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Questions tagged [over-voltage-protection]

Additional internal or add-on parts to a fixed voltage regulator to prevent the output voltage from exceeding a preset limit if internal voltage regulation fails. Some OVP designs include an SCR to short the output and blow a fuse, rather than risk damage to downstream hardware.

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35 views

Will my zener diode work again with a polyfuse after a overvoltage?

I am trying to make a simple overvoltage & current limiting circuit for my PCB. I made the following circuit. The zener will break down and conduct current to ground. Since its resistance has ...
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49 views

overvoltage protection of opamps

simulate this circuit – Schematic created using CircuitLab I see diodes arranged like D1 and D2 sometimes used to prevent nuisance tripping of a power supply's internal overvoltage protection ...
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61 views

Over-voltage protection system for a 7 - 20 A Load with 4 - 5.5 V output from PSU

The power supply used on the product, is a DC-DC buck controller 24 V in (3 - 5.5 V out). I need some suggestions to help protect a load (LED Display) which draws roughly 5 - 15 A the power supply on ...
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63 views

How much buffer room is required for a varistor?

I am working on a circuit board design that uses a fuse resistor for protecting from short circuits and a varistor to protect from over voltage. The board is a simple power supply of only a few watts. ...
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82 views

Voltage regulator and loss of ground

I have a design that has a +24VDC supply, a 7805 voltage regulator converting it to 5 volts and then a microcontroller and some peripherals behind the regulator. The design and the 24V supply ...
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30 views

Digital voltage stabilizer relay diagram

I am using this voltage stabilizer relay diagram below, which provides a 16 step-up level. I need to edit it, so that I can made it to work as step-down in case of high voltages such as 245 and above. ...
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67 views

How to shutdown SG3525 inverter with op amp

I'm trying to make an overload protection and low battery indication circuit for my 50 watt inverter. I have made an overload protection circuit using op-amp, but when an overload event occurs the ...
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66 views

Input protection on a DC jack

I am designing an battery powered instrument with around 20-40Ah 3S li-ion batteries in it along with a 10A 3S(12.6v) external charger. Due to ease of availability and the current capacity I have ...
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29 views

Over voltage and under voltage with time delay device

I made a circuit as shown in the attached picture. It is an " over voltage and under voltage protection device with delay time" it worked properly at the first, but later it stopped giving any output. ...
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31 views

DMX protection circuit (diode clipper)

TL;DR I’m building a board that bridges the common types of DMX connector (various forms of XLR, RJ45, tails and product-specific terminals). There is a possibility that someone could accidentally ...
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18 views

Voltage applying to cpld I/O pin while VCCio isn't connected

I have a pcb based around a coolrunner II cpld . My problem is as follows. An other ic generated at it's output a logic '1' (around 3.5V ) and the signal was driven to an input pin of the cpld while ...
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44 views

LED current source circuit design concerns

TL;DR: Read the bulleted list below. I am designing a simple constant current source to power up some LEDs inside arcade buttons. My project consists of 20 of these buttons. Every button is ...
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86 views

Crowbar Circuit for 35V OVP - What parts should I use?

Please excuse my confusion, because I really don't understand what the "150mA max continuous cathode current" means on the datasheet for the LM431. I'm also not sure it'll work in the crowbar circuit ...
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97 views

LTC4366 killing MOSFETs

I designed a circuit around LTC4366 as per the picture below. However numerous MOSFETs have been damaged and become useless. Mosfets used : STH12N120K5-2; IXFT50N85XVH; STW13NK100Z - All are rated to ...
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39 views

Techniques for accurate 5.5 Vdc active voltage clamp

We are currently using TI ISOW7841 Digital Isolation modules /w built-in isolated 5 Vdc DC-DC converter Datasheet. We are having rare failures. Failure shows up as the module running much hotter ...
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52 views

SMPS Over Voltage Protection

I have some related questions here and I hope I get better understanding thru this forum. ATX SMPS has Over Voltage Protection. Does it mean that it will shut itself down in over voltage situation or ...
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1answer
60 views

high power - overvoltage protection

I am designing a circuit to protect a load from over-voltage. The voltage at the load must be around 380VDC and the current consumption will be around 2A. In normal operation the Power Supply must ...
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43 views

Reverse polarity protection for symmetrical input

I have a symmetrical voltage input I need to protect agains reverse polarity, and over-voltage. Here is the reverse polarity protection I designed. Is it correct ? I can't find much information about ...
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58 views

Short-circuit protection, reverse polarity automotive

I am designing a power circuit and would like to integrate the ic VN5160S to protect it, but I have doubts about the position of it. Would the ic VN5160S be before the DC / DC converter in my circuit? ...
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28 views

ESD/overvoltage protection with DM1231-02SO TVS array

I'm protecting a USB2.0 IC against ESD and overvoltage at the USB connector using a Diodes Incorporated DM1231-02SO TVS (dual) array. The datasheet labels the pins IN and OUT, but it's not 100% clear ...
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66 views

Transistor Reverse Biasing - AC

I am working on a project which require to activate a 24V Rated relay using a 3.3V rated IO. To provide adequate isolation I have added a Opto-isolater stage. In order to increase the current output ...
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1answer
110 views

Overvoltage protection for AC relay dilemma

I am currently designing a safety-related device that has to open a relay when a certain event occurs. During most of its life, this relay will be closed, and only open if the safety event occurs, ...
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157 views

What the function of zener diode on this picture

I am confuse, why we need clamping with zener diode because it doesnt matter when vgs goee below zero, cmiiw
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Long wires causing Raspberry Pi to die?

I've been working on a simple project involving a Raspberry pi and some switches. I would never thought I would have any problem for something as simple as a switch, but here I am. The 2 wires from ...
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1answer
48 views

Protecting 0..10 Vdc PLC input from voltage divider failures

I'm working on an off-grid PLC based battery bank monitor and dump load controller to replace commercial units that don't work really well with our lithium ion battery bank. In addition, I plan to ...
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3answers
115 views

How long do I have before my sensitive components get fried?

I'm using this IC (https://www2.mouser.com/datasheet/2/609/ADM1270-878589.pdf) to control the current and the voltage on some of the outputs of a PCB that controls the power to other PCBs, which have ...
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277 views

Simple reverse and overvoltage protection circuit for drive a fan

What is the simplest/minimal circuit or component i can use to drive and protect a fan from overvoltage and reverse polarity? A mosfet per fan seens a option for reverse polarity, still if there's a ...
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48 views

How can I tell whether a DC device will accept a greater voltage than stated? [closed]

Over the time, as an amateur, I've developed a sense that DC powered devices with internal circuitry should be fed with the voltage stated on the case. Having seen certain devices (e.g a portable USB ...
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1answer
63 views

Connector pins protection from overvoltage

I have a connector which has the following lines: 12V 3.3V GND SDA (I2C) SCL (I2C) The connector might get wet with water and I would like to protect the circuit from the resulting over-voltage in ...
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198 views

What is Metal Oxide Varistor (MOV), meaning of its specification and how it protects circuit from over-voltages?

Hello, I have a circuit in which a voltage source is connected to some sort of RC Load. To protect this circuit , there is an Metal Oxide Varistor (MYN15-681K). The Pics of circuit and datasheet ...
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1answer
86 views

Schematic for input protection with NMOS? Does this really work?

I was reading an old schematic and found this and sketched it up; (see box in image "Some kind of protection") The closest thing to this schematic that I've been able to find, that could have briefly ...
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1answer
48 views

Historical: I am trying to get a handle on when output voltage was used to protect from faulty LEDs

I am interested in when a simple over voltage detector was first used to protect LED arrays from damage caused by one faulty unit. I have a reference from 1999 but am sure I saw something first ...
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214 views

Slow-blow fuse equivalent for overvoltage?

Working on an compact electronic ballast design (~5 W load), I see the need for an over-voltage protection circuit that has a 'slow-blow' characteristic. When a lamp is turned on, a striking voltage ...
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2answers
204 views

3.3V overvoltage limiter circuit topology

I need to design, using discrete components only, a shunt voltage limiter that drains little or no current (less than 2mA, the lower is better) at 3.3V, and ensure that, when driven at more than 4V, ...
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2answers
503 views

Supercapacitors in series

Can I charge series of 4 Maxwell BCAP3000 supercapacitors with constant current method using an adjustable Power Supply, and exceed the voltage rated for single cell? What I mean is to charge the ...
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1answer
160 views

Limit MPPT solar charger output voltage

I have a problem with my mppt solar voltage regulator. I have a campervan with three 320 W solar panels (Voc 40.8 V, Vmpp 33.3 V) connected in series on the roof, and two 260 Ah, 12 V AGM batteries ...
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118 views

Simple Power Sink Circuit

I've got a test bench for brushless DC motors, which is supplied with a regulated power supply unit. The motor itself is driven by an electronic speed control (ESC), which feeds energy back to the ...
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1answer
334 views

Dimensioning SCR crowbar circuit

I need to dimension an SCR crowbar circuit to reach a certain level of protection against overvoltage, without increasing much the complexity of the circuit of my control card. The need is to protect ...
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1answer
424 views

12V 12A resettable crowbar circuit

The idea is to protect the input stage of a control card from improper power supply connection. The power supply is a standard desktop AC-DC power adapter (Meanwell GST160A12) with inbuilt shortcut, ...
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3answers
170 views

Protection diodes for Arduino pin passing current to +5V rail when powered down - what to do?

simulate this circuit – Schematic created using CircuitLab In the circuit above, I'm using a resistor (R1) and a couple of protection diodes (D3 and D4) to keep the voltage on an Arduino pin ...
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1answer
107 views

Push-pull amplifier

The question is concerned the output current of push-pull amplifier once the over-current protection is activated. The resistor Rs(one between base and emitter of the over-current protection ...
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2answers
153 views

Protecting 0 to 5V Arduino pins from +/- 10V oscillating input

Background: I want to connect a Eurorack Synthesizer Low-Frequency Oscillator, which can range from -10V to 10V, to an Arduino pin which can only accept 0V to 5V. I don't mind if the negative ...
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1answer
90 views

Converting 6c (3s2p,4.5v) DC motor to 1s4p 18650 charging/protection

Having a hard time figuring this one out, I am trying to convert a 4.5v 25w dc fan from an air mattress pump to run off a rechargeable battery pack made with 18650's. This is going to be charged and ...
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2answers
237 views

Protecting microcontroller digital output pin from ESD, reverse connection, and other possible user error

I want to protect an output pin from ESD, reverse connection, and other possible user error that might cause damages to my circuit. This pin output pulses depend on the amount of water passing through ...
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1answer
102 views

How can the overvoltage prodection inhibit the voltage to let the voltage doesn't reach the destrutive level?

This is the voltage conditioning schematic,including OVP(overvoltage prodection) and LDO(low drop-out regulator),the OVP limits \$V_{buck}\$ to inhibit it reaching destrutive voltage level. When \$V_{...
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1answer
46 views

Protecting reset pin from overvoltage

I'm designing a board with a control port. The control port allows an external controller to reboot the system by pulling the BRD_RESET low, effectively restarting ...
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3answers
208 views

History of ESD protection

These days you can't read anything about electronics without hearing about the dire consequences of omitting ESD protection from your designs. It seems this wasn't always the case. If you look at ...
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2answers
265 views

overshoot and undershoot on 3 volt pulse

i am interfacing a system, this system output signal of 200ns digital pulse with repetition time of every 3ms. Ideal voltage of signal would be 0v to 3.3V but signal coming from system have high ...
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460 views

Overvoltage protection circuit

I have a PCB with 3 inputs: Ground 5V (logic IC power supply) User-selectable 5V or 12V (motor power supply) There are two types of motors, 5V and 12V. If the user selects the wrong DIP switch up-...
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2answers
149 views

Non-resettable zener/polyfuse for overvoltage protection

My setup is two DC-DC converters (hobby BECs) supplies, one acting as a backup for the other. A relay, powered by the primary BEC will automatically switch to the secondary BEC if the output from the ...