having an energy storage device coupled across a complementary switch thereof. In one embodiment, a conductive path is coupled across the energy storage device to substantially discharge the energy storage device and thereby reduce current stress in the complementary switch when the converter turns on. In another embodiment, a controller, coupled to the complementary switch, provides a drive waveform to drive the complementary switch. The controller increases a duty cycle of the drive waveform as the converter turns off.
Abstract:
For use with a buck-based converter having a rectifier that receives current from a secondary side of a isolation transformer, an active clamp and a method of operating the buck-based converter to manage reverse recovery energy therein. In one embodiment, the active clamp includes: (1) an auxiliary transformer coupled across the isolation transformer and (2) an auxiliary switch, interposed between the auxiliary transformer and the rectifier, that: (2a) closes as a function of an output voltage of the rectifier to cause the auxiliary transformer to receive reverse recovery energy from the rectifier and deliver the reverse recovery energy to a primary side of the isolation transformer and (2b) opens to limit a magnetic flux of a core of said auxiliary transformer.
Abstract:
An AC-AC ballast system for a discharge lamp (e.g., a fluorescent lamp), which includes a PFC converter which incorporates an isolation transformer, and a DC-AC inverter provided on the secondary side of the isolation transformer. Because the AC line input is isolated from the lamp load by the transformer in the PFC converter, the switching frequency of the PFC converter can be advantageously significantly higher than the lamp current frequency (and the switching frequency of the DC-AC inverter), to thereby enable a significant reduction in the size and weight of the ballast system, without an increase in the emission of EMI radiation from the lamp. In this regard, the ballast system of the present invention can be thought of as a two-frequency ballast system having an isolated PFC converter.
Abstract:
For use with a buck-based converter having an isolation transformer, a snubber circuit and a method of damping a transient in the power rectifying diode due to its reverse recovery. In one embodiment, the snubber circuit includes: (1) a capacitor, coupled to a power rectifying diode in the buck-based converter, that receives energy from the power rectifying diode during a reverse recovery period thereof and (2) a flyback converter, coupled to the capacitor, that receives the energy from the capacitor and delivers the energy to a voltage source on the primary side of the isolation transformer.
Abstract:
A braking mechanism of a wheeled device is provided, including: a main body, configured to be connected to the wheeled device including at least one wheel; an adjusting member, disposed on the main body and including a rod and a first abutting member adjustably positioned on the rod; a braking member, movably disposed on the main body; and an elastic member, abutted between the first abutting member and the braking member so that the braking member is biased by the force of the elastic member toward the at least one wheel to frictionally contact the at least one wheel.
Abstract:
An annular device includes an annular main body, a battery mounting portion, and a battery cover. The battery mounting portion protrudes from an inner surface of the main body, and includes a first arcuate element and a second arcuate element opposite to each other. The battery cover is operable to clasp the battery mounting portion, and includes a first arcuate member and a second arcuate member opposite to each other. The first arcuate member clasps the first arcuate surface, and the second arcuate member clasps the second arcuate surface.
Abstract:
A card connector for receiving a micro-SIM card and a micro-SD card therein includes an insulating housing, a plurality of signal terminals and conductive terminals, and a supporting tray. The insulating housing defines an accommodating chamber. The signal terminals are disposed in the insulating housing with contact portions thereof projecting into the accommodating chamber. The conductive terminals are disposed in the insulating housing with touching portions thereof projecting into the accommodating chamber. The supporting tray defines a first receiving space and a second receiving space for receiving the micro-SIM card and the micro-SD card therein respectively. The supporting tray together with the micro-SIM card and the micro-SD card is inserted into the accommodating chamber. Bottoms of the first receiving space and second receiving space are opened freely to make the micro-SIM card electrically contact with the contact portions and the micro-SD card electrically contact with the touching portions.