Questions tagged [switching-losses]

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18
votes
2answers
18k 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 ...
12
votes
4answers
43k 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
8
votes
2answers
18k 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-...
7
votes
4answers
5k 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 ...
7
votes
1answer
3k 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 ...
5
votes
1answer
163 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 ...
4
votes
2answers
737 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 ...
4
votes
2answers
576 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 ...
4
votes
0answers
3k 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 (...
3
votes
1answer
545 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%...
3
votes
1answer
1k 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 ...
3
votes
1answer
6k 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 ...
1
vote
2answers
1k 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 ...
1
vote
3answers
975 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 ...
1
vote
1answer
72 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 ...
1
vote
4answers
1k 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?
1
vote
1answer
2k 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? ...
1
vote
1answer
17k views

How to use “Voltage controlled switch” in OrCAD?

In this OrCAD project, I tried to build really basic DC-DC Converter with use of "S" or "SBreak" parts in OrCAD's Analog Library. But, According to analysis (picture below), the blue DC line should ...
1
vote
1answer
110 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 = ...
1
vote
2answers
7k 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 ...
1
vote
0answers
31 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 ...
1
vote
1answer
109 views

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

Having a lot of difficulties sharing a uSD card between two devices (Atmel micro which uses the SPI, and the camera). We used to do this using relays and all worked fine but cards got faster and ...
0
votes
3answers
493 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. ...
0
votes
1answer
50 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 ...
0
votes
1answer
104 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 ...
0
votes
1answer
93 views

How to replace microswitches with electronic switches in a voltage / resistor ladder circuit

Hello everyone, I am relocating a pair of transmission control levers to a different location within a car. At present each lever actuates a pair of SPST microswitches (at the same time) ...
0
votes
2answers
1k 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 ...
0
votes
1answer
761 views

MOSFET inverter switching losses/events - 3-phase motor

To keep this simple, let's focus on one half-bridge which supplies sinusoidal current to the motor. Q1 is the high side MOSFET and Q2 is the low side MOSFET. SPWM outputs change twice per period - so ...
0
votes
1answer
558 views

switching power loss calculation in sinusoidal pulse width modulation

How do i calculate the switching power loss in sinusoidal pulse width modulation SPWM in a H bridge inverter (4 IGBTs), and precisely is it linearly proportional to the frequency switching or to the ...
0
votes
0answers
83 views

How to add thermal model on SOAtherm-Nmos block in LTspice

I would like to analyze the junction temperature of a SCT3022AL MOSFET during switching operation on LTspice. Followint the Spice model and the thermal model of the MOSFET: https://www.rohm.com/...
0
votes
0answers
872 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 ...