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Questions tagged [undervoltage]

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0
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1answer
20 views

Understanding Undervoltage in LTC2965 - 100V Micropower Single Voltage Monitor?

The undervoltage specifications for this IC is a bit confusing to me as this is the first time I'm working with these kind of circuits. Aim : I want to monitor the voltage of a battery pack (...
2
votes
1answer
45 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? ...
0
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0answers
38 views

Chip(s) or solution to protect DC circuit with wide input voltage

I am looking for a solution to protect a DC motor control circuit with an input voltage of 12-55VDC from overvoltage, undervoltage, reverse polarity and overcurrent. Now, there are ICs doing just ...
0
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0answers
73 views

Undervoltage/capacitor problems with Raspberry Pi

My question is about the correct way to add a capacitor to a circuit with a Raspberry Pi driving a servo. I have seen undervoltage events in the logs of my app when the servo runs so I added a 470uF/...
0
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1answer
68 views

Why does this LTC1440 Comparator switch so slowly?

I am trying to build an undervoltage protector for a 6S LIPO battery. My idea was to use a comparator to switch off an NMOSFET when the battery fell below a preset voltage, 20V: R20, R21 and C20 ...
0
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1answer
279 views

DW01 2s protection

I want to protect 2 18650 batteries with single DW01. The problem is how to increase the protection voltage on DW01 . I have read that I should use voltage divider on VCC pin. I just want to make sure ...
0
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0answers
24 views

Protection circuit for applying external voltages at the output of live isolated DC-DC converter

I am designing a tester for 15v power supplies (based on isolated converters). I have to test whether the supply turns itself off or not under fault condition (under voltage and over voltage). Since, ...
0
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1answer
59 views

Calculating an operational amplifier with changing power source

I've been stuck since days to calculate an operational amplifier circuit used as an under-voltage protection. At first my design: simulate this circuit – Schematic created using CircuitLab The ...
0
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1answer
91 views

Switching between 2 power supplies upon dropping below cutoff voltage efficiently

I am making a circuit which is powered by a lipo battery of 11.1V(3.7V*3). I need to check for the lipo's under-voltage so that the circuit automatically switches to a second lipo when the first one ...
0
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0answers
150 views

Simple under-voltage protection for 3 cell LiPo

I am building a circuit that will require the use of a 3 cell LiPo battery. In order to protect the battery I would like to include a simple circuit that cuts the power when the battery cells drop ...
0
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1answer
522 views

Low voltage supply to ups

Circumstances : The power supply to our home is faulty and runs very low. Sometimes as low as 138V, most of the time 170V, but never 220V as it should. (We are in South Africa) Sometimes the UPS ...
2
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1answer
152 views

Lead-Acid battery discharged to 5V - how much damage?

Something in my bike (USB Charger, Hella Socket itself) has made a short circuit leading to deep discharge of Lead-Acid battery. Battery was down to 5.2V for time counted in minutes. I've ...
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5answers
2k views

What is purpose of an Undervoltage Sensing Circuit?

I am wondering what is the purpose of an IC such as the MC34064. Is it just to ensure a reset of microcontrollers upon power up or are there other reasons? I used to make a simple transistor switching ...
0
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1answer
80 views

Powering 4 12V 0.45Amp fans off USB?

This question actually has a few parts. Basically I have 4 12V 0.45 A computer fans,which I want to use in a DIY cooling pad project I'm currently working on. I know that as per the standard USB 2.0 ...
0
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2answers
1k views

Controlling BLDC with IR 2130 - stuck at fault, unable to reset

I'm working right now with the following circuit, trying to drive the BLDC motor with it. I don't exactly know how it works (especially the overcurrent sensing part) and the man that designed it is ...
1
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1answer
1k views

Voltage Cutoff Circuit for battery based application

Here is schematic of battery charging circuit. The battery voltage at 100% charge is 4.2V and it gradually decrease and is 3.2V, discharging below 3.2V will affect the battery life. How to make sure, ...
1
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1answer
34 views

Hi-voltage required for 100% SoC in LA banks?

Talking large banks of expensive true-deep-cycle cells, not the stuff you see in mass retail channels. Maybe the 6v golf cart batts from Sam's, at the "value" low end. I think end-of-life ratings are ...
2
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0answers
558 views

Simple Zener diode circuit for UVLO

Please see this circuit attached in this post/. Basically, I want to build a simple UVLO CCT for my LED controller and I came up with this circuit. simulate this circuit – Schematic created ...
0
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1answer
145 views

Laptop Charger Failure during AC supply undervoltage

My Laptop Charger is rated 240V AC Voltage. While plug in the outlet the undervoltage occurs (using multitester) the voltage is 107V. At that instant my charger is very hot, right now my charger is ...
0
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2answers
303 views

Can undervoltage kill a circuit? [duplicate]

I was fooling around with a DFPlayer Mini MP3 player, which looks like a really nice and easy to use device. For some reason I couldn't get mine to output sound on its speaker outputs, so I decided it ...
0
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2answers
84 views

Voltage supervisory circuit selection

I am trying to understand how to choose a suitable voltage supervisor IC for a given project. I have two questions: if I have a digital IC, in its datasheet there is information about the minimum ...
0
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1answer
673 views

Avoid voltage drop on DC motor start-up with h-bridge

I'm trying to control a 12V DC brushed motor (4A with load ) with an H-bridge , TLE5205 datasheet ( 5A , 6A peak , 40V , integrated free-Wheeling diodes ), but when using a 3S1P lipo battery ( 11.1V , ...
1
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1answer
1k views

Low voltage cutoff circuit with Zener and BJT

I have a circuit that's supposed to cut off at <4V. It instead caps the voltage at 3.3-ish and reduces the voltage linearly below that. Zener - 3.3v Source - 5V +-5V
17
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4answers
1k views

Is there any benefit to using a voltage booster (such as Batteriser) on “dead” batteries?

The Batteriser [Edit: removed dead, harmful link] is a crowd-funded product intended to extend battery life by boosting the voltage. It is basically a joule thief that is in a tiny package that slips ...
16
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7answers
62k views

How bad is it to undervoltage a 12-volt lead-acid battery?

I had a heated discussion with a few colleagues today revolving around how low of a voltage was alright for 12 volt lead-acid battery; they were in the opinion that the low voltage warning buzzer and ...
1
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1answer
312 views

Help with high current single cell lithium charging

I am designing a system to charge a single cell lithium battery. It requires pass-through, path-selection, over and under voltage protection. The bottom line is this system needs to power a device ...
5
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4answers
7k views

To protect a LiPO cell from undervoltage, how low current is low enough?

This may seem like a topic beaten to death, but bear with me.. this is an apparently ignored wrinkle. Over the past several weeks I've been designing various circuits to protect a LiPO cell from under-...
0
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3answers
1k views

Motor undervoltage

In the situation of a motor losing voltage, say it's rated for 240vac, but it's only receiving 190vac, what happens in terms of the power triangle? Does current increase, does it slow down and reduce ...
2
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1answer
2k views

USB current limiter and under/overvoltage protection

I know recent motherboards already provide these, but lately USB ports are also available in many different gizmos (smartphone chargers, TVs, standalone players, etc.), which I am often tempted to use ...
0
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1answer
151 views

ST1S10 step-down regulator - can I drive the EN pin from the voltage divider?

The ST1S10 step-down regulator (http://www.st.com/web/en/resource/technical/document/datasheet/CD00169322.pdf) has an INHibit (active low) / ENable (high) input terminal, like any other DC-DC ...
0
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3answers
436 views

Driving TEC below rated voltage

Can a TEC driving IC such as the MAX1979 rated for TEC voltages up to 6V be used to control a 12V TEC - can TEC work under their rated voltage, with the amount of heat moved controlled by current, or ...
4
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2answers
3k views

Stabilizing the UVLO feature on a DC/DC converter

Very many DC/DC controller IC's utilize an under voltage lockout feature by way of an external pin monitoring the applied voltage and comparing it with some internal reference, putting the IC into ...
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2answers
1k views

Are there any single chip solutions for single cell LiPo battery protection? If not, any references?

I can't seem to find one, but does anyone know of a single chip solution for LiPo battery protection on a single cell/3.7V battery? Looking for things like over-current/overvoltage/undervoltage ...
1
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1answer
305 views

Choosing values of resistive divider, versus pullup resistor value

I have a slight Catch-22 with my circuit portion shown below. The ADM6320 is, among other things, an undervoltage detector with factory threshold of 2.93 V (thus Reset output pin toggles when VCC <...
0
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1answer
1k views

Choosing Fuses or MCB in 24VDC vehicle circuit

I am currently designing a 24VDC circuit for a small vehicle. I personally prefer using MCB's since they are simple to reset and easy to detect faults in the system, although i do find it rather hard ...
4
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4answers
2k views

Decoupling capacitor across Raspberry Pi GPIO input (+ Arduino + robotics)

I've been messing around with a robot kit from Parallax (the BOE Shield Kit), which has a 5xAA (7.2 V?) power source. The BOE shield includes its own 5 V regulator, which is used to control ...
1
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4answers
8k views

Undervolting PWM fan from 12V to 5V [closed]

What will happen if I feed a 12 Volts rated PWM fan with 5 V driving voltage? Given all the other variables stay the same (PWM control signals) - will it reduce RPM? By how much? What happens to the ...
5
votes
2answers
206 views

Scaling voltage to meet two conditions at once

I am using an IC (STM6600) which, among other functions that I need, is also capable of Undervoltage Monitoring. It works like this: The IC monitors VCC in comparison to two thresholds, V_Low and ...
7
votes
1answer
7k views

Under Voltage Protection for LiPo Battery

I have a 3Cell LiPo battery which I am going to use with an RC Car, and I want to design a circuit to protect the battery cells from going under ~3.3v each. So what do you think of this design? As ...
5
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4answers
329 views

Placement of undervoltage monitor and cutoff

Suppose I have a circuit running at 3.30V, supplied via an LDO regulator (e.g., ADP124), powered by a Li-ion battery. In other words: Now, I would like to implement an undervoltage cutoff to "turn ...
3
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4answers
524 views

Possible to fry a circuit with a power supply under its current requirement?

I recently had someone explain to me that he was told he fried a laptop's hard disk by putting it in an external drive enclosure that was not rated to supply sufficient current. (Apparently the disk ...
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3answers
437 views

How much negative voltage is too much for a µC?

I've been attempting to measure some stuff and trying to be careful about what I feed into my microcontrollers. I've had difficulty figuring out how to keep things within perfect limits, though. For ...
2
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1answer
2k views

Safe operating area for different types of battery chemistry?

I'm trying to find the safe operating area for various types of batteries; in particular I need minimum and maximum termination voltages, although information on temperature / power / current is also ...
2
votes
2answers
481 views

Do LEDs Need UVLOs (Undervoltage-Lockouts)?

I'm currently working on a project involving (I think 3mm, 1.5VDC) Infrared LEDs. However, due to my photoresistor, I think the current, voltage, or whatever (forgot) will vary greatly to minuscule ...
2
votes
2answers
3k views

11-16V DC voltage stabilization for 13.8V powered ham radio

I am looking for any resources on how to construct a relatively high power (25A, 13.8V) voltage stabilizer (or voltage booster if you like) for my 13.8V powered ham radio. The problem I try to ...
6
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4answers
9k views

how to build a low-voltage disconnect switch for DC 12.4V 70A?

How can I make a device that will make the power connected as long as the voltage of the power-supply keeps over 12.4 V (adjustable) and disconnect it if it falls below? It also must connect the ...
17
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2answers
8k views

Circuit to protect against undervoltage?

What is the simplest way to regulate the min DC voltage in a circuit? Is it possible to do with zener diodes? ...