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99 Threads found on edaboard.com: Switching Loss
Have you got the various loss terms in analytical (or vector) form with appropriate indices? Efficiency is 1 minus the sum of all ineffiencies (loss terms). Conduction loss in each switch for its duty factor, which in turn follows step-down ratio; switching losses which depend on frequency, VIN and VOUT; (...)
I am using MOSFET as switch and I want to find the switching power loss. ..you should read the article on high speed mosfet drive by laszlo balogh..... - - - Updated - - - ...pages 4 to about page 10 or so
Does this operating frequency has anything to do with creating EMI?? Yes, in offline designs, the conducted emissions graphs start at you are better off choosing a switching frequency below 150khz. ..then again, for the sake of switching loss reduction, its best to stay below 150khz anyway with an offline flyback. I am
Crrs @ 24V doesn't give the effectiv capacitance, due to non-linear characteristic. You better use plateau charge from Qg graph. Expectable rise/fall time is about 100 ns according to my calculation, switching loss about 0.5 W, still moderate. Junction-to-ambient thermal resistance of 62 K/W demands for heat sink, e.g. a small PCB mounted type
This 101 nW is consumed for 140kSps sampling rate? Or it is DC power? If first case You have to interest with switching algorithm optimisation, If second, probably You have some stupid leakage on switches.
My application: 124819 This is an idealize full bridge switch mode DC-DC boost power supply as I know it (with a MOSFET full bridge drive and full bridge rectifier). The power supply output is 300 volts at 1 amp nominal and 2 amps peak output. Power supply input is 12 volts at a necessary amount of current. Under th
If this is 3GHz continuous / balanced (-ish) switching then it could be as simple as a blocking cap and a bias resistor network on the other side. Zero delay and trivial loss are upsides, the need for some preamble period for the bias network to stabilize could be an application issue. Does it really need anything more elaborate, and if so, why?
HI I am going to build a High voltage switching Power supply using IC MAX1771. I have a doubt regarding the decoupling tantalum capacitor which is placed at the point where 12V is coming in to the board before it goes to inductor. The recommended value is 100uF,35v tantalum but what if i use a 100uf, 16v TANTALUM CAPACITOR in its place as it is
Capture time increases as SNR decreases among other design factors, so predicting when locked when switching often requires a lock detector. If signal drops out due to fading loss, lock detector is needed. If using simple PLL synthesis with clean signals, it may not be needed except for fault detection reasons.
Thanks for the quick reply Skyguy. Much appreciated. Will design a simple CC ckt and see if it works. BTW with the switching ckt, is the configuration of the P channel MOSFET good? Or will I need a pull down resistor from the gate to ground? Overall' would the ckt work with the switching the way I want? Suggest modifications if any. Thanks!
Something like that was trialled to automatically operate street lighting many years ago. A detector circuit in the lamp controller looked for a brief DC offset in the mains caused by one or more missing half cycles. It think it was abandoned quickly for several reasons, primarily that it upset filter circuits and the combined effect of many (re)c
Flyback is ok, though you will get more switching loss and rcd clamp loss. If you can tightly couple pri and sec then your losses of these will be much less. Flyback ok because your I(out ) is low Half bridge can be problematic...read the LM5039 datasheet to see this problem. two tran forward....bad because you need hi (...)
If RDS(on) in switching power supplies is the main source of power loss, why cant we connect many MOSFETs in parallel in order to minimize the resistance?
Hi, if SIMULINK allows you to measure the current and voltage for the IGBT (Ic and Vce) are we able to compute the switching loss for the IGBT? Thanks.
Hi all, Designed Flyback Topology based SMPS.Now want to convert SMPS in to Zero Voltage switching Flyback SMPS. How to design ZVS Flyback Converter? Thanks & waiting For Knowledge Enhancement,:thinker: Sachin
That would depend a lot on what kind of chop rate you are considering, and what conduction loss vs switching loss trade you are happy with. I think a little spreadsheet work would help you with that decision process. You can probably find something good enough on the Web, to make a start.
Driving high power IGBT's is not like driving a Relay. There are different design rules for 3rd and 4th generation IGBT's where Rg affects speed and power dissipation due to high gate load charges during switching. The best driver is a faster low impedance driver during switching time to minimize transient power loss during (...)
Page 7 (LHS) of the following (below) article is totally wrong, do you agree? It says that regarding active clamp forward converters, ?With sufficiently fast gate drive, the turn off of Q1 can be virtually lossless.? (Q1 being the main power mosfet). This is impossible, current cannot suddenly go to zero in Q1 and cannot immediately diver
Hello everyone! It's good to be back after a long time :) I need to design a nice switching power supply that will be used to power my electronic projects. I need a variable 15-0-15 dual voltage with per-line regulation (for example I want to be able to set -4V and +13V), and two fixed voltages of +5V and +3.3V (the 3.3V might be easily achievab
Hello and Well-Wishes To All, I have designed and built a load resonant full bridge inverter that operates at 85kHz. The inverter is to be used in multi-kilowatt inductive power transfer (Please see attached pictures and video links below for a sample of the set-up). I?m presently in the process of characterizing the inverter?s switching losses
The isolated outputs are 5V/50mA and 12V/500mA. In this case it is reasonably efficient to drop the 12V to 5V using a linear regulating IC. Your power loss is 350 mW (7 x .05), which will not generate extreme heat. To isolate the 12V, it can come from a transformer-based switching power supply. Does a particul
For power dissipated by MOSFET, switching loss and conduction loss should be taken into account. May I know should I take snubber losses into account as well as my circuit has the snubber circuit? Thanks
I've Designed one recently. I got 96%. The points are, make your transformer good, make a stable HF oscillation. And use more FETs than required. That will reduce switching loss.
Different switch technlogies are available, to be chosen dependent on the yet unclear specifications (power level, acceptable insertion loss, required isolation, switching speed).
Unfortunately you are only posting scarce code snippets, you we can't see what you are exactly doing. Viewing these snippets, I get the impression that you are operating the stepper motor completely wrong. E.g. switching the stepper off is a no-no because it most likely causes loss of position. I think, Alexander's game of questions and answe
Hello, The Active clamp forward can certainly be arranged to have zero switch_on switching loss (by suitable sizing of the leakage inductance). Since at switch off, much of the FET drain current is diverted into the clamp capacitor, (ie rather than it going through the drain_source of the FET) can we also say that the switch_off (...)
Both LM317 and 7812 are linear voltage regulators.Both will do the job and may require decent size heat sink to dissipate the heat generated during regulation process. I would use switching regulators instead of linear ones,like LM2576 they out perform linear ones in every aspect. Try Google first,and you will tones of information about the voltage
Other than those that are listed here, Noise coupling can be a big issue for an analog block driving the long line till the destination. If the long line is passing near any digital switching blocks, then it would affect the signal on the line. For this the driving block should have good drive strength i.e. low impedance.
Hello, The switching loss of a DCM flyback is virtually zero at turn on (because theres no current flowing)...........however, it has high switching loss at turn off.......supposing I add an RCD snubber to the fet...............can I confirm that this doesn't make for overall efficiency increase, but does make (...)
If you already have a circuit where you can measure actual switching times, you can measure switching losses directly. If you don't have the circuit, you most likely don't know the exact switching times and can't calculate losses.
Hi Dynamag and welcome to EDABoard, For measuring You can use Hall sensor ACS712, A1302, or any other similar. Power supply for circuit should be done using switching tech, 7812, 7805 is linear and will make some power loss according to circuit design and needs. Best regards, Peter
Hi Is there an online HTML or an Excel calculator to calculate power loss/dissipation of switching MOSFETs in BUCK synchronous DC/DC converters? I found formulas online, and in datasheets, but those are useless in practice as they only explain what is happening, but there are always 1-2 unexplained or not provided variables. Without knowing the
Hi all, I need an SPDT or a SPST switch (Absorptive) which has the following requirements. Freq : 9 GHz to 10 GHz insertion loss : < 1 dB switching speed : 100ns (Maximum) Power handling : 5 Watt CW. Connectorized : SMA both sides I am searching for the part for a long time ,Please help me out if anyone knows the part is avail
Hello, what is the formula for MOSFET switching losses & Rectifier diode losses? and please explain me how to calculate them? Hi Madhu.b switching loss of a mosfet will given by : 1/T integral over Rdson*Id^2 dt from zero up to ton . and fo a diode : 1/T integral over Vdon*id^2 dt Best Wishes Goldsmith
You can use linear dropout regulators, they r low cost and reliable. Yes, they r lossy and can be realized using an op-amp. Search google with keyword "op-amp regulator" and u get 100's of circuits on images click. But if ur application is battery powered or u r concerned with power loss, then u can go for buck dc-dc switching regulators. U (...)
In order to calculate the gate current for driving the gate of a MOSFET by PWM at ~40Khz, I use the formula for peak current "Ip" located on the 4th page of the publication question is what is a systematic way of calculating Ton term in that formula? A smaller Ton results in lower switching loss,
Hi; Since this is a battery energized system and power efficeincy is important using a switching regulator might be a more reosnable solution. It will increase the efficiency (less power loss on regulator). And this TI device can boost also, it means when your battery goes down to ie 3.1V can still supply 3.3V to your devices. But an LDO can do tha
7805 is not exactly a voltage converter. what are you actually trying to do ? Just interfacing a 30v switching signal to uC input pins ? If so, wouldn't a simple resistive divider + zener protection be enough ?
What is the output power? What is the switching frequency? For the MOSFET, you have three types of losses involved: conduction loss, switching loss and gate charge loss. To decrease conduction loss you need to use a MOSFET or a combination of MOSFETs will lower overall (...)
Hi, 1. Need to consider RMS values. These values are also used for switching loss calculation; Peak values may be limited by control strategies and protective devices for faults. 2. After loss, and heatsink/cooling solution calculation, estimate IGBT temperature; if close to 80C, use this value. Anyway, using this value allow a headroom for (...)
For low loss switching with the said voltage and current level, mechanical relays seem to be best suited. There are also small SMD versions. RF capable solid state relays are of course an option, but will most likely involve higher switch resistance and also crosstalk by switch capacitance.
Hello, I would go for mosfet as in your voltage range the voltage drop across the component (due to rdson) is much lower compared to an IGBT. Also the switching loss for mosfet is less. All will result in less cooling requirements. You can control inrush current by taking load current into account. It will reduce stress on batttery, lo
Resonant switching high voltage IGBT circuits are usually working below 10 kHz based on switching loss considerations, hard switching circuits in a low kHz range, just to shine a light on state-of-the-art. You didn't however tell about your switching frequency constraints, so it's hard to determine if the (...)
1) If snubber is to protect the switching transistor, then if the max voltage during turnoff of device is lesser than the Max VDS rating of mosfet, do we still need snubber? 2) If we implement snubber at primary winding of flyback transformer, do we need to add protection across the switching mosfet? 3) While designing snubber if we calculate pea
Hello, I'm looking to use a PFET as a switch. I want to be able to switch a small ac signal (~20 MHz) that is connected to the source with an appropriate DC bias to ensure the PFET remains on. I've tested with some general purpose PFETs and have noticed that as I go up in frequency the voltage of the ac signal begins to diminish to the point w
In power electronics, the Silicon BJT is replaced by the MOSFET and IGBT. At low voltage (say below 200V), mosfet has low on-state voltage drop and is fast. The BJT may have even lower on-state voltage drop at higher voltage, but has poor off-switching characteristic because of the storage time, so switching loss will be higher than in (...)
Hi, In some data sheets, the Eon, Eoff and Ets dissipated energies are presented in switching characteristics of a power IGBT switch. My question, from those energy values (in mJ unit) how can calculate power losses in terms if watts, I mean what the time to be used to get the total power loss from the total energy loss (...)
Hello would you agree that the rquation for "CGD ave" on page 4 of this is nonsense....?........ If vds spec was 25V, and vds off was 600V, then Cgd would be smaller with the higher drain voltage , which is nonsense. I am trying to calculate switching losses for a flyback , but i am close t
gm*RL is commonly known as the voltage gain (simplified expression) of a transistor stage. Notice that the formula is referring to Miller effect. So RL is obviously means the load resistance. But the relation only applies in linear operation, and thus apparently, it's introduced to the discussion without further impact. In switching operation,
Right, and I didn't say the bias supply provides energy when discharging the gate. When charging up the capacitance, you draw C*V^2 from the supply. Half of this is immediately dissipated in the driver, and half is delivered to the gate capacitance. While discharging the gate, the 1/2CV*2 in the capacitor is dissipated in the driver again; none