Parasitic capacitance

About: Parasitic capacitance is a research topic. Over the lifetime, 10029 publications have been published within this topic receiving 110331 citations.

Design Considerations for Very High Frequency dc-dc Converters

Abstract: This document describes several aspects relating to the design of dc-dc converters operating at frequencies in the VHF range (30–300 MHz). Design considerations are treated in the context of a dc-dc converter operating at a switching frequency of 100 MHz. Gate drive, rectifier and control designs are explored in detail, and experimental measurements of the complete converter are presented that verify the design approach. The gate drive, a self-oscillating multi-resonant circuit, dramatically reduces the gating power while ensuring fast on-off transitions of the semiconductor switch. The rectifier is a resonant topology that absorbs diode parasitic capacitance and is designed to appear resistive at the switching frequency. The small sizes of the energy storage elements (inductors and capacitors) in this circuit permit rapid start-up and shut-down and a correspondingly high control bandwidth. These characteristics are exploited in a high bandwidth hysteretic control scheme that modulates the converter on and off at frequencies as high as 200 kHz.

A robust, low-cost and low-noise artificial skin for human-friendly robots

Abstract: As robots and humans move towards sharing the same environment, the need for safety in robotic systems is of growing importance. Towards this goal of human-friendly robotics, a robust, low-cost, low-noise capacitive force sensing array is presented with application as a whole body artificial skin covering. This highly scalable design provides excellent noise immunity, low-hysteresis, and has the potential to be made flexible and formable. Noise immunity is accomplished through the use of shielding and local sensor processing. A small and low-cost multivibrator circuit is replicated locally at each taxel, minimizing stray capacitance and noise coupling. Each circuit has a digital pulse train output, which allows robust signal transmission in noisy electrical environments. Wire count is minimized through serial or row-column addressing schemes, and the use of an open-drain output on each taxel allows hundreds of sensors to require only a single output wire. With a small set of interface wires, large arrays can be scanned hundreds of times per second and dynamic response remains flat over a broad frequency range. Sensor performance is evaluated on a bench-top version of a 4×4 taxel array in quasi-static and dynamic cases.

A post-CMOS micromachined lateral accelerometer

Abstract: In a post-complementary metal-oxide-semiconductor (CMOS) micromachining technology, the process flow enables the integration of micromechanical structures with conventional CMOS circuits which are low-cost and readily available. This paper presents a lateral capacitive sensing accelerometer fabricated in the post-CMOS process. Design advantages include electrically isolated multimetal routing on microstructures to create full-bridge capacitive sensors, and integration to increase transducer sensitivity by minimizing parasitic capacitance. In a size of 350 /spl mu/m by 500 /spl mu/m, this accelerometer has a 1 mG//spl radic/(Hz) resolution and a linear range of at least /spl plusmn/13 G. The fundamental limitations of mechanical and electronic noise for acceleration sensing are addressed.

Methods and apparatus for control of inductively coupled power transfer systems

Abstract: A power pick-up for an Inductively Coupled Power Transfer (ICPT) system is provided having a resonant pick up circuit. The natural frequency of the pick-up circuit may be varied by controlling the conductance or capacitance of a variable reactive in the resonant circuit. The load being supplied by the pick-up circuit is sensed, and the effective capacitance or inductance of the variable reactive component is controlled to vary the natural resonant frequency of the pick-up circuit to thereby control the power flow into the pick-up to satisfy the power required by the load.

Dc/dc converter switching at zero voltage

Abstract: A two switch, DC/DC converter provides sufficient inductive energy storage at the termination of the "on" period of each switch to alter the charge on the intrinsic and stray capacitance of the combination of switches producing zero voltage across the alternate switch prior to its turn on. A short dead-band between the turn on pulses provided by the control circuit allows time for this transition. Thus the energy stored in the capacitance of the switches is returned to the source and load rather than being dissipated in the switching devices. This greatly improves the efficiency of the converter particularly when operating at high frequency. The unique topology of the converter provides other new and useful characteristics in addition to zero voltage switching capability such as operation as constant frequency with pulse-width-modulation for regulation, quasi-square wave output current, and the ability to integrate the magnetic elements with or without coupling.