{583} Current Sense Resistor Calculation
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- Опубліковано 15 лип 2024
- Current Sense Resistor Calculation in Flyback Converter UC3843 DCM Flyback SMPS design. current sense resistor or current shunt resistor in Current-mode control is widely used for switching mode power supplies due to its high reliability, and it protects and limits the current at peak output power operation,
Download Current Sense Calculation bit.ly/3jxHHl6
The current sense signal is an essential part of a current-mode switch mode power supply design; it is used to regulate the output and also provides overcurrent protection. The current sensing circuit for UC3843 in current-mode control provides the protection at full load operation and ads the current limiting facility in the design. The sense resistor RS monitors the current. it is connected at source pin of the mosfet and ground line of the dc rail. the all current have to flow through this resistance and it is causes to drop voltage across this sense resistance. thus these dropped voltage are fed to isense pin of the UC3842, UC3843, UC3844, UC3845, as the current reaches are at its peak primary current value, it detects the peak voltage for the current sense comparator, which immediately terminates the drive pulse until the voltage across this sense resistance drop below 1 volt. The UC384x family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lockout featuring start-up current less than 0.5mA, a precision reference trimmed for accuracy at the error ampinput, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem-pole output stage designed to source or sink high peak current.
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#current #sense #resistance
SMPS practical tutorial • SMPS Switching switch ...
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Current Sense Resistor Calculation, in Flyback Converter, UC3843 DCM Flyback SMPS design, how current sense resistor work, how to make a shunt current sense resistor, how to use current sense resistor, haseeb electronics, how to design smps, how to design smps switch mode power supply, how to design smps power supply, smps design calculations, smps power supply design calculations, how to find burnt out resistor value, smps design tutorial, smps circuit design tutorial
00:00 Introduction
00:14 What is Current Sense Shunt Resistor
00:57 Why Current Limit sense resistor is used in SMPS
01:07 How Current Sense resistor Works
02:01 How to calculate output power
03:59 How to test frequency of PWM IC using multimeter
04:50 How to calculate time period
07:17 How to calculate inductor value in flyback smps
10:35 How to calculate peak primary current in smps
14:48 How to test current limit signal in SMPS - Наука та технологія
شكرا للنشر يا غالي
thanks a lot dear brother
I am not only learning about smps... But many things in basic electronics... Which I was unaware/ignourent for such a long time, many thanks to you sir!!! 🙏🙏🙏🙏
it is my pleasure
special thanks for your beautiful words
Another incredibly useful video. Very well explained. Thank you for sharing your knowledge with us!!
Walikumaslam Bhai me agai ap k ghr zabadst sharing
best regards and special thanks
Awesome, you explain everything very well and fluently.
Thank you.
best regards 💕
W Salam good work big like nic shering stay safe stay blessed u
thanks a lot dear sister
There's no one on UA-cam who takes these things up in such detail. Very well explained sir thanks a lot for being supportive.
special thanks for your valuable comment
Beautiful video
Haseeb is the best , thank you from Uruguay.
i am thankful for your valuable words
I really appreciate your teaching,I have a lot of interest in learning more and more electronics repair and I have learned a lot from you, thank you very much and God bless you,
You are very welcome
Mashaallh beautiful sharing
Very informative video. Thank you so much.
it is my pleasure
great job Weldon
thanks Raj Bhai
Thank you so much
You're most welcome
Awesome video dear friend, have a happy Sunday!
thanks a lot dear friend
Well don
Nice video good content thanks for shining a very beautiful and wonderful videos
Many many thanks
Hamare ghar Bhi Aaya Karen
Thank you very much
You are welcome
You are amazing teacher! Thank you so much Sir
You are very welcome
Beautiful Share Liked Very Much # 250
thanks a lot Zargar Bhai
perfect 👏👏👏
Nice sharing
thanks a lot
Very interested video
thanks a lot
one of the best way u have explained . Thanks a lot for such a wonderful teaching. This calculation seems to be little bit complicated.
thanks a lot
no it is not complicated
it is the simplest most calculation, which i shared
Thank you sir ..🙏
Sir every video is informative..
With nice deep explaination.. with formulas and examples..🙏
special thanks dear brother
You are great brother
Thank you so much 😀
Amazing teaching, thx for sharing.
special thanks for your encouraging comment
please accept my best regards
very good instructive keep my thumb up for you sir
Many thanks
Good sharing bai
Many many thanks dear sister
Excellent thanks for sharing this informative video
thanks a lot
I appreciate your work sir.you are real may Allah protect you and those who believe in you.
Jazaak Allah khairan
Very useful information sir thanks for sharing this knowledge to us
thanks a lot
good job thanks
جزاک اللہ خیرا
رمضان مبارک
شكرا لك على هذه القناه الجميلة
most welcome dear brother
Good video nice sharing well done new friend
most welcome dear
Very good explain. Thank you sir.
You are welcome
Wise Master... You are a great Teacher... I hope to learn your powerful techniques... We must keep the art of Electronic Repair alive.. Inshallah.
special thanks and best wishes
Like done ✅.
Nice sharing 😊
special thanks
Thanks
most welcome
thanks.
You're welcome
walikum salam nice sharing 🇺🇸
W assalam Bhai 🌹
Mashallah thanks for sharing
thanks a lot dear sister
Multimeters have their own internal resistance as well. That’s why when measuring the current sense with regular meter it will not show correct value. You need an oscilloscope or a true peak to peak measuring device.this guy is a real good teacher. Ty for showing us how to prove it. Well done.
yes dear your right
multimeters have internal resistance but that is much high so these don't effect too much,
biggest effect is that the multimeters use RMS or TRMS sampling method and their high frequency is not good specially higher frequencies and duty cycle based pulses.so that's why we need oscilloscope to measure peak voltage or we need four wire measuring technique to get true rms value then we can convert in peak value by multiplying with 1.414
@@HaseebElectronics Awsome ty.
You are excellent in teaching
Very very honor to you dear sir
Many many thanks
Big like 104 fantastic video 😌 have a great day and be safe ☺️
best regards and special thanks
ما شاء الله عليك
best regards
Good
Anazing explanation
thanks a lot dear
Süper
wa'alaikumsalam
great sir
thanks a lot
Mashallah brother very nice very beautiful
thanks bhai
Good 👍👋👋
thanks a lot dear friend
Current Sence Resistor Kalkulator👍🏻👍🏻
So nice
thanks a lot
Tq ( sir)
Good....
thanks bhai
AssLamualaikum Warahmatullah ibarahkhatuhu. Well done brother.
Very good explanation.
Masha Allah for such work.❤️
وعليكم السلام ورحمة الله وبركاته
thanks a lot dear brother
👌👌👌👍
thanks a lot
Your all videos are so informative I watch regularly I learnt so many things can u please tell how to caculate power of current sense resistor
👍
it is my pleasure
17:17 Alhamdulillah full watching the video 👍
thanks a lot dear
.ماشاء الله بهوت تميز هي
thanks a lot dear brother
Salaam Janab Bhai Saab
wa salaam dear brother
I was expecting to see the one voltage drop that you explained in the oscilloscope.. with load...instead of 116mV without load. Can the inductance of transformer primary be found on data sheet or measure with LCR meter?
Sir, thank you for the amazing videos, I have gained so much knowledge from following your explanations.
Could you please make a video with focus on possible short circuits in the output side of SMPS? I am trying to fix my laptop adapter but unable to locate shorted component. In off board testing, output terminals of the adapter are showing continuity. For reference, I am working on a 135W, 20V Lenovo adapter using DAP019E IC(input side) and DAS01B IC & DAS05 IC(output side). I have checked all capacitors, MOSFETs and optocoupler after removing them from the board but the short still remains. I'm extremely motivated to fix this adapter and learn more about SMPS in the process. Thank you again.
kartınızda yanmış bir kısım var mı? var ise tüm yanmış kısmı temizleyin !
(this is article is turkish)
❤️❤️❤️❤️❤️Amazing Sir, can u please tell me that how to find max operating frequency of output rectifier diode, like sr360, fr107 etc and can we connect two diode in parallel to increase rectifier current?🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏
Hi sir,
Can we substitute L primary value with LCR meter ?
I would expect the inductor efficiency adjustment to be 1/efficiency, meaning a requirement to increase the size of the inductor with a 10% reduction in efficiency. So, 0.9 should be in the denominator?
Amazing teaching there dear haseeb sir,you are an awesome teacher.insallah we hope to see more of your amazing videos.
Jazaak Allah khair
رمضان مبارک و کل عام و انتم بخیر
11:40 - Please tell the name of the calculator app you’re using. I like the decimal grouping and number of places displayed. Impressive!
play.google.com/store/apps/details?id=cz.hipercalc&hl=en
hiper calculator from google play store
Thank you very much for your educational videos... I have learn many points from you..... Sir I have SMPS power supply (FDPS-100N-R5) and it is working some times with small vibration sound... most of the time not working.... I have checked many components and all are okay... please give advice to solve this problem...
thanks a lot
please check that the transformer core pieces are not separated.
check the VCC capacitor connected to the VCC pin
check output side capacitors
good explanation. during this calculation of inductor, what is the convert value of 2.5
it is to use for DCM flyback calculation
I've been following you for some time now. Could you provide the circuit for this source? Thanks
I wish someday you would discuss car ECU, how it works.. tnx.
yes dear i am already trying to arrange for it. as i receive too many suggestion to explain ECU assemblies
What if we don’t find exact value current sense resistor when blown. Please help.
Kindly explain the proper connection of pin 1 and 2 of any uc38xx because it given me serious problem the IC can't start and if I touch the + probe lead of my multimeter it will start oscillating and the frequency is not stable
Thanks
dear i have 1 doubt should Rds of mosfet not incorporated
Thank you very much
How calculate input watt for this board 72 watt in output
72 watt + losses
72 x 110% = 79.2 watt approximately
take 110% of the output power, it will include the input all losses and the switching losses and transformer losses
LG double door PCB mein kya 5 tar wali supply kam karegi
Outstanding!!!
Can I have a PDF of Lpr calculation, thank you in advance.
thanks a lot
i added the link of the calculation in the video description
please check description
@@HaseebElectronics thank you so much bro
please how do we calculate or know the auxiliary voltage.
auxiliary voltage are to be calculated by checking the
VCC voltage, UVLO lower & upper limits.
after winding, finally it can be adjusted by adding a current limiting resistance at vcc pin to compensate the difference in calculation and practical winding turns
Teach more
jzakm allah khir Mr HASEEB important Q can you replay to me ?
if this SMPS 6A in output MAX is this translate in primery as 2.94A
2.94A in prim = 6A in secondary
so this protect output from overcurrent?
Haseeb
Where did you obtain the duty cycle value of 48%? Because looking at the datasheet, max duty cycle for UC3843 states 100%. Is this a design choice? What if you were using UC3844 or UC3845 where in the datasheet it states max duty cycle to be around 48%?
Secondly, there's not really a need to go back and forth looking for inductance L of the primary coil and plugging things back and forth. The Ipeak can be calculated from the simplified expression below because a lot of the expressions cancels out.
Duty_cycle = t_on/t
Ipeak = 2.5/Transformer_efficiency/Duty_cycle*Pout/VinDC_min
Ipeak = 2.5/0.9/0.48*72/141.4=2.946A
When choosing Rsense value, are we choosing for a value where Ipeak is below the saturation current of the primary coil? Also we are simply choosing a value from worst case scenario. Whereas in normal operational mode, we do not really approach this region?
Lastly, I have a question about the scenario where the input voltage is 230VAC, what happens then? How do I figure out what current is running through Rsense? Does the duty cycle now change because VinDC is much larger (and the duty cycle is changed from the feedback loop of the SMPS)?
Thank you.
best regards and special thanks
1. the Dmax for 3842/43 is 96% for CCM operation. but when we discuss DCM operation, then its duty cycle is limited upto 48% maximum, above than this the core drives in saturation
2. as any power supply is calculated and designed in worst case scenario, Low line voltage & peak output power, in this situation the SMPS controller must utilize its maximum duty cycle
when the line voltage will increase, the SMPS controller will change its duty cycle to maintain regulation
at that time the current in primary will not reach to peak, because in this situation the transformer works in linear region, because the magnetic fields is in building up stage
@@HaseebElectronics OK thank you for the reply. Sorry, I'm not too familiar with the terms. . . DCM? CCM? Where do I see this in the datasheet?
EDITED: Nevermind, I found in some other datasheet about Discontinuous Current Mode and Continuous Current Mode.
As for #2, ok that makes sense. So in the design scenario, I have to make sure that my selected PWM chip will be able to output the duty cycle at the higher line voltage?
I have an issue with a SMPS circuit and I can't seem to figure it out. It's a Ridgid charger that was designed to 110VAC with a PWM chip that carries the marking 6853M27 and JCS4N60FB MOSFET. I was trying to modify the charger so it would work up to 230VAC. It partially worked when I changed out the bulk capacitor and MOV at the high-side input to be suitable for 230VAC line voltage. The charging circuit was shutting off but there were no sparks or short circuits. Turns out later I found out that the auxiliary winding of the transformer that is providing Vdd to the PWM chip was too high of a voltage causing the PWM to go into OVP and shutting off.
However, when I was probing, my probe accidentally slipped and short a leg of Rsense to GND of the PWM chip. This caused the MOSFET to short circuit failure between Drain and Source, I believe my Rsense resistor went into open circuit and a few rectifier diodes on the high side also went into open circuit. When I was trying to fix it, I I replaced components with what I believe are suitable substitutes but I can't seem to get the board to work again without something short-circuiting or blowing. I was wondering if you might be open to help with troubleshooting? I can provide more details and circuit diagrams/picture of the board etc. But if you're too busy, I also understand. Thank you!
Assalaam alykum jnaab.
Kya LED bulb ke ripearing me use full vdo bnaayege aap.?
🤲
Here 2.5 means?
Three years before i ask you a question why for hout mosfet is not use instead of transistor in crt t.v
Dear Sir
Really i remember that and i missed it
i am sorry for that
but i will try my best to explain it. many questions were delayed due to my health issues, but now i am back on platform and will address
sir
if possible please
send your question on my whatsapp again
i lost that question. i tried to find it but i couldn't
if possible please send to 00962-79-116-1084
salam sir, you took frequency practically.but what if the current sense reisistor is burnt and our supply is no more working.how we can take the frequency then?
yes
for that purpose we can calculate frequency using RT CT Value
check video number 559
What the value of the 5 band resistor, yellow, purple, gold, gold and white?🙏
if the right most color band is white
then it is capacitor
it is 4.7pf */-5% 900volt
Leser printer dc power suplly explain
Can we calculate peak voltage from rms?
multiply RMS *1.414 = v peak
check video number 305 for more details
@@HaseebElectronics 🙏ok
@@HaseebElectronics sir you said that we can not measure peak voltage so. . If we do not have oscilloscope in that case, can we calculate the peak value using the above formula?
@@HETRM exactly yes
@@HaseebElectronics thankyou🙏
To me this video was not so much about the circuit but more about how an engineer thinks through a problem.
best regards and special thanks
Sir 2.5 converter means pls
2.5 is used for DCM flyback conversion
The vdc 300 why. 110*1.41=141 vdc
Yahi video Urdu me pesh karen
Shukria
Ji bhai ye video 2-3 din mein mere urdu channel (haseeb electronics urdu ) per upload ho gi
إن شــاء الله
Hi Haseeb please check your email question about private tutoring if you offer it.
yes brother i replied to your email just before few minutes
Nice sharing
best regards and special thanks