New answers tagged power-electronics
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RP2350 or RP2040 Power Setup
No, you can't connect 5V to IOVDD. RP2040 has a maximum rating of of 3.63V after which it will damage. So you can't run it with 5v IO, and it needs no changes to any "capacitor setup" due to ...
- 172k
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Impact of Input Capacitor on the Derivation of the Small-Signal Model of the Buck-Boost Converter
Most of the small-signal analyses consider a perfect input source so that the voltage biasing the converter is constant and equal to zero volt in ac analysis. In reality, the source features an output ...
- 23.5k
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Impact of Input Capacitor on the Derivation of the Small-Signal Model of the Buck-Boost Converter
If your model has the supply as a voltage source the addition of the capacitor does nothing. if you model is more realistic, the capacitor makes the supply more like a voltage source.
- 36.4k
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RP2350 or RP2040 Power Setup
You're putting the horse in front of the cart by deciding on the microcontroller before considering the architecture.
You can either isolate the USB and use a 5V-capable microcontroller, then you'd ...
- 100k
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How to Keep a Constant Output Voltage While Using MPPT?
PV panels behave as a voltage limited current source... or a current limited voltage source, which is the same. Their I-V curve looks like this:
The main issue is, any given level of illumination ...
- 81.6k
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How to Keep a Constant Output Voltage While Using MPPT?
MPPT means Maximum Power Point Tracking. The algorithm assumes that all the power put out from the panels can be absorbed by a load. If the load can't absorb that power, and "can't" means ...
- 174k
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How to Keep a Constant Output Voltage While Using MPPT?
The whole point of MPPT is that you have a load that can accept variable amounts of current. In other words, you can't charge a battery at constant voltage or constant current if you want to use MPPT -...
- 178k
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Driving a transformer with an AC to AC converter
Using an SCR 'chop' drive will add a lot of harmonics to the waveform. If your goal is to have a known AC voltage profile, those harmonics will make this impossible to control: you could have some ...
- 58.2k
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Using IGBTs for controlling heating loads
Recently I had to develop a low-EMI heater control.
I simply used more heating elements, each element having lower power, and triacs to turn them on and off. Thus, at any moment, the only loads in the ...
- 81.6k
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Using IGBTs for controlling heating loads
Using IGBTs will help with lower EMI and lower reactive power (better power factor).
Not necessarily. IGBTs are just another type of switch that can be turned on and off by its control terminal, ...
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Can a boost converter output different voltage levels according to the reference voltage?
As @D.A.S. mentioned, most adjustable converters use an external voltage divider that presents a scaled-down version of the output to a feedback pin and adjust the output to keep the voltage at the ...
- 23.1k
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Automatic switching between two 24V power supplies
I know this is an old thread, but I don't see an answer to one of his questions.
As above, reverse the drain and source connections for M1.
I am unable to find any PMOS with higher VGS rating.
Once ...
- 23.2k
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Turning off the high side power MOSFET without disrupting circuit functionality
As Jens said, a switch to Q1B to gnd will shut-off FET safely with 6 V max and appears as less than a 1mA load with a threshold of 2~3V.
Any NPN open collector or Nch drain will work as a on/off ...
- 148k
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NMOS based negative load switch schematic
If you're not using the optocoupler's isolation, then it's not necessary to deal with the drawbacks like low CTR issues etc. Here's a suggestion:
First schematic uses a common base transistor. When &...
- 81.6k
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NMOS based negative load switch schematic
Refer to the FODM8801 datasheet, to find these data:
CTR \$\frac{I_C}{I_{LED}}\$ could be as low as 100% (C model) or 35% (A model)
LED forward voltage could be as high as \$V_F=+1.8V\$
These ...
- 47.1k
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NMOS based negative load switch schematic
The circuit looks OK to me.
The FET model IPB072N15N3 is an overkill for the 2 A load current, but it will work.
I would prefer 10-20 kΩ as R2 to provide faster turn off. This is not an issue using ...
- 8,335
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NMOS based negative load switch schematic
I am assuming the microcontroller ground is isolated from the power ground, and in that case it seems ok. Of course you could add some filtering and decoupling, but i also think you omitted it for ...
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Buck/boost inductor design calculation
I think you are misusing the formulas because they are producing minus signs for inductance. Below the formulas are these words for equation 3: -
...
- 473k
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Accepted
Trapezoidal shape of signals in BLDC motors
Only two phases are driven at one time, the third phase is "Hi-Z" or "Off". You will also notice that only one change is made between each "sector" (as named in your ...
- 3,002
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Trapezoidal shape of signals in BLDC motors
The trapezoid shape refers to the back EMF, not the driving voltage.
In your photo, the blue phase is driven "high" to VDC; the green phase is driven "low" to 0V, and the red phase ...
- 850
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Does voltage rating of wires matter if I only intend to pass a very small amount of current?
In practice, if the insulation is thick enough to actually physically hold together as you handle the wires, then it will stand several hundred volts. But if the wire is rated at 60 V, then your ...
- 174k
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Output Capacitor of Buck Converter
\$I_C = I_L - \frac{V_O}{R_L}\$
If \$I_L\$ is greater than the load current (\$\frac{V_O}{R_L}\$) then the capacitor is charged
If \$I_L\$ is less than the load current (\$\frac{V_O}{R_L}\$) then the ...
- 473k
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Does voltage rating of wires matter if I only intend to pass a very small amount of current?
The current rating of a wire is based on its heating effect due to its resistance. At some point it will melt the insulation and possibly start a fire.
The voltage rating is based on the insulation ...
- 180k
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Does voltage rating of wires matter if I only intend to pass a very small amount of current?
Yes. It matters (kind of obviously; the current doesn't matter to the voltage between your conductor and its environment at all, and that's what matters for the insulation you need).
- 100k
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Output Capacitor of Buck Converter
Everywhere it is treated as if there is a single node equation for period 1 and 2, why ?
I assume you mean that the standard treatment is that there is one set of equations in position 1, and a ...
- 47.1k
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How to find mean length per turn (MLT) for magnetic design from ferrite cores datasheet?
Conventional low frequency transformers with a square or rectangular core and no waste laminations. I put the measurements of say Miles Platts bobbins into a database including the wdg width for 1 ...
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Accepted
Buck converter node equation
The current equation is exactly the same for both scenarios i.e. \$I_C = I_L - \frac{V}{R}\$. Or, putting it another way, \$I_L = I_C + \frac{V}{R}\$ (more clearer).
Any part of the equation does ...
- 473k
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Would a 24V automotive system experience heavy parasitic draws from having a 24V to 12V converter fitted for retrofitting 12V lighting systems
The converter will draw some bias current even when idle (no output load), so you likely need to shut the converter off when no lights are on if the vehicle will be idle for some time. It won't ...
- 902
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How does a voltage transformer work under load?
Under load, the secondary winding current creates its own flux,
directed against the magnetizing flux.
Not really; consider the situation of the secondary load beings resistive. Then the secondary ...
- 473k
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How does a voltage transformer work under load?
It occurs across the primary winding’s leakage impedance as the increased primary current under load causes greater voltage drops across the winding’s resistance and leakage reactance, so although the ...
- 1,871
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How does a voltage transformer work under load?
The primary voltage drop is to generate the flux that counters the flux from the secondary current.
- 902
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Accepted
Boost PFC small-signal model for determining transfer function
There are several methods to determine the control-to-output transfer function of a PFC. However, the common denominator to all of these approaches is the control law that is adopted by the PFC. For ...
- 23.5k
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Is \$i(t)=i(\omega t)\$ always valid in power electronics?
I believe your question has nothing to do with power electronics but only to do with how those terms are expressed.
In your first image, the capacitor current \${i_C}\$ is simply represented as a ...
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Getting a +5 V supply from a negative 48 V , non-isolated (Telecom)
Here's the LTspice sim of the LT8709 suggested by Heath:
The parts were selected to give a 5V output, but they may not all be the best values, so you should look at the data sheet to determine the ...
- 902
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Getting a +5 V supply from a negative 48 V , non-isolated (Telecom)
Consider the LT8709, which is designed to be used for a variety of negative-input functions--including this typical application that's almost exactly what you want:
You will need to modify this ...
- 38.5k
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Getting a +5 V supply from a negative 48 V , non-isolated (Telecom)
A small isolating DC-DC converter module, with 36V-72V input range, and 5V 1A output is the easiest approach. -48V to negative input, 0V to positive input. Then connect the 0V output to 0V input, and ...
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Efficient Multi-Voltage Output in PoE Circuit via Custom Transformer
What type of device are you powering? The simplest (and probably cheapeast) way for high efficiency is to simply to buck the PoE voltage unisolated to whatever voltages you need. There is no strict ...
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Forced CCM Buck Operation
Modern buck converters switch to DCM at low load currents for better efficiency.
The trade-off is higher ripple due to DCM.
With an extremely sensitive digital circuit like an FPGA being powered, that ...
- 172k
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