Innovation is critical in today’s engineering world and it demands technical knowledge and the highest level of creativity. Seeing compact articles that solve design problems or display innovative ways to accomplish design tasks can help to fuel your electronics creativity.
You can find many very circuit ideas at ePanorama.net circuits page.
In addition to this links to interesting electronics design related articles worth to check out can be posted to the comments section.
1,841 Comments
Tomi Engdahl says:
Analog is Everywhere
https://www.digikey.com/en/product-highlight/m/microchip-technology/analog-products?dclid=CI_I6vybl_0CFX3huwgdrfcAgg
Microchip has a comprehensive portfolio of cost-effective and reliable signal chain, power management, and Interface solutions for a wide variety of applications.
Tomi Engdahl says:
LEM – 50 vuotta sähkömittausten kärkinimenä
https://etn.fi/index.php/tekniset-artikkelit/14591-lem-50-vuotta-saehkoemittausten-kaerkinimenae
Tomi Engdahl says:
LEM – 50 vuotta sähkömittausten kärkinimenä
https://www.uusiteknologia.fi/2023/02/15/alykas-ipd-kytkinpiiri-korvaa-releet/
Piirivalmistaja ROHM on esitellyt uudet auto- ja teollisuussovelluksiin tarkoitetut matalan puolen älykkäät IPD-kytkinpiirit. Niissä on aiempaa pienemmät tehohäviöt ja patentoidulla TDACC-tekniikalla toteutetut turvatoiminnot.
ROHM:n IPD-piirit on suunniteltu korvaamaan korvaavat esimerkiksi mekaaniset releet ja mosfetit. 1- ja 2-kanavaiset 40 voltin kytkimet kattavat valmistajan BV1LExxxEFJ-C- ja BM2LExxxFJ-C. Tuotteet on suunniteltu auto- ja teollisuussovelluksiin.
Eri piirimallit pystyvät ohjaamaan maksimissaan 40 voltin jännitettä kolmesta ampeerista aina 17,5 ampeeriin asti. Sarjaan kuluu muun muassa 2-kanavainen 40mΩ (ON-vastus) tuotteen kompaktissa SOP-J8-kotelossa. Uudet kytkimet sopivat valmistajan mukaan myös hyvin induktiivisten kuormien ohjaamiseen.
Tomi Engdahl says:
Single-Platform Design Can Reduce the Cost of Research and Development for Cordless Power Tools
https://www.allegromicro.com/en/insights-and-innovations/technical-documents/p0193-single-platform-for-power-tools?utm_source=electronicdesign.com&utm_medium=referral&utm_campaign=Personif.ai&utm_term=&utm_content=p0193-single-platform-design-power-tools
Tomi Engdahl says:
Integrated Power Loss Brake Features Lower Energy Consumption and Reduce Costs in Data-Center Fan Applications
https://www.allegromicro.com/en/insights-and-innovations/technical-documents/p0214-motor-driver-enables-plb-in-server-fans?utm_source=electronicdesign.com&utm_medium=referral&utm_campaign=Personif.ai&utm_term=&utm_content=p0214-motor-driver-enables-plb-in-server-fans
Modern server applications need uninterrupted service. Accommodating this requirement can result in adverse scenarios—from inefficient airflows created by reverse-rotating fan blades that have lost power to dangerous maintenance and repair procedures conducted in the presence of high-speed fan blades. To overcome these adverse airflows and maintenance scenarios, features can be implemented to stop a fan when it loses power or begins to rotate from an unpowered state. A fan with such a power-loss brake (PLB) can reduce energy cost and improve thermal efficiency. This article discusses how the back-electromagnetic force (BEMF) from the motor of a fan that has lost power can be harnessed to implement a PLB function that improves efficiency and creates safer operational environments. Newly introduced sensorless fan drivers with the PLB capability are presented as options that provide the desired improved safety and thermal efficiency and simplify fan design and logistics.
Implementing Power-Loss Braking
Implementing a PLB function in a server fan requires the integration of several additional components, including a Schottky diode, input caps, and a gate driver. As a result, this solution comes with tradeoffs—The increased bill of materials (BOM) complicates logistics, and size limitations in server cooling fans can make integration of these components challenging.
Tomi Engdahl says:
Simple Amplifier Options Improve Dynamic Range in ADC Interfaces
Feb. 14, 2023
In a signal-conditioning op-amp application there are a number of different approaches to take—what noise and SFDR advantages might one offer over another.
https://www.electronicdesign.com/technologies/analog/article/21795102/renesas-electronics-simple-amplifier-options-improve-dynamic-range-in-adc-interfaces?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230208017&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Noise Figure And Spurious Free Dynamic Range
Matching source impedances to amplifier input impedances using resistors is a common design practice. But there are multiple ways of doing this that have different effects on performance, depending on the topology employed.
Analysis of these effects requires an understanding of noise figure (NF) and spurious-free dynamic range (SFDR). NF indicates the sensitivity of a mixed-signal circuit. SFDR indicates the input amplitude range the circuit can handle.
Tomi Engdahl says:
High-Quality Power Modules at Low Cost
Keep your BoM under control, and save development time! Modular converters were always considered to be more expensive than discrete solutions. However, with the commissioning of its own SMT factory, RECOM is able to offer select converter series at very attractive prices.
https://www.digikey.com/en/product-highlight/r/recom-power/power-e-series?dclid=CLfezPjmmf0CFQoKewod-JkMnQ
Tomi Engdahl says:
High-Speed, Dual-Channel Digital Isolator Offers Optocoupler Alternate
Feb. 13, 2023
These 8-pin narrow-body devices provide rugged isolation up to 4,000 V (peak) and 2,830 V (rms) for 100-Mb/s digital signals.
https://www.electronicdesign.com/technologies/power/whitepaper/21259954/electronic-design-highspeed-dualchannel-digital-isolator-offers-optocoupler-alternate?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230208018&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
https://www.edn.com/cancel-pwm-dac-ripple-with-analog-subtraction-revisited/
Tomi Engdahl says:
https://www.edn.com/cancel-pwm-dac-ripple-with-analog-subtraction-but-no-inverter/
Tomi Engdahl says:
Clever Capacitor Constructions Let This New Receiver Chip Reject 40 Times More Interference
By combining parallel and serial capacitor networks, a novel chip design dramatically boosts its ability to handle harmonic interference.
https://www.hackster.io/news/clever-capacitor-constructions-let-this-new-receiver-chip-reject-40-times-more-interference-bc76f770757d
Tomi Engdahl says:
Can Zener or Schottky diodes be used as a substitute for varicap diodes in tuning a VCO?
https://electronics.stackexchange.com/questions/428486/can-zener-or-schottky-diodes-be-used-as-a-substitute-for-varicap-diodes-in-tunin
Tomi Engdahl says:
Fault1SLUA863B – January 2018 – Revised May 2020
Submit Documentation Feedback Copyright © 2018–2020, Texas Instruments Incorporated
Understanding the Short Circuit Protection for Silicon Carbide MOSFETs
Understanding the Short Circuit Protection for Silicon
Carbide MOSFETs
https://www.ti.com/lit/an/slua863b/slua863b.pdf?ts=1677834387421&ref_url=https%253A%252F%252Fwww.google.co.uk%252F
Silicon Carbide (SiC) MOSFET has become the
potential substitute for Silicon (Si) IGBT for various
applications such as solar inverters, on-board and off-
board battery chargers, traction inverters, and so forth.
Comparing it Si IGBT, SiC MOSFET has more
stringent short circuit protection requirements. To
make the most use of SiC MOSFET and ensure a
robust system operation, a fast and reliable short
circuit protection circuit is needed.
Compared to IGBT, which has similar blocking voltage
and current rating, SiC MOSFET has a smaller chip
area, which makes the parasitic capacitance smaller
than IGBT and increases the intrinsic switching speed.
However, the smaller chip area means the SiC
MOSFET die has lower thermal dissipation capability.
During short circuit conditions, the surge current
generates a significant amount of joule heating and the
die can be destroyed in a short period of time without
enough capability to dissipate the heat. With a smaller
die size, the surge current capability of SiC MOSFET
is lower than that of IGBT.
The output characteristics of SiC MOSFET and IGBT
are different too. IGBT typically works in the saturation
region during the normal ON state. When a short
circuit happens, the collector current IC increases and
goes through a sharp transition from the saturation
region to the active region. The collector current gets
self-limited and becomes independent of VCE.
Consequently, the increase in IGBT current and power
dissipation become self-limited.
On the other hand, SiC MOSFET works in the linear
region during normal ON operation. During a short
circuit event, the SiC MOSFET enters the saturation
region.
The drain current keeps
increasing along with the increasing Vds. The device is
destroyed before reaching the transition point. These
characteristics make the short circuit protection for SiC
MOSFETs very different than IGBT.
Short Circuit Protection Methods Comparison
The short circuit protection is important to ensure a
robust system and best use of the device. A qualified
short circuit protection circuit should realize a fast
detection and shut down the device without false
trigger. Three short circuit protection schemes which
are commonly used today will be analyzed and
compared, including desaturation detection, shunt
resistor sensing scheme, and senseFET current
sensing scheme.
The circuit consists of a resistor, a blanking capacitor,
and a diode. When the device turns on, a current
source charges the blanking capacitor and the diode is
conducted. During normal operation, the capacitor
voltage is clamped at the forward voltage of the
device. When short circuit happens, the capacitor
voltage is quickly charged to the threshold voltage
which triggers the device shutdown.
For IGBT, the desaturation threshold voltage is
normally set around the transition voltage, as the
current can be virtually limited afterward for IGBT to
withstand a longer period of time. It needs more
attention to design the desaturation circuit for a SiC
MOSFET. The blanking time designed for IGBT is too
long to protect SiC MOSFET.
RS
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VOCTH CFLT
OC FaultRS
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VOCTH CFLT
OC Faultwww.ti.com
2 SLUA863B – January 2018 – Revised May 2020
Submit Documentation Feedback
Copyright © 2018–2020, Texas Instruments Incorporated
Understanding the Short Circuit Protection for Silicon Carbide MOSFETs
transition voltage of SiC MOSFET is normally very
high, so the current cannot be limited. With the
preferred short circuit shutdown time less than 2 μs,
the desaturation threshold voltage needs to be set
lower. On the other hand, the fast switching speed of
the SiC MOSFET generates noise during turnon
transition. The short circuit detection time should be
designed long enough to avoid the false trigger, which
makes the desaturation circuit design challenging for
the SiC MOSFET.
The shunt resistor sensing scheme is shown in
Figure 2. A small resistor is connected in series in the
power loop to sense the current. This scheme is
straight forward and can be flexibly adopted in any
system. A high precision resistor and fast ADC are
needed to guarantee the accuracy of the signal and
detection time. The drawback of this method lies in the
power loss. In a high power system, high current
generates large power loss on the shunt resistor. In a
low power system, larger resistance is needed to
ensure the accuracy of the sensing signal, which also
generates loss and reduces efficiency in low power
applications
The senseFET current sensing scheme is shown in
Figure 3. The senseFET is normally integrated in the
power module, connecting in parallel with the main
device to scale down the device current. The scaled
down current is then measured by an accurate shunt
resistor. The detection time is short as the sensed
current is synchronous with the device current.
Summary
SiC MOSFET is a promising substitute for IGBT in
order to achieve a more compact and efficient system.
A short circuit scheme for SiC MOSFET should be
evaluated from the following aspects: fast response
time, low power loss, high accuracy, high noise
immunity, and low cost. Efforts should be made from
the protection circuits, gate driver, and PCB layout to
improve the overall performance. The UCC217XX
family has the best in-class overcurrent and short
circuit protection feature.
Tomi Engdahl says:
Application Note
2022-05-09
Rev.2.0
1
. Do not design your products or systems based on the information on this document. Please contact
your Toshiba sales representative for updated information before designing your products.
© 2019-2022
Toshiba Electronic Devices & Storage Corporation
Description
This document summarizes some tips for designing peripheral circuits that should be noted
when you use the VCE(sat) detection function of a smart gate driver coupler such as
TLP5214A/TLP5214/TLP5212/TLP5222.
The VCE(sat) detection (DESAT detection) circuit which detects the rise of the collector or drain
voltage (VCE) when an over-current flows into the power semiconductor switch device
(hereinafter referred to ‘power device’) driven by the gate driver by causes, such as a short
circuit of load, makes the power device turn off, and protects it. However, the VCE may rise
unusually and largely due to the inductances of the loads when the power device switches, and
if it enters the DESAT terminal, an erroneous detection of the DESAT detection circuit may
occur. In three-phase inverters and other inverters, noise generated during switching of other
phases may cause an erroneous detection of the DESAT detection circuit due to noise circulating
through power supply lines and GND lines or electromagnetic induction between wires.
This document provides tips to reduce the likelihood of DESAT false detections.
Smart Gate Driver Coupler
Tips for Designing DESAT
Detection Circuits
https://toshiba.semicon-storage.com/info/application_note_en_20220510_AKX00766.pdf?did=66192
The DESAT detection circuit detects the voltage at the collector or drain of the power device to
be driven through the DESAT terminal. When the voltage exceeds the specified voltage(VDESAT),
the SGD coupler stops the power device and outputs a fault signal from the FAULT_N terminal
s. DESAT-pin is
more impedances than other wiring and is more susceptible to inductions and entering from
other wiring. Therefore, the wiring should not be adjacent to the wiring through which current
pulses flow or to the wiring tied to nodes where large potential fluctuations occur.
(1) The wiring for DESAT detection is not brought close to the DESAT detection wiring of
the other power devices connected to the collectors (drains) of the power devices
having the highest voltage fluctuations.
(2) The wiring for DESAT detection does not run parallel to the gate drive wiring of the
IGBT through which the current pulses flow.
(3) The RDESAT, DDESAT, and CBLANK should be placed near the SGD so that the low-pass
filtering effects of the RDESAT, DDESAT, and CBLANK can be maximized. (The effect of the
filter will be described later.)
Tomi Engdahl says:
A desaturation fault detection circuit provides protection for power semiconductor switches (IGBT or MOSFETs) against short-circuit current events which may lead to destruction of these power switches.9 Jan 2012
https://docs.broadcom.com/wcs-public/products/application-notes/application-note/238/903/av02-0258en-an_5324-acpl-332j-09jan2012.pdf
Tomi Engdahl says:
A desaturation detection circuit is embedded in both the high- and low-side output stages and monitors the IGBT collector-to-emitter voltage by means of an external high voltage diode.
Tomi Engdahl says:
What is transistor desaturation?
IGBT desaturation means the C-E voltage of the IGBT rises (usually by too high a collector current). When the IGBT is turned on, its collector voltage is in the 2.. 3V ballpark. D_Desat pulls Pin 14 of the driver down to that voltage plus one diode drop.
Topic: How does it work? IGBT Gate Driver – Desaturation Fault Detection (Read 3111 times)
https://www.eevblog.com/forum/projects/how-does-it-work-igbt-gate-driver-desaturation-fault-detection/
IGBT desaturation means the C-E voltage of the IGBT rises (usually by too high a collector current).
When the IGBT is turned on, its collector voltage is in the 2..3V ballpark. D_Desat pulls Pin 14 of the driver down to that voltage plus one diode drop. Inside the IC there’s a current source that supplies current from V_cc2 When the IGBT desaturates, its collector voltage rises quickly way above 7V. D_Desat blocks that voltage, it is reverse biased now. The current source pulls pin 14 to a voltage near V_cc2, which is higher than 7V.
Bridge shoot through “never” happens in a correctly designed IGBT bridge circuit, desat detection is rather used for output short circuit detection.
They’re rather terse about it, but it looks like they’re doing it simply by sourcing a current out of the DESAT pin (see the I_DESAT spec and figure) and monitoring the voltage there. When the voltage charges up, collector voltage must be high; when it’s pulled low, collector is saturated.
This is a low side IGBT driver. One leg of the IGBT touches ground while the top (Where the … go) is the load you are switching to ground.
The Ddesat diode is there to prevent the potentially high voltage (for example 600V) that is present there when the IGBT is in the off state from getting to the driver chip and likely blowing it up. But when the IGBT turns on the voltage across it will quickly drop down to a low voltage (0.2 to 3V). The more current the IGBT is conducting trough itself the more voltage drop it will have. If this current becomes too large the IGBT will get out of its saturation region and this causes the voltage to start rising quickly, so suddenly there might be 50V across the IGBT. If there is say 30A flowing trough it this would make the IGBT disipate 50V*30A=1500W and for a small TO-220-ish package IGBT means that it will spectacularly self destruct in the next few milliseconds with a loud bang, sparks flying, fire, and IGBT pieces raining down all over the room. Since this is generally considered a “very bad situation” the driver chip tries to detect it and quickly turn the transistor off before it happens.
So if the chip sources a bit of current (few mA) into the forward direction of the diode the voltage you see on the other side of the diode becomes the IGBT voltage drop + 0.6V of the diode. This lets the chip sense the voltage drop on the IGBT and if it becomes too high it knows the IGBT is about to explode.
Although DESAT protects the IGBT from blowing up immediately you have a limited amount of DESAT events the part can survive.
With a too weak gate driver the uncertainty in timeing gets larger thus increasing the risc of shoot-through events causing the part to fail early even with a proper implementation of the DESAT function…
Tomi Engdahl says:
https://etn.fi/index.php/tekniset-artikkelit/14664-aelykaes-hilaohjain-helpottaa-tehopiirien-suunnittelua
Tomi Engdahl says:
Smart Low-Side Switches Cut Power Loss, Can Replace Relays and MOSFETs
March 2, 2023
ROHM’s new series of 1- and 2-channel, 40-V intelligent low-side switches are designed for automotive and industrial applications, especially systems such as car body control, and engine and transmission control units.
https://www.electronicdesign.com/markets/automotive/article/21261167/electronic-design-smart-lowside-switches-cut-power-loss-can-replace-relays-and-mosfets?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230223140&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
The Basics of Anti-Aliasing Low-Pass Filters (and Why They Need to be Matched to the ADC)
https://www.digikey.com/en/articles/the-basics-of-anti-aliasing-low-pass-filters?dclid=CIfM3Lm5zv0CFf8NogMdk0oI7w
Tomi Engdahl says:
https://www.electronicdesign.com/technologies/analog/article/21261391/three-major-design-pitfalls-plaguing-new-analog-signalpath-designers?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230301127&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
Top Tips: What to Consider When Selecting a Termination Style for Specific Applications
Feb. 8, 2023
Selecting a termination style for a variety of applications can be a complex job. These tips will provide important information about a number of termination types, how each is manufactured, and the different mounting technologies used.
https://www.electronicdesign.com/tools/learning-resources/whitepaper/21253827/millmax-mfg-corp-top-tips-what-to-consider-when-selecting-a-termination-style-for-specific-applications
Tomi Engdahl says:
https://www.digikey.com/en/articles/why-and-how-to-use-digital-filters-for-analog-to-digital-conversions?dclid=CMHKw_Tr0P0CFSMKewodDAYL-w
Tomi Engdahl says:
Addressing high-voltage design
challenges with reliable and
affordable isolation technologies
https://www.ti.com/lit/wp/slyy204a/slyy204a.pdf?HQS=null-null-hv-hvisolation_slyy204-asset-whip-electronicdesign_psfi_isolation_l1-wwe_awr&ts=1678433479218&ref_url=https%253A%252F%252Fwww.electronicdesign.com%252F
Tomi Engdahl says:
https://bmf3d.com/resource/part-of-the-week-land-grid-array/?utm_campaign=2023-q1-electronic-design-personifi&utm_source=part-week-land-grid-array
Tomi Engdahl says:
https://www.electronicdesign.com/markets/automation/video/21258469/electronic-design-silicon-microphone-detects-emergency-vehicle-sirens?utm_source=EG+ED+Auto+Electronics&utm_medium=email&utm_campaign=CPS230301136&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
https://www.electronicdesign.com/tools/learning-resources/whitepaper/21253827/millmax-mfg-corp-top-tips-what-to-consider-when-selecting-a-termination-style-for-specific-applications
Tomi Engdahl says:
https://www.electronicdesign.com/technologies/power/article/21261871/electronic-design-infineon-gears-up-for-a-future-powered-by-gan
Tomi Engdahl says:
Exploring power distribution networks (PDNs)
Visualizing the effect of bulk and decoupling capacitors
https://hackaday.io/project/189938-exploring-power-distribution-networks-pdns
We are all taught the importance of bypass or decoupling capacitors, but mostly through rules-of-thumb we ought to follow, such as: “each IC should have a 0.1 µF capacitor”, “add one 1 µF for every eight ICs”, place decoupling capacitors “as close as possible”, and so on. There’s very little about experimentally measuring and verifying the effect of capacitor networks.
The standard for measuring PDN impedance is a vector network analyzer (VNA) in a 2-port shunt-thru connection. VNAs are very expensive, and most VNAs are designed for communications applications instead of general impedance analysis (frequency ranges into the 10s of gigahertz, but bottoming out at hundreds of kilohertz or the low single-digit megahertz range). I’ve been exploring using a more humble setup of a spectrum analyzer with tracking generator to get good results, as long as some reasonable assumptions are guaranteed.
Tomi Engdahl says:
https://www.electronicdesign.com/technologies/analog/article/21261647/electronic-design-enhanced-3dprinting-technique-yields-custom-mems-sensors?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230301128&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
https://www.electronicdesign.com/markets/automation/article/21261678/neuronicworks-positioning-a-linear-servo-motor-with-a-pid-controller?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230301128&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
PCIe For Hackers: The Diffpair Prelude
https://hackaday.com/2023/03/14/pcie-for-hackers-the-diffpair-prelude/
PCIe, also known as PCI-Express, is a highly powerful interface. So let’s see what it takes to hack on something that powerful. PCIe is be a bit intimidating at first, however it is reasonably simple to start building PCIe stuff, and the interface is quite resilient for hobbyist-level technology. There will come a time when we want to use a PCIe chip in our designs, or perhaps, make use of the PCIe connection available on a certain Compute Module, and it’s good to make sure that we’re ready for that.
PCIe is everywhere now. Every modern computer has a bunch of PCIe devices performing crucial functions, and even iPhones use PCIe internally to connect the CPU with the flash and WiFi chips. You can get all kinds of PCIe devices: Ethernet controllers, high-throughput WiFi cards, graphics, and all the cheap NVMe drives that gladly provide you with heaps of storage when connected over PCIe.
PCIe is a point-to-point bus that connect two devices together – as opposed to PCI, an older bus, that could connect a chain of devices on your mainboard. One side of a PCIe link is a device, and another is a host. For instance, in a laptop, your CPU will have multiple PCIe ports – some used to connect the GPU, some used to connect a WiFi card, some used for Ethernet, and some used for a NVMe drive.
Each PCIe link consists of at least three differential pairs – one is a 100 MHz clock, REFCLK, that is (almost) always required for a link, and two pairs that form a PCIe lane – one for transmit and another for receive. This is an x link – you can also have 2x, 4x, 8x and 16x links, with four, eight sixteen and thirty-two differential pairs respectively, plus, again, REFCLK. The wider the link, the higher its throughput!
Treating Your Diffpairs With Respect
First off, you want to keep both of the pair’s signals close to each other throughout their length. The closer the two signals are, the better external interference cancellation works, and the less noise they radiate – given that often, multiple diffpairs run next to each other, this will help signal integrity of other pairs as well. Speaking of running separate diffpairs next to each other, you’ll want to keep them away from each other and other things – be it ground fills on the same layer, high-frequency signals. A great rule of thumb is the 5W rule, which says you need to have at least five trace width’s worth of clearance between a diffpair’s trace center and other signals. You don’t always have this much space, but it’s good to adhere to this as much as possible.
You will also want to make sure that there is an uninterrupted ground path right under these signals, alongside the entire pair – having a ground fill is ideal.
Then, there’s the little-talked-about matter – impedance matching. If you’re getting a differential pair from point A to B, you will want to make sure that you get the impedance right, and the basics of it are simpler than you might think.
Now, this means that you have to make sure the impedance for your PCIe link is good along its entire path – which, in practice, means picking suitable connectors and tuning your PCB trace widths and spacings. PCIe hardware is mostly built with 85 Ω impedance in mind. Things like receivers, transmitters, and PCIe-intended connectors are outside your control, and to get the impedance of the entire path is reasonably uniform, you have to adjust the parts under your control to the same value. For a start, if you have to use connectors for your PCIe link, pick ones that don’t have too significant of an impedance mismatch. A good bet is using high-speed connectors or connectors built with PCIe-like signals in mind – full-size PCIe, M.2, mPCIe, USB3, USB-C, and a lot of high-speed connector families from various manufacturers.
Now to tuning the impedance of your diffpair’s PCB traces. Differential pair impedance depends on a lot of variables in reality, but if you’re a hacker starting out, there are simplified calculators that get you most of the way there – this one is my favourite. Scroll down to “Edge-Coupled Surface Microstrip”, leave track height at 35 for routing diffpairs on 1 oz copper layers, leave dielectric constant at 4.3 unless your PCB fab gives you a different value.
https://www.multi-circuit-boards.eu/en/pcb-design-aid/impedance-calculation.html
Now, if you have ever tinkered with PCIe, you might have stumbled upon some forbidden knowledge: in practice, you don’t really-really have to do all of the above.
You might have heard that PCIe runs over wet string – the first known reference to this is in a 2016 presentation on console hacking at 33C3.
nd, unsurprisingly, there’s a big grain of truth – PCIe will still work in suboptimal conditions, and there’s an example after example of it in hacker and consumer worlds! Perhaps the most widely available example of PCIe abuse is passing an 1x PCIe link using USB3 cabling, something the “mining” PCIe risers do – which means that you can just go to your computer accessories store and buy a product that is only possible thanks to some PCIe abuse.
Something else that you might’ve seen and forgotten like a bad dream, is [TobleMiner] putting a x8 PCIe link through, shudder, prototyping wires – for the sake of testing out an adapter idea for cheap high-speed networking cards from HP servers, not compatible with regular PCIe slots both pinout-wise and mechanically.
PCIe is quite a bit more forgiving than quite a few other interfaces, say, USB3. There are link training mechanisms – when a PCIe connection is established, the receiver and transmitter play around with their internal parameters, adjusting them until they reach the fastest speed possible while keeping error rate low, using these parameters for the entire connection afterwards. There are also retransmissions for packets that failed to be received. PCIe has exceptional stability in practice.
It’s clear that PCIe link training has some unique parts to it – for instance, to help you make your layout better, PCIe also lets you invert any differential pair, except REFCLK, by swapping the negative and positive signals, and this will be detected and flawlessly compensated for during link training. Other technologies like USB3, HDMI, or DisplayPort don’t support such quality-of-engineer-life features. Other interfaces often require that multiple lanes should be the same length – making sure that data on one set of pairs doesn’t arrive faster than on the other. PCIe, however, is fine with across-pair mismatches as well, also detecting and compensating for these during link training. These two aren’t meant to be resilience features as much as they’re ease-of-layout features meant to help you design PCBs faster and better, but it sure helps that they’re there.
Try Your Best, No Matter What
Does this resillience help hackers? Yes, absolutely – these two ease-of-layout features are used in basically any professional PCIe design, and if you’re in less sterile conditions, you can push PCIe further at your own risk. On the other hand, don’t just skirt every rule because you’ve seen someone do that – put some good-faith effort into following these five guidelines, even if you’re limited to a two-layer PCB and might never get the perfect impedance value. Following these rules will not only teach you some diffpair discipline for later projects, it will make your PCIe signals all that more resillient and error-free, and your PCIe devices more happy. It might feel good to dismiss all or some of these guidelines, since sometimes it might just work out, but the extra half hour calculating proper impedance on your board will help you ensure that your PCB doesn’t need a second revision and stays loyal to your interests throughout its entire life.
So, here’s a guideline: treat your PCIe differential pairs with respect. If you’re using a two-layer PCB and you’re doing a prototype on the cheap and you want quick turnaround time, don’t just give up on impedance because the traces would need to be way too wide to reach 85 ohms – open the calculator and see just how much you can get the impedance down anyway. Lowering isolation height lowers impedance, so consider going for 0.8mm PCB if your project’s mechanical aspects let you. Move your components around if that helps your PCIe tracks follow a better path, with less noise along the way. Perhaps link training will knock an imperfect link down a generation or two, but that’s better than not reaching a stable link at all. Put your best effort following these guidelines with what you’re given, and the differential pairs will respect your intentions in return.
For instance, if you’re using KiCad, here’s a simple demonstration on how to get a PCIe 1x link from one point to another, routing differential pairs while taking care of impedance, clearances, and via stitching.
PCIe x1 link diffpair routing example (KiCad 7)
https://www.youtube.com/watch?v=dZC2e_oUon8
Tomi Engdahl says:
AmberSemi’s Newly Taped-Out IC Extracts DC From AC Mains
March 15, 2023
The company’s manufacturing milestone represents the start of commercialization and technology integration with key product and semiconductor partners.
https://www.electronicdesign.com/technologies/power/article/21262055/microwaves-rf-ambersemis-newly-tapedout-ic-extracts-dc-from-ac-mains?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230309172&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
In Booth #131 at APEC 2023, Amber Semiconductor will feature the first tapeout of one of its three core technologies: The company’s AC Direct DC Enabler has entered the manufacturing and integration phase. The fabless house’s chip extracts dc directly from ac mains without the use of transformers, rectifier bridges, or filtering.
The AC Direct DC Enabler silicon chip enables dynamic delivery of dc power on demand while requiring only half the components of today’s standard, comparable systems. By pairing dynamic power capabilities with a much smaller system size, AmberSemi hopes to enable significantly more capabilities and features to be added into electrical endpoints without altering the standard footprints of products. Such products include smoke detectors, doorbell cameras, thermostats, smart products, appliances, intelligent HVACR, and more.
The technology can be paired with key semiconductor devices like microcontrollers and wireless radios to create AC Direct semiconductor systems. These would enable both housekeeping power plus outside sensor power provisioning from the single AC Direct system.
Configurable Converter
The AC Direct DC Enabler operates as a configurable power converter, without the need for rectifier bridges, input filtering, or transformers. The device converts a wide supply voltage range of 25 to 277 V ac, 50/60 Hz input to a regulated 1.8 V to 24 V dc, with a capability of up to 5 W of power across all voltages. In addition, two auxiliary regulated dc outputs providing 5.0 V and 3.3 V, respectively, are available.
Tomi Engdahl says:
Spray-On Coating Provides EMI Shielding that Easily Switches On/Off
March 15, 2023
By electrically “teasing” the ions using an electrolyte-bearing MXene film, it can be switched between being a barrier or being transparent to RF energy.
https://www.electronicdesign.com/technologies/industrial/article/21262043/electronic-design-sprayon-coating-provides-emi-shielding-that-easily-switches-onoff?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230309172&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
What you’ll learn:
Why and where room-scale EMI shielding is needed.
How MXenes can be used for electrically controllable EMI shielding.
The performance achieved with this switchable shielding.
Many situations arise in which you need to provide RF shielding for a “public” room or large enclosed area, yet where standard anechoic-chamber EM-absorbent foam isn’t appropriate, attractive, or sufficiently rugged. Such shielding may be needed so that electromagnetic energy from within the room doesn’t leak out to avoid being intercepted or compromised. Conversely, it may be a setting where people talking on their phones would be annoying to others, such as a theater.
Tomi Engdahl says:
Home » 190+ DIY Audio Projects » Stereo Audio Switch Circuit
https://www.electroschematics.com/stereo-switch/
Signal Detecting Auto Power-On Unit
https://sound-au.com/project38.htm
Tomi Engdahl says:
Module 5.3
Audio Optocouplers
https://learnabout-electronics.org/Semiconductors/opto_53.php
In audio systems isolation between inputs and higher voltage/current equipment is usually provided by audio transformers, however it is also possible to use specialised audio optocouplers such as the IL300, which uses an infra red LED to illuminate one photodiode as an output device and a second photodiode to provide feedback, ensuring improved linearity and wider frequency range than phototransistor or photoresistor alternatives.
However it is also possible to use some of the much cheaper, general purpose phototransistor optocouplers for audio applications, such as the popular 4N25 illustrated in Fig. 5.3.2 also from Vishay, which is normally used for low frequency digital signals (in saturation mode) or DC applications (in linear mode) for limited audio applications.
For the 4N25 to provide isolation for audio signals the input to the infrared LED must be appropriately biased with a DC voltage, so that when a modulating AC (audio) signal is applied, the current through the LED can be varied without the optocoupler output reaching either saturation or cut off. This is really an extension of the linear mode of operation, and can be applied using either one of two basic configurations, phototransistor or photodiode.
The circuit shown in Fig. 5.3.4, adapted from a design in Newnes Electronic Circuits Pocket Book by Ray Marston (ISBN 10:1-4832-9192-8) uses the 4N25 connected as a phototransistor to pass audio signals whilst isolating the input and output circuits.
However, because Fig. 5.3.4 uses a 4N25 in phototransistor mode, the useful bandwidth of the circuit is rather limited, as shown in Fig. 5.3.5 making it useful for speech, but lacking gain at frequencies above 8kHz, a typical effect due to the large base/emitter junction capacitance of the phototransistor.
Fig. 5.3.6 shows an improved circuit with a full audio bandwidth, achieved by using the 4N25 in photodiode mode where only the collector base junction is used, forming a photodiode with much less capacitance than with the full phototransistor. The downside of this method is that the 4N25 output is now reduced to milli-volts rather than volts. For this reason it is necessary to add a buffer amplifier (IC3a) having high input impedance, immediately after the optocoupler.
The audio bandwidth of the circuit is now increased to cover a useful range from about 400Hz to 18kHz as shown in Fig. 5.3.7; still not hi-fi but quite useful as part of an audio amplifier for many isolation purposes.
Tomi Engdahl says:
https://community.element14.com/learn/learning-center/essentials/w/documents/27957/an-introductory-guide-to-microphone-operation
Tomi Engdahl says:
https://www.electricalengineeringtoolbox.com/2017/07/how-to-calculate-inductance-of-electric.html
Tomi Engdahl says:
Standalone Active EMI Filter ICs Support High-Density Power Supply Designs
March 20, 2023
These EMI filter ICs enable engineers to design smaller, lighter, and more affordable power supplies while optimizing system performance, efficiency, and reliability.
https://www.electronicdesign.com/technologies/power/article/21262244/microwaves-rf-standalone-active-emi-filter-ics-support-highdensity-power-supply-designs
In its Booth #916 at APEC 2023, Texas Instruments (TI) is debuting the industry’s first standalone active electromagnetic interference (EMI) filter ICs, enabling engineers to implement smaller and lighter EMI filters. Such filters can enhance system functionality at reduced system cost while simultaneously meeting EMI regulatory standards.
With electrical systems growing denser and more interconnected, mitigating EMI is a critical system design consideration for engineers. TI’s new portfolio of standalone active EMI filter ICs can sense and cancel common-mode EMI by as much as 30 dB at frequencies between 100 kHz and 3 MHz in single- and three-phase AC power systems. This capability enables designers to reduce the size of chokes by 50%, compared to purely passive filter solutions, and meet stringent EMI requirements.
One of the main challenges when designing high-density switching regulators is how to implement a compact and efficient design of the EMI input filter. Through capacitive amplification, these new active EMI filter ICs enable engineers to shrink the inductance value of common-mode chokes by as much as 80%, helping to cost-effectively achieve improved mechanical reliability and increased power density.
The new family of active EMI filter ICs consists of the TPSF12C1 and TPSF12C3 for single- and three-phase commercial applications and TPSF12C1-Q1 and TPSF12C3-Q1 for automotive applications. These devices can efficiently reduce the heat generated in a power-supply EMI filter, which also extends filter capacitor lifetimes and increases system reliability.
Tomi Engdahl says:
https://www.mwrf.com/technologies/semiconductors/article/21262129/microwaves-rf-standalone-active-emi-filter-ics-support-highdensity-power-supply-designs?utm_source=RF+MWRF+Today&utm_medium=email&utm_campaign=CPS230317066&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
Survey: Artificial Intelligence and Electronic Design
March 21, 2023
We would like to find out what you are doing with artificial intelligence and machine learning in your development environment.
https://www.electronicdesign.com/resources/industry-insights/article/21262395/electronic-design-survey-artificial-intelligence-in-electronic-design?utm_source=EG+ED+Auto+Electronics&utm_medium=email&utm_campaign=CPS230316043&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
Hot Off the APEC 2023 Show Floor
March 21, 2023
Here are some of the new products catching our attention on the show floor at the Applied Power Electronics Conference in Orlando.
David Maliniak
https://www.electronicdesign.com/technologies/power/media-gallery/21262366/microwaves-rf-hot-off-the-apec-2023-show-floor?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230316025&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
Three Major Design Pitfalls Plaguing New Analog Signal-Path Designers
March 6, 2023
Wouldn’t it be great to not repeat the same amplifier application errors many new designers fall into? Read on to head off these common confusions and oversights.
https://www.electronicdesign.com/technologies/analog/article/21261391/three-major-design-pitfalls-plaguing-new-analog-signalpath-designers?utm_source=EG+ED+Update:+Power+and+Analog&utm_medium=email&utm_campaign=CPS230317003&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Having been on the receiving end of designer queries from 1985 forward, there are some common oversights and misunderstandings that show up regularly. These essentially fall into three areas:
Not considering the actual operating voltage range on the I/O or internal pins of the device being used.
Misunderstanding the elements that contribute to an output dc offset or drift error.
Accidentally building an oscillator (or even worse, a nominally stable design that slips over into oscillation over production and/or temperature ranges).
Tomi Engdahl says:
13 reasons to start using Power Stage Designer
https://e2e.ti.com/blogs_/b/powerhouse/posts/13-reasons-to-start-using-power-stage-designer?HQS=app-null-null-powerdesignresources_powerstagedesigner-exexnl-ta-electronicdesign_0322-wwe_cons&DCM=yes&dclid=COn2kcmU_v0CFY2PmgodKgQJkg
For more than a decade, TI’s Power Stage DesignerTm tool has been a great design aid for electrical engineers when calculating the currents and voltages of different power-supply topologies. I believe it is an easy tool to start a new power-supply design, because it executes all calculations in real time, and you get direct feedback.
Our latest version of Power Stage Designer includes a new topology and two new design functions on top of its existing set of features that will help you further accelerate your design time for developing power supplies.
The new tool contains a field-effect transistor (FET) losses calculator, a current-sharing calculator for parallel capacitors, an AC/DC bulk capacitor calculator, a resistor-capacitor (RC) snubber calculator for damping ringing across rectifiers, a resistor-capacitor-diode (RCD) snubber calculator for flyback converters, an output-voltage resistor-divider calculator, dynamic analog and digital output-voltage scaling calculators, a unit converter, a Bode plotting tool for loop compensation, a load-step calculator, and a filter designer. Let’s look at each of these 13 features in detail.
Tomi Engdahl says:
Radical Approach: Active EMI Filter IC Shrinks Higher-Power AC-DC Supplies
March 24, 2023
A new IC-based approach to EMI filtering in ac-dc power subsystems dramatically cuts inductor size and offers other benefits as well.
https://www.electronicdesign.com/technologies/power/article/21262674/electronic-design-radical-approach-active-emi-filter-ic-shrinks-higherpower-acdc-supplies?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS230323063&o_eid=7211D2691390C9R&rdx.identpull=omeda|7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
Inductor Cores: Material and Shape Choices
https://www.mag-inc.com/Design/Design-Guides/Inductor-Cores-Material-and-Shape-Choices?gclid=EAIaIQobChMIkdSi7dP-_QIVLgqiAx2QLgJtEAAYASAAEgLDmPD_BwE
Tomi Engdahl says:
INDUCTORS 101
https://www.vishay.com/docs/49782/49782.pdf
Tomi Engdahl says:
https://www.electronics-tutorials.ws/transformer/transformer-construction.html
Tomi Engdahl says:
https://www.allaboutcircuits.com/textbook/alternating-current/chpt-9/phasing/
Tomi Engdahl says:
https://electronics.stackexchange.com/questions/6657/what-do-phase-dots-on-an-inductor-mean