Challenges involved in the use of capacitive sensors: an overview

Size: px
Start display at page:

Download "Challenges involved in the use of capacitive sensors: an overview"

Transcription

1 Challenges involved in the use of capacitive sensors: an overview Martin Jaiser Capacitive sensing is an attractive technology: a capacitive sensor is easy to understand, and relatively easy and cheap to manufacture compared to other technologies. Just by configuring two physical parameters the geometry of the plates and the characteristics of the dielectric the designer can produce a measurable signal. Parameters measured by capacitive sensing technology today include pressure, humidity, proximity and acceleration. In vehicles, fuel level, rain and seat occupancy sensors are also based on capacitive principles. And of course it is impossible to imagine a sophisticated consumer electronics device today without a capacitive touchscreen display. But unfortunately, for all the popularity of these sensors their use poses numerous problems for the designer to solve. Capacitive sensors are affected by temperature variations and by EMI Their operation may be impaired or distorted by environmental artefacts such as humidity or by contaminants such as dust and dirt When relatively precise measurement of variations in capacitance is required, their implementation is not easy. This article examines the traditional ways in which capactive sensing is implemented today, highlighting their advantages and drawbacks. It then introduces two new architectures from ams, and compares their operation to that of the traditional methods. 1. Traditional ways of measuring capacitance 1.1 Time-based principles: By far the most common method used today to measure capacitance is to measure time/frequency. Usually an unknown capacitance is used to modify an oscillator circuit: the change in the frequency may be converted into a measure of capacitance. Alternatively, the effect of a known impedance on the charge or discharge curve of an unknown capacitance may be measured. The easy way to measure capacitances in the pf range is to measure the time constant using a known impedance. The time constants will be in the region of a few µs, assuming that the user chooses to avoid using a noisy, high-impedance resistor. Measuring such small time constants precisely calls for the use of GHz clocks. If using a PLL circuit instead, it will have to have extremely low jitter, which means that it will be expensive. Page 1 / 9

2 The alternative to the impedance method is to use an oscillator circuit (see Figure 1): on the one hand this is easy to design with low-cost components; on the other, it has multiple sources of measurement error, because it is affected not only by changes in temperature but also in supply voltage. Fig. 1: the time-based principle of capacitance measurement 1.2 Charge-balancing method: The principle of the charge-balancing method is to transfer the charge of a fully charged, known capacitance to an unknown capacitance: then calculating the charge remaining in the known capacitance reveals the magnitude of the unknown capacitance (see Figure 2). At its simplest, this involves charging the known capacitance, and transferring the charge simply by connecting the known and the unknown capacitances together using a switch. It sounds simple but the devil is in the detail. First, the switch needs an input capacitance very much less than the value of the capacitance to be measured. When measuring capacitances in the pf range, such a switch is hard to implement. What is more, this input capacitance must be very stable over temperature. Second, the impedance of the amplifier used to measure the state of charge must be extremely high: even an amplifier with impedance of >1GΩ would add error to the measurement. Such impedance values might be achievable in a laboratory environment, but in the field, exposed to dust and humidity over potentially years of operation, an amplifier with such characteristics cannot realistically be found. Page 2 / 9

3 One exception should be mentioned: at the nanoscale, MEMS accelerometers use the principle of balancing capacitances to achieve very high measurement accuracy. Fig. 2: simplified circuit for implementing the charge-balancing method 1.3 Bridge circuits: This method uses a circuit very similar to a classic Wheatstone bridge circuit. Just like the Wheatstone bridge, it involves a comparison between two voltage dividers: a known path, and a path including the capacitance to be measured (see Figure 3). The difference between the two centre voltages is amplified and digitised. The supply to the bridge should be an AC voltage of an appropriate frequency. At the board level, this method for measuring capacitance is rarely used. This is because it calls for three equal capacitances, with limited tolerance for variance between the three. This is expensive to realise in practice. At the chip level, however, this is much easier to implement. Capacitances in the pf range are common and do not need to be realised exactly: the proportion must be known accurately, and the absolute value must be known once only, but it does not need to be trimmed to a specific value. In addition, since the on-chip capacitances have very similar temperature characteristics, the circuit s capacitance measurements are stable over temperature. Page 3 / 9

4 Fig 3: use of a bridge circuit for measuring an unknown capacitance 2.0 New ways of measuring capacitance 2.1 The Capacitance-to-Digital Converter: Technically speaking, the term capacitance-to-digital converter (CDC) can be applied to any converter using a modified charge-balancing or switched capacitor-input circuit. In practice, usually only sigma-delta converters are called CDCs. The CDC is an inversion of the usual charge-balancing circuit. Normally, a charge-balancing input stage has two known (usually equal) capacitances, and a known reference voltage. The aim is to measure a second, unknown voltage. The CDC does the opposite: it uses two known (usually equal) voltages and a reference capacitance, and measures the remaining (unknown) capacitance (see Figure 4). Page 4 / 9

5 Fig. 4: the input structure of a CDC It is best to start the explanation of the circuit at the input of the integrator. It is here that the charge values are compared. In order for the circuit to be able to sense capacitance variances, the input of the comparator needs to be zero on an average basis. This means that the comparator must switch the reference voltage as often into the upper part of the circuit as needed to compensate for the charge value in the lower part of the circuit. The more often this needs to be done, the higher the value of the measured capacitance. (This simple explanation ignores the considerable body of signal and filter theory underpinning the operation of a sigma-delta converter.) The advantage of this circuit is that it benefits from the high resolution and accuracy of sigma-delta converters, which are combined with relatively low speed. As the measured capacitance is connected to the virtual ground of the input of the integrator, there is no need to take account of any parasitic capacitances parallel to ground. In any case, jamming signals from outside the chip can often be suppressed by the large digital filters used in sigma-delta converters. Furthermore, the reference capacitance can usually be made in such a way that it has a similar temperature gradient to Page 5 / 9

6 that of the measured capacitance. In many ways, then, the CDC is able to provide accurate measurements of capacitance that are free of distortion or error. There is a problem with the CDC, however: it has no way to detect parallel low-impedance paths, which can appear over time as a result of environmental artefacts such as humidity or dirt. Such contaminants distort the device s measurements by discharging the capacitance while it is being measured. As a result, a portion of the charge does not reach the integrator, and so when environmental contamination occurs, the measured value of the capacitance ends up being lower than it should be. 2.2 The PICO-CAP method In south west Germany near the city of Karlsruhe is based a company named acam Messelektronik, a subsidiary of sensor and semiconductor manufacturer ams (Unterpremstätten, Austria, The speciality of acam is the ultra-precise time-to-digital converter, which uses a ring oscillator built from an odd number of digital inverters. The smallest measurable time constant of this ring oscillator is the delay of a single such inverter, enabling the device to operate at measurement frequencies of some 10GHz. (These on-chip high-frequency operations never reach the board level, where they could cause severe EMI/RFI problems.) Using an acam time-to-digital converter, the measurement of small capacitances in the pf range is a simple matter of measuring the discharge time, using the so called PICO-CAP method. To compensate for any temperature or process variations, the user can compare the measured discharge time with the discharge time of a reference capacitance built in the same process as the measured capacitance. Both measurements will use the chip s internal clock, so clocking variations attributable to temperature changes have no effect. But the PICO-CAP method also has other benefits. It can easily detect whether the measured capacitance is really connected, or whether there is an open wire or short circuit, since the charging of the capacitance is via a high impedance in the initial portion of the charging process (see Figure 5). The final portion is performed using the measurement impedance. By looking at the charging curve, the system can detect whether it is measuring a short circuit, an open wire or the proper capacitance. Fig. 5: how the PICO-CAP method charges a capacitance Page 6 / 9

7 To eliminate the distorting effect of parasitic capacitances, PICO-CAP provides a method for detecting and measuring their magnitude. Internal switches provide access to these parasitics, switching the measurement capacitance in a specific order, in both single ended and differential mode to ground and supply (see Figure 6). Fig. 6: internal switches enable the detection and compensation of parasitic capacitances The PICO-CAP method for measuring capacitance is fast, provides high resolution and accuracy, and is relatively easy for the system designer to implement. Having said this, there can be problems with large capacitances, which can cause the time-to-digital converter to capture large unwanted signals. The main measuring element is a comparator, and if this is saturated there is no filter after it able to calculate the real signal. This means that unwanted parallel conductances cannot be measured and detected. Fortunately there is a measurement principle that is able to handle this effect: the frequency demodulation method. 2.3 The frequency demodulation method: Many applications are exposed to considerable interference from external sources. Capacitive sensors are as described above very susceptible to such disturbance. The reason for this is that the plates of a capacitor tend to work as antennas for interfering signals. In certain applications, such as seat occupancy sensing, the measured capacitance is relatively small, while the area of the sensor plates is large. What is more, such sensors are exposed to environmental factors which do not affect the capacitance itself, but which build up a parallel conductance which affects the charging and discharging of the capacitance. Most measurement methods suffer from error when this occurs. Now ams has developed a method for handling these problems, to be implemented in a new series of standard products. The method is ready for testing with sample test chips. The chip generates a measurement frequency which is applied via an amplifier stage to the measured capacitance. The current is measured and filtered into a very narrow band using a high performance band-pass filter (see Figure 7). This filtering ensures that only the frequency ranges around Page 7 / 9

8 the excitation signal s frequency are measured; any interfering frequencies in other bands are simply ignored. After filtering the measurement signal, a synchronous demodulator splits it into phase and quadrature signals (I and Q). So the final result passed to the ADC is in phase with the voltage (resistive) and 90 out of phase (capacitive). Therefore the conductance not only does not distort the result of the capacitive measurement, it is also known. As a result, its value may be used in special applications. Fig. 7: block diagram of the frequency demodulation method The ams frequency demodulation method, then, not only suppresses any interfering conductance, but actually makes it measurable. In addition, interfering frequencies may be suppressed, or the measurement frequency may be changed to avoid interference on the frequency band in use. Furthermore, the ams chip features a separate terminal which provides a driver to any shield on the cables connected to the capacitance. By exciting it with the measurement signal, the ams chip can eliminate the effect of the supply cable s capacitance. This new method developed by ams suppresses external sources of capacitance extremely effectively: experiments with steering wheels, in which a capacitive sensor is used to detect the proximity of the driver s hands, were unaffected by switching current pulses of up to 10A (supplying a heater circuit). Page 8 / 9

9 The new frequency demodulation method, then, captures highly accurate measurements of small capacitance values, while providing very high immunity to the external sources of interference to which large capacitive sensors are inherently vulnerable. Summary Capacitive sensors are widely used in the electronics industry: they are cheap to make, easy to understand and their implementation is not especially problematic. Having said that, difficulties can arise when precise measurement of changes in capacitance is required, as the capacitance values of the sensor are normally small in the pf range. Providing precise, robust and repeatable results over years of operation in the field calls for a good understanding of the nature of the sensors and of the available methods of measuring capacitance. This article describes and compares six methods, some widely used and others newly developed. It discusses the benefits and drawbacks of the different measurement principles and provides insight into the problems each suffers from, and ways to solve them. It also provides hints about the implementation of direct measurement, and advice about parasitics and other potential sources of distortion. Biography Martin Jaiser gained his diploma in electronic engineering from the University of Karlsruhe. He then held several positions in sales and field applications engineering at Analog Devices, Rambus and Elmos. Since 2012, he has been working as a field applications engineer specializing in automotive applications at ams AG, with a particular focus on position sensing, inductive and capacitive sensing, and NFC. For further information ams AG Martin Jaiser Field Applications Engineer Tel: +43 (0) martin.jaiser@ams.com Page 9 / 9

MAS.836 HOW TO BIAS AN OP-AMP

MAS.836 HOW TO BIAS AN OP-AMP MAS.836 HOW TO BIAS AN OP-AMP Op-Amp Circuits: Bias, in an electronic circuit, describes the steady state operating characteristics with no signal being applied. In an op-amp circuit, the operating characteristic

More information

High Voltage Power Supplies for Analytical Instrumentation

High Voltage Power Supplies for Analytical Instrumentation ABSTRACT High Voltage Power Supplies for Analytical Instrumentation by Cliff Scapellati Power supply requirements for Analytical Instrumentation are as varied as the applications themselves. Power supply

More information

Programmable-Gain Transimpedance Amplifiers Maximize Dynamic Range in Spectroscopy Systems

Programmable-Gain Transimpedance Amplifiers Maximize Dynamic Range in Spectroscopy Systems Programmable-Gain Transimpedance Amplifiers Maximize Dynamic Range in Spectroscopy Systems PHOTODIODE VOLTAGE SHORT-CIRCUIT PHOTODIODE SHORT- CIRCUIT VOLTAGE 0mV DARK ark By Luis Orozco Introduction Precision

More information

EMI and t Layout Fundamentals for Switched-Mode Circuits

EMI and t Layout Fundamentals for Switched-Mode Circuits v sg (t) (t) DT s V pp = n - 1 2 V pp V g n V T s t EE core insulation primary return secondary return Supplementary notes on EMI and t Layout Fundamentals for Switched-Mode Circuits secondary primary

More information

Digital to Analog Converter. Raghu Tumati

Digital to Analog Converter. Raghu Tumati Digital to Analog Converter Raghu Tumati May 11, 2006 Contents 1) Introduction............................... 3 2) DAC types................................... 4 3) DAC Presented.............................

More information

1. Oscilloscope is basically a graph-displaying device-it draws a graph of an electrical signal.

1. Oscilloscope is basically a graph-displaying device-it draws a graph of an electrical signal. CHAPTER 3: OSCILLOSCOPE AND SIGNAL GENERATOR 3.1 Introduction to oscilloscope 1. Oscilloscope is basically a graph-displaying device-it draws a graph of an electrical signal. 2. The graph show signal change

More information

Laboratory 4: Feedback and Compensation

Laboratory 4: Feedback and Compensation Laboratory 4: Feedback and Compensation To be performed during Week 9 (Oct. 20-24) and Week 10 (Oct. 27-31) Due Week 11 (Nov. 3-7) 1 Pre-Lab This Pre-Lab should be completed before attending your regular

More information

Tire pressure monitoring

Tire pressure monitoring Application Note AN601 Tire pressure monitoring 1 Purpose This document is intended to give hints on how to use the Intersema pressure sensors in a low cost tire pressure monitoring system (TPMS). 2 Introduction

More information

STF201-22 & STF201-30

STF201-22 & STF201-30 Description The STF201 is a combination EMI filter and line termination device with integrated TVS diodes for use on downstream USB ports. It is constructed using a proprietary technology that allows passive

More information

CAN Bus Transceivers Operate from 3.3V or 5V and Withstand ±60V Faults

CAN Bus Transceivers Operate from 3.3V or 5V and Withstand ±60V Faults CAN Bus Transceivers Operate from 3.3V or 5V and Withstand ±6 Faults Ciaran Brennan design features The LTC2875 is a robust CAN bus transceiver that features ±6 overvoltage and ±25kV ESD tolerance to reduce

More information

DIGITAL-TO-ANALOGUE AND ANALOGUE-TO-DIGITAL CONVERSION

DIGITAL-TO-ANALOGUE AND ANALOGUE-TO-DIGITAL CONVERSION DIGITAL-TO-ANALOGUE AND ANALOGUE-TO-DIGITAL CONVERSION Introduction The outputs from sensors and communications receivers are analogue signals that have continuously varying amplitudes. In many systems

More information

Microcontroller to Sensor Interfacing Techniques

Microcontroller to Sensor Interfacing Techniques to Sensor Interfacing Techniques Document Revision: 1.01 Date: 3rd February, 2006 16301 Blue Ridge Road, Missouri City, Texas 77489 Telephone: 1-713-283-9970 Fax: 1-281-416-2806 E-mail: info@bipom.com

More information

Measuring Temperature withthermistors a Tutorial David Potter

Measuring Temperature withthermistors a Tutorial David Potter NATIONAL INSTRUMENTS The Software is the Instrument Application Note 065 Measuring Temperature withthermistors a Tutorial David Potter Introduction Thermistors are thermally sensitive resistors used in

More information

DDX 7000 & 8003. Digital Partial Discharge Detectors FEATURES APPLICATIONS

DDX 7000 & 8003. Digital Partial Discharge Detectors FEATURES APPLICATIONS DDX 7000 & 8003 Digital Partial Discharge Detectors The HAEFELY HIPOTRONICS DDX Digital Partial Discharge Detector offers the high accuracy and flexibility of digital technology, plus the real-time display

More information

Chapter 6: From Digital-to-Analog and Back Again

Chapter 6: From Digital-to-Analog and Back Again Chapter 6: From Digital-to-Analog and Back Again Overview Often the information you want to capture in an experiment originates in the laboratory as an analog voltage or a current. Sometimes you want to

More information

W a d i a D i g i t a l

W a d i a D i g i t a l Wadia Decoding Computer Overview A Definition What is a Decoding Computer? The Wadia Decoding Computer is a small form factor digital-to-analog converter with digital pre-amplifier capabilities. It is

More information

Impedance Matching and Matching Networks. Valentin Todorow, December, 2009

Impedance Matching and Matching Networks. Valentin Todorow, December, 2009 Impedance Matching and Matching Networks Valentin Todorow, December, 2009 RF for Plasma Processing - Definition of RF What is RF? The IEEE Standard Dictionary of Electrical and Electronics Terms defines

More information

An extended EMC study of an electrical powertrain for transportation systems

An extended EMC study of an electrical powertrain for transportation systems European Association for the Development of Renewable Energies, Environment and Power Quality (EA4EPQ) International Conference on Renewable Energies and Power Quality (ICREPQ 12) Santiago de Compostela

More information

Harmonics and Noise in Photovoltaic (PV) Inverter and the Mitigation Strategies

Harmonics and Noise in Photovoltaic (PV) Inverter and the Mitigation Strategies Soonwook Hong, Ph. D. Michael Zuercher Martinson Harmonics and Noise in Photovoltaic (PV) Inverter and the Mitigation Strategies 1. Introduction PV inverters use semiconductor devices to transform the

More information

Precision Analog Designs Demand Good PCB Layouts. John Wu

Precision Analog Designs Demand Good PCB Layouts. John Wu Precision Analog Designs Demand Good PCB Layouts John Wu Outline Enemies of Precision: Hidden components Noise Crosstalk Analog-to-Analog Digital-to-Analog EMI/RFI Poor Grounds Thermal Instability Leakage

More information

TDA4605 CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS

TDA4605 CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS Fold-Back Characteristic provides Overload Protection for External Diodes Burst Operation under Short-Circuit and no Load Conditions

More information

ICS514 LOCO PLL CLOCK GENERATOR. Description. Features. Block Diagram DATASHEET

ICS514 LOCO PLL CLOCK GENERATOR. Description. Features. Block Diagram DATASHEET DATASHEET ICS514 Description The ICS514 LOCO TM is the most cost effective way to generate a high-quality, high-frequency clock output from a 14.31818 MHz crystal or clock input. The name LOCO stands for

More information

Loop Bandwidth and Clock Data Recovery (CDR) in Oscilloscope Measurements. Application Note 1304-6

Loop Bandwidth and Clock Data Recovery (CDR) in Oscilloscope Measurements. Application Note 1304-6 Loop Bandwidth and Clock Data Recovery (CDR) in Oscilloscope Measurements Application Note 1304-6 Abstract Time domain measurements are only as accurate as the trigger signal used to acquire them. Often

More information

Buffer Op Amp to ADC Circuit Collection

Buffer Op Amp to ADC Circuit Collection Application Report SLOA098 March 2002 Buffer Op Amp to ADC Circuit Collection Bruce Carter High Performance Linear Products ABSTRACT This document describes various techniques that interface buffer op

More information

CONDUCTED EMISSION MEASUREMENT OF A CELL PHONE PROCESSOR MODULE

CONDUCTED EMISSION MEASUREMENT OF A CELL PHONE PROCESSOR MODULE Progress In Electromagnetics esearch C, Vol. 42, 191 203, 2013 CONDUCTED EMISSION MEASUEMENT OF A CELL PHONE POCESSO MODULE Fayu Wan *, Junxiang Ge, and Mengxiang Qu Nanjing University of Information Science

More information

Simplifying System Design Using the CS4350 PLL DAC

Simplifying System Design Using the CS4350 PLL DAC Simplifying System Design Using the CS4350 PLL 1. INTRODUCTION Typical Digital to Analog Converters (s) require a high-speed Master Clock to clock their digital filters and modulators, as well as some

More information

EMI in Electric Vehicles

EMI in Electric Vehicles EMI in Electric Vehicles S. Guttowski, S. Weber, E. Hoene, W. John, H. Reichl Fraunhofer Institute for Reliability and Microintegration Gustav-Meyer-Allee 25, 13355 Berlin, Germany Phone: ++49(0)3046403144,

More information

Agilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy

Agilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy Agilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy Application Note RF & Microwave Spectrum Analyzers Table of Contents 3 3 4 4 5 7 8 8 13 13 14 16 16 Introduction Absolute versus relative

More information

Considering the effects of UPS operation with leading power factor loads

Considering the effects of UPS operation with leading power factor loads Considering the effects of UPS operation with leading power factor loads Over the past five years, a new generation of data processing and communications equipment has become prevalent in modern data centers

More information

Power Supplies. 1.0 Power Supply Basics. www.learnabout-electronics.org. Module

Power Supplies. 1.0 Power Supply Basics. www.learnabout-electronics.org. Module Module 1 www.learnabout-electronics.org Power Supplies 1.0 Power Supply Basics What you ll learn in Module 1 Section 1.0 Power Supply Basics. Basic functions of a power supply. Safety aspects of working

More information

Evaluating AC Current Sensor Options for Power Delivery Systems

Evaluating AC Current Sensor Options for Power Delivery Systems Evaluating AC Current Sensor Options for Power Delivery Systems State-of-the-art isolated ac current sensors based on CMOS technology can increase efficiency, performance and reliability compared to legacy

More information

White Paper: Electrical Ground Rules

White Paper: Electrical Ground Rules Acromag, Incorporated 30765 S Wixom Rd, Wixom, MI 48393 USA Tel: 248-295-0880 Fax: 248-624-9234 www.acromag.com White Paper: Electrical Ground Rules Best Practices for Grounding Your Electrical Equipment

More information

AVX EMI SOLUTIONS Ron Demcko, Fellow of AVX Corporation Chris Mello, Principal Engineer, AVX Corporation Brian Ward, Business Manager, AVX Corporation

AVX EMI SOLUTIONS Ron Demcko, Fellow of AVX Corporation Chris Mello, Principal Engineer, AVX Corporation Brian Ward, Business Manager, AVX Corporation AVX EMI SOLUTIONS Ron Demcko, Fellow of AVX Corporation Chris Mello, Principal Engineer, AVX Corporation Brian Ward, Business Manager, AVX Corporation Abstract EMC compatibility is becoming a key design

More information

Application Note 58 Crystal Considerations for Dallas Real-Time Clocks

Application Note 58 Crystal Considerations for Dallas Real-Time Clocks www.maxim-ic.com Application Note 58 Crystal Considerations for Dallas Real-Time Clocks OVERVIEW This application note describes crystal selection and layout techniques for connecting a 32,768Hz crystal

More information

TLI4946. Datasheet TLI4946K, TLI4946-2K, TLI4946-2L. Sense and Control. May 2009

TLI4946. Datasheet TLI4946K, TLI4946-2K, TLI4946-2L. Sense and Control. May 2009 May 2009 TLI4946 High Precision Hall Effect Latches for Industrial and Consumer Applications TLI4946K, TLI4946-2K, TLI4946-2L Datasheet Rev. 1.0 Sense and Control Edition 2009-05-04 Published by Infineon

More information

The Do s and Don ts of Pressure Transducers

The Do s and Don ts of Pressure Transducers The Do s and Don ts of Pressure Transducers ABSTRACT When specifying a pressure transducer for a process measurement, a number of items have to be considered. Some of the more important ones are discussed

More information

Common Mode Choke Filtering Improves CMRR in Ethernet Transformer Applications. Application Note. June 2011

Common Mode Choke Filtering Improves CMRR in Ethernet Transformer Applications. Application Note. June 2011 Common Mode Choke Filtering Improves CMRR in Ethernet Transformer Applications June 2011 Application Note Common mode chokes provide an effective EMI filtering solution for Ethernet transformer applications.

More information

Pressure Transducer to ADC Application

Pressure Transducer to ADC Application Application Report SLOA05 October 2000 Pressure Transducer to ADC Application John Bishop ABSTRACT Advanced Analog Products/OpAmp Applications A range of bridgetype transducers can measure numerous process

More information

CHAPTER 2B: DIODE AND APPLICATIONS. D.Wilcher

CHAPTER 2B: DIODE AND APPLICATIONS. D.Wilcher CHAPTER 2B: DIODE AND APPLICATIONS D.Wilcher 1 CHAPTER 2B: OBJECTIVES Analyze the operation of 3 basic types of rectifiers Describe the operation of rectifier filters and IC regulators Analyze the operation

More information

Application Note 58 Crystal Considerations with Dallas Real Time Clocks

Application Note 58 Crystal Considerations with Dallas Real Time Clocks www.dalsemi.com Application Note 58 Crystal Considerations with Dallas Real Time Clocks Dallas Semiconductor offers a variety of real time clocks (RTCs). The majority of these are available either as integrated

More information

4 SENSORS. Example. A force of 1 N is exerted on a PZT5A disc of diameter 10 mm and thickness 1 mm. The resulting mechanical stress is:

4 SENSORS. Example. A force of 1 N is exerted on a PZT5A disc of diameter 10 mm and thickness 1 mm. The resulting mechanical stress is: 4 SENSORS The modern technical world demands the availability of sensors to measure and convert a variety of physical quantities into electrical signals. These signals can then be fed into data processing

More information

Programmable Single-/Dual-/Triple- Tone Gong SAE 800

Programmable Single-/Dual-/Triple- Tone Gong SAE 800 Programmable Single-/Dual-/Triple- Tone Gong Preliminary Data SAE 800 Bipolar IC Features Supply voltage range 2.8 V to 18 V Few external components (no electrolytic capacitor) 1 tone, 2 tones, 3 tones

More information

Supply voltage Supervisor TL77xx Series. Author: Eilhard Haseloff

Supply voltage Supervisor TL77xx Series. Author: Eilhard Haseloff Supply voltage Supervisor TL77xx Series Author: Eilhard Haseloff Literature Number: SLVAE04 March 1997 i IMPORTANT NOTICE Texas Instruments (TI) reserves the right to make changes to its products or to

More information

1+1 PROTECTION WITHOUT RELAYS USING IDT82V2044/48/48L & IDT82V2054/58/58L HITLESS PROTECTION SWITCHING

1+1 PROTECTION WITHOUT RELAYS USING IDT82V2044/48/48L & IDT82V2054/58/58L HITLESS PROTECTION SWITCHING 1+1 PROTECTION WITHOUT RELAYS USING IDT82V2044/48/48L & IDT82V2054/58/58L APPLICATION NOTE AN-357 1.0 INTRODUCTION In today's highly competitive market, high quality of service, QOS, and reliability is

More information

Solar Energy Conversion using MIAC. by Tharowat Mohamed Ali, May 2011

Solar Energy Conversion using MIAC. by Tharowat Mohamed Ali, May 2011 Solar Energy Conversion using MIAC by Tharowat Mohamed Ali, May 2011 Abstract This work introduces an approach to the design of a boost converter for a photovoltaic (PV) system using the MIAC. The converter

More information

Transmission Line Terminations It s The End That Counts!

Transmission Line Terminations It s The End That Counts! In previous articles 1 I have pointed out that signals propagating down a trace reflect off the far end and travel back toward the source. These reflections can cause noise, and therefore signal integrity

More information

LM118/LM218/LM318 Operational Amplifiers

LM118/LM218/LM318 Operational Amplifiers LM118/LM218/LM318 Operational Amplifiers General Description The LM118 series are precision high speed operational amplifiers designed for applications requiring wide bandwidth and high slew rate. They

More information

Measuring Insulation Resistance of Capacitors

Measuring Insulation Resistance of Capacitors Application Note Measuring Insulation Resistance of Capacitors A common use of high resistance measuring instruments (often called megohmmeters or insulation resistance testers) is measuring the insulation

More information

Application Note, Rev.1.0, September 2008 TLE8366. Application Information. Automotive Power

Application Note, Rev.1.0, September 2008 TLE8366. Application Information. Automotive Power Application Note, Rev.1.0, September 2008 TLE8366 Automotive Power Table of Contents 1 Abstract...3 2 Introduction...3 3 Dimensioning the Output and Input Filter...4 3.1 Theory...4 3.2 Output Filter Capacitor(s)

More information

Signal Processing in So.ware and Electric Field Sensing

Signal Processing in So.ware and Electric Field Sensing Signal Processing in So.ware and Electric Field Sensing CSE 466: So.ware for Embedded Systems Winter 2009 B. Mayton University of Washington CSE & Intel Research SeaMle CSE

More information

1ED Compact A new high performance, cost efficient, high voltage gate driver IC family

1ED Compact A new high performance, cost efficient, high voltage gate driver IC family 1ED Compact A new high performance, cost efficient, high voltage gate driver IC family Heiko Rettinger, Infineon Technologies AG, Am Campeon 1-12, 85579 Neubiberg, Germany, heiko.rettinger@infineon.com

More information

MEASUREMENT SET-UP FOR TRAPS

MEASUREMENT SET-UP FOR TRAPS Completed on 26th of June, 2012 MEASUREMENT SET-UP FOR TRAPS AUTHOR: IW2FND Attolini Lucio Via XXV Aprile, 52/B 26037 San Giovanni in Croce (CR) - Italy iw2fnd@gmail.com Trappole_01_EN 1 1 DESCRIPTION...3

More information

Conducted EMI filter design for SMPS

Conducted EMI filter design for SMPS Conducted EMI filter design for Jukka-Pekka Sjöroos Helsinki University of Technology Power Electronics Laboratory Conducted EMI filter design for Introduction EMI in Common Mode(CM noise Differential

More information

application note The Measurement and Suppression of RF Interference from TDMA Phones GSM Cellular Introduction

application note The Measurement and Suppression of RF Interference from TDMA Phones GSM Cellular Introduction APPLICATION NOTE AN-3 The Measurement and Suppression of RF Interference from TDMA Phones Introduction While the recent explosion of mobile telephone usage has improved the quality of life for many in

More information

Cable Discharge Event

Cable Discharge Event Cable Discharge Event 1.0 Introduction The widespread use of electronic equipment in various environments exposes semiconductor devices to potentially destructive Electro Static Discharge (ESD). Semiconductor

More information

Vehicle data acquisition using CAN By Henning Olsson, OptimumG henning.olsson@optimumg.com

Vehicle data acquisition using CAN By Henning Olsson, OptimumG henning.olsson@optimumg.com Vehicle data acquisition using By Henning Olsson, OptimumG henning.olsson@optimumg.com Introduction: Data acquisition is one of the best tools to increase the understanding of vehicle behavior. One can

More information

Use and Application of Output Limiting Amplifiers (HFA1115, HFA1130, HFA1135)

Use and Application of Output Limiting Amplifiers (HFA1115, HFA1130, HFA1135) Use and Application of Output Limiting Amplifiers (HFA111, HFA110, HFA11) Application Note November 1996 AN96 Introduction Amplifiers with internal voltage clamps, also known as limiting amplifiers, have

More information

Digital Systems Ribbon Cables I CMPE 650. Ribbon Cables A ribbon cable is any cable having multiple conductors bound together in a flat, wide strip.

Digital Systems Ribbon Cables I CMPE 650. Ribbon Cables A ribbon cable is any cable having multiple conductors bound together in a flat, wide strip. Ribbon Cables A ribbon cable is any cable having multiple conductors bound together in a flat, wide strip. Each dielectric configuration has different high-frequency characteristics. All configurations

More information

SINGLE-SUPPLY OPERATION OF OPERATIONAL AMPLIFIERS

SINGLE-SUPPLY OPERATION OF OPERATIONAL AMPLIFIERS SINGLE-SUPPLY OPERATION OF OPERATIONAL AMPLIFIERS One of the most common applications questions on operational amplifiers concerns operation from a single supply voltage. Can the model OPAxyz be operated

More information

The front end of the receiver performs the frequency translation, channel selection and amplification of the signal.

The front end of the receiver performs the frequency translation, channel selection and amplification of the signal. Many receivers must be capable of handling a very wide range of signal powers at the input while still producing the correct output. This must be done in the presence of noise and interference which occasionally

More information

TIMING-DRIVEN PHYSICAL DESIGN FOR DIGITAL SYNCHRONOUS VLSI CIRCUITS USING RESONANT CLOCKING

TIMING-DRIVEN PHYSICAL DESIGN FOR DIGITAL SYNCHRONOUS VLSI CIRCUITS USING RESONANT CLOCKING TIMING-DRIVEN PHYSICAL DESIGN FOR DIGITAL SYNCHRONOUS VLSI CIRCUITS USING RESONANT CLOCKING BARIS TASKIN, JOHN WOOD, IVAN S. KOURTEV February 28, 2005 Research Objective Objective: Electronic design automation

More information

DDX 7000 & 8003. Digital Partial Discharge Detectors FEATURES APPLICATIONS

DDX 7000 & 8003. Digital Partial Discharge Detectors FEATURES APPLICATIONS DDX 7000 & 8003 Digital Partial Discharge Detectors The HAEFELY HIPOTRONICS DDX Digital Partial Discharge Detector offers the high accuracy and flexibility of digital technology, plus the real-time display

More information

BSNL TTA Question Paper-Instruments and Measurement Specialization 2007

BSNL TTA Question Paper-Instruments and Measurement Specialization 2007 BSNL TTA Question Paper-Instruments and Measurement Specialization 2007 (1) Instrument is a device for determining (a) the magnitude of a quantity (b) the physics of a variable (c) either of the above

More information

ARRL Morse Code Oscillator, How It Works By: Mark Spencer, WA8SME

ARRL Morse Code Oscillator, How It Works By: Mark Spencer, WA8SME The national association for AMATEUR RADIO ARRL Morse Code Oscillator, How It Works By: Mark Spencer, WA8SME This supplement is intended for use with the ARRL Morse Code Oscillator kit, sold separately.

More information

New High Current MOSFET Module Offers 177 µω R DS(on)

New High Current MOSFET Module Offers 177 µω R DS(on) ew High Current Offers 177 µω R D(on) By William C. Kephart, Eric R. Motto Application Engineering owerex Incorporated Abstract This paper describes a new family of high current modules optimized for industrial

More information

Cancellation of Load-Regulation in Low Drop-Out Regulators

Cancellation of Load-Regulation in Low Drop-Out Regulators Cancellation of Load-Regulation in Low Drop-Out Regulators Rajeev K. Dokania, Student Member, IEE and Gabriel A. Rincόn-Mora, Senior Member, IEEE Georgia Tech Analog Consortium Georgia Institute of Technology

More information

Operational Amplifier - IC 741

Operational Amplifier - IC 741 Operational Amplifier - IC 741 Tabish December 2005 Aim: To study the working of an 741 operational amplifier by conducting the following experiments: (a) Input bias current measurement (b) Input offset

More information

Case Studies in On-Line Measurement of PD in Motors Fed by Voltage Source PWM Drives

Case Studies in On-Line Measurement of PD in Motors Fed by Voltage Source PWM Drives Case Studies in On-Line Measurement of PD in Motors Fed by Voltage Source PWM Drives G.C. Stone, I. Culbert, H.G. Sedding Qualitrol-Iris Power Mississauga, Ontario, Canada Abstract On-line partial discharge

More information

Continuous-Time Converter Architectures for Integrated Audio Processors: By Brian Trotter, Cirrus Logic, Inc. September 2008

Continuous-Time Converter Architectures for Integrated Audio Processors: By Brian Trotter, Cirrus Logic, Inc. September 2008 Continuous-Time Converter Architectures for Integrated Audio Processors: By Brian Trotter, Cirrus Logic, Inc. September 2008 As consumer electronics devices continue to both decrease in size and increase

More information

REPORT ON CANDIDATES WORK IN THE CARIBBEAN ADVANCED PROFICIENCY EXAMINATION MAY/JUNE 2008 ELECTRICAL AND ELECTRONIC TECHNOLOGY (TRINIDAD AND TOBAGO)

REPORT ON CANDIDATES WORK IN THE CARIBBEAN ADVANCED PROFICIENCY EXAMINATION MAY/JUNE 2008 ELECTRICAL AND ELECTRONIC TECHNOLOGY (TRINIDAD AND TOBAGO) CARIBBEAN EXAMINATIONS COUNCIL REPORT ON CANDIDATES WORK IN THE CARIBBEAN ADVANCED PROFICIENCY EXAMINATION MAY/JUNE 2008 ELECTRICAL AND ELECTRONIC TECHNOLOGY (TRINIDAD AND TOBAGO) Copyright 2008 Caribbean

More information

Non-contact surface charge/voltage measurements Fieldmeter and voltmeter methods

Non-contact surface charge/voltage measurements Fieldmeter and voltmeter methods Dr. Maciej A. Noras Abstract Methods of measurements of surface electric charges and potentials using electrostatic fieldmeters and voltmeters are discussed. The differences and similarities between those

More information

Speed Control Methods of Various Types of Speed Control Motors. Kazuya SHIRAHATA

Speed Control Methods of Various Types of Speed Control Motors. Kazuya SHIRAHATA Speed Control Methods of Various Types of Speed Control Motors Kazuya SHIRAHATA Oriental Motor Co., Ltd. offers a wide variety of speed control motors. Our speed control motor packages include the motor,

More information

Op Amp Circuit Collection

Op Amp Circuit Collection Op Amp Circuit Collection Note: National Semiconductor recommends replacing 2N2920 and 2N3728 matched pairs with LM394 in all application circuits. Section 1 Basic Circuits Inverting Amplifier Difference

More information

THE STRAIN GAGE PRESSURE TRANSDUCER

THE STRAIN GAGE PRESSURE TRANSDUCER THE STRAIN GAGE PRESSURE TRANSDUCER Pressure transducers use a variety of sensing devices to provide an electrical output proportional to applied pressure. The sensing device employed in the transducers

More information

A PC-BASED TIME INTERVAL COUNTER WITH 200 PS RESOLUTION

A PC-BASED TIME INTERVAL COUNTER WITH 200 PS RESOLUTION 35'th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting San Diego, December 2-4, 2003 A PC-BASED TIME INTERVAL COUNTER WITH 200 PS RESOLUTION Józef Kalisz and Ryszard Szplet

More information

Optimised For Audio Analogue PCB design for the digital era.

Optimised For Audio Analogue PCB design for the digital era. Optimised For Audio Analogue PCB design for the digital era. David G. Tyas IKON AVS Ltd, 238 Ikon Estate, Hartlebury, Worcs.. DY10 4EU www.ikonavs.com 1. Introduction With increasing emphasis on digital

More information

Isolated AC Sine Wave Input 3B42 / 3B43 / 3B44 FEATURES APPLICATIONS PRODUCT OVERVIEW FUNCTIONAL BLOCK DIAGRAM

Isolated AC Sine Wave Input 3B42 / 3B43 / 3B44 FEATURES APPLICATIONS PRODUCT OVERVIEW FUNCTIONAL BLOCK DIAGRAM Isolated AC Sine Wave Input 3B42 / 3B43 / 3B44 FEATURES AC averaging technique used to rectify, amplify, and filter 50 Hz to 400 Hz sine-wave signals. Accepts inputs of between 20 mv to 550 V rms to give

More information

AC/DC Power Supply Reference Design. Advanced SMPS Applications using the dspic DSC SMPS Family

AC/DC Power Supply Reference Design. Advanced SMPS Applications using the dspic DSC SMPS Family AC/DC Power Supply Reference Design Advanced SMPS Applications using the dspic DSC SMPS Family dspic30f SMPS Family Excellent for Digital Power Conversion Internal hi-res PWM Internal high speed ADC Internal

More information

Experiment1: Introduction to laboratory equipment and basic components.

Experiment1: Introduction to laboratory equipment and basic components. Experiment1: Introduction to laboratory equipment and basic components. 1 OBJECTIVES. This experiment will provide exposure to the various test equipment to be used in subsequent experiments. A primary

More information

Electronics for Analog Signal Processing - II Prof. K. Radhakrishna Rao Department of Electrical Engineering Indian Institute of Technology Madras

Electronics for Analog Signal Processing - II Prof. K. Radhakrishna Rao Department of Electrical Engineering Indian Institute of Technology Madras Electronics for Analog Signal Processing - II Prof. K. Radhakrishna Rao Department of Electrical Engineering Indian Institute of Technology Madras Lecture - 18 Wideband (Video) Amplifiers In the last class,

More information

Design and Applications of HCPL-3020 and HCPL-0302 Gate Drive Optocouplers

Design and Applications of HCPL-3020 and HCPL-0302 Gate Drive Optocouplers Design and Applications of HCPL-00 and HCPL-00 Gate Drive Optocouplers Application Note 00 Introduction The HCPL-00 (DIP-) and HCPL-00 (SO-) consist of GaAsP LED optically coupled to an integrated circuit

More information

Note monitors controlled by analog signals CRT monitors are controlled by analog voltage. i. e. the level of analog signal delivered through the

Note monitors controlled by analog signals CRT monitors are controlled by analog voltage. i. e. the level of analog signal delivered through the DVI Interface The outline: The reasons for digital interface of a monitor the transfer from VGA to DVI. DVI v. analog interface. The principles of LCD control through DVI interface. The link between DVI

More information

NTE2053 Integrated Circuit 8 Bit MPU Compatible A/D Converter

NTE2053 Integrated Circuit 8 Bit MPU Compatible A/D Converter NTE2053 Integrated Circuit 8 Bit MPU Compatible A/D Converter Description: The NTE2053 is a CMOS 8 bit successive approximation Analog to Digital converter in a 20 Lead DIP type package which uses a differential

More information

GT Sensors Precision Gear Tooth and Encoder Sensors

GT Sensors Precision Gear Tooth and Encoder Sensors GT Sensors Precision Gear Tooth and Encoder Sensors NVE s GT Sensor products are based on a Low Hysteresis GMR sensor material and are designed for use in industrial speed applications where magnetic detection

More information

Line Reactors and AC Drives

Line Reactors and AC Drives Line Reactors and AC Drives Rockwell Automation Mequon Wisconsin Quite often, line and load reactors are installed on AC drives without a solid understanding of why or what the positive and negative consequences

More information

Precision Diode Rectifiers

Precision Diode Rectifiers by Kenneth A. Kuhn March 21, 2013 Precision half-wave rectifiers An operational amplifier can be used to linearize a non-linear function such as the transfer function of a semiconductor diode. The classic

More information

Crosstalk effects of shielded twisted pairs

Crosstalk effects of shielded twisted pairs This article deals with the modeling and simulation of shielded twisted pairs with CST CABLE STUDIO. The quality of braided shields is investigated with respect to perfect solid shields. Crosstalk effects

More information

ICS379. Quad PLL with VCXO Quick Turn Clock. Description. Features. Block Diagram

ICS379. Quad PLL with VCXO Quick Turn Clock. Description. Features. Block Diagram Quad PLL with VCXO Quick Turn Clock Description The ICS379 QTClock TM generates up to 9 high quality, high frequency clock outputs including a reference from a low frequency pullable crystal. It is designed

More information

LM 358 Op Amp. If you have small signals and need a more useful reading we could amplify it using the op amp, this is commonly used in sensors.

LM 358 Op Amp. If you have small signals and need a more useful reading we could amplify it using the op amp, this is commonly used in sensors. LM 358 Op Amp S k i l l L e v e l : I n t e r m e d i a t e OVERVIEW The LM 358 is a duel single supply operational amplifier. As it is a single supply it eliminates the need for a duel power supply, thus

More information

Zero voltage drop synthetic rectifier

Zero voltage drop synthetic rectifier Zero voltage drop synthetic rectifier Vratislav Michal Brno University of Technology, Dpt of Theoretical and Experimental Electrical Engineering Kolejní 4/2904, 612 00 Brno Czech Republic vratislav.michal@gmail.com,

More information

Signal Types and Terminations

Signal Types and Terminations Helping Customers Innovate, Improve & Grow Application Note Signal Types and Terminations Introduction., H, LV, Sinewave, Clipped Sinewave, TTL, PECL,,, CML Oscillators and frequency control devices come

More information

Failure code manual. content

Failure code manual. content Failure code manual content 一 wall split AC series 2 二 floor standing AC series. 4 三 portable AC series.. 5 四 dehumidifer 6 五 DC inverter single split series...7 六 DC inverter multi-split series 10 1 一

More information

TESTS OF 1 MHZ SIGNAL SOURCE FOR SPECTRUM ANALYZER CALIBRATION 7/8/08 Sam Wetterlin

TESTS OF 1 MHZ SIGNAL SOURCE FOR SPECTRUM ANALYZER CALIBRATION 7/8/08 Sam Wetterlin TESTS OF 1 MHZ SIGNAL SOURCE FOR SPECTRUM ANALYZER CALIBRATION 7/8/08 Sam Wetterlin (Updated 7/19/08 to delete sine wave output) I constructed the 1 MHz square wave generator shown in the Appendix. This

More information

AN ISOLATED GATE DRIVE FOR POWER MOSFETs AND IGBTs

AN ISOLATED GATE DRIVE FOR POWER MOSFETs AND IGBTs APPLICATION NOTE AN ISOLATED GATE DRIVE FOR POWER MOSFETs AND IGBTs by J.M. Bourgeois ABSTRACT Power MOSFET and IGBT gate drives often face isolation and high voltage constraints. The gate drive described

More information

Chapter 6 PLL and Clock Generator

Chapter 6 PLL and Clock Generator Chapter 6 PLL and Clock Generator The DSP56300 core features a Phase Locked Loop (PLL) clock generator in its central processing module. The PLL allows the processor to operate at a high internal clock

More information

HITACHI INVERTER SJ/L100/300 SERIES PID CONTROL USERS GUIDE

HITACHI INVERTER SJ/L100/300 SERIES PID CONTROL USERS GUIDE HITACHI INVERTER SJ/L1/3 SERIES PID CONTROL USERS GUIDE After reading this manual, keep it for future reference Hitachi America, Ltd. HAL1PID CONTENTS 1. OVERVIEW 3 2. PID CONTROL ON SJ1/L1 INVERTERS 3

More information

Touch Screen Technology. Taking apart a tablet

Touch Screen Technology. Taking apart a tablet Touch Screen Technology Topics covered: 1) Resistance, Capacitance, Charge, Voltage, and Current 2) Introduction to simple circuits Taking apart a tablet For example, an ipad2 Touchscreen Motherboard Lots

More information

Subminiature Load Cell Model 8417

Subminiature Load Cell Model 8417 w Technical Product Information Subminiature Load Cell 1. Introduction... 2 2. Preparing for use... 2 2.1 Unpacking... 2 2.2 Using the instrument for the first time... 2 2.3 Grounding and potential connection...

More information

White Paper: DC Resistance Unbalance Testing: Easy, Low-Cost Insurance for Your PoE Systems

White Paper: DC Resistance Unbalance Testing: Easy, Low-Cost Insurance for Your PoE Systems White Paper: DC Resistance Unbalance Testing: Easy, Low-Cost Insurance for Your PoE Systems Originally ratified by IEEE in 1999 and 2003 respectively, gigabit Ethernet (1000BASE-T) and power over Ethernet

More information

AppNote 404 EM MICROELECTRONIC - MARIN SA. EM4095 Application Note RFID. Title: Product Family: TABLE OF CONTENT. Application Note 404

AppNote 404 EM MICROELECTRONIC - MARIN SA. EM4095 Application Note RFID. Title: Product Family: TABLE OF CONTENT. Application Note 404 EM MICROELECTRONIC - MARIN SA AppNote 0 Title: Product Family: Application Note 0 EM095 Application Note RFID Part Number: EM095 Keywords: RFID Transceiver, Reader Chip, EM095 Date: 5 September 00 TABLE

More information