Abstract: An indirect clamping topology may be used to protect against the damaging effects of an electrostatic discharge event. An input node of a device is protected by a guard. The guard is driven by a signal from a unity-gain amplifier that flows through a resistance. The input node is clamped to the guard by a diode, and the guard is clamped to a low-impedance rail by another diode. The resistance of the low-impedance rail is less than that of the resistance through which the signal from the unity-gain amplifier flows, so that voltage resulting from the event flows to the low-impedance rail and not to the amplifier.

Abstract: A low power analog output circuit is disclosed that utilizes a low pass filter driven by a bit stream to render a waveshaped output signal based upon a raw digital data signal. The analog output circuit includes sequential bit pattern selection logic that receives as an input, the raw digital data signal. The analog output circuit also includes a bit pattern storage that specifies bit stream sequences that are selected in accordance with control signals generated by the state machine based upon its current state and the current raw digital data signal. The analog output circuit includes an output stage driven by a digital input signal corresponding to values provided by a bit stream sequence selected from the bit pattern storage. The output stage comprises a low pass filter circuit having an effective time constant that is greater than a hold period associated with a single bit of the bit stream sequence that drives the digital input signal.

Abstract: A method and system comprising providing a plurality of control signals, the control signals having one or more on periods that do not coincide with the on periods of the other control signals and a first frequency at which the one or more on periods are repeated, the method and system also including driving a plurality of process measurement transducers in response to the control signals by selectively coupling the transducers to ground, and capturing the output of the process measurement transducers within the one or more on periods of the control signals.

Abstract: The systems described herein include a multivariable transmitter with one or more bridge sensors for measuring absolute pressure, differential pressure, and temperature of a process fluid in a pipe. In order to reduce current draw, the sensors are excited one at a time, each during an on period of a drive signal. Each sensor output is captured by a gated integrator that is coupled to the sensor output within the on period. The gated integrator stores a value representative of the sensor output on a node that may then be sampled by an analog-to-digital converter. Using this approach, the analog-to-digital converter may sample at a frequency independent of the frequency of the sensor drive signal. For example, the analog-to-digital converter may sample at a frequency that is less than one-half the frequency of the on period, in order to avoid certain artifacts of the digitization process.

Abstract: A method and apparatus are provided for inhibiting the formation of inlet vortices in a turbofan engine/nacelle installation 10 for use with an aircraft. The present invention redirects fan air from a fan air bypass duct 16, in a generally downward direction from the outer nacelle 18 in order to generate an air curtain 48 for inhibiting inlet vortex formation.