Questions tagged [switching-losses]

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28 votes
3 answers
31k views

Which has better efficiency: step-up or step-down switching voltage regulator?

I have a Lithium battery pack circuit that converts 4.2V (two 4.2V cells in parallel) to 5V. Another option is to use a step-down converter from 8.4V (two 4.2V cells in series) to 5V. Considering ...
dawid's user avatar
  • 471
15 votes
4 answers
55k views

Difference between High- and Low- side switching of power?

Is there any real difference between high- and low-side switching? Assume: Switching is for on/off control of an object (My case RPi) Base/Gate can be driven to Vcc and GND
Alexander M's user avatar
11 votes
4 answers
13k views

How to increase mosfet switching speed, and decrease switching losses?

I hope this is not a too broad question, but what are the best practices to achieve fast switching on a MOSFET driven by a PWM signal? My current knowledge tells me I can do two things: 1 - To use ...
Marcovecchio's user avatar
10 votes
3 answers
5k views

Dual active bridge converter

I'm having issues calculating the power losses associated with the operation of a bidirectional isolated dual active bridge DC/DC converter. The converter is controlled using phase shift modulation (...
mr313's user avatar
  • 101
9 votes
2 answers
21k views

How to determine maximum PWM frequency for transistor (2SK2554)

How can I determine (estimate) maximum reasonable PWM frequency for 2SK2554 transistor? I found timings in datasheet: I could estimate frequency from this (and make sure that all these times are 20-...
Kamil's user avatar
  • 6,004
8 votes
1 answer
5k views

How to determine BJT switching time

Is there some standard way to get information about BJT (Bipolar Junction Transistor) rise and fall times (the high power ones) ? In essence a IGBT is a BJT being driven by a FET, so there should be ...
Diego C Nascimento's user avatar
5 votes
1 answer
212 views

What are the implications of a MOSFET not listing switching losses in the data sheet?

Many MOSFETs do not specify switching losses in their data sheets. Does this imply that the losses are too low to worry about? Too high for the device to be used in a switching application? Variable ...
Stephen Collings's user avatar
5 votes
2 answers
1k views

Speeding up turn-on and off with VOM1271 Photovoltaic MOSFET Driver (/optocoupler)

It's my first post here so please do not hesitate to tell me if I'm not doing it right :-) A bit of context : we need to switch an array of power resistors (1,3kW, 1ohms) in order to test under load ...
VoltsAndNuts's user avatar
4 votes
2 answers
1k views

synchronous buck ls-FET switching losses and dead time minimization

I'm designing a Synchronous buck converter. I'm having doubts regarding the following: In the rectifying period of the converter, using a Schottky diode in parallel with the low side MOSFET will ...
mik's user avatar
  • 175
4 votes
1 answer
776 views

MOSFET fast turn-off not enough

I have a PWM bridge driving a higher than 1k load from 200V supply. The simplified, equivalent schematic is this: The drivers I'm using are slow turn-on/fast turn-off and, in the schematic, it's a 50%...
a concerned citizen's user avatar
4 votes
1 answer
117 views

Push-Pull DC converter - resonance in the waveform

I'm building 48v to 200v Push-Pull DC converter. And now I'm close to finishing the project, but when I checked the waveform on the transformer I discovered that it looks like this: (on this picture ...
darth taco tmp's user avatar
4 votes
0 answers
977 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 ...
Richard Escobia's user avatar
4 votes
1 answer
11k views

Calculation of diode switching losses

I am an Electrical Engineering student. I'm in my final year and doing a thesis about soft switching. I am trying to grasp the calculation of diode switching losses. I'm having the impression that ...
Simon R's user avatar
  • 185
3 votes
2 answers
2k views

Why does this circuit speedup the switching time and reduce losses?

I am a little confused as to how this circuit works: According to this website its function is to speedup charge time of the MOSFET as well as reduce losses. How does D1 and Q2 actually work to make ...
Alex's user avatar
  • 479
3 votes
3 answers
541 views

Does body diode reduce MOSFET switching loss in a power converter?

In power converters, it is common that MOSFETs are fed a PWM signal to have cyclic switching. Part of the power is lost in the process. Does the body diode reduce this loss? It seems most power ...
FlakR's user avatar
  • 749
3 votes
2 answers
2k views

Switching loss calculation formula

I read an article talking about the power switching loss formula, and I am curious about one thing. How to use math to prove the 1/6 and 1/2 in these two waveforms? Could someone give me some idea?
EEC's user avatar
  • 413
3 votes
2 answers
167 views

Measurement with High Voltage Differential Probe

I am doing a measurement with this a 100 MHz high voltage differential probe with voltage derating. As per datasheet of TT-SI 9110 probe, the derating curve looks like below. What impact this voltage ...
Alison's user avatar
  • 337
3 votes
1 answer
675 views

How to calculate thermal heat from a switching voltage regulator?

I found this answer here which explains how to calculate the watts that are dissipated in a switching voltage regulator, but once you calculate the watts dissipated how do you know how much ...
Trev347's user avatar
  • 1,032
3 votes
1 answer
2k views

PWM motor heating

Every man and his dog are controlling DC motors with PWM. Nowadays microprocessors are popular and offer more flexibility than 555 timers and general mixed signal analog electronic. The song remains ...
Autistic's user avatar
  • 14.6k
3 votes
1 answer
142 views

SEMIKRON: Effect of gate inductance on Eon (Switching losses)

I was reading the AN1403 "Determining Switching Losses of SEMIKRON IGBT modules" from SEMIKRON. https://www.semikron.com/service-support/downloads/detail/semikron-application-note-...
Jess's user avatar
  • 3,046
3 votes
1 answer
249 views

Problems sharing data on a common uSD between a camera and micro; - Switch (TS3A27518E)

We are having a lot of difficulties sharing a uSD card between two devices (an Atmel micro which uses the SPI, and a camera). We used to do this using relays, and all worked fine, but cards got faster ...
FeelingPuzzled's user avatar
2 votes
1 answer
327 views

In MOSFET switching loss calculation, where does the 0.5 factor come from?

I am going through this material for calculating the switching loss of the mosfet.(https://www.monolithicpower.com/frequency-selection-in-switching-power-supply-designs-part-i) The switching loss ...
Hari's user avatar
  • 2,183
2 votes
1 answer
195 views

How does the buck regulator soft start condition reduce the unwanted voltage drops from high impedance power sources?

I have been studying the functionality of the soft start function. I understood how it will help to reduce the overshoot of the output voltage as well. Here, my intention is to understand the meaning ...
student7's user avatar
  • 319
2 votes
2 answers
98 views

Can a thyristor regain its forward/reverse blocking capability if the current through it is "instantly" brought to zero?

I am imagining a situation where we have several series-connected thyristors, say 10, each that can block a voltage of 100V. So, the ten series-connected thyristors together can block a total voltage ...
CaptainFantastic's user avatar
1 vote
3 answers
4k views

Baker Clamp application for PNP Transistor

I have an issue related to Baker Clamp application for PNP Transistor. I know how to implement the Baker Clamp for NPN Transistor. However I do not know how to do it for PNP. So could anyone can ...
Mert Karadeniz's user avatar
1 vote
2 answers
422 views

Lower duty cycle less efficient?

Assume you have a DC voltage V, ideal switch (no switching losses) operating at some frequency f and duty cycle ...
abc's user avatar
  • 639
1 vote
4 answers
4k views

Why are switching losses proportional to switching frequency?

Actually in soft switching converters an increase in frequency increases switching losses? Can anyone explain why?
Raj's user avatar
  • 137
1 vote
2 answers
282 views

MOSFET Selection criteria considering conduction losses, switching losses and working frequency

I am trying to choose a suitable MOSFET for my full-bridge resonant converter for wireless power transfer. The circuit topology is something like the following. Specifications: rated power \$-~500 W\$...
Pojj's user avatar
  • 858
1 vote
1 answer
88 views

How to calculate the switching loss of an OR Gate?

This is the datasheet of the OR gate. Current consumption as per the datasheet is 25 uA. (Electrical Characteristics table - Page 4 Input current Icc = 25 uA). I am wondering how power consumption ...
vt673's user avatar
  • 897
1 vote
1 answer
4k views

Is there a formula to figure out power loss of a power inverter?

Is there a formula that will give me a ball park idea of how much power I will lose when I run my DC battery bank through a power inverter? Is this something that varies depending on the inverter? ...
BenAlabaster's user avatar
1 vote
1 answer
23k views

How to use "voltage controlled switch" in OrCAD?

In this OrCAD project, I tried to build a really basic DC-DC converter with use of "S" or "SBreak" parts in OrCAD's Analog Library. But, according to analysis (picture below), the ...
Bay's user avatar
  • 226
1 vote
1 answer
370 views

Does supply voltage affects stepper motor driver heat dissipation?

Below is a block diagram of a stepper motor controller with an external mosfet h-bridge that drives one of the stepper's coils. Let's say that the coil has 2ohm DC resistance and 3mh inductance, the ...
user1139880's user avatar
1 vote
2 answers
4k views

Dynamic and Active Leakage in CMOS

I studied various techniques to reduce the leakage power consumption in CMOS design. Leakage currents can be static and active. I understand the meaning of static (standby) leakage, but I am ...
ssinghal's user avatar
1 vote
1 answer
472 views

Is 0.5CossVdc^2 included in Pswitching losses of MOSFET?

This document (page 3) from TI states that switching losses of a High Side (HS) MOSFET (of a Synchronous Buck Converter) are: Then is states that another part of the mosfet losses are: which ...
LoukasGr's user avatar
1 vote
1 answer
203 views

Strange behaviour while simulating switching loss

I am trying to simulate gate charge profile and switching loss curves of transistor as in the circuit below. I used ideal current source (30uA) for load, clamp diode (piecewise-linear model with ron = ...
emnha's user avatar
  • 1,609
1 vote
2 answers
9k views

Diode losses in switching power supply

I couldn't find a simple approx formula for calculating diode reverse recovery losses! I am not doing any rocket science, so I just need an approx formula (not worried much about temperature effects ...
Power_Electronics's user avatar
1 vote
0 answers
350 views

Reverse recovery body diode in synchronous buck converter

I am building a synchronous buck converter from 72 V to 4.2 V 2 A. Is there a way to lower the losses of the lowside MOSFET’s body diode? I am using a switching frequency of 300 kHz and with the ...
p_karis's user avatar
  • 103
1 vote
0 answers
227 views

Can a voltage peak detector circuit detect square wave overshoot voltage?

I'm building a simple inverter with an inductive-capacitive load. I wonder if I have overshoot voltage like this on my IGBT: I want to detect this overshoot, but since I don’t have an oscilloscope I'...
Maulana's user avatar
  • 21
1 vote
0 answers
311 views

High efficiency pwm current limiter for charging supercap from alkaline battery

I'm designing device which uses two alkaline C-batteries in series as power source, and sends SMS messages using SIM800. On average 1 message per day is sent. Goal is to maximize battery life. Allowed ...
juha.mattila's user avatar
1 vote
0 answers
41 views

Is zero loss turn-off possible for thyristors?

Consider this very basic circuit: simulate this circuit – Schematic created using CircuitLab Don't mind the values - they don't matter, as this question is conceptual. Imagine that Vcomm is ...
CaptainFantastic's user avatar
1 vote
0 answers
4k views

MOSFET switching losses in LTSpice

I've made a simulation of three-phase MOSFET rectifier in LTSpice. I am simulating different conduction angles and calculating efficiency. However, I would like to also take a look at the switching ...
jurij's user avatar
  • 251
0 votes
2 answers
59 views

Any advantage in AC-DC or DC-DC with past, large form factor semiconductors?

I want to clarify this question with my real-world example: Say you have a device which contains some AC-DC converter (or DC-DC) for rather high power specs (10 kW up to 300 kW, not in the same ...
Vroomfondel's user avatar
0 votes
2 answers
222 views

Power loss of MOSFET

How can I calculate the power loss of a dpak Mosfet after adding thermal vias around it? I added a 14x7 matrix of 0.5mm THT vias with in between distance of 1.3mm to relieve the thermal stress around ...
Bananabread's user avatar
0 votes
1 answer
153 views

Flyback diode choice

I am curious about how to determine the turn ratio to get the minimum power loss. Assuming n=Np/Ns Vin=380, Vo=40, different turn ratios can get the same output because Vo =VinD/(n(1-D)). When the n ...
EEC's user avatar
  • 413
0 votes
1 answer
63 views

Efficiency curve of synchronous DC-DC controller with external MOSFETs

I'm designing a 48V to 12V, 300W buck converter. I am considering using the LM5148 controller and NTMFSC004N08MC switches. I'm confused about how synchronous DC-DC controllers can list efficiency ...
w00t's user avatar
  • 198
0 votes
3 answers
910 views

N-Mosfet switch circuit strange behavior laboratory power supply

I'm dealing with an N-Mosfet switch circuit to control, through PWM, the temperature of a heater resistor. The mosfet is a IRFS7430-7PPBF. The load is driven at 12V and has a power rating of 80W. ...
Francesco's user avatar
  • 1,025
0 votes
1 answer
67 views

Why is an LLC converter designed to operate in the ZVS region? how does the Resonance in the LLC circuit contribute to low "MOSFET losses"?

For the first question I understand that operating in the ZCS region can result in shoot through but why does that happen? I understand that an LLC converter uses the leakage inductance of the ...
Sudhanva Gokhale's user avatar
0 votes
1 answer
261 views

IGBT Turn-on switching energy loss

I found this formula to calculate \$E_{\text{on}}\$ for an IGBT: $$E_{\text{on}} = \int\limits_{t_1}^{t_2}p_v(t)\text{ d}t = \int\limits_{t_1}^{t_2}v_{CE}(t) \times i_C(t)\text{ d}t$$ How can I ...
Laz's user avatar
  • 19
0 votes
1 answer
193 views

Junction temperature calculation

I have a question regarding the calculation of the junction temperature of MOSFETs and IGBTs. An estimation is possible with: $$T_j = P \times R_{th} + T_a$$ Let us assume that the thermal resistance (...
Noah's user avatar
  • 143
0 votes
1 answer
560 views

Linear power supply vs SMPS (losses in transformer)

We know that, in a power supply, there are always losses taking place. If we have a linear power supply, the major source of loss is the core loss in the transformer. But in an SMPS, where we have a ...
APM's user avatar
  • 83