Questions tagged [undervoltage]

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24 views

Transistor for UnderVoltage Lockout (UVLO)

this is a circuit in LM2596 datasheet which suggests using zener+bjt combo to protect against UnderVoltage in regulator input : it turns the regulator off using its ON/OFF pin. I have many D882, ...
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0answers
25 views

Choosing the right Over-Voltage protection circuit

TLDR : Ideal supply voltage of a device is 12v DC (labeled near jack). User may mistakenly provide anything from 3 to 24 DC (or maybe 220v AC). how to protect the circuit against Over-Voltage ? how to ...
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1answer
125 views

Undervoltage lockout

I would like to do a simple undervolatge lockout. I thought a BJT as a switch like this: In normal conditions I would have 30V (and -30 and the othre rail) and 25 mA to 50 mA. These power rails will ...
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2answers
137 views

How do ASIC designers approach designing for extremely low supply voltages like 0.3V?

In ASIC design, there is a tradeoff between performance and energy efficiency. Since most consumer CPU's are designed for maximum performance, they operate at high voltages and clock frequencies, ...
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1answer
35 views

1200w dc-dc boost converter low voltage protection not working

I've purchased a 1200w dc-dc converter with the model number SZ-BT07CCCV. I'm using it to convert 12v from a big battery to 24V. the converter comes with three potentiometers according to the ...
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2answers
93 views

How to prevent a Lipo/Li-Ion-Battery from catching fire after a complete self discharge with a following accidentally recharge

From the following Youtube video (at 3:15min) I got that it is dangerous to recharge a Lipo/Li-Ion-Battery after it was completely discharged (0V), because it will catch fire. https://youtu.be/...
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1answer
68 views

Constant current driver and undervoltage protection for lipos

I'm searching for a way to drive a couple LEDs with a single-cell LiPo battery, such that the LEDs will be cut off completely when the LiPo voltage drops below, say, 3.3V. PCB space, component count ...
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0answers
105 views

Under voltage lockout circuit design

I need to be able to switch a load circuit off when the output voltage from a buck boost converter is around 3V (or below 4V or 5V). The converter is powered by a 10W solar panel and the load can draw ...
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1answer
55 views

Undervoltage Testing of a LDO or Switching DC-DC Converter

I am using a Regulator section in - UJA1076 this IC Input Voltage = 16V Output Voltage = 5V Load Current = 0.1A My question is, I want to test the undervoltage condition 90% and 70% as mentioned in ...
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1answer
32 views

resistor selection for TPS3700DDCR undervoltage circuit

I am designing an undervoltage circuit for a lipo battery project. I found this tutorial here which lead me to the TPS3700. I am wanting the undervoltage condition to be 3 volts. The part that I am ...
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2answers
56 views

Combine voltage sources [closed]

I have a Baldor DG6E generator. It must produce 120V/240V but I bought it and it has three wires as outlets - every one produces 120V. I want to combine two wires to produce 240V. How can I combine ...
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2answers
140 views

Should I add an undervoltage protection for lithium battery-powered projects?

I am designing a board with a microcontroller (an ESP32) that will be in deep sleep most of the time. The board will run on a 1-cell lithium battery (not sure if I will use a Li-poly or a Li-ion). ...
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0answers
420 views

Can undervolting damage my laptops fans?

so I started reading a lot about undervolting etc. and tried it myself. I use a lenovo yoga 920 and I dont do any hard workloads, but the fan noises annoyed me as lenovo is known for its loud fans. I ...
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0answers
604 views

How can I use 2 Tp4056 as protection circuit for diy 2s li ion battery?

Hi I want to use 2 Tp4056 modules as over-discharge protection circuit for my DIY 2s li ion battery pack. Those will not be used for charging! hence will not share input! The load is an arduino nano ...
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2answers
106 views

Voltage protection with 555 timer not working

Briefing I am using Multisim to simulate a circuit before building it. The voltage protection circuit with a regulator works fine and the timer circuit works fine as well separately. When I try ...
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2answers
66 views

MOSFET Gate-Source voltage in protection circuit

I'm creating board which is supposed to withstand OV/UV and reverse voltage. I've chosen LTC4365CTS8#TRMPBF(datasheet) IC to deal with this problem. In reference schematic for 24V input they are using ...
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0answers
45 views

What is a better way to prevent over-discharge in this low current circuit?

I made a nightlight and was very happy with the dim yet usable output and runtime (months), but my assumptions about battery safety were wrong. I expected the LDO 3.3 V regulator to stop output when ...
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1answer
109 views

Will this UVLO work?

I'm referring to one answer here What if (power supply) was 24V, the VCC is 3v3 delayed by 1 second? If you apply power then your (power loss detect) will be higher than the Vcc rail for 1 second? ...
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1answer
200 views

Undervolting BLDC motor on electric bicycle

I plan to build a DIY electric bicycle using a standard geared BLDC hub motor (36V and 250W rated, 500W peak). To get 36V rated battery, at least 10 Li-ION 18650 cells are to be connected in series (...
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2answers
187 views

How to supply either 5V or 0V without the gradual PSU voltage bleed?

I have a 200W 5VDC power supply (Meanwell LRS 200-5). When I shut off the AC it takes about 60s for the supply to drain fully through the connected sensitive components (processors and storage drives)....
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3answers
110 views

A device used to logically turn on a circuit with voltage being the input parameter

I’m working on a project which utilizes a power-source which is liable to vary. I have a micro-controller sitting at the output of an LDO (Low Dropout Regulator). I’m concerned about the LDO ...
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1answer
31 views

Under-voltage lockout programming on Delta D12F200 DC/DC converter

I recently decided on the Delta D12F200 DC/DC converter for my current project (datasheet: https://www.mouser.com/datasheet/2/632/DS_D12F200-1141659.pdf). My project will be powered by lithium ion ...
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0answers
85 views

Smart undervoltage protection

what is the simplest way to regulate the min DC voltage in a circuit? ...
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0answers
31 views

Motor-side of BLAC supply goes into overvoltage when regenrative braking using an LM5060

I am currently using an LM5060 for protection of the motor supply on my BLAC motor driver. Everything works well until I decelerate the motor quickly, this makes the supply voltage peak above the OVP ...
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3answers
332 views

UVLO for Energy Harvester circuit

A good background on the problem can be found in the document: (Under Voltage Lock-Out Design Rules for Proper Start-Up of Energy Autonomous Systems Powered by Supercapacitors). The above document ...
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1answer
135 views

Reducing the start-up voltage of a low voltage cut-off circuit

I just built this circuit, with the intent to use it as a low-voltage cut-off switch for a single li-ion cell. It works great, but once it's triggered it needs about 7 volts to turn back on, so I ...
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1answer
94 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
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1answer
131 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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0answers
263 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/...
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1answer
101 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 ...
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1answer
1k 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 ...
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1answer
65 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 ...
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1answer
393 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 ...
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1answer
1k 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 ...
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2answers
471 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
3k 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 ...
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1answer
269 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 ...
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2answers
2k 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 ...
2
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1answer
4k 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
40 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 ...
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0answers
1k 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
337 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 ...
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2answers
691 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 ...
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2answers
117 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
922 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 , ...
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1answer
2k 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
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4answers
2k 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 ...
24
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8answers
101k 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
327 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 ...
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4answers
10k 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-...