Questions tagged [undervoltage]
92 questions
27
votes
8 answers
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 ultimate automatic shutoff was annoying and a…
MikeFoxtrot
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18
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4 answers
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 over the cell.
Dave Jones of EEVBlog did a video…
JYelton
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17
votes
3 answers
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?
Desired performance:
Input > 3.3 VDC Output = Input
Input = 3.3 VDC Output = Input
Input < 3.3 VDC Output = 0.
PICyourBrain
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11
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5 answers
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 circuit (with RC) for resetting microcontrollers…
GeneCode
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8
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4 answers
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-voltage, if the user of my device carelessly…
Randy
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7
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1 answer
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 you can see in the schematic, I am using the…
Fahad Alduraibi
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6
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4 answers
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 power back, but only if it rises above 13.5 V.
This…
ria
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5
votes
2 answers
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 standby if this threshold is breached. Usually…
smoothVTer
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5
votes
2 answers
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 V_High (which is just V_Low+V_Hysteresis).
When VCC…
Thomas E
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5
votes
4 answers
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 off the power", because of these two coexistent…
boardbite
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4
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3 answers
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 seems to suggest that a hysteresis comparator…
hekete
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4
votes
2 answers
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 disconnected load sources and recharged the battery using…
uosiu
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3
votes
2 answers
Can the UVLO threshold be below the minimum supply voltage?
I need to reduce the power dissipation of a MOS used in a battery charger MCP73842.
To achieve this, I can reduce the supply voltage. From the datasheet, I see that the minimum power supply voltage is 8.7 V (page 3), but the maximum UVLO threshold…
user220456
3
votes
4 answers
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 servos that in turn spin the wheels of the robot. The…
Devin R
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3
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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, have large caches, use complex branch predictors,…
Thorondor
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