摘要:
DC-DC voltage converter structures and methods are provided that employ first and second transistors which are switched to control currents through an inductor and a capacitor to thereby provide an output voltage substantially equal to a predetermined reference voltage. Preferably included is a voltage feedback loop in which an error voltage is fed back to a loop comparator and further included is a current feedback loop that provides to the comparator a first voltage ramp whose amplitude is proportional to the amplitude of the converter's input current. The output signal of the comparator sets the duty cycles of the first and second transistors. In each converter period, the first and second transistors of the voltage converter respectively control, through the inductor, a first current with a rising slope and a second current with a falling slope. Finally, converter stability is enhanced by providing a second voltage ramp having a slope related to a fraction (e.g., ½) of the falling slope and then comparing the error voltage of the voltage feedback loop to the sum of the first and second voltage ramps.
摘要:
Voltage regulator structures and methods embodiments are provided which employ a high-side N-type switching transistor to thereby enhance system efficiency and also reduce the die area required by these regulator structures. This structure and its advantages, however, require a gate drive signal higher than the input voltage of the voltage regulator. The embodiments resolve this need with a bias capacitor in a bootstrapped arrangement and a control loop arranged to maintain a bias voltage across the capacitor sufficient to always insure rapid switching of the high-side switching transistor during a pulse-width modulation (PWM) operational mode. The embodiments further include a second control loop arranged to insure sufficient voltage across the capacitor during a pulse-frequency modulation (PFM) operational mode.
摘要:
This utility model is a kind of direct printable rubber magnet, including bonded magnet. The said bonded magnet is applied with coating on surface. The said coating is cemented to the said bonded magnet surface. With coating on surface, this rubber magnet can be directly printed, written and/or beautified on the surface, achieving same effect which current rubber magnets must achieve after laminating with plastic or paper. This makes its structure more simple and can be accomplished by common coating method, so it is reasonable-crafted, simple-operated, easy-applied and cost-saving. This rubber magnet is also easy to be recycled. As this product has no plastic or paper which is difficult to be recycled, and the coating holds a tiny percentage and can be recycled together with the bonded magnets without any other separating process, it is easy to be recycled with low cost, so it is good for environment protection.
摘要:
A method and device is provided for regulating the air-fuel mixture provided to an engine of a stand-by electrical generator during the exercise thereof. The engine is exercised at a predetermined speed less than the normal operating speed of the engine and each cylinder receives an air-fuel mixture having an air component and a fuel component. To exercise the engine, the air component and the fuel component in the air-fuel mixture provided to the engine is reduced. In addition, the volume of the air-fuel mixture provided to each cylinder of the engine is balanced.
摘要:
DC-DC voltage converter structures and methods are provided that employ first and second transistors which are switched to control currents through an inductor and a capacitor to thereby provide an output voltage substantially equal to a predetermined reference voltage. Preferably included is a voltage feedback loop in which an error voltage is fed back to a loop comparator and further included is a current feedback loop that provides to the comparator a first voltage ramp whose amplitude is proportional to the amplitude of the converter's input current. The output signal of the comparator sets the duty cycles of the first and second transistors. In each converter period, the first and second transistors of the voltage converter respectively control, through the inductor, a first current with a rising slope and a second current with a falling slope. Finally, converter stability is enhanced by providing a second voltage ramp having a slope related to a fraction (e.g., ½) of the falling slope and then comparing the error voltage of the voltage feedback loop to the sum of the first and second voltage ramps.
摘要:
A heat exchanger is provided for dissipating heat from a fluid. The heat exchanger includes a plurality of stacked pairs of plates. Each pair of plates includes a first plate and a second plate. The first plate extends along a first axis and has first and second sides. The first side of the first plate has a generally sinusoidal recess therein that extends along the first axis. The second plate extends along a second axis and has first and second sides. The first side of the second plate has a generally sinusoidal recess therein that extends along the second axis and that is out of phase with the sinusoidal recesses in the first side of the first plate. The first side of the first plate and the first side of the second plate form a mating relationship with each other such that the recess in the first side of the first plate communicates with the recess in the first side of the second plate at a plurality of axially spaced locations.
摘要:
DC-DC voltage converter systems are provided in which a switching voltage converter is arranged with an inductor to switch first and second currents with duty cycles D and D′ determined by an error voltage Verr to thereby maintain an output voltage Vout. A transconductance amplifier having an amplifier output provides the error voltage Verr in response to the output voltage and a reference voltage Vref. A ripple current Irpl is provided to the amplifier output in response to the difference between the error voltage Verr and a clamp voltage Vclmp. Finally, a current comparator generates a skip signal to turn off the first and second currents in response to a selected threshold of the ripple current. In this process, the ripple current Irpl substantially clamps the error voltage Verr to the clamp voltage Vclmp. Preferably, the current comparator is arranged to provide the skip signal in response to the selected first threshold of the ripple current Irpl and retract the skip signal in response to a selected second threshold of the ripple current Irpl.