Questions tagged [common-mode-choke]
A type of choke in which two coils are wound on a single core in order to pass differential currents while blocking common mode currents.
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How to create schematic of common mode choke that reflect on Common mode, differential mode and mixed mode? [closed]
I aim to create a schematic that can replicate the results exactly as seen in the measured S4P file. I have conducted the measurement using a VNA and am attempting the schematic simulation in CST. ...
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Can a common mode choke be used to filter a SMPS dual power supply?
I have a switched mode dual power supply with +12V, GND and -12V outputs. I'm seeing a lot of high frequency noise on the output of this power supply that I'd like to attempt to filter out. The noise ...
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Current Rating in Common Mode Choke
What is the meaning of this current rating which says "unbalanced" current?
I know in common mode chokes the common mode current rating is given. Why here it is written as Iunbal.?
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How can I select a common mode choke for DC/DC power conversion stages
I want to attenuate 15 MHz noise signal using a common mode choke at 5 V power lines stage of a circuit that generate digital signals with less than 100Mhz.
When you use a common mode choke for a ...
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How are SPICE files created compared to S4P files generated from a VNA?
When measuring impedance versus frequency using the same data in both SPICE and S4P formats, why do I obtain different results?
COMMON MODE IMPEDANCE
Common mode impedance 10514 Ohm at 79.1 MHz
S4P ...
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LTspice parameters
I want to know how the .mod/.lib files in Ltspice are created by manufacturers. Let's say we have a Common Mode Choke (CMC). It will have some parameters as per its equivalent model at different freq ...
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Challenges in Bandwidth in Common mode Choke Modeling
I'm currently working on characterizing a common mode choke (CMC). However, I'm encountering difficulties aligning the bandwidth of my model with the measured results. Specifically, when I attempt to ...
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Why is a bandwidth discrepancy occurring despite consistent Q factors in the given Graph?
I was trying to do curve fitting the common-mode choke in CST Studio according to the selected S4P file from TDK (ACT1210G-800-2P-TL05).
However, the common-mode impedance measured from the file does ...
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Why my Common mode choke with 2 turns showing multiple Peaks in the graph?
I analyzed the CMC choke by Wurth Electronics (part no: 744830039080) using VNA and obtained the insertion loss for both common mode and differential mode.
The graphs match with the datasheet:
While ...
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Why is the core resistance modeled as 2*Rp and capacitance as Cp/2 in a common-mode choke?
I directed my attention to a paper regarding the modeling of common-mode chokes. Within this paper, the authors structured the circuit in such a manner that they designated the core resistance (...
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Choke Placement for POE top or bottom?
a colleague designed the pcb and I wanted to remove the bottom components and place them on top so that we may attach a flex pcb to the back side.
Attached is an image of the L3 choke, is there a ...
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Is Noise filter needed for CAN passthrough?
The structure is simply diagrammed as follow. My Board provides only routing connecting each connector for other ECUs using CAN channel.
My queistion is if i need additional CMCs on the routing. Are ...
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Multiple resonance frequencies of common-mode choke
In the datasheet of the CMC (common-mode choke) below (Würth Elektronik 744830017132), the impendence vs frequency graph has multiple peaks (resonances) which I marked.
The first one is the Self ...
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Common mode choke placement for good EMC performance
I am interfacing a deserializer with Quectels smart module.
The CSI lines of the deserializer are connected to the CSI lines of smart module.
A common mode choke is placed in between them. The ...
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Common-Mode or Differential-Mode Choke Circuit
This circuit, located at the entrance of our power circuits in the products produced in the company I work for, caught my attention. The design of the circuit was completed a long time ago, and now ...
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Sizing a Common Mode Choke - Inrush or Normal Current
I am looking to use an LS05-13B05R3 in a design, and am looking at a choke such as the RN114-0.3-02-47M. Is this suitable given the lower current requirement of the LS05, or should I size it for the ...
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Equivalent circuit of CM and DM EMI filter
This is the diagram of an EMI filter consisting of both CM and DM filters:
This is the equivalent circuit of the CM filter:
Could someone explain why in the equivalent circuit, it's Lcm and not 2Lcm?...
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Common mode choke on internal cable to pass EMC testing
I am undecided whether or not to add a common mode choke in my product that needs to undergo EMC testing for CE marking. Let me describe my case... My device is split into 2 parts, connected with each ...
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Is this component correctly used?
So, There is this schematic that a previous collegue made for a project that I took over that have some EMC problems (Burst/EFT).
The problem is that 12V on the secondary side of the transformer(not ...
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inductance for choke inductor EMI filter
How do you select the choke inductance for an EMI filter?
I'm trying to design an EMI filter for a primary side of a transformed which takes 230VAC and steps it down to 24VAC at maximum of 600VA (~3A ...
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Common mode choke impedance selection USB 2.0 Data line [duplicate]
Below schematic shows a USB connection diagram.IN this you can see a common mode choke (DLW21HN900SQ2L)
The common mode choke impedance is given as 90 Ohms @ 100 MHz .The USB is working at 480Mbps.
I ...
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Saturation current of Common Mode Choke
I am currently designing a driver for a brushed DC-Motor.
The motor is driven by a full bridge (PWM) that switches at about 20kHz.
For our application, it is required to increase the inductance of the ...
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Surge suppresor design - DM, CM chokes and resistor is series with varistor
While designing a surge suppressor, I came up with an online schematic where they use a differential mode choke and a common mode choke.
I put one toroid choke coil as the differential mode choke.
...
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How to choose a common-mode choke for DisplayPort 1.4?
I'm trying to pick a CMC for a DisplayPort 1.4 interface which I'm going to impalement in my design.
I came across this LCFE121002A900TG CMC which I found at Mouser (let's say I'm interested in the ...
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How to check the polarity of a common-mode choke?
I purchased some common-mode chokes and the documentation provided states:
As this pinout does not correspond to other chokes of the same format, I have doubts about the position of the dots (pins 1 ...
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Why are there two common-mode chokes on AC input?
This is a part of an AC/DC converter schematic from TI.
There are two common-mode chokes on the AC input side.
I have no idea why two CMCs (L100, L101) are used.
Could anyone explain this?
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Common mode choke - short?
I am experiencing weird behavior with a common mode choke and had a few questions.
The circuit in question is this:
I am using a desktop power supply at 28V and 200mA current. This is the first time ...
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Measuring / estimating unknown common mode choke and transformer
Out of curiosity and to improve my reverse-engineering skills, I'm currently reverse engineering a rather simple 12V switch-mode power supply adapter.
Most of the markings and the topologies are fine, ...
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What is the exact type of this common mode choke?
I have this(on the picture) element missing from my PCB but I cannot find the exact model and specification.
The text on it says G8276D3. Can somebody recognize it?
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ESD protection only with a common mode choke
In general, for a successful CAN/CAN FD communication one needs protection against ESD pulses and common mode noise. Most of the time the protections are made by TVS diodes and common mode choke (see ...
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USB-C pulldown resistors before or after common-mode choke?
I'm designing a board with a USB-C upstream-facing port (UFP) for power only (no data). I've included a common-mode choke, as well as a ferrite bead filter in pi configuration. Since I'm presenting as ...
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Isolation voltage of common mode choke, if used as coupled inductor?
I have a project where I need a small coupled inductor for isolated low baudrate communication. The line is short and I don't really care if only half of signal goes through.
I need it really cheap, ...
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Signal reference with common-mode filter on the power lines
What is the recommended way to handle the following situation regarding the control signals?
Since the ground is separated with a common-mode choke between the source and the destination I'm thinking ...
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10 dBuV EMI noise suppression from 0.8 to 1.8 MHz
The 30 V 500 mA power supply I'm working on needs to pass the EMC (EN55015) test. I am attaching the necessary circuit diagram (common mode and differential mode filters) to pass the test according to ...
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Paralleling common mode chokes
Regular chokes can certainly be used in parallel so that multiple smaller chokes with a lower current rating can be used. But does this also work for common mode chokes?
I would assume that ...
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Common Mode Choke Usage
I am using a ACM70V-701-2PL-TL00 Datasheet to attempt to filter out A/C ripple in an in-vehicle audio device. I've run the input 12v through one channel of the ...
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Common mode choke - Why only impedance?
Why are most common mode chokes only given with a impedance curve, inductance at a specific frequency and current rating (this is clear😅).
Wouldn't be S-parameter better? I know it's more work, but ...
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Common mode choke - alternative part
I have sent out a PCB for manufacture and the manufacturer has suggested an alternative part.
The application is a mains powered (220V AC 50Hz) device. The common mode choke is being used to filter ...
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Can CM choke windings be used for LC filter at the output of SMPS or DC-DC Converter?
I need to filter out switching noise at the output of SMPS/DC-DC converter with an LC filter.
I have a bunch of CM chokes lying around.
Can I use a common-mode choke:
with both CM windings connected ...
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How to choose a common mode choke for ethernet?
I'm currently working on a design which contains gigabit ethernet. Due to some weird size constraints, I can't use a magjack or one of those transformer ICs, so I'm using discrete magnetics. I've ...
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Use of common choke with more than 2 wires
I've been looking around and I couldn't really get a good answer to this question, not even in Henry Ott's book (so far), so here it goes:
What is the best approach when there is the need to place a ...
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DC-DC fixed voltage output converter and EMI Design, where to begin and roadmap?
I'm in a group of people tasked to design and implement a DC-DC converter with an output voltage of 24 volts, with an input voltage from 9 to 36V, with an EMI filter, which must comply with the ...
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Common-mode choke on LTSpice
Can someone suggest to me how to select a three-phase common-mode choke with self and mutual inductance in LTSpice?
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Isolated BNC connector in metal chassis, EMC considerations
I consider using an isolated BNC connector for a precision application, in which the BNC Shell will be either grounded via an internal switch or used as a Guard electrode. The motivation behind this ...
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Why are common mode chokes with 90 ohm @ 100 MHz recommended for USB 2.0 Hi-Speed data lines?
When one looks at common mode chokes for USB 2.0 applications choke manufacturers always recommend CMC with a common mode impedance of 90 ohms @ 100 MHz.
Example
How does this relate to
USB 2.0 ...
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How to choose DC resistance parameter of a USB 2.0 common mode choke?
How do i know whether i have to choose a bigger sized common mode choke with lower DC resistance for USB 2.0 D+/D- lines or using a smaller one with higher DC resistance is also just ok?
In fact there ...
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Why do common-mode EMI filters lack damping networks?
I've been going through the design of a few different EMI filters, mainly for buck converter inputs.
In many cases the leakage inductance of the CM choke can provide enough inductance for the ...
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If a common mode choke (CMC) is added between PWM signal and PWM return without additional chassis return path, will it act as a common mode filter?
In this schematic a common mode choke is added between PWM output and PWM ground (return path.) There is no other return path to load (like through parasitic capacitance to chassis.) In this case, ...
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What Common Mode Choke choose for EMI filtering at 250v
I'm designing a PCB with a microcontroller that have to handle 3 Relays. The main power source is an AC Inlet socket 250v, the maximum current for all the circuit from this source is 15A (I included a ...
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Common mode filtering a shunt: "active" vs. "passive" strategies (diff. amp vs. common mode choke)
If you are trying to observe a relative small voltage across a shunt resistor and you are finding common mode noise interference induced in the signal, in what cases would you choose to use something ...
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