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Questions tagged [inrush-current]

The high current, that often occurs when first plugging an appliance in the power supply.

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Relationship between inrush current, blowing the fuse and switching power supplies with PFC

I'm having the problem that my (switching) power supply of my new "mobile workstation" (laptop) is blowing the 230V/16A (about 40 years old) fuse (circuit breaker) most of the time when ...
U. Windl's user avatar
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Protection against inrush current on battery charger

I'm designing a PCB for a battery powered robot. This battery must manage both the charge of and discharge of a 8S (29 V nominal) Li-ion battery. The voltages of the application cause big inrush peaks ...
Pablo Daniel's user avatar
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Inrush current: Additional capacitor or NTC to handle voltage spikes?

I will power an ESP32-S3 using a LDO (MCP1825S) which will require a 1 µF capacitor on the input and a 10 µF capacitor on the output. Both of them are ceramic ones, so typically have a low ESR: In a ...
Tintenfisch's user avatar
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Using an Active Inrush Current Limiter as an Alternative to a Pre-Charge Circuit in EVs

I'm currently working on a master's thesis during an internship at an automotive company that manufactures EVs. The thesis focuses on improving a pre-charge circuit for an EV. In EVs, a pre-charge ...
Ben50's user avatar
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Can inrush current of an SMPS damage EMI filters?

I am assembling an electronic product using off-the-shelf components. I want to connect the device directly to the power socket, so I plan on using a switching power supply (this) to get the 12V ...
AjejeBrazorf's user avatar
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1 answer
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Input capacitor / Inrush current

I am developing an electronic control board for a brushless motor. The motor in question is part number FR_2057_B_FMM from FAULHABER. The motor is powered at 24V and 62.5W. For the three-phase ...
Kolia's user avatar
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Seeking a good solution for mitigating the effects of high in-rush current caused by an AC-DC converter [closed]

Many AC-DC power supplies (say, 220VAC to 24VDC) have huge inrush current values. For example, a device might have an inrush current of 80A@230VAC. This raises the question of how to handle the ...
Dmitri Nesteruk's user avatar
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Would an AC EMI filter capacitors contribute to inrush current?

Shown below is an EMI filter for an AC input. My doubt is when I analyse the inrush current, should I be considering the contribution due to all three capacitors? a) Differential mode capacitors b) ...
Dynamic_equilibrium's user avatar
1 vote
1 answer
164 views

Choosing an NTC thermistor for inrush current limiting at 5 V

I'm designing a very simple circuit to enable a Raspberry Pi to power down safely in the event of a power outage. It is comprised of a supercapacitor, a diode to prevent reverse current flow, and a ...
yeah's user avatar
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Initial current surge

I designed a PCB that takes an input of 110Vdc and steps it down to 5Vdc for a microcontroller and a couple of ICs. At the input, I have a reverse protection diode, an inrush limiter circuit, and a ...
HV16's user avatar
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LTspice inrush current simulation

I'm trying to simulate the inrush current of a system that I measured with an oscilloscope before. In my simulation I have a voltage bouncing effect on the wire between the supply and the Rshunt that ...
SteveninJ's user avatar
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Reverse polarity protection + inrush current limiting with mosfets schematic

What do you think about this schematic? I want to put this before a DCDC 24 to 5V with maximum 1A. Any comments or suggestions? The aim of this circuit is to have a soft start with the resistor R2 in ...
Gigapel's user avatar
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Inrush current limiter thermistor acting up

One of the power amps I am working on uses a thermistor for inrush current limiting (SL15 25003) as shown in the schematic below (ICL1). When I was testing the unit it seemed to me that there was some ...
Zen Max's user avatar
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Current limiter tight tolerance

Background: The existing current limiter in the design has a relatively large tolerance primarily because of the component tolerance of the current limiter transistor. Note; the temperature and ...
Cuba havana's user avatar
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41 views

Powering up an AC-DC power supply under load

Is it safe to power up a AC-DC power supply while it is connected to a load? Specifically what I'm trying to do is replace an AC espresso water pump with a 24V/2A Brushed DC water pump. Additionally a ...
Tate Mazer's user avatar
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2 answers
152 views

Ways to charge a VERY LARGE capacitor in a 3-phase bridge rectifier circuit

I need to charge two 1500uF-450V capacitors off of a 3-phase 220Vrms-60Hz line using a very robust bridge rectifier (datasheet) as well as both capacitors datasheet (datasheet). Here's the simulation ...
Iron Maiden's user avatar
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Inrush current limiting in high power inverters without using contactors

We have a 10kW inverter which is used to control a PMSM inverter and need some help to design a better inrush current limiter during startup. The general approach would be to let the DC bus charge ...
AK47's user avatar
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2 answers
130 views

How to measure inrush current over 3 minutes

I have a DC electronic system that takes approx. three minutes to boot up, and I have to decide what gauge wire to make power cables. During boot up, this system powers on several different sub-...
mikey B's user avatar
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342 views

Inrush current when turning amplifier on is causing RCBO to trip

TL;DR - when turning on an amplifier, it trips the RCBO. Might it be related to the fact I'm using a smart switch? Or the wrong type of RCBO? Or can I introduce an inrush current device? How can I ...
hazymat's user avatar
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Pre-charge for 230 V household appliances

Most common household appliances (TVs, LED drivers, etc.) have short inrush current (50-60 A). As I understand it is for charging input side capacitors. Can I use pre-charge system with resistor, to ...
Ri Di's user avatar
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2 votes
1 answer
138 views

What to do to prevent relay contacts from fusion

I am looking at an EV charger, a very simple 3-phase AC unit. Basically, it's a power outlet with a bunch of relays and a microcontroller. As I understand it, the input of an EV Onboard Charger (OBC) ...
TQQQ's user avatar
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MOSFET Inrush Current limiter

May I know how to calculate the value of C1, R1, and R2 in the below-shown circuit? The input voltage is 12 V.
Chitharanjan's user avatar
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Why is this precharge circuit not functioning?

Although this question sounds basic but, I have been trying to implement this precharge circuit to safely turn on the inverter without overloading the system, however especially when I powered it on, ...
Hazardous Voltage's user avatar
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248 views

Why are SMD components not good for high power applications?

I have been using this capacitive power supply to drive a circuit (an OP amp and relay), but what I can't understand is that when I tried using an SMD resistor (R2) after some testing (turning on and ...
Hazardous Voltage's user avatar
3 votes
1 answer
198 views

N-channel MOSFET fails as an inrush controller

We have designed a inrush controller using the LTM9100 controller. The LTM9100 basically controls the ramp rate of the gate voltage, which in-turn controls the raise time of the DC bus across the load....
AK47's user avatar
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2 votes
2 answers
266 views

Is it ok to connect a 10000 μF Capacitor to a lithium-ion battery directly?

I have a 24 V lithium-ion battery which will pump as Iᵐᵃˣ 40 A and I need to connect a capacitor directly to the 24 V battery which will be 10000 μF(10 mF). The usage of it is to keep the system ...
Hazardous Voltage's user avatar
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85 views

LED driver inrush current

I'm using a LDD-700L Meanwell LED driver to drive 5 Power LEDs in series. The LEDs require a Vfd of 3.9VDC and a current of 700mA. The driver seems OK, except during startup. When voltage is applied ...
Joggem's user avatar
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161 views

Inrush current limiting for 120V AC powered circuit

I have a load that I'm powering from a 60W AC-to-DC converter that has a stated cold start inrush current of 30A@120V: https://www.meanwellusa.com/upload/pdf/IRM-60/IRM-60-spec.pdf (the 15V output ST ...
davegravy's user avatar
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Calculating thermistor value to replace fixed resistor

I have a circuit that uses a 5W 100Ω fixed resistor for inrush limiting. I'd like to replace it with a thermistor for better efficiency. I've not found any information referencing what resistance to ...
AlphaSixSierra's user avatar
2 votes
1 answer
63 views

What is the main influence on the current when charging a capacitance?

If I have some capacitance C that is being charged through a resistor R, is the amplitude of the current peak only depending on R or also to some degree on C? In other words, will the current change, ...
l.voe's user avatar
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1 vote
3 answers
2k views

P-Channel MOSFET used as a load switch, practical doubt about Vgs

UPDATE AT THE BOTTOM in a battery powered project with high current I'm using a P MOSFET as load switch in place of a mechanical switch to prevent inrush current and consequent spark on the switch ...
Fabio's user avatar
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4 votes
1 answer
920 views

How do I select a replacement ICL NTC thermistor for a PSU?

I want to replace an ICL (inrush current limiting) NTC thermistor in a vintage computer PSU (for Amiga 1200). This question is similar to 'Selecting an NTC for inrush current limiting', except that ...
Nick Bolton's user avatar
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Overview of inrush current limiting (AC/DC convertor)

I'm tinkering with what amounts to a "smart switched outlet"... which is really just a glorified way of saying I have a bunch of devices that run off 110VAC and need 12VDC for internal "...
Matthew's user avatar
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1 vote
2 answers
250 views

Inrush current on current sense resistors

The problem is on a circuit which implements PFC circuitry. There are two parallel 0.36R current sense resistors located in the inrush current path. These resistors measure the PFC current through the ...
ohkann_'s user avatar
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1 answer
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Circuit for capacitor charging and IC enable

I'm trying to find a solution to a problem I have where I need to drive an ESP8266 from a power source that is rated for 250 mA. The ESP8266 will have an average current way lower than 250 mA but it ...
evading's user avatar
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0 answers
103 views

LM9022 add softstart for inrush current

I have a VFD filament driver (LM92022) and i need to add a soft start for stop inrush current, for increase life time of the filament tube. This solution its ok? My tube working at 2.4v Ac / 80 ma. ...
arduplay's user avatar
2 votes
1 answer
69 views

Current control loop compensation network

I have an application that uses n-channel Mosfet as a high-side switch controlled by an IC driver. The point of the Mosfet is to manage the inrush current to the load. I understand that the resistor ...
Robert's user avatar
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2 votes
1 answer
109 views

Rewinding a 6 V DC motor and decreasing inrush current

I have a small simple 6 V DC motor and I would like to rewind its rotor. The motor has 2 magnets. The rotor has 3 poles to wind. Normally each part has 169 turns of winding with 0.15 mm2 copper wire. ...
Elentronics's user avatar
1 vote
1 answer
161 views

Why is the MOSFET current taking time to rise in linear mode of operation?

In the below current limiter circuit, why is the MOSFET current rising slowly? Shouldn't the MOSFET current follow the equation \$i_D=\kappa(V_{GS}-V_{th})^2\$? Ref: How to Make Linear Mode Work
Dynamic_equilibrium's user avatar
0 votes
1 answer
138 views

Transformers have inrush current, but is there a voltage overshoot when switched on?

Conventional transformers for 50 or 60 Hz have more or less inrush current when switched on to the grid voltage. Worst-case inrush happens when the primary winding is connected at an instant around ...
Uwe's user avatar
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1 vote
1 answer
220 views

Help with series NTC sizing

The inrush current of my 12V/10A rated SMPS exceeds the inrush current limit of a rocker switch so I need to dampen the inrush current by an NTC as shown below. (I know there are other methods but ...
user1245's user avatar
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2 votes
1 answer
136 views

Efuses, inrush and output drooping

Here's a simplified efuse diagram: Here is the efuse configurations in my circuit: The load is not present on this pcba. There is a 100mm long cable connecting this board to the load which is a ...
Hasman404's user avatar
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0 answers
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How large is too large a capacitance across SMPS?

I have a circuit that operates from a 16 VAC input from a transformer. For the purposes of this question, just consider it to be a linear power supply: AC -> full wave bridge rectifier -> large ...
user318003's user avatar
1 vote
1 answer
539 views

Inrush rating of relays

I have trouble understanding the specification for inrush contact in relay contacts (more or less the issue in SMPS inrush time) Background: I have some beefy power supplies (about 16A at full load) ...
Lorenzo Marcantonio's user avatar
8 votes
6 answers
2k views

How to find the root cause of this relay failure

The following is the schematic for the relay section of the board: VBAT: 45-56 V. RY_REAR_MOT: Power to the front motor controller RY_REAR_MOT_EN: 3.3 V enable signal from the MCU. On power up, this ...
Hasman404's user avatar
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2 votes
0 answers
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Sensitivity of Inrush Current Circuit

I'm new to LTSpice and analog design - I'm having a bit of a struggle getting a feel for the behavior of this inrush limiting circuit. Stole the design from another SE post, but playing with the ...
EENewbie's user avatar
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1 answer
213 views

Add inrush current limiter to board for USB compliance

I have no experience with current inrush limiter designs. I have to design a simple prototype in which I have to adapt a USB port to be USB compliant but instead of 5 V to 3.3 V (nothing else changes) ...
FranMartin's user avatar
0 votes
1 answer
131 views

Maximum inrush current and contact rating?

I am doing a hobby project where I am using a thermostat which has a contact rating of 230 VAC, 5 A. Please see below thermostat details (RS link also contains full datasheet). I want to drive a ...
elecrobot's user avatar
2 votes
0 answers
54 views

Inrush NTC thermistor vs. frequent on/off

NTC thermistors has high resistance at normal temperature, thus limiting the effect of a surge of current during power-up. Its resistance lowers after itself heating up during normal operation, ...
FlakR's user avatar
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0 votes
2 answers
896 views

Understanding inrush current and mitigation methods

I want to be able to automatically switch on an AC-DC power supply edit for clarity: it's a constant current LED Driver [edited again for further clarity- the driver won’t actually be driving LEDs- ...
Derek Hershman's user avatar

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