Pulse Rate Output Research Articles

A Signal Conditioning Circuit for Piezoresistive Pressure Sensors With Variable Pulse-Rate Output

A signal conditioning circuit with variable pulse-rate output for piezoresistive pressure sensors based on CMOS current-mode building blocks is presented. The proposed circuit uses an instrumentation amplifier (IA) based on operational floating amplifiers (OFA), adapted for resistive sensors. This IA offers output current which is independent of tracking and offset errors. Two piezoresistors with current supply are used against four piezoresistors of the basic Wheatstone bridge. A new temperature compensation technique for the pressure sensitivity is described. Also a very advantageous SPICE model for piezoresistive sensors is introduced. Simulation as well as experimental results are included to demonstrate the performance of the circuit.

An integrated gas flow sensor with high sensitivity, low response time and a pulse-rate output

Abstract Silicon integrated flow sensors based on a thermal operating principle are widely known. Major disadvantages of conventional thermal flow sensors are the low output signal voltages, as well as high response time. A sensor based on a constant temperature operating principle, called the thermal sigma-delta modulation technique, highly reduces those drawbacks. The output signal of the presented smart thermal flow sensor is a TTL-compatible pulse-rate modulated voltage. A 10-bit resolution can be obtained within 20 ms.

An integrated absolute temperature sensor with sigma-delta A–D conversion

A smart absolute temperature sensor is described, which provides a pulse-rate output and is highly suitable for communication with microprocessors. The temperature sensor generates an absolute temperature current as well as a reference current. Both signals are used in a sigma-delta A–D converter, which provides a clock-synchronous pulse rate. This fully synchronized output signal offers important advantages over asynchronous signals, such as frequency or duty cycle. The last suffers from digital interference, which is often unrecognized. Smart sensors with on-chip digital processing or bus communication need synchronized A–D converters to prevent this problem.

New method for reactive power and energy measurement

The properties of an electronic reactive power and energy measurement method based on a frequency-controlled power-to-pulse-rate conversion are analyzed. The reactive power and energy measurements can be efficiently performed by using a simple integrating circuit as a phase shifter, and frequency-controlled analog-to-pulse-rate converter. A low value of the output pulse rate should not be considered as an inherent disadvantage of the method. By introducing a phase-locked loop in order to achieve high pulse-rate output, the benefit of high resolution is added to the method. The improved electronic structure for the measurement can be implemented in the design of reactive power and energy standards. For precision var-hour meters based on the proposed method, it is possible to have an efficient error-checking and adjustment procedure. The proposed method allows reactive power and energy measurement to be made in single- and poly-phase, symmetrical and unsymmetrical, and balanced and unbalanced networks.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>