Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [switching-transients]

34 questions
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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 absorption capabilities: Extending the line on…
kellogs
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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 the Vds(on) and Vds(off) values from? Are…
Richard Escobia
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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 primary inductance being 6mH. I am using the standard…
Farvez Farook
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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 defective components and now the power supply seems…
Berk7871
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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 edge: Picture of the rising edge: On the…
user181297
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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)) tested on the same V_GS, V_DS, I_D. Why is the…
Daniel Spinu
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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 the waveform looks like this: (MOSFET turns on at…
Sai Sandeep Lolla
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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 problematic when dealing with peak charging current from a…
PStechPaul
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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 transition time is the time it takes for the diode to go…
MPA95
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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 facing some issues regarding transient loads, say…
Dhaval Lalani
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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 transistor. Before 1 µs the switch is open. After 1 µs…
NoiseEngineer
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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 27VDC with fan. The 120 VAC is coming from an…
mrbean
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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 translates to zero average voltage over a…
R N
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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 = 0 we got 12V at S node. Because it 's open…
Suvi_Eu
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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. But some system operation will switching them on,…
Suvi_Eu
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