SlideShare a Scribd company logo
1 of 7
Download to read offline
• A very high frequency de-bounce on the power supply jack during insertion
Power Spikes Isolation to avoid corruption within sensitive ICs
By Avinash Babu, Sr. Architect, and Harshith Kasyap, Module Lead, Mistral Solutions Pvt. Ltd.
Introduction of spikes in systems during insertion of power supply jacks is observed in a majority of designs.
These spikes are mainly caused due to:
• Equalization of ground between power adapter and battery-powered system
In most cases, the ICs on the board don't respond to such events. This is because they are either not yet
powered by the board's main supply or they don't have sensitive electronics inside to react to it (in case of
battery-powered systems).
Some of the electronic circuits that are generally affected are,
• Circuits which monitor the power line for variation, to detect tamper
• Circuits constructed for secure transaction authorization needs, such as tamper detection capabilities.
The following case study explains the way we went about resolving a power spike issue that is not common. As
you will observe, the nature of the power spike in itself and the complexity of the design made the job tougher.
The case study highlights the step-by-step method we followed to isolate and resolve the issue and our learning
through this process.
• It was in the GHz frequency range
Case study: Corruption within ASIC designed for tamper detection
We came across a situation where an ASIC chip for generating a secure code and storing it in a battery-backed
RAM, was sensitive to these spikes. In fact, the function of the ASIC in the design was tamper detection, and
spike was one of the kinds of tamper being detected. It was a catch-22 situation for us. The built-in tamper
detection circuit was designed to detect excursions on its RAM supply and automatically erase the sensitive data
to protect unauthorized data access. During the insertion/removal of power jack to the boards, the battery-
backed RAM inside the on-board ASIC was getting corrupted as this was read as a tamper.
The system had two power sources: a Li-Ion battery and a 5V DC input through a standard wall power adapter.
The characteristic of the spike were as follows,
• It had peak-to-peak amplitude of around 25V
• It appeared on all the signals on the board
• It occurred at the moment of contact of the power adapter to the board power jack
• It had both positive and negative swing.
Figure 1 shows a snapshot of the spike.
Figure 1: Snapshot of the spike
What made the job tougher was that,
• The spike caused ground bounce, which induced the spike in-turn to appear on all the signal lines
throughout the board
• Due to the high frequency of the spike, it would jump layers on the PCB
• Use of decoupling capacitors that were placed very close to the battery, ferrite beads or FET switches
(and any solid state isolation device) on the input power and ground lines were not a solution mainly
because of the high frequency and energy of the spike
• If either supply or ground was isolated on the board, the spike would enter the board through capacitors
at the input
• It had both positive and negative swing. Had the swing been towards a single direction, it would have
been easier to address the issue.
Believing that the power adapter was not able to source enough power to the electronics on the board, we also
put in Mega Ohm resistors in the path of power. The presence of Mega ohm resistor steeply decreases the
current; thereby applying a minimal load on the adapter. Though the board doesn't power ON in this setup, the
purpose of this experiment was to determine if the spike was caused by loading the adapter or due to the
Power supply load or power jack insertions de-bounce
Initially we approached the problem with a simplistic view and changed the power adapter suspecting that the
adapter was not able to source enough power into the unit. We tried powering the unit using a battery as this is
considered more regulated. We also loaded the adapter using a resistor assuming that if there was a steady flow
of current, the power jack insertion will not introduce a sudden load to the power adapter and upset the DC/DC
functionality inside the adapter.
mechanical insertion of the power jack. We observed that the power spike reduced by 5V in amplitude but this
was not sufficient spike reduction.
Figure 2 shows a snap of the reduced spike.
Figure 2: Snapshot of the reduced spike
As a next step to using the Mega Ohm resistor, we placed an NTC resistor in the power path to offer high
resistance when the power was applied and slowly reduced the resistance to allow normal current flow. This only
reduced the amplitude of the power spike by 5V.
Doing all these experiments made one thing clear; that this was not a power supply load issue. This was power
jack insertions de-bounce. We tried changing the power jack but this did not help. We also tried using a slide
switch assuming it would reduce the mechanical insertion issues; but this too did not remove the spikes.
Filtering out the spike
Having realized that the issue was due to the mechanical insertion, we wanted to filter out the noise from the
power lines. To do this, we used the most frequently used filter, the LC filter, to block the noise. This too failed
and we realized that the noise was not only on the power lines but on the ground layer as well.
Once we identified that the spike was occurring on both power and ground planes, we required a differential
logic for the spike from both planes to compensate each other. We used a common mode choke across the
power and ground lines. Since the two inductors are mutually coupled, we expected that the spike on one line
would be induced on the other line as well, thus maintaining the same difference between power and ground in
the output. This somehow did not work.
Slow starting the power
When the common mode choke experiment failed, we tried slow-starting the power to the unit similar to the ones
we find in DC switchers, where a timing circuit can configure the time lag between the input power and stable
output power. We put in FET switches on both the power and ground entry points, with a timing circuit to switch
on power supply with a time lag, so that the spike due to the insertion of the power jack occurs but does not pass
on to the electronics on board. This failed as the power spikes jumped the barrier junctions of the reverse
protection diodes.
We followed this by placing reverse biased diodes in the path of power and ground lines assuming that diodes
placed in the opposite direction of current flow would not allow the spikes to enter the electronics on board. This
too failed as the spikes jumped these barriers as well.
Bypassing the power spike to ground
Next, we placed micro Farad range capacitors expecting them to store a lot of charge and aid in slowing the
power on rise time by offering this capacitance to the power adapter. This also did not work as the capacitors did
not react fast enough. Pico Farad range capacitors did not help either as they could not store enough charge to
compensate for the spike. As a next step, we removed all the capacitors that were visible to the power adapter
during insertion, given that capacitor appears as short at the moment of application of a step voltage. This
momentary short might have caused power adapter to over correct its output because of high current flow and
cause spike. All these did not help.
We also tried using TVS diodes but these are designed for high voltages but lower frequency of operation and
they just did not react to the high frequency spike.
Transformer Based Isolation
At this point, we had to find a kind of isolation that was complete. This is when we thought about transformer
based isolation. An isolation transformer provides complete isolation from primary to secondary both on the
power and ground. The nature of transformer operation required the input to be varying. But, for handheld
equipment, providing AC directly is not an option for want of space for the high power components. So, isolation
transformers have to be used at DC levels. This solution uses a DC switcher to pulse the DC into a pulse
transformer, which operates without hysteresis effects. The output was filtered using a high value capacitor. The
power spike was isolated from the electronics by this kind of isolation.
Now to prevent the spike from appearing on all ASIC supplies, the ASIC section and related components had to
be isolated from the remaining part of the board. To prove this concept, a test board was fabricated. This test
board contained the ASIC, RAM backup battery and related components for ASIC to function. All the signals
going from the processor to ASIC section were wired from the main board (existing design which had ASIC
vulnerable to spikes). The ASIC section on the main board was disconnected from the processor.
The test board would draw both power and interface signals from the main board, which pass through isolators.
The test board contained a DC-DC isolator to isolate both power and ground from the main board. Interface
signals running from the main board to the test board pass through interface-specific isolators such as USB
isolator and I2C isolators. All these isolators had separate power and ground pins for non-isolated (main board)
and isolated (ASIC section of test board) section. Thus there was no direct connection between the isolated and
non-isolated power and ground layers. The ASIC section was completely isolated from the main board.
During testing, it was observed that there were no spikes at the ASIC side of the isolators even though spikes
were present on the other side (main board side). There was no path for the spike to reach ASIC section
because only the isolators are present in between the ASIC section and the main board.
The block diagram in Figure 3 provides a logical representation of the isolation.
Figure 3: Block diagram showing logical representation of an isolation
JACK
MAIN POWER AND GROUND
LAYERS
ASIC BATTERY
SEPARATE POWER AND GROUND
LAYERS
DC-DC
ISOLATOR
POWER GND
INTERFACE
ISOLATORS
UART I2C USB
TRANFORMERS
GPIOs
POWER GND UART I2C USB GPIOs
Below are the schemes for the ground plane (Figure 4) and power plane split (Figure 5) that was required to
realize the isolation on the same PCB.
Figure 4: Ground plane
Figure 5: Power plane split
This kind of solution comes with a few constraints:
• High power rated transformers are needed, if isolation is designed right at the power input. This can be
mitigated by using more isolation transformers on individual power rails, but again these are bulky
components and will cause real estate issues on the board.
• All signal and power lines have to be isolated, if isolation is designed only for a section, but this needs
smaller transformers.
• This solution is difficult to incorporate in a mobile environment. Advances in manufacturing technology
will help here.
Why did isolation work?
Even though transformers respond only to variations in the input voltage, which in our case is caused by the
spike, there is a certain cut-off frequency. Since we have used a low frequency power transformer with cut-off
frequency in the range of hundreds of KHz, this GHz noise has no path for getting into the isolated circuit.
Advantages
Isolation, by definition, offers protection against high voltage induction and provides noise immunity. Selecting a
transformer for the required application involves identifying the proper cut-off frequency and its harmonics.
Conclusion
When a sensitive IC is used in a design, isolation is very important. This should be achieved for both the
interface signals using electronic components and ground by constructing the right plane split in the PCB. The
power spikes are very high frequency signals and therefore, behave more like RF signals and jump over
commonly used electronic barriers like filters, diodes and switches. If the power spike disturbs ground
equalization the spike is observed everywhere. Complete isolation of the sensitive electronics in such cases is a
good solution, but this comes at a cost (components, real-estate etc.) and the designer needs to make a
balanced decision.
About the Authors:
Avinash Babu is a Sr. Architect with Mistral Solutions and has been instrumental is designing CE products like
handheld devices, network video recorders, wireless cameras, rapid product prototyping modules and
multimedia platforms based on ARM and PowerPC architecture.
Harshith Kasyap is Module Lead with Mistral Solutions and has been involved with in designing electronics for
varied applications like transformer control, battery management for electric vehicles, wireless tactical
computers, handheld secure authentication devices, Power Quality analyzers and multimedia products on ARM
platforms.
Mistral is a technology design and integration company providing end-to-end services for product development
and deployment. Mistral’s Product Engineering Services are delivered through a proven development process,
designed for embedded product development. Mistral’s hardware and software team works together in a
seamless manner providing expert product designs covering board and FPGA Designs, BSP and Firmware
developments, Embedded Application developments, integration of third party solutions, verification/validation,
product prototyping, production coordination and product sustenance services.
(This article was featured on EDN Asia and EE-Times in Jan 2012 and Dec 2011 respectively)

More Related Content

What's hot

Automated Electrical Protection System For Domestic Application
Automated Electrical Protection System For Domestic Application Automated Electrical Protection System For Domestic Application
Automated Electrical Protection System For Domestic Application Anand Parakkat Parambil
 
RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...
RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...
RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...shiv kapil
 
Advancements in inverter technology
Advancements  in inverter technologyAdvancements  in inverter technology
Advancements in inverter technologyBhanu Teja
 
LOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CARE
LOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CARELOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CARE
LOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CAREieijjournal
 
Power grid synopsis
Power grid synopsisPower grid synopsis
Power grid synopsisParveen Jaat
 
Mosfet based ups cum-eps
Mosfet based ups cum-epsMosfet based ups cum-eps
Mosfet based ups cum-epsjayonline_4u
 
Wireless mobile charging by Inductive Coupling.
Wireless mobile charging by Inductive Coupling.Wireless mobile charging by Inductive Coupling.
Wireless mobile charging by Inductive Coupling.siddhant212
 
Report Automatic led emergency light
Report Automatic led emergency lightReport Automatic led emergency light
Report Automatic led emergency lightVatsal N Shah
 
ppt of Elcb( earth leakage circuit breaker)
ppt of Elcb( earth leakage circuit breaker)ppt of Elcb( earth leakage circuit breaker)
ppt of Elcb( earth leakage circuit breaker)stanley christy
 
Electronics Project Book
Electronics Project BookElectronics Project Book
Electronics Project BookVarun Bansal
 
Inductive shielded superconducting fault current limiter: test results for sc...
Inductive shielded superconducting fault current limiter: test results for sc...Inductive shielded superconducting fault current limiter: test results for sc...
Inductive shielded superconducting fault current limiter: test results for sc...Franco Moriconi
 
Mains operated under voltage over voltage trip switch
Mains operated under voltage over voltage trip switchMains operated under voltage over voltage trip switch
Mains operated under voltage over voltage trip switchEdgefxkits & Solutions
 
Introduction to IDT Wireless Power IC Solutions (Inductive Charging)
Introduction to IDT Wireless Power IC Solutions (Inductive Charging)Introduction to IDT Wireless Power IC Solutions (Inductive Charging)
Introduction to IDT Wireless Power IC Solutions (Inductive Charging)Integrated Device Technology
 

What's hot (20)

Automated Electrical Protection System For Domestic Application
Automated Electrical Protection System For Domestic Application Automated Electrical Protection System For Domestic Application
Automated Electrical Protection System For Domestic Application
 
Relay
RelayRelay
Relay
 
RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...
RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...
RESIDENTIAL SCALE LO VOLTAGE DISTRIBUTION AND ON GRID POWER SUPPLY USING SOLA...
 
Advancements in inverter technology
Advancements  in inverter technologyAdvancements  in inverter technology
Advancements in inverter technology
 
LOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CARE
LOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CARELOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CARE
LOW POWER SI CLASS E POWER AMPLIFIER AND RF SWITCH FOR HEALTH CARE
 
Power grid synopsis
Power grid synopsisPower grid synopsis
Power grid synopsis
 
Mosfet based ups cum-eps
Mosfet based ups cum-epsMosfet based ups cum-eps
Mosfet based ups cum-eps
 
Wireless mobile charging by Inductive Coupling.
Wireless mobile charging by Inductive Coupling.Wireless mobile charging by Inductive Coupling.
Wireless mobile charging by Inductive Coupling.
 
Sensitive switch
Sensitive  switchSensitive  switch
Sensitive switch
 
Report Automatic led emergency light
Report Automatic led emergency lightReport Automatic led emergency light
Report Automatic led emergency light
 
ppt of Elcb( earth leakage circuit breaker)
ppt of Elcb( earth leakage circuit breaker)ppt of Elcb( earth leakage circuit breaker)
ppt of Elcb( earth leakage circuit breaker)
 
Electronics Project Book
Electronics Project BookElectronics Project Book
Electronics Project Book
 
About Solar Inverter
About Solar Inverter About Solar Inverter
About Solar Inverter
 
Electronics 01
Electronics 01Electronics 01
Electronics 01
 
Inductive shielded superconducting fault current limiter: test results for sc...
Inductive shielded superconducting fault current limiter: test results for sc...Inductive shielded superconducting fault current limiter: test results for sc...
Inductive shielded superconducting fault current limiter: test results for sc...
 
Mains operated under voltage over voltage trip switch
Mains operated under voltage over voltage trip switchMains operated under voltage over voltage trip switch
Mains operated under voltage over voltage trip switch
 
Introduction to IDT Wireless Power IC Solutions (Inductive Charging)
Introduction to IDT Wireless Power IC Solutions (Inductive Charging)Introduction to IDT Wireless Power IC Solutions (Inductive Charging)
Introduction to IDT Wireless Power IC Solutions (Inductive Charging)
 
Electrical Installations
Electrical InstallationsElectrical Installations
Electrical Installations
 
Relay Switch
Relay SwitchRelay Switch
Relay Switch
 
Power Supply Unit
Power Supply UnitPower Supply Unit
Power Supply Unit
 

Similar to Power Spikes Isolation to avoid corruption within sensitive ICs Solutions

Pre Final Year project/ mini project for Electronics and communication engine...
Pre Final Year project/ mini project for Electronics and communication engine...Pre Final Year project/ mini project for Electronics and communication engine...
Pre Final Year project/ mini project for Electronics and communication engine...Shirshendu Das
 
Development of underground line fault detector
Development of underground line fault detectorDevelopment of underground line fault detector
Development of underground line fault detectorDODDI NAGASAI
 
Automatic IN/OUT Indicator with Doorbell Manual
Automatic IN/OUT Indicator with Doorbell ManualAutomatic IN/OUT Indicator with Doorbell Manual
Automatic IN/OUT Indicator with Doorbell ManualTezpur University
 
Fabrication Of Low Power Audio Amplifier Using IC LM386
Fabrication Of Low Power Audio Amplifier Using IC LM386Fabrication Of Low Power Audio Amplifier Using IC LM386
Fabrication Of Low Power Audio Amplifier Using IC LM386Kapil Tapsi
 
How to Build Your Own Power Supply
How to Build Your Own Power SupplyHow to Build Your Own Power Supply
How to Build Your Own Power SupplyEng. Emad Al-Atoum
 
Electronics 01
Electronics 01Electronics 01
Electronics 01snakeaye
 
Electrical instuments.pptx
Electrical instuments.pptxElectrical instuments.pptx
Electrical instuments.pptxRohith sai
 
project report on plc based load sharing
project report on plc based load sharingproject report on plc based load sharing
project report on plc based load sharingVivek Arun
 
EE375 Electronics 1: lab 1
EE375   Electronics 1: lab 1EE375   Electronics 1: lab 1
EE375 Electronics 1: lab 1Loren Schwappach
 
Electrical Engineering Interview Questions
Electrical Engineering Interview QuestionsElectrical Engineering Interview Questions
Electrical Engineering Interview Questionsashiesh0007
 
Electrical interview-questions-answers
Electrical interview-questions-answersElectrical interview-questions-answers
Electrical interview-questions-answersRaghavendra Kiran
 
IRJET- Underground Cable Fault Distance Locator
IRJET- Underground Cable Fault Distance LocatorIRJET- Underground Cable Fault Distance Locator
IRJET- Underground Cable Fault Distance LocatorIRJET Journal
 

Similar to Power Spikes Isolation to avoid corruption within sensitive ICs Solutions (20)

electronic componets
electronic componetselectronic componets
electronic componets
 
Power supply
Power supplyPower supply
Power supply
 
Pre Final Year project/ mini project for Electronics and communication engine...
Pre Final Year project/ mini project for Electronics and communication engine...Pre Final Year project/ mini project for Electronics and communication engine...
Pre Final Year project/ mini project for Electronics and communication engine...
 
Development of underground line fault detector
Development of underground line fault detectorDevelopment of underground line fault detector
Development of underground line fault detector
 
Mba ebooks
Mba ebooksMba ebooks
Mba ebooks
 
Automatic IN/OUT Indicator with Doorbell Manual
Automatic IN/OUT Indicator with Doorbell ManualAutomatic IN/OUT Indicator with Doorbell Manual
Automatic IN/OUT Indicator with Doorbell Manual
 
Randeep.pptx
Randeep.pptxRandeep.pptx
Randeep.pptx
 
Fabrication Of Low Power Audio Amplifier Using IC LM386
Fabrication Of Low Power Audio Amplifier Using IC LM386Fabrication Of Low Power Audio Amplifier Using IC LM386
Fabrication Of Low Power Audio Amplifier Using IC LM386
 
How to Build Your Own Power Supply
How to Build Your Own Power SupplyHow to Build Your Own Power Supply
How to Build Your Own Power Supply
 
Electronics 01
Electronics 01Electronics 01
Electronics 01
 
Electrical instuments.pptx
Electrical instuments.pptxElectrical instuments.pptx
Electrical instuments.pptx
 
project report on plc based load sharing
project report on plc based load sharingproject report on plc based load sharing
project report on plc based load sharing
 
EE375 Electronics 1: lab 1
EE375   Electronics 1: lab 1EE375   Electronics 1: lab 1
EE375 Electronics 1: lab 1
 
ISRO Funded IEEE Paper
ISRO Funded IEEE PaperISRO Funded IEEE Paper
ISRO Funded IEEE Paper
 
Electrical Engineering Interview Questions
Electrical Engineering Interview QuestionsElectrical Engineering Interview Questions
Electrical Engineering Interview Questions
 
Devices part 1
Devices part 1Devices part 1
Devices part 1
 
Electrical interview-questions-answers
Electrical interview-questions-answersElectrical interview-questions-answers
Electrical interview-questions-answers
 
BASIC ELECTRICAL EMERSON EDUARDO RODRIGUES
BASIC ELECTRICAL EMERSON EDUARDO RODRIGUESBASIC ELECTRICAL EMERSON EDUARDO RODRIGUES
BASIC ELECTRICAL EMERSON EDUARDO RODRIGUES
 
Electrical q
Electrical qElectrical q
Electrical q
 
IRJET- Underground Cable Fault Distance Locator
IRJET- Underground Cable Fault Distance LocatorIRJET- Underground Cable Fault Distance Locator
IRJET- Underground Cable Fault Distance Locator
 

More from Mistral Solutions

An infographic from Mistral explaining Semiconductors
An infographic from Mistral explaining SemiconductorsAn infographic from Mistral explaining Semiconductors
An infographic from Mistral explaining SemiconductorsMistral Solutions
 
Interfacing a Thermal Printer using an AM437x PoM
Interfacing a Thermal Printer using an AM437x PoMInterfacing a Thermal Printer using an AM437x PoM
Interfacing a Thermal Printer using an AM437x PoMMistral Solutions
 
IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...
IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...
IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...Mistral Solutions
 
Designing a Product on Module for Health and Wellness Applications
Designing a Product on Module for Health and Wellness ApplicationsDesigning a Product on Module for Health and Wellness Applications
Designing a Product on Module for Health and Wellness ApplicationsMistral Solutions
 
iOS Application Development for Drones
iOS Application Development for DronesiOS Application Development for Drones
iOS Application Development for DronesMistral Solutions
 
Hardware Software Co-Design - White Paper
Hardware Software Co-Design - White PaperHardware Software Co-Design - White Paper
Hardware Software Co-Design - White PaperMistral Solutions
 
RTM Break Out Card - Datasheet
RTM Break Out Card - DatasheetRTM Break Out Card - Datasheet
RTM Break Out Card - DatasheetMistral Solutions
 
Algorithm for Lossy Image Compression using FPGA
Algorithm for Lossy Image Compression using FPGAAlgorithm for Lossy Image Compression using FPGA
Algorithm for Lossy Image Compression using FPGAMistral Solutions
 
High-Definition Rugged DVR - Case Study
High-Definition Rugged DVR - Case StudyHigh-Definition Rugged DVR - Case Study
High-Definition Rugged DVR - Case StudyMistral Solutions
 
Customized SoC for Industrial Automation Markets
Customized SoC for Industrial Automation MarketsCustomized SoC for Industrial Automation Markets
Customized SoC for Industrial Automation MarketsMistral Solutions
 
The Amazing World of Infotainment
The Amazing World of InfotainmentThe Amazing World of Infotainment
The Amazing World of InfotainmentMistral Solutions
 
Infographic - Sonar Subsystems
Infographic - Sonar Subsystems Infographic - Sonar Subsystems
Infographic - Sonar Subsystems Mistral Solutions
 

More from Mistral Solutions (20)

Field Dominance Algorithm
Field Dominance AlgorithmField Dominance Algorithm
Field Dominance Algorithm
 
An infographic from Mistral explaining Semiconductors
An infographic from Mistral explaining SemiconductorsAn infographic from Mistral explaining Semiconductors
An infographic from Mistral explaining Semiconductors
 
SMARC Development Kit
SMARC Development KitSMARC Development Kit
SMARC Development Kit
 
Satellite based SCADA systems
Satellite based SCADA systemsSatellite based SCADA systems
Satellite based SCADA systems
 
AM437x Application board
AM437x Application boardAM437x Application board
AM437x Application board
 
SMARC module
SMARC moduleSMARC module
SMARC module
 
Interfacing a Thermal Printer using an AM437x PoM
Interfacing a Thermal Printer using an AM437x PoMInterfacing a Thermal Printer using an AM437x PoM
Interfacing a Thermal Printer using an AM437x PoM
 
IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...
IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...
IoT based Industrial Gateway (IoT-SDK) built around Sitara™ AM437x processors...
 
Designing a Product on Module for Health and Wellness Applications
Designing a Product on Module for Health and Wellness ApplicationsDesigning a Product on Module for Health and Wellness Applications
Designing a Product on Module for Health and Wellness Applications
 
iOS Application Development for Drones
iOS Application Development for DronesiOS Application Development for Drones
iOS Application Development for Drones
 
Hardware Software Co-Design - White Paper
Hardware Software Co-Design - White PaperHardware Software Co-Design - White Paper
Hardware Software Co-Design - White Paper
 
India Needs an OEM Evolution
India Needs an OEM EvolutionIndia Needs an OEM Evolution
India Needs an OEM Evolution
 
RTM Break Out Card - Datasheet
RTM Break Out Card - DatasheetRTM Break Out Card - Datasheet
RTM Break Out Card - Datasheet
 
Algorithm for Lossy Image Compression using FPGA
Algorithm for Lossy Image Compression using FPGAAlgorithm for Lossy Image Compression using FPGA
Algorithm for Lossy Image Compression using FPGA
 
High-Definition Rugged DVR - Case Study
High-Definition Rugged DVR - Case StudyHigh-Definition Rugged DVR - Case Study
High-Definition Rugged DVR - Case Study
 
Customized SoC for Industrial Automation Markets
Customized SoC for Industrial Automation MarketsCustomized SoC for Industrial Automation Markets
Customized SoC for Industrial Automation Markets
 
The Amazing World of Infotainment
The Amazing World of InfotainmentThe Amazing World of Infotainment
The Amazing World of Infotainment
 
Assistive technology
Assistive technologyAssistive technology
Assistive technology
 
Infographic - Sonar Subsystems
Infographic - Sonar Subsystems Infographic - Sonar Subsystems
Infographic - Sonar Subsystems
 
Infographic - Drone
Infographic - DroneInfographic - Drone
Infographic - Drone
 

Recently uploaded

Tales from a Passkey Provider Progress from Awareness to Implementation.pptx
Tales from a Passkey Provider  Progress from Awareness to Implementation.pptxTales from a Passkey Provider  Progress from Awareness to Implementation.pptx
Tales from a Passkey Provider Progress from Awareness to Implementation.pptxFIDO Alliance
 
Oauth 2.0 Introduction and Flows with MuleSoft
Oauth 2.0 Introduction and Flows with MuleSoftOauth 2.0 Introduction and Flows with MuleSoft
Oauth 2.0 Introduction and Flows with MuleSoftshyamraj55
 
TopCryptoSupers 12thReport OrionX May2024
TopCryptoSupers 12thReport OrionX May2024TopCryptoSupers 12thReport OrionX May2024
TopCryptoSupers 12thReport OrionX May2024Stephen Perrenod
 
(Explainable) Data-Centric AI: what are you explaininhg, and to whom?
(Explainable) Data-Centric AI: what are you explaininhg, and to whom?(Explainable) Data-Centric AI: what are you explaininhg, and to whom?
(Explainable) Data-Centric AI: what are you explaininhg, and to whom?Paolo Missier
 
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)Paige Cruz
 
Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...
Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...
Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...Skynet Technologies
 
Working together SRE & Platform Engineering
Working together SRE & Platform EngineeringWorking together SRE & Platform Engineering
Working together SRE & Platform EngineeringMarcus Vechiato
 
Continuing Bonds Through AI: A Hermeneutic Reflection on Thanabots
Continuing Bonds Through AI: A Hermeneutic Reflection on ThanabotsContinuing Bonds Through AI: A Hermeneutic Reflection on Thanabots
Continuing Bonds Through AI: A Hermeneutic Reflection on ThanabotsLeah Henrickson
 
Microsoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - QuestionnaireMicrosoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - QuestionnaireExakis Nelite
 
TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...
TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...
TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...marcuskenyatta275
 
1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPT
1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPT1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPT
1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPTiSEO AI
 
How we scaled to 80K users by doing nothing!.pdf
How we scaled to 80K users by doing nothing!.pdfHow we scaled to 80K users by doing nothing!.pdf
How we scaled to 80K users by doing nothing!.pdfSrushith Repakula
 
Design and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data ScienceDesign and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data SciencePaolo Missier
 
Event-Driven Architecture Masterclass: Challenges in Stream Processing
Event-Driven Architecture Masterclass: Challenges in Stream ProcessingEvent-Driven Architecture Masterclass: Challenges in Stream Processing
Event-Driven Architecture Masterclass: Challenges in Stream ProcessingScyllaDB
 
Using IESVE for Room Loads Analysis - UK & Ireland
Using IESVE for Room Loads Analysis - UK & IrelandUsing IESVE for Room Loads Analysis - UK & Ireland
Using IESVE for Room Loads Analysis - UK & IrelandIES VE
 
WebRTC and SIP not just audio and video @ OpenSIPS 2024
WebRTC and SIP not just audio and video @ OpenSIPS 2024WebRTC and SIP not just audio and video @ OpenSIPS 2024
WebRTC and SIP not just audio and video @ OpenSIPS 2024Lorenzo Miniero
 
Vector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptxVector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptxjbellis
 
Generative AI Use Cases and Applications.pdf
Generative AI Use Cases and Applications.pdfGenerative AI Use Cases and Applications.pdf
Generative AI Use Cases and Applications.pdfalexjohnson7307
 
ChatGPT and Beyond - Elevating DevOps Productivity
ChatGPT and Beyond - Elevating DevOps ProductivityChatGPT and Beyond - Elevating DevOps Productivity
ChatGPT and Beyond - Elevating DevOps ProductivityVictorSzoltysek
 

Recently uploaded (20)

Tales from a Passkey Provider Progress from Awareness to Implementation.pptx
Tales from a Passkey Provider  Progress from Awareness to Implementation.pptxTales from a Passkey Provider  Progress from Awareness to Implementation.pptx
Tales from a Passkey Provider Progress from Awareness to Implementation.pptx
 
Oauth 2.0 Introduction and Flows with MuleSoft
Oauth 2.0 Introduction and Flows with MuleSoftOauth 2.0 Introduction and Flows with MuleSoft
Oauth 2.0 Introduction and Flows with MuleSoft
 
TopCryptoSupers 12thReport OrionX May2024
TopCryptoSupers 12thReport OrionX May2024TopCryptoSupers 12thReport OrionX May2024
TopCryptoSupers 12thReport OrionX May2024
 
(Explainable) Data-Centric AI: what are you explaininhg, and to whom?
(Explainable) Data-Centric AI: what are you explaininhg, and to whom?(Explainable) Data-Centric AI: what are you explaininhg, and to whom?
(Explainable) Data-Centric AI: what are you explaininhg, and to whom?
 
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
 
Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...
Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...
Human Expert Website Manual WCAG 2.0 2.1 2.2 Audit - Digital Accessibility Au...
 
Working together SRE & Platform Engineering
Working together SRE & Platform EngineeringWorking together SRE & Platform Engineering
Working together SRE & Platform Engineering
 
Continuing Bonds Through AI: A Hermeneutic Reflection on Thanabots
Continuing Bonds Through AI: A Hermeneutic Reflection on ThanabotsContinuing Bonds Through AI: A Hermeneutic Reflection on Thanabots
Continuing Bonds Through AI: A Hermeneutic Reflection on Thanabots
 
Microsoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - QuestionnaireMicrosoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - Questionnaire
 
TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...
TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...
TEST BANK For, Information Technology Project Management 9th Edition Kathy Sc...
 
1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPT
1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPT1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPT
1111 ChatGPT Prompts PDF Free Download - Prompts for ChatGPT
 
Overview of Hyperledger Foundation
Overview of Hyperledger FoundationOverview of Hyperledger Foundation
Overview of Hyperledger Foundation
 
How we scaled to 80K users by doing nothing!.pdf
How we scaled to 80K users by doing nothing!.pdfHow we scaled to 80K users by doing nothing!.pdf
How we scaled to 80K users by doing nothing!.pdf
 
Design and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data ScienceDesign and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data Science
 
Event-Driven Architecture Masterclass: Challenges in Stream Processing
Event-Driven Architecture Masterclass: Challenges in Stream ProcessingEvent-Driven Architecture Masterclass: Challenges in Stream Processing
Event-Driven Architecture Masterclass: Challenges in Stream Processing
 
Using IESVE for Room Loads Analysis - UK & Ireland
Using IESVE for Room Loads Analysis - UK & IrelandUsing IESVE for Room Loads Analysis - UK & Ireland
Using IESVE for Room Loads Analysis - UK & Ireland
 
WebRTC and SIP not just audio and video @ OpenSIPS 2024
WebRTC and SIP not just audio and video @ OpenSIPS 2024WebRTC and SIP not just audio and video @ OpenSIPS 2024
WebRTC and SIP not just audio and video @ OpenSIPS 2024
 
Vector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptxVector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptx
 
Generative AI Use Cases and Applications.pdf
Generative AI Use Cases and Applications.pdfGenerative AI Use Cases and Applications.pdf
Generative AI Use Cases and Applications.pdf
 
ChatGPT and Beyond - Elevating DevOps Productivity
ChatGPT and Beyond - Elevating DevOps ProductivityChatGPT and Beyond - Elevating DevOps Productivity
ChatGPT and Beyond - Elevating DevOps Productivity
 

Power Spikes Isolation to avoid corruption within sensitive ICs Solutions

  • 1. • A very high frequency de-bounce on the power supply jack during insertion Power Spikes Isolation to avoid corruption within sensitive ICs By Avinash Babu, Sr. Architect, and Harshith Kasyap, Module Lead, Mistral Solutions Pvt. Ltd. Introduction of spikes in systems during insertion of power supply jacks is observed in a majority of designs. These spikes are mainly caused due to: • Equalization of ground between power adapter and battery-powered system In most cases, the ICs on the board don't respond to such events. This is because they are either not yet powered by the board's main supply or they don't have sensitive electronics inside to react to it (in case of battery-powered systems). Some of the electronic circuits that are generally affected are, • Circuits which monitor the power line for variation, to detect tamper • Circuits constructed for secure transaction authorization needs, such as tamper detection capabilities. The following case study explains the way we went about resolving a power spike issue that is not common. As you will observe, the nature of the power spike in itself and the complexity of the design made the job tougher. The case study highlights the step-by-step method we followed to isolate and resolve the issue and our learning through this process. • It was in the GHz frequency range Case study: Corruption within ASIC designed for tamper detection We came across a situation where an ASIC chip for generating a secure code and storing it in a battery-backed RAM, was sensitive to these spikes. In fact, the function of the ASIC in the design was tamper detection, and spike was one of the kinds of tamper being detected. It was a catch-22 situation for us. The built-in tamper detection circuit was designed to detect excursions on its RAM supply and automatically erase the sensitive data to protect unauthorized data access. During the insertion/removal of power jack to the boards, the battery- backed RAM inside the on-board ASIC was getting corrupted as this was read as a tamper. The system had two power sources: a Li-Ion battery and a 5V DC input through a standard wall power adapter. The characteristic of the spike were as follows, • It had peak-to-peak amplitude of around 25V • It appeared on all the signals on the board • It occurred at the moment of contact of the power adapter to the board power jack • It had both positive and negative swing. Figure 1 shows a snapshot of the spike.
  • 2. Figure 1: Snapshot of the spike What made the job tougher was that, • The spike caused ground bounce, which induced the spike in-turn to appear on all the signal lines throughout the board • Due to the high frequency of the spike, it would jump layers on the PCB • Use of decoupling capacitors that were placed very close to the battery, ferrite beads or FET switches (and any solid state isolation device) on the input power and ground lines were not a solution mainly because of the high frequency and energy of the spike • If either supply or ground was isolated on the board, the spike would enter the board through capacitors at the input • It had both positive and negative swing. Had the swing been towards a single direction, it would have been easier to address the issue. Believing that the power adapter was not able to source enough power to the electronics on the board, we also put in Mega Ohm resistors in the path of power. The presence of Mega ohm resistor steeply decreases the current; thereby applying a minimal load on the adapter. Though the board doesn't power ON in this setup, the purpose of this experiment was to determine if the spike was caused by loading the adapter or due to the Power supply load or power jack insertions de-bounce Initially we approached the problem with a simplistic view and changed the power adapter suspecting that the adapter was not able to source enough power into the unit. We tried powering the unit using a battery as this is considered more regulated. We also loaded the adapter using a resistor assuming that if there was a steady flow of current, the power jack insertion will not introduce a sudden load to the power adapter and upset the DC/DC functionality inside the adapter.
  • 3. mechanical insertion of the power jack. We observed that the power spike reduced by 5V in amplitude but this was not sufficient spike reduction. Figure 2 shows a snap of the reduced spike. Figure 2: Snapshot of the reduced spike As a next step to using the Mega Ohm resistor, we placed an NTC resistor in the power path to offer high resistance when the power was applied and slowly reduced the resistance to allow normal current flow. This only reduced the amplitude of the power spike by 5V. Doing all these experiments made one thing clear; that this was not a power supply load issue. This was power jack insertions de-bounce. We tried changing the power jack but this did not help. We also tried using a slide switch assuming it would reduce the mechanical insertion issues; but this too did not remove the spikes. Filtering out the spike Having realized that the issue was due to the mechanical insertion, we wanted to filter out the noise from the power lines. To do this, we used the most frequently used filter, the LC filter, to block the noise. This too failed and we realized that the noise was not only on the power lines but on the ground layer as well. Once we identified that the spike was occurring on both power and ground planes, we required a differential logic for the spike from both planes to compensate each other. We used a common mode choke across the power and ground lines. Since the two inductors are mutually coupled, we expected that the spike on one line would be induced on the other line as well, thus maintaining the same difference between power and ground in the output. This somehow did not work.
  • 4. Slow starting the power When the common mode choke experiment failed, we tried slow-starting the power to the unit similar to the ones we find in DC switchers, where a timing circuit can configure the time lag between the input power and stable output power. We put in FET switches on both the power and ground entry points, with a timing circuit to switch on power supply with a time lag, so that the spike due to the insertion of the power jack occurs but does not pass on to the electronics on board. This failed as the power spikes jumped the barrier junctions of the reverse protection diodes. We followed this by placing reverse biased diodes in the path of power and ground lines assuming that diodes placed in the opposite direction of current flow would not allow the spikes to enter the electronics on board. This too failed as the spikes jumped these barriers as well. Bypassing the power spike to ground Next, we placed micro Farad range capacitors expecting them to store a lot of charge and aid in slowing the power on rise time by offering this capacitance to the power adapter. This also did not work as the capacitors did not react fast enough. Pico Farad range capacitors did not help either as they could not store enough charge to compensate for the spike. As a next step, we removed all the capacitors that were visible to the power adapter during insertion, given that capacitor appears as short at the moment of application of a step voltage. This momentary short might have caused power adapter to over correct its output because of high current flow and cause spike. All these did not help. We also tried using TVS diodes but these are designed for high voltages but lower frequency of operation and they just did not react to the high frequency spike. Transformer Based Isolation At this point, we had to find a kind of isolation that was complete. This is when we thought about transformer based isolation. An isolation transformer provides complete isolation from primary to secondary both on the power and ground. The nature of transformer operation required the input to be varying. But, for handheld equipment, providing AC directly is not an option for want of space for the high power components. So, isolation transformers have to be used at DC levels. This solution uses a DC switcher to pulse the DC into a pulse transformer, which operates without hysteresis effects. The output was filtered using a high value capacitor. The power spike was isolated from the electronics by this kind of isolation. Now to prevent the spike from appearing on all ASIC supplies, the ASIC section and related components had to be isolated from the remaining part of the board. To prove this concept, a test board was fabricated. This test board contained the ASIC, RAM backup battery and related components for ASIC to function. All the signals going from the processor to ASIC section were wired from the main board (existing design which had ASIC vulnerable to spikes). The ASIC section on the main board was disconnected from the processor. The test board would draw both power and interface signals from the main board, which pass through isolators. The test board contained a DC-DC isolator to isolate both power and ground from the main board. Interface signals running from the main board to the test board pass through interface-specific isolators such as USB isolator and I2C isolators. All these isolators had separate power and ground pins for non-isolated (main board) and isolated (ASIC section of test board) section. Thus there was no direct connection between the isolated and non-isolated power and ground layers. The ASIC section was completely isolated from the main board. During testing, it was observed that there were no spikes at the ASIC side of the isolators even though spikes were present on the other side (main board side). There was no path for the spike to reach ASIC section because only the isolators are present in between the ASIC section and the main board. The block diagram in Figure 3 provides a logical representation of the isolation.
  • 5. Figure 3: Block diagram showing logical representation of an isolation JACK MAIN POWER AND GROUND LAYERS ASIC BATTERY SEPARATE POWER AND GROUND LAYERS DC-DC ISOLATOR POWER GND INTERFACE ISOLATORS UART I2C USB TRANFORMERS GPIOs POWER GND UART I2C USB GPIOs
  • 6. Below are the schemes for the ground plane (Figure 4) and power plane split (Figure 5) that was required to realize the isolation on the same PCB. Figure 4: Ground plane Figure 5: Power plane split This kind of solution comes with a few constraints: • High power rated transformers are needed, if isolation is designed right at the power input. This can be mitigated by using more isolation transformers on individual power rails, but again these are bulky components and will cause real estate issues on the board. • All signal and power lines have to be isolated, if isolation is designed only for a section, but this needs smaller transformers. • This solution is difficult to incorporate in a mobile environment. Advances in manufacturing technology will help here. Why did isolation work? Even though transformers respond only to variations in the input voltage, which in our case is caused by the spike, there is a certain cut-off frequency. Since we have used a low frequency power transformer with cut-off frequency in the range of hundreds of KHz, this GHz noise has no path for getting into the isolated circuit.
  • 7. Advantages Isolation, by definition, offers protection against high voltage induction and provides noise immunity. Selecting a transformer for the required application involves identifying the proper cut-off frequency and its harmonics. Conclusion When a sensitive IC is used in a design, isolation is very important. This should be achieved for both the interface signals using electronic components and ground by constructing the right plane split in the PCB. The power spikes are very high frequency signals and therefore, behave more like RF signals and jump over commonly used electronic barriers like filters, diodes and switches. If the power spike disturbs ground equalization the spike is observed everywhere. Complete isolation of the sensitive electronics in such cases is a good solution, but this comes at a cost (components, real-estate etc.) and the designer needs to make a balanced decision. About the Authors: Avinash Babu is a Sr. Architect with Mistral Solutions and has been instrumental is designing CE products like handheld devices, network video recorders, wireless cameras, rapid product prototyping modules and multimedia platforms based on ARM and PowerPC architecture. Harshith Kasyap is Module Lead with Mistral Solutions and has been involved with in designing electronics for varied applications like transformer control, battery management for electric vehicles, wireless tactical computers, handheld secure authentication devices, Power Quality analyzers and multimedia products on ARM platforms. Mistral is a technology design and integration company providing end-to-end services for product development and deployment. Mistral’s Product Engineering Services are delivered through a proven development process, designed for embedded product development. Mistral’s hardware and software team works together in a seamless manner providing expert product designs covering board and FPGA Designs, BSP and Firmware developments, Embedded Application developments, integration of third party solutions, verification/validation, product prototyping, production coordination and product sustenance services. (This article was featured on EDN Asia and EE-Times in Jan 2012 and Dec 2011 respectively)