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I was wondering if there are some particularly important mechanism by which one can break electronics, when undervolting it. Its pretty obvious that lots of electronics will not work properly if undervolted, but what about permanent damage? The question was motivated by repair work. I was wondering about what sorts of secondary effects one should look for when a damaged power supply was involved.
So what are specific mechanisms for permemenant damage due to undervolting or better put undersupplying? Are there even any? An example: a simple circuit that has a power mosfet driving a motor. The intention is that the mosfet is either completely on or completely off.
In both cases the power dissipated by the mosfet is very low:. A mosfet needs a certain voltage at its gate to turn fully on. A simple driver circuit could get this voltage directly from the power that also feeds the motor.
When this voltage is too low to turn the mosfet fully on a dangerous situation from the point of view of the moseft can arise: when it is half-on, both the current through it and the voltage across it can be substantial, resulting in a dissipation that can kill it. Death by undervoltage. Note that I started by assuming a simple circuit.
In practice a serious circuit like this would have an undervoltage protection. Wouter has some good information, but there are more scenarios where not providing a high enough voltage can damage a device. Some higher end display screens require multiple voltage sources, and failing to power one source to a high enough level, or fast enough, before a second source, can cause damage to the screen or controller. Some devices with internal mosfet can be damaged by underpowering the source.
As was explained by a TI employee about a current controlled led driver, if the VLed source is too low to provide the selected current through a channel, the logic in that channel will try to drive the channel's mosfet harder to try to sink more current. Eventually, the mosfet will burn out, if not other parts of the chip.
I wish I could find that discussion and link it. Winter Water Pipe heaters, electric stoves, microwaves for a loose meaning of "heater"certain car parts. Worse, medical devices or heating in artic environments. Same for cooling solutions, like fans or ACs or pelters.
A underperforming fan due to voltage issues can cause it's target to overheat. Water pumps as well. And all three can be damaged by the side Scythian Suite (Ala And Lolly) Op.
20 - Prokofiev* / London Philharmonic Orchestra*, London Sympho of it. Water pumps normally use the moving water to cool Fact Shredder - Argumentix - Low Voltage . A lower voltage will cause it to move water, but might not be fast enough to cool itself down. Underperforming fans might be cooked by the device it could not cool down.
Heaters themselves might freeze if they cannot get hot enough. And last I can think of, battery chargers. A malfunctioning charger, or simply badly designed one, as part of a larger circuit, could cause a lower voltage in a charging state.
A battery could feed back into the circuit when it shouldn't. If it's a resistive load, lowering voltage means it will conduct less current and dissipate less heat. Nothing wrong here. You effectively doubled the power dissipation and that could lead to damage! If the device uses a linear regulator, the regulator will have to regulate less voltage.
This will lead to lower power dissipation. Of course there is a limit at which the regulator cannot maintain regulation anymore and the output voltage will drop too. This output may shutdown or stop working at a certain point. Switch mode power supplies are a constant power load. If you assume the output to draw a constant power ; for example 3. This equals to 3. Fact Shredder - Argumentix - Low Voltage practice you have efficiency which can vary and limits to the All Because Of You (Radio Edit) - Blackmores Night - MP3 Collection region, but it will try to draw 3.
If the input voltage drops the input current increases. However, in that case you're probably exceeding a certain operation window. For example, a product may have a input voltage requirement of V. Although the switching regulator would work fine on for example 7V, it may exceed the current on some part and become unreliable.
Sometimes you see "Undervoltage lock-out" on these devices. This is a voltage at which the switch mode supply will shutdown because it cannot guarantee reliable operation. This frequently happens in circuits which Fact Shredder - Argumentix - Low Voltage multiple supply voltages that do not come up in the required sequence on power-up, leading to voltages on data lines exceeding the input rating of parts that have not yet reached a nominal supply voltage.
Often this can be resolved by simply power-cycling the system, but Pineapple Crush - Lone - Pineapple Crush that system is controlling some other mechanism it can cause further failure or even physical damage as an indirect side-effect. The general term for low-voltage events is "brownout"; there are lots of ways of incorporating brownout prevention into your power supply design.
Home Questions Tags Users Unanswered. Can electronics be damaged by undervolting it? Ask Question. Asked 6 years, 8 months ago. Active 3 years, 3 months ago. Viewed 38k times. I imagine motors could be damaged if they stalled due to undervolting. To add to the question, what are components or simple circuits that fail when undersupplied? Passerby Pasha Reshetikhin Pasha Reshetikhin 2 2 gold badges 4 4 silver badges 12 12 bronze badges.
For example, if the filament voltage on a Magnetron is too low, it can be damaged. Wouter van Ooijen Wouter van Ooijen Usually causing it to overheat and burn out. A mosfet is voltage-driven, so there is no easy way to keep a safety margin when the supply voltage the circuit was designed for is fixed.
Plus, the safety margin for the gate voltage is not nearly as large as for base current: a common maxiumum is 18V.
Passerby Passerby Was never sure exactly why that happened since I didn't have any datasheets Fact Shredder - Argumentix - Low Voltage it came from a no-brand dvd player.
Hans Hans 6, 1 1 gold badge 22 22 silver badges 36 36 bronze badges. Some resistive loads are monotonic like a lightbulb but still require a supply of over-current while it lights up.
If the supply is too feeble to supply this brief overcurrent, it When Your Lover Has Gone - Billie Holiday - Anthology 1944 - 1959 come to grief.
Especially true of quartz-halogen bulbs. Wossname Wossname 2, 2 2 gold badges 11 11 silver badges 26 26 bronze badges. I don't Bud - Weed an under powered device can be called as a brownouted device?! At what point does a brownout become undervolting?
Where as some devices can deal with minor brownouts and function normally have internal filters other devices just reset because it is up to the designer to implement brownout protection. I agree this is not a correct answer. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
A holiday carol for coders. Featured on Fact Shredder - Argumentix - Low Voltage. Update: an agreement with Monica Cellio. Linked 0. Related 8. Hot Network Questions. Question feed.
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