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Questions tagged [undervoltage]

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18 votes
3 answers
16k 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? ...
PICyourBrain's user avatar
  • 3,745
0 votes
1 answer
852 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 ...
user175577's user avatar
27 votes
8 answers
119k 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 ...
MikeFoxtrot's user avatar
10 votes
4 answers
12k 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-...
Randy's user avatar
  • 3,255
7 votes
1 answer
8k 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 ...
Fahad Alduraibi's user avatar
7 votes
4 answers
11k 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 ...
ria's user avatar
  • 2,015
5 votes
4 answers
415 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 ...
boardbite's user avatar
  • 4,942
2 votes
1 answer
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 ...
Rob's user avatar
  • 291
1 vote
0 answers
24 views

Connecting a second power source to a drain of an OFF P-Mosfet

As a follow-up question to my previous question regarding a circuit that passes voltages above 17 V, I wanted to be sure how to connect output of the solution circuit to my application. The output is +...
Firas Abd El Gani's user avatar
1 vote
1 answer
328 views

Implementing UVLO on battery charging and boost controller ICs

I recently bought a Adafruit PowerBoost 1000 Charger and found out it does not have 32.V UVLO to protect the battery. The boost controller IC has low voltage sense (LBO goes low when undervoltage) ...
7E10FC9A's user avatar
  • 429
0 votes
1 answer
1k 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 ...
Neeko's user avatar
  • 51
0 votes
1 answer
924 views

Undervoltage protection circuit design review

I want to design an undervoltage protection circuit. The nominal supply voltage is \$48 V\$ and the maximum load current is about \$ 0.5A\$. If the supply drops to about \$39 V\$ or below, a P-FET ...
F. Heisenberg's user avatar
0 votes
1 answer
2k 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 ...
JavaCake's user avatar
  • 193