Current Measurement Applications Handbook

Zetex Plc

Description

Current Measurement Applications Handbook Contents Page No. Introduction 2 Chapter 1: Resistive DC current measurement 3 Chapter 2: Zetex ZXCT product description 9 Chapter 3: ZXCT application notes 10 Chapter 4: Magnetic AC and DC current measurement 20 Chapter 5: Zetex ZMC product description 24 Chapter 6: ZMC application notes 25 AN39 - 1 SEMICONDUCTORS ISSUE 4 - FEBRUARY 2004 Application Note 39

• resistive dc


• high-side measurement


• inter-circuit offsets


• current measurement


• low- medium


• page no


• high yes

Informations

• Publié par: pefav
• Nombre de lectures: 12
• Langue: English

Extrait

Application Note 39

Current Measurement Applications Handbook

Introduction

Contents

Chapter 1: Resistive DC current measurement

Chapter 2: Zetex ZXCT product description

Chapter 3: ZXCT application notes

Chapter 4: Magnetic AC and DC current measurement

Chapter 5: Zetex ZMC product description

Chapter 6: ZMC application notes

ISSU E 4 - FEBRUARY 2004

AN39 - 1

Page No.

2

3

9

10

20

24

25

S E M I C O N D U C T O R S

Application Note 39

Introduction Currentmeasurementwithinelectronic 1) e El q e u c i t p r m on e i n c t f o u n se d s i , s i t n ri t b e u r t n e a d lf p a o ul w t e li r m s i y ti s n te gi m n s. circuitry is a common requirement in portable, handheld equipment, through to automotive  2) Auto shutdown functions for DC motor applications. This application handbook  control (replacing slipping mechanical explores these factors for AC and DC current  clutches). measurement and the implications on cost and performance for different approaches. BasicOpen loop systems application topologies are explored including typical example calculations for configuration.  tienrrCuresueasm some e forrsysothe amedaddnallbvaia esstllylusuatem,mie Basic application types critical. 1) Current measurement in instrumentation Closed loop systems (bench power supplies, ammeters, current •  probes). Current is measured and is modified to a reference value by some control element. ACresponsecanbecriticalhere. 2)P ci o rc w u e i r try c , on es s p u e m ci p a t l i l o y n po m rt e a a b s le ur b e a m tt e e n r t y Examples include:  powered consumer items. 1) Switching power supplies with current limiting functions or switch mode battery ohtesusdde aFtcrotsahdtteerminethetypeof m charging circuits. 2) PWM control of solenoids (automotive  Magnitude of current valve applications).  The need for electrical isolation 3) RF transmit control loops in portable  Accuracy cellular equipment, where transmitted power is adapted with distance.  AC response 4) Control of bias currents in (RF) power  Cost amplifiers. Summary matrix of methods and  Current is compared to some preset value erpmrofecna and is switched off if exceeded. Examples include:  Figure 1 below shows the methods described in this handbook and a rough comparison between the most common factors found in current measuring application.

Figure 1 Matrix of common measurement methods

Type

Current Isolated range

Resistive V.low-high No Magnetic Med-v.high Yes r O e p s t is o t - i c v o e upled Med-highYes

S E M I C O N D U C T O R S

Accuracy AC response Non-intrusive Cost

- High h M i e g d h ium Medium Medium Low- Low- medium medium

AN39 - 2

No Yes No

Low- medium

High Low- medium

ISSU E 4 - FEBRUARY 2004