Jiri Haze

A Method for In-Situ, Total Ionising Dose Measurement of Temperature Coefficients of Semiconductor Device Parameters

This work presents and discusses a test method developed to allow the measurement of total ionising dose induced changes in temperature effects on electronic devices for space and nuclear applications. Two demonstration experiments testing commercial PMOS transistors were performed, using different methods of I-V curve measurement. The temperature of the devices during irradiation was controlled precisely using a commercial thermoelectric cooler. A programmable temperature controller combining digital and analogue control techniques was developed for this project. The experimental results allow better insight into the field of temperature sensitivity of PMOS devices.

BandPass Sigma-Delta Modulator for Capacitive Pressure Sensor

The paper deals with bandpass sigma-delta modulator (BP SDM), which is used for conversion of signal from capacitive pressure sensor. This approach is absolutely new and unique, because this kind of modulators is utilized only for wireless and video applications. The main advantage of BP SDM is due to its defined band. That is why it is resistant against offsets of its subcuircits. Another important advantage is low power consumption, since the BP SDM digitizes only narrow band instead of whole Nyquist band with similar dynamic range. The paper shows basic ideas of this approach and simulation results with ideal and real modulator. The main stages are implemented in switched-capacitor (SC) technique. The modulator layout is presented as well.

The Integrated Unit for MEMS Based Pressure Measurement

The article deals with a custom based integrated measurement unit (IMU), which serves as processing device for MEMS based pressure measurement. The IMU consists of the three elementar stages, measurement stage, processing stage and communication stage. They are implemented on the one single board. The measurement block has 16-bit resolution with 64 provided measurement ranges to sutisfy appropriate accuracy. The power supply is 5 V, which allows to measure current with 238 nA step within 1 mA measurement range. The communication stage is based upon I2C standard.

Digital Synchronization Utilizing Harmonic Signal Generator for Capacitive Pressure Sensor Measurement

The harmonic signal generator utilizing sigma-delta modulation for capacitive pressure sensor measurement was designed in AMIS CMOS 0.7 mum technology. Harmonic signal generator is one of the important parts of complex measurement system for capacitive pressure sensor measurement. Whole capacitive measurement system is based on bandpass (BP) Sigma-Delta modulation. Phasing of harmonic signal and digital sampling signal is main requirement for proper function of capacitive pressure sensor measurement utilizing BP Sigma-Delta modulator. Harmonic signal generator was designed using VHDL. Synthesis of digital synchronization utilizing harmonic signal generator was accomplished in Cadence BuildGates and implemented in Cadence Silicon Ensemble.

New Trends in Evaluation of the Sensors Output

The area of physical quantity processing in recent sensoric applications demands for high accuracy, low distortion, fast response and low power consumption. There are many physical quantities, which could be processed, mainly pressure, temperature, humidity etc. The pressure processing is one of the most important issues for designers. There exist many problems, which have to be solved i.e. how to measure relative and absolute pressure, how to process signal from sensor with low amplitude, how to withdraw noise and parasitics and so on. The pressure is usually measured using capacitive principle (Lee & Wise., 1982), (Chavan & Wise, 2001), (He et al., 2007). The capacitor is formed by measuring membrane and substrate, see Fig. 1. When the pressure is applied, the membrane is deformed and the distance between membrane and substrate changes. It causes the change of capacity, which is processed in next stages.

Switched Current 12-Bit Capacity to Digital Delta-Sigma Modulator

This paper describes the design of the proposed capacity to digital converter. Some important simulations of the converters behavior are presented as well. For capacity value processing second order delta-sigma modulator with input adjusting circuitry was used. The switched current (SI) technique was used in the proposal. It brings small dimensions of the chip and easy integration into the digital circuitry.

Modeling and design of novel architecture of multibit switched-capacitor sigma-delta converter with two-step quantization process

This paper presents a novel architecture of high-order single-stage sigma-delta (\sigma \delta) converter for sensor measurement. The two-step quantization technique was utilized to design of novel architecture of \sigma \delta? modulator. The time steps are interleaved to achieve resolution improvement without decreasing of conversion speed. This technique can be useful for low oversampling ratio. The novel architecture was designed to obtain high dynamic range of input signal, high signal-to-noise ratio and high reliability. This paper describes steps involved in a new VHDL design of a decimation filter for a \sigma \delta modulator. Parameters of decimation filter are derived from the specifications of the overall \sigma \delta modulator. The proposed architecture of switched-capacitor (SC) \sigma \delta modulator was simulated with nonidealities blocks, such as sampling jitter, noise, and operational amplifier parameters (white noise, finite dc gain, finite bandwidth, slew rate and saturation voltages). The novel architecture of SC \sigma \delta modulator with twostep quantization process was designed and simulated in MATLAB SIMULINK.

Sensor analysis of liquid pollution

The new portable microfluidic device for field measurement of organophosphorous pesticides toxicity is presented. The device consists of two loop pumps. The first loop assures the mixing of solution. The 95% of solution circulates through the first loop. The second loop consists of capillary which creates the hydrodynamic resistance and the chamber with the miniature electrochemical detector. The detection is based on the inhibition of acetylcholinesterase. The enzyme acetylcholinesterase is immobilized on the detector made by thick film technology forming together a biosensor. The analyzed sample is detected in the flow of supporting buffer. The biosensor detects the integral sample toxicity. The signal from biosensor is evaluated by Bioanalyzer electronic unit. It is destinated for detection of traces of pesticides in washout from leaves, for direct measurement in rivers, ponds, waste waters and drinking water sources.

In-Situ Measurement of Total Ionising Dose Induced Changes in Threshold Voltage and Temperature Coefficients of RADFETs

This work presents results of a total ionising dose experiment, during which p-channel RADFETs were irradiated and measured under different gate bias conditions using an in-situ technique. The measurement system allowed threshold voltage shifts and temperature sensitivity of the shift to be measured during irradiation to 60 krad(Si) and the subsequent 55 day period of annealing. The experimental results obtained allow improved insight into temperature sensitivity related problems of RADFET based dosimetry systems for space and terrestrial applications. The results show that the radiation-induced decrease in mobility, caused by the interface trap build-up, has a predominant effect on RADFET temperature coefficients.

In-situ measurement of total ionising dose induced degradation of various commercial voltage references

This work presents results of a total ionising dose experiment, during which commercial voltage references were irradiated and measured under different bias conditions using an in-situ technique. The measurement system allowed various electrical parameters of the voltage references to be measured during irradiation to 100 krad(Si) and the subsequent 50 day period of annealing. The experimental results obtained allow improved insight into total ionising dose induced degradation of data acquisition systems for space and terrestrial applications. The results show that the selected commercial voltage references can be used for high-precision data acquisition systems on board low-cost missions like CubeSats, which are typically exposed to a limited radiation dose.