Questions tagged [inrush-current]

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

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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) ...
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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 ...
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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 ...
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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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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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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 ...
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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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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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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 ...
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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 ...
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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) ...
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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.
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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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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
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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....
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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 ...
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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 ...
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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 ...
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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
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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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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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How to determine the safe current limit for inrush protection?

How do I tell what level of current is safe for inrush limiting for capacitors? How should I determine R1? simulate this circuit – Schematic created using CircuitLab
Sudip Kongbrailatpam's user avatar
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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 "...
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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 ...
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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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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
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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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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
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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
Divya K.S's user avatar
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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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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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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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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
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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
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6 answers
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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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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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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
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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
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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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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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Does limiting inrush current prolong inrush time?

Let's say you have a power supply that at 110 V draws 1.3 A max in its steady state, but has an inrush of up to 50 A. If you want to limit that inrush current to 5 A, you could use a 22 ohm resistor. ...
Derek Hershman's user avatar
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2 answers
684 views

Will this method theoretically reduce inrush current during relay turn on?

When a relay is connected to a purely capacitive load and an AC supply voltage is turned on, it will experience inrush current. Since the potential difference of an AC voltage can be represented by $$...
chuackt's user avatar
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Rectifier circuit behavior - Need an intuitive understanding

Case1: OUT Series res = 10 ohm -> spiky input current reaching upto 15 A -> capacitor charging fast After a long time: Case 2: OUT series res = 100 ohm -> almost sinusoidal input current ...
Divya K.S's user avatar
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High side n-MOS driver without charge pump

I couldn't find details of this circuit configuration in an internet search. Most online results are about P-MOSFET in high side path or N-channel MOSFET with charge-pump/IC based driver. simulate ...
Divya K.S's user avatar
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Resistor surge current rating: Why is the pulse energy withstand capability lower for short duration?

As per an online surge capability calculator, the pulse energy withstand capability is low initially and increases with higher pulse width. In short, we are not allowed to pass a narrow high current ...
Divya K.S's user avatar
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