Tor Sverre Lande

Delta-sigma modulators using frequency-modulated intermediate values

This paper describes a new first- and second-order delta-sigma modulator concept where the first integrator is extracted and implemented by a frequency modulator with the modulating signal as the input. The result is a simple delta-sigma modulator with no need for digital-to-analog converters, allowing straightforward multibit quantization. Without the frequency modulator, the circuit becomes a frequency-to-digital converter with delta-sigma noise shaping. An experimental first- and second-order modulator has been implemented in a 1.2-/spl mu/m standard digital CMOS process and the results confirm the theory. For the first-order modulator an input signal amplitude of 150 mV resulted in a signal-to-quantization noise ratio (SQNR) of /spl ap/115 dB at 2 MHz sampling frequency and signal bandwidth of 500 Hz.

Ultra low-voltage/low-power digital floating-gate circuits

This paper describes a novel technique for implementing ultra low-voltage/low-power digital circuits. The effective threshold voltage seen from a control gate is adjusted during a UV-light-activated tuning procedure. The optimal effective threshold voltage matching the supply voltage and speed may be programmed by UV light through an activated conductance between the power rails and the floating gates. Measured results are provided for gates operating down to 0.4-V power supply, using a standard double-poly CMOS process.

Programming floating-gate circuits with UV-activated conductances

A programming technique for controlling the floating gates (FGs) in ultra-low-voltage (ULV) floating-gate circuits is presented. Simple ULV PG current-scaling and level-shifting circuits are discussed. The current scaling and level shifting are accomplished using only minimum sized transistors and floating capacitors. Floating-gate current multiplier and divider circuits are described. Measured results are provided,.

Ultra-low-voltage floating-gate transconductance amplifiers

Ultra-low-voltage (ULV) floating-gate differential amplifiers are presented. In this paper, we present several different approaches to CMOS ULV amplifier design. Sinh-shaped and tanh-shaped transconductance amplifiers are described. Measured results are provided.

CTBV Integrated Impulse Radio Design for Biomedical Applications

Improving quality of service in wireless communication links is of vital importance in biomedical applications. Limitations of current technology are evident with a limited number of channels and prone to fading. In this paper, we are exploring impulse radio as a feasible technology for health monitoring and even as novel detached sensors. By exploring advanced deep submicron technology and novel architectures, improved quality of service may be granted. Additional interesting biomedical functionality of the impulse radio is detached body sensors (short-range medical radar).

Delta-sigma converters using frequency-modulated intermediate values

This paper describes a new first and second-order delta-sigma modulator (DSM) concept where the first integrator is extracted and implemented by a FM oscillator with the modulating signal as the input. The result is a simple DSM with no need for DACs, allowing straightforward multi-bit quantization. Without the FM oscillator, the modulator becomes a F/D converter with delta-sigma noise shaping.

Physical Working Principles of Medical Radar

There has been research interest in using radar for contactless measurements of the human heartbeat for several years. While many systems have been demonstrated, not much attention have been given to the actual physical causes of why this work. The consensus seems to be that the radar senses small body movements correlated with heartbeats, but whether only the movements of the body surface or reflections from internal organs are also monitored have not been answered definitely. There has recently been proposed another theory that blood perfusion in the skin could be the main reason radars are able to detect heartbeats. In this paper, an experimental approach is given to determine the physical causes. The measurement results show that it is the body surface reflections that dominate radar measurements of human heartbeats.

A Sub-

A new current-mode bandgap reference circuit (BGR) which is capable of generating sub-1-V output voltage is presented. It has not only the lowest theoretical minimum current consumption among published current-mode BGRs, but also additional advantages of an inherent curvature-compensation function and not requiring NPN BJTs. The curvature-compensation is achieved by utilizing the exponential behavior of sub-threshold CMOS transistors to compensate the BJT base-emitter voltage high-order temperature dependence. By taking advantages of the continuing development of CMOS technology, sub- μW power consumption is achieved with a reasonable core area. Related design considerations and challenges are discussed and analyzed. The proposed BGR is realized in a TSMC 90 nm process. Measurement results shows a temperature coefficient without trimming as low as 10.1 ppm/°C over a temperature range of 70 °C because of the proposed curvature-compensation technique. The average value is 32.6 ppm/°C which could be improved by trimming resistor ratios. The average power consumption at room temperature is 576 nW, with a core area of only 0.028 mm2.

\mu{\rm W}

An analog continuous-time neural network with on-chip learning is presented. The 4-3-2 feed-forward network with a modified back-propagation learning scheme was build using micropower building blocks in a double poly, double metal 2μ CMOS process. The weights are stored in non-volatile UV-light programmable analog floating gate memories. A differential signal representation is used to design simple building blocks which may be utilized to build very large neural networks. Measured results from on-chip learning are shown and an example of generalization is demonstrated. The use of micro-power building blocks allows very large networks to be implemented without significant power consumption.

Bandgap Reference Circuit With an Inherent Curvature-Compensation Property

An area efficient technique for tuning floating-gate circuits is described. The effective threshold voltage seen from a control gate can be programmed to virtually any value. The floating-gate transistor (FGMOS) may be used to implement low-power/low-voltage digital -and/or analog circuits.