Abstract: A system for controlling surge pressure and deployed into a wellbore drilled using a managed pressure drilling technique includes auto-fill float equipment allowing flow into a liner casing string, a drillpipe diverter providing a flow path between a drillpipe landing string and an annulus, and a drillpipe flow restrictor selectively blocking the flow path from the top of the drillpipe landing string while allowing fluid to be displaced up the liner casing string and into the annulus. The drillpipe flow restrictor and the drillpipe diverter are convertible to provide a flow path from the wellbore through the auto-fill float equipment to a top surface while blocking flow through the diverter into the annulus. The auto-fill float equipment is convertible to block the flow path from the wellbore into the liner casing string, while allowing fluid to flow from the liner casing string into the wellbore.

Abstract: The present invention relates to a folded differential amplifier having very high output impedance capable of being operated at frequencies of the order of gigahertz.

Abstract: The reliability and operability of semiconductor devices is improved using a circuit arrangement that protects the device against malfunction and harm during operation. According to an example embodiment of the present invention, a semiconductor device includes a protection circuit that is adapted to discharge excess current and/or voltage in response to the voltage level at an input pad and to the operating condition of the device. The circuit protection circuit is configured to a first configuration during a power-up mode and to a second configuration during a power-down mode. When the voltage at the input pad reaches a selected threshold, the input voltage is discharged.

Abstract: The present invention relates to a folded differential amplifier having very high output impedance capable of being operated at frequencies of the order of gigahertz.

Abstract: The reliability and operability of semiconductor devices is improved using a current source that advantageously exhibits stability during startup, operates at low voltages and can be used with a variety of integrated circuit devices including operational amplifiers. An example embodiment of the present invention is directed to a PTAT current sourcing circuit that includes first and second current paths and a folded current-drawing arrangement in which first and second bipolar transistors provide a substantially-reduced minimum operating voltage. In a more particular example embodiment, the PTAT current sourcing circuit comprises a first current path including a pair of cascoded MOS-type transistors inter-coupled at a first node, and including another MOS-type circuit in series with the pair of cascoded MOS-type transistors.

Abstract: The reliability and operability of semiconductor devices is improved using a current source that advantageously exhibits stability during startup, operates at low voltages and can be used with a variety of integrated circuit devices including operational amplifiers. An example embodiment of the present invention is directed to a PTAT current sourcing circuit that includes first and second current paths and a folded current-drawing arrangement in which first and second bipolar transistors provide a substantially-reduced minimum operating voltage. In a more particular example embodiment, the PTAT current sourcing circuit comprises a first current path including a pair of cascoded MOS-type transistors inter-coupled at a first node, and including another MOS-type circuit in series with the pair of cascoded MOS-type transistors.

Abstract: The present invention is directed to a method and apparatus for producing a square wave output signal with a clock circuit that possesses characteristics of low current consumption, relatively tight duty cycle control, and versatility over a wide range of voltages and input signal frequencies down to, and including DC. Exemplary embodiments receive an input signal, and process the input signal into an output square wave signal. A processing of the input signal is achieved using at least one current mirror for controlling a duty cycle of the output square wave signal said at least one current mirror being implemented in part with at least one pair of cascoded transistors. The processing is further achieved with an output stage having at least one inverter operatively connected with a node between the transistors of the at least one pair of cascoded transistors to control switching of the at least one pair of cascoded transistors.

Abstract: A PTAT current source comprising a first branch including a bipolar transistor structure connected in diode configuration, and first and second sub-branches coupled to the bipolar transistor structure, the first sub-branch including a p-channel MOSFET transistor connected in diode configuration and an n-channel MOSFET transistor which is not connected in diode configuration, and the second sub-branch including a p-channel MOSFET transistor not connected in diode configuration and an n-channel MOSFET transistor connected in diode configuration; and a second branch including a bipolar transistor structure connected in diode configuration, and third and fourth sub-branches coupled to the bipolar transistor structure, the third sub-branch including a p-channel MOSFET transistor connected in diode configuration and an n-channel MOSFET transistor which is not connected in diode configuration, and the fourth sub-branch including a p-channel MOSFET transistor not connected in diode configuration and an n-channel MOSF

Abstract: A dolly for moving a snowmobile on a supporting surface such as a garage floor, ground, etc., wherein the dolly may be positioned beneath the snowmobile from the forward portion of the snowmobile. The dolly has a jack associated therewith which may be operated to raise the track portion of the snowmobile from the ground. The forward end of the dolly may then be moved upwardly so that the skis of the snowmobile are also moved out of engagement with the supporting surface. The snowmobile may then be conveniently moved from one location to another.

Abstract: A switching oscillator constituted by two inverters is provided with a system of current mirrors each arranged to provide a small proportion of load current from the load of one transistor to the load circuit of the other such as to drive the load currents into equilibrium.

Abstract: A CMOS small-signal amplifier is arranged to drive separately but in synchronism the transistors of an output stage comprising a first output transistor of a first conductivity type and a second output transistor of a second conductivity type. Each of these output transistors is driven by a respective intermediate stage comprising a current source transistor and a driver transistor directly coupled to an input terminal and a control node of the respective output transistor. The current source transistors are biassed such that the said output transistors have a symmetrical duty cycle. There may be a single bias line connected to a current source transistor in one intermediate stage and a system of current mirrors coupling the bias line to the current source transistor in the other intermediate stage.