Questions tagged [switching-transients]
The switching-transients tag has no usage guidance.
37
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Transient analysis of RC DC circuit
The task is to find the current that flows through capacitor C. I tried to analyse the circuit using mesh analysis but failed. I need to find the current through C during switching (t=0) and steady-...
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Do all SMPS ICs have an internal dead-time for the MOSFETs, specifically the LTC7878?
I am trying to improve myself in power electronics and currently trying to build a Buck-Boost converter. I chose LTC7878 for this purpose since it meets my requirements.
My issue is that while I am ...
2
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2
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Transient analysis in presence of faults
While reading Shenkman's Transient Analysis of Electric Power Circuits I came across the following problem:
... This circuit represents the equivalent of a d.c. supply network. At the instant of time
...
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Is it good idea to cascade SEPIC converters to extend the input voltage range of the XL6009?
I'm currently working on designing a current controlled SEPIC converter with a wider range of input voltage for a medium sized power application which can be powered by a lithium battery.
The existing ...
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Switching times of a MOSFET
I've encountered a problem that I don't understand. Let's take two MOSFETs of the same model and the same batch (one with lower on-resistance (V1.T1) and the other with higher on-resistance (V1.T5)) ...
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ESP32 bootloader circuit exchange with MOSFET:s
I was looking at ESP32 documentation typical application setup, I researched the schematic below which has been referenced and discussed as a time sensistive circuit using the capacitor to delay en to ...
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122
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How to protect a high-voltage output stage from very high transients
Usually in electronics, one can use MOV or TVS diodes to get rid of voltage transients. That's because most applications run at a voltage of 500 V or less.
But assume I want to protect the output ...
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216
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Load-dump grade TVS diode - datasheets misleading?
This datasheet seems to promote specific TVS diodes as good for absorbing an automotive load-dump. This graph seems to support the idea:
However, these other graphs seem to contradict any load-dump ...
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68
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Transient peaks during MOSFET switching (feed-forward)
I am working on a circuit, part of which looks like this:
Signal SW is switching the MOSFET on and off such that the nodes ac+ and ac- are shorted (modulated). When SW is high to turn on the MOSFET ...
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549
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Peak switching power in MOSFET as seen in LTSpice, and reduction using snubber or gate resistor
I am exploring a tentative design to limit current for charging a VFD bus link capacitor from the AC mains. Simple analog current limiters using resistors and transistors are inefficient and ...
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924
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RLD + RC Snubber for MOSFET
I'm currently making a DC-DC SMPS power supply that converts 331VDC (rectified from 240VAC) to 60VDC with a maximum output current of 10 amps. I've asked once on this forum about a general problem on ...
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Using AC rated thermostat to control DC current? Hope to use an AC rated thermostat to switch a DC current into a solar charge controller
I need to turn off solar input ,DC, when battery box gets below freezing. I can only find AC rated remote bulb thermostats for this as they do not use battery energy for switching. Switching current ...
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196
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Switching Transient Protection For ADC Pin
I am playing around with one old transformer. I am trying to use it in combination with voltage divider to get AC 230V main into DC range (0-3.3V) suitable for ESP32 ADC input. I build circuit for ...
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What is "drive" (in units of coulomb) in this datasheet?
In the datasheet of the family of step-recovery diodes (they are essentially PIN diodes with the I layer "very thin") MMDx of MACOM (link here), following figure is given
I understand that ...
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333
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Will a parallel diode across 24Vdc line be effective for relay coil surge relief?
In our factory, a controller malfunctions many times.
I think, it's becuase of relay coil open surge (24Vdc line, Coil 350mA per each).
So, I put the schottky diode across the DC24V Line in parallel.
...
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How will a PWM controlled relay affect a 800VA transformer on the primary side compared to the secondary side?
Application: A machine that seals boxes with plastic wrapping. The box is sealed by applying a heating element to the plastic for a few seconds.
I have a 800VA (220VAC to 54VAC) transformer connected ...
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315
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AC Transient analysis of an RL or RC circuit
When an AC input is applied, the inductor in initial condition (uncharged) does not act as an open circuit, even though the magnitude of instantaneous AC voltage constantly varies.
Why is its behavior ...
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Why am I seeing voltage spikes on the output of an LM2596?
I have been working on building a DC/DC converter for an ESP32 using an LM2596.
With a few prototypes out in the wild I'm seeing them reboot randomly.
Having the circuit back on my desk with a scope I'...
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893
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Regarding transient analysis of RC circuit
Here I am trying to find the input current I(t) and Vc(t).
From my calculation, it's evident that Vc(0+)=Vc(0-)=0V and Vc(∞)= 10V but I am confused about the first capacitor. When t=0, it acts like a ...
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526
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Secondary snubber in flyback converter
I am designing a flyback converter.
Input = 180-240 Vac
Output = 15 V, 0.4 A
The secondary output seems to be oscillating when the diode is turns on. Oscillating frequency is around 27 MHz.
I am using ...
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Secondary voltage spike in flyback transformer
simulate this circuit – Schematic created using CircuitLab
I am using a TNY264 IC to make a custom flyback transformer. (U1 is the TNY264.)
The primary to secondary turns ratio is 10 with the ...
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383
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TL431 vs. SMPS transient response
I am currently working with few 150 W SMPS designs for industial applications with heavy transient load condition. Current design works well by mean of line/load regulation and device reliability but ...
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How to determine Vds(on) and Vds(off) for switching loss calculation?
In the Infineon Application Note, two of the parameters they've used to calculate the switching loss of the MOSFET are Vds(on) and Vds(off).
Is the Vds(off) the blocking voltage?
Where do they obtain ...
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High Voltage Switching with Mosfets
I am currently working on a prototype that is going to generate a burst of pulse of high voltages (e.g. 1KV).
To do this, I first made a voltage multiplier and feed the mains voltage (230Vrms) ...
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Which characteristic of a BJT determines the timing in the following given application?
I currently face a question about the BJT circuit given here:
We see a 2N3904 transistor with constant base current of 2 mA. A switch seperates a 15 V/20 ohm source from the collector of said ...
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201
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AP22802 Load Switch Sometimes Burning Unexpectedly!
I have been using AP22802 high-side load switch on many projects for non-inductive loads without any problem until now.
But sometimes it was burning even it has light loads (5V/10~150mA).
If input ...
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102
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Gate Current Calculation and Practical Mosfet Selection
Vnoo3 is the drive voltage, and Ig is the gate current. What I am wondering is:
1) How to calculate the peak Ig on the rising edge of the pulsed gate voltage? For instance, using the spice image ...
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494
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Effect of drain inductance on MOSFET turn off
I have made a simple circuit in LTSpice to test MOSFET turn-off time.
Inductance is changed from 1.5nH to 1.5mH in a few steps. The next picture shows gate-to-source voltage and drain-to-source ...
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Mechanical Switch Causes Transients from AC-DC Power Supply
I'm having trouble getting rid of output transients from this Mean Well PSU right after the AC input is switched.
https://www.meanwell.com/Upload/PDF/RPS-500/RPS-500-SPEC.PDF
The PSU is a RPS-500 ...
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436
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Transient time in buck converter
To my understanding the reactive components in a converter should not store energy over a switching period, otherwise they will blow up. An in inductor for example abides by volt-second balance, which ...
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Large negative current spike in N-Channel MOSFET source when turn-off
I am working on repairing a power supply board of a LCD TV (200W power), more specifically, the PFC section (active power factor correction). See schematic (adapted from here):
I've replaced some ...
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How to tackle circuit containing time variable resistor?
simulate this circuit – Schematic created using CircuitLab
For instance above schematic find current as function of time in circuit above
I studied it about months before and am not able to ...
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Finding equivalent capacitance and resistance from DC circuit with combinations of R and C
In order to get the simplest RC circuit and get equivalent circuit tau:
How can be its transient studied if before t = 0 there only exists one resistive part of circuit? I's obvious that before t = ...
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Where exactly appears the channel capacitance and Ron when switch on DG442 switches
I have this switch in a circuit, actually there is 30 switches.
https://www.vishay.com/docs/70053/dg441.pdf
When system is not executing any operation, switches are off. Sx and Dx are not connected. ...
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how to convert a normally closed curcuit to normally open
Just got a problem at work and I need help fixing it.
I have a water meter that is normally closed and after 5 litres of water has been used it opens that circuit, now the input board that I have ...
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Current spikes on rising and falling edge of NPN BJT switch
I am simulating a simple NPN BJT switch for PWM in LTspice, and I observe some current transients on the rising and falling edges that I do not understand. The circuit is here:
Picture of the falling ...
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Effect of switching spikes (400ns duration) on capacitor rated voltage
I have a motor drive which uses 63V electrolytic capacitors, which are the part with lowest-rated voltage on the drive's DC link. I measured the switching spikes on the DC link voltage (carefully, ...
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