Questions tagged [switching-transients]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
1 vote
2 answers
86 views

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 ...
user avatar
0 votes
1 answer
119 views

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 ...
user avatar
  • 99
0 votes
1 answer
32 views

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 ...
user avatar
  • 1
0 votes
0 answers
63 views

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 ...
user avatar
  • 87
1 vote
0 answers
40 views

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 ...
user avatar
  • 534
0 votes
3 answers
88 views

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. ...
user avatar
0 votes
1 answer
40 views

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 ...
user avatar
0 votes
3 answers
147 views

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 ...
user avatar
0 votes
3 answers
332 views

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'...
user avatar
  • 23
0 votes
3 answers
372 views

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 ...
user avatar
0 votes
0 answers
168 views

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 ...
user avatar
3 votes
0 answers
366 views

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 ...
user avatar
1 vote
1 answer
241 views

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 ...
user avatar
3 votes
0 answers
367 views

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 ...
user avatar
0 votes
1 answer
660 views

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) ...
user avatar
  • 432
1 vote
1 answer
123 views

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 ...
user avatar
0 votes
1 answer
110 views

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 ...
user avatar
0 votes
0 answers
63 views

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 ...
user avatar
0 votes
1 answer
281 views

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 ...
user avatar
1 vote
1 answer
263 views

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 ...
user avatar
  • 565
0 votes
2 answers
188 views

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 ...
user avatar
  • 11
2 votes
0 answers
621 views

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 ...
user avatar
-1 votes
2 answers
141 views

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 ...
user avatar
1 vote
0 answers
89 views

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 = ...
user avatar
  • 613
1 vote
3 answers
143 views

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. ...
user avatar
  • 613
1 vote
1 answer
2k views

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 ...
user avatar
  • 11
2 votes
1 answer
730 views

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 ...
user avatar
1 vote
4 answers
535 views

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, ...
user avatar
  • 13.8k