1.ADI的数字隔离器基础知识

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Isolated Power Transmission Diagram
The World Leader in High Performance Signal Processing Solutions
iCoupler Products
ISO Products
Multi-ch standard digital isolators
Wear

out Accelerated by:
Increased current Most are rated to 85C Higher Temperature ratings increase price and reduce speed
9
Chip-Scale Transformer Isolation
Photo
detector absorbs light and turns it into current Current Transfer Ratio (CTR) defines performance
8
Optocoupler CTR Affects Lifetime
LEDs
Ware out with Use Lower output current for the same input current
Wide

SO-16 Package
Insulation

thickness
Creepage 7.6mm Clearance >8mm
20um polyimide is acceptable for reinforced if tested
7.6mm
20um
Polyimide Isolation
®
The World Leader in High Performance Signal Processing Solutions
Digital Isolation Tips and Techniques
April 2012
Agenda
Isolation
background iCoupler technology background iCoupler & isoPower theory Features of iCoupler technology ADI isolation products and applications iCoupler products quality and reliability
standard for low-cost isolation
GaAs
or GaAlAs LEDs emit light when current passes through it
5-20mA
typically used Speed is directly correlated to current

IEC


(EU and ROW)
Basic Insulation
Insulation required to provide users protection from shock Single insulation system that is equal to double insulation by design and tested

1 Pulse / Second
50%
high-voltage pulse
10%
Simulating Lightning Strike SiO2 is brittle and cannot withstand >8 kV surges
4
1-2uS
50uS
Different Types of Isolation
Detect Data Edges
Encode as Pulses
Transfer Through Transformer
Decode Pulses
Reconstruct Data
Rising Edge
Falling Edge
Insulation: between coils and between substrates
Insulation required to provide users protection from shock
Single Insulation Double Insulation
Two independent single insulation systems applied to protect the same circuit iCouplers provide the equivalent to double insulation in a single system


Transformer and Package Provide Up To 5 kV rms Isolation
Direction of Isolation Barrier
Transformer Chip
iCoupler Technology Background
Polyimide Isolation
The World Leader in High Performance Signal Processing Solutions
iCoupler Technology Background
Optocoupler Technology
LED
Photodetector
Signal
The
isolator of choice for decades
Reinforced Insulation

5
Isolation Terminology Physical Dimensions

Clearance Shortest distance through the air between conductive parts Board limited by pads < package
3
Isolation Terminology
Working
Time Related Breakdown Ratings
Voltage
Withstand Voltage Measurement
60 sec Viso 1 sec 1.2 x Viso
Continuous
operation, AC or DC Voltage at which Insulation Lifetime is Specified Measure of long-term reliability

Creepage Shortest distance across a surface between conductive parts Package limitation is the end
Board and Package have Different Measurements When Combined the Minimum Sets the System Limit
2
The Isolation Function
Galvanic
Isolation – No Current Flow
Isolator
Point B
Information Flow No Current Flow Isolation Barrier Typical Application Characteristics High Voltage High-Precision Communications Long-Distance Communications
Functional


Insulation
Insulation required for a circuit to work
Separate Different Voltages Eliminate Ground loops Not safety related
UL


Rating (US, Japan)




Performance Integration Power Consumption Ease-of-Use Reliability
Magnetic Rather Than Optical Transmission
High-Fidelity Signal Transfer 10% Power Consumption No Wearout and Low Variation Over Time and Temperature Robust Isolation and High Common Mode Transient Immunity
Converters
ΣΔ Modulator
RS-232
isoPower
I2 C
2.5 kV rms 5 kV rms IEC 60601-1
USB
USB 2.0 12 Mbps
CAN
isoPower
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5kV Digital Isolator Certifications
ADI IEC60950 IEC60601 Medical VDE V 0884-10 VDE IEC60747-5-2
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Error Correction/Failsafe Circuitry

Glitch Filter

Reduces noise Blocks pulses that are too narrow for the transmitter

Transmit Refresh Circuitry


Receiver Watchdog Timer

Resend Data 1µs after the last change on input Ensures correct data state is transmitted every µs

If no pulse received within approximately 3µs, then output is set to default low Ensures safe output state, if transmitter is not functioning properly
Isolated gate driver
Half-bridge isoPower 4A Halfbridge
RS-485
Integrated transforme r driver Integrated isoPower half/full duplex 0.1 A Fullbridge
0.1A halfbidge
Point A
Why

Isolate?
Safety Communication with Unreferenced Electronics Elimination of Ground Loop Noise Fault Tolerance Confinement of Electrical Noise Ground Potential Differences
源自文库Encoder
Primary Windings
Polyimide Insulator
20µm
Decoder
Secondary Windings
Polyimide Strength ≥ 10 kVRMS insulation
(300VRMS/μm @ 20 μm)
Signal Transmission Operational Diagram
125 °C automotive AEC-Q100 ESD inhanced 5 kV medical IEC 606011
isoPower
Integrated DCDC converters Integrated PWM and transformer driver
High speed
1 kV
Small package
Withstand
Defining

Voltage
Surge Voltage Measurement
VIOSM
90%
Data Sheet Spec
1 kVrms, 2.5 kVrms, and 5kVrms 100% tested in production
Surge
Short-term