Siemens Milltronics Process Instruments, Inc.

Milltronics Ltd.

Claude Mercier

Quinton Lyon

A current limiter circuit which exhibits a low dropout voltage. The current limiter circuit is suitable for protecting process control equipment operating on a current loop. The current limiter circuit includes an interface for coupling to the current loop, and a current source element coupled to the process control equipment. The current source element comprises a current limiter circuit to limit the current flowing to the process control equipment, and a voltage reference circuit coupled to the current limiter circuit provides a predetermined voltage reference during operation of the current source element.

Current limiter with low drop voltage for surge protection and fuse protection

A current loop control circuit for a process variable transmitter coupled to a receiver at a remote location through a two-conductor current loop. The current loop control circuit efficiently utilizes the current in the loop to produce an optimal voltage and current for the operation of the process variable measurement transmitter.

Current loop control circuit for a time of flight ranging system

A loss-less diode equivalent circuit which functions to reduce and eliminate the forward bias voltage or drop associated with conventional diodes. The loss-less diode comprises a reverse connected MOSFET device which is configured with a clamping circuit and coupled to an input stage. The drain is coupled to the input stage which receives an input signal. The source of the MOSFET device provides an output port for charging a capacitor in a conduction or on state.

Circuit for loss-less diode equivalent

A capacitive pump circuit suitable for use in loop powered level measurement and time of flight ranging systems. The capacitive pump circuit comprises an input buffer, a level shifter and an output stage. The input buffer receives a clocking signal which is also coupled to the input of the output stage through the level shifter. The output from the input buffer is switched by the output stage to charge a capacitor and generate a voltage output which has the opposite polarity of the voltage supply rail. According to another aspect, a capacitive voltage doubler circuit is provided which is also suitable for use in loop powered level measurement and time of flight ranging systems.

Circuit for a lossless capacitive pump

A calibration module and methods for a time-of-flight ranging system. The calibration module may be built into the circuitry of the time-of-flight ranging system and allows various operating parameters to be measured and evaluated. The calibration modes include amplitude calibration, frequency calibration, and time delay calibration. The calibration mode also includes an electronic noise measurement mode. The calibration modes may be initiated on power-up or reset, or in response to user input or time-based trigger.

Method and apparatus for on-board calibration in pulse-echo acoustic ranging system

An envelope detector for detecting the envelope of an input signal. The envelope detector includes an inverter for inverting the input signal and two offsetting circuits for offsetting the input signal and the inverted input signal so as to align the peaks of the signals with zero volts. The two offset signals are then summed, which results in a signal proportional to the inverted envelope of the input signal.

Apparatus for detecting the envelope of an input signal

A universal switching power supply for generating one or more output voltage levels wherein the power supply is operable over a range of AC and DC input supply voltages. The universal switching power supply achieves a ratio between the highest voltage and lowest voltage of at least 27. The universal switching power supply also features an intrinsically safe output. The intrinsically safe output circuitry comprises a multi-layer PCB with a planar core transformer.

Intrinsically safe universal switching power supply

An electronic relay for use with an ultrasonic transducer. The electronic relay selectively couples the ultrasonic transducer to an electronic circuit. The transducer includes an input/output port for receiving excitation signals from the circuit and for transmitting echo signals back to the circuit. The electronic relay comprises a solid state switch and a leakage control circuit. The solid state switch is connected between the transducer and the electronic circuit. The switch is responsive to an actuation signal from the circuit for opening and closing the switch. The leakage control circuit is coupled to the switch and functions to control leakage current when the switch is open so as to electrically isolate the transducer from the electronic control circuit.

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Peterborough, Canada

Claude Mercier