Search Engine

Mosfet Problem

Add Question

422 Threads found on Mosfet Problem
Short-circuiting the mosfet would not help much to prevent simulation errors, particularly if the mosfet model is not likely to trustworthy represent the parameters of the real-world device. You are also not providing any gate resistence as would be expected at an authentic circuit. I would recomend you start by using some working curcuit/topolo
AS RdsON goes lower in mosfetS CIss and Coss increases. If your series cap is small compared to this, then the impedance ratio at this frequency will determine the response time THus if resonant , smaller L bigger C in the buck boost resonant circuit. or change the mosfet with better FOM for RdsOn*Ciss FOM is a designers figure of merit, you cal
I don't know the AWR AO tool, sorry. Does your CMOS Ring Oscillator use the same mosfet models (BSIM3V322(P)) as the "Push Push" Oscillator example?
Hi everyone, Currently, I am repairing a Power Supply 24V 20A of Siement, I have a problem with 2 power BJT and a mosfet. The BJT is BU508 and mosfet is BUK543-50B. The mosfet is switching on for the BJTs, and the BJTs is switching on for tranformer. They are broken, I have replaced the mosfet is IRFZ44 (I (...)
Maybe this? FDG332PZ P-Channel PowerTrench? mosfet -20V, -2.6A, 97mOhm
Dear all, Can anyone explain in details about soi structure.why it is good/bad.what are the issues with structure.the i-v model for this type of structure. Thanks.
Hi Geeks, I am doing a 250V 50Hz 500W bipolar spwm inverter project using Atmel microocntroller .I successfully generated signals and using look up tables to control output voltage.Now the problem is when i apply spwm signals to the mosfet the mosfet does not turn fully on.I checked the gate voltage it is around 3.15v (Vavg) at spwm duty (...)
you have to actually connect up the bottom mosfet and run both hi and lo in order for the upper gate drive to work......!
Hi, everyone, here is the problem, i used spice in of IC615 to convert the spice netlist to schematic, it says successful, but the width of mosfet is not correct, it is all 2u,which is obvious not right, but the total width of mosfet is exactly property in the netlist. I set the reference library and map file, so does anyone know this (...)
Hiii friends, .... if not how to make it working condition without changing circuit? what is the type no of the mosfet you have assembled already ?
Do you expect a mosfet being turned on with 1V gate voltage? Show the gate waveform.
Hi all, I simulate a clock oscillator with hspice using a priopretary mosfet model (.option scale=0.12u) . The weird thing is that in Hspice X-2005.09 under Windows 7 there is no problem at all. However, when I try to simulate the exactly same netlist in Hspice A-2008.03-SP1 under Linux I get the message: **error** reference 0:nfe
The TC4421A/TC4422A are improved versions of the earlier TC4421/TC4422 family of single-output mosfet drivers. result is better dead time and separate hi/lo outputs to control dead time in next stage. The problem is not that RdsOn is 2 Ohms max but that the
The 3.3V mosfet isn't appropriate for its 5V input voltage. Seems there is a voltage breakdown of the bulk-drain junction. You will need a 5V mosfet in this application. Or perhaps you can limit the bulk-drain voltage to max. 3.3V by design provisions.
Hi everyone, 115815115816 In the first picture, the circuit does not work when it is connected to the sbreak switch. In the second picture, the circuit works when it is connected to the gate driver (E) and the mosfet (IRF150), but the result goes wrong. I connected the upper dual flyback cir
Hi all, I am testing my designed circuit all things is alright, except the drivers. the driver circuit is shown in below picture. it is ok when mosfet is not connected to the source (second picture). but when I connect drain of the mosfet to the positive rail of the source (power section), the output waveform of the driver turn like the third pic
You didn't report any results (e.g. calculated versus measured losses), so I can just guess that you understimated the losses caused by charging the mosfet output capacitances. I presume you have varied deadtime to verify that it's not a cross-conduction problem.
Hi, I am aware that in order not to burn a n-ch while driving inductive load, a flyback diode is being used. I am current using a half bridge to drive a BLDC motor. The half bridge mosfet chip kept burning out. The n-ch was ok. It was always the p-ch that kept burning. The p-ch becomes a permanent short circuit. Flyback diode had been plac
For the mosfet Q3, from datasheet it looks like it cannot function at switching frequencies of more than 5.55MHz with typical values. Check the Switching Characteristics in its datasheet.
Some authors are ongoingly suggesting this pull-down resistors although you don't find it in any manufacturers application note or datasheet. The problem of increased bootstrap current demand has been already addressed. In fact there's a very small gate driver supply voltage range where the push-pull driver isn't yet driving l
Hello dear edaboard members ; I'm really tired of getting the same error from proteus :( I have 48 to 12 V dc-dc converter pre-design(not completed to apply in real life) with UC2525 PWM regulator chip. My problem is when i am trying to drive to mosfet gates(IRFZ44N) PWM-A(pin-11) is nearly correct but PWM-B(pin-14) is about to gnd.(some 1V peak
My last question is how to calculate the input power with cadence i tried (Iavg*V) but it is too large Iavg*V is of course right. The question is how much power is consumed by shoot-trough, simulataneous conduction of both mosfets. You may want to generate separate gate signals with deadtime.
It's not clear what the gate resistor is, it looks like 1.1K to me, but I'm not sure; in fact, I can't really read anything on that schematic. That 1.1K would be inexplicably large, but shouldn't cause a static problem. It's also not clear what "1 Volt at low state" means. You mean when the mosfet is on? (Low). Or when the Gate voltage is low
HEllo, I want to plot the thermal impedance vs pulse width tp at different duty-cylce for a mosfet in pspice. I've the RC thermal network with me. I could plot for single shot but not able to plot at different duty-cycle. Thanks.
Using a complementary BJT voltage follower raises respectively reduces low and high level by about 0.7 V which involves no problem with standard mosfets.
hi i'm doing a battery balance project while using your mcu. i have an technical question for using battery. i'm using npn mosfet and for controll the batteries which are series connected. can i send 5v to npn fet for make it logic 1? or do i have to send to higher voltage of batteries(higher than 70v)?
i used lm339 comparator with the attached circuit .i want to drive mosfet but the output in simulation is 2.2 v on the pin1 of the comparator .however it should be Vsat. when i decreased R1 to 10 ohm the output on led increased to 5.1 v .what is the problem . i want to get 11 v from this circuit at least and that will only happened if i put R1 = 0
Hi guys. I have to design a comparator operating at high frequency (500MHz) The topology is based on the smetrical ota with crosscoupled load. From rom what I have been exploring I concluded that for the cross coupled mosfet the value of the W has to be lower than the L, that is, for example, 0.12/0.34. The transistors that I AM using are the 3.3
THe unspecified problem I believe is the OPs largest voltage Vdd is Vref or not much more and that 1 to 2V causes problems for precise tolerance of Vgs threshold, e.g. tolerance 1.5V +/-0.5V. The next is availability. THere are sub 1V Vgs switches, but what tolerance? What is required is an ultralow threshold switch with a low threshold. In t
greetings, To evaluate a mosfet driver IC, I have implemented shown circuit. The upper switch work well. it means when it switch ON, upper lamp gets ON and the other lamp get OFF. but when down switch is fired, the down lamp does not get OFF, however the upper lamp get ON, even when I provide continuous high gate signal the gate resistor is 12 o
please am building a buck converter but am having problem with driving the mosfet switch at 20khz Show all work for best support. schematic, BOM, layout, DSO traces.
PWM regulator used to drive mosfet has FB pin to which sample of output voltage through attenuator is connected. For last circuit it is done with 1M and 6.19k resistors and at 200V output voltage FB gets 1.23V. FB is input to error amplifier with reference 1.24V. Take a look at LT1172 datasheet it has internal circuit.
OK, do not put a full bridge to replace D6,7. You do need a snubber across the mosfet say 150pF 1kV, and 47 ohm for starters (2W), also a string of zeners across the mosfet, 750 volts worth, say 5 x 150V 1.3W in series, and snubbers across D6,7 say, 1nF 500V, and 10 ohm for starters (2W). The 1N5399 is too slow, you need 2 x 600V U-fast i
Do you mean that the external diode is not needed? Yes, very clearly. In addition, you can ask if the diode is needed at all. But that's a theoretical question because it's present in any mosfet. The dominant problem of the transformer push-pull converter is overvoltage after switch-off, caused by the transformer leakage inductan
If you leave sufficient dead time in the mosfet drive, e.g. 5% then there is a natural reset of the core flux as long as the applied volt seconds are not too different, and this generally keeps the core flux with in reasonable bounds, the exceptions are pulse loads which are odd multiples of the switching half period long.
Question: Since you refer to P-devices, then your schematic #2 has the correct mosfet icons. However they still have a connection from the gate to the lower terminal. Did you intend this?
hello, i have made an inverter using cd4047 as per the circuit diagram i have uploaded here.. as per the circuit diagram gate pulse are given to the mosfet from pin 10 and pin 11 of the IC . but when i apply 12v to the ic i am getting 12v at pin 10 but not getting any voltage at pin 11 but i am getting 12v from pin 13 so i have connected 100ohm re
A Jfet can be used as a current source when its gate is connected to its source. Because a Jfet has depletion mode and conducts its maximum current when Vgs is zero.. A mosfet cannot be used because it has enhancement mode.
there are better ways to protect against an always ON PWM signal. run PWM digital signal through external logic gates being the most simple. on gate driver side, easiest way is to employ desat protection, even with mosfet switch. no problem.
Hi, read datasheet: is PIC capable of driving 100mA and keep an eye on the voltage. increasing current: * the simplest way is to just add a mosfet or BJT. * or complete halfbridge * or driver IC... it depens on what you need. * min voltage, at max sink current * max voltage at max source current * frequency * what load: completely resistive,
You are shown a P Ch FET for a low side switch which should be an N ch enh. mode mosfet. THe RdsOn must be lower than that of the LED. (<1 ohm) depending on p/n Since your input voltage is too high ( >7V, your could actually use 2 or 3 LED's in series to get more power out then use smaller R's What is the point of alternating IR light, if the fra
I have PWM of very low frequency and very low duty cycle. And max voltage comes out are 3.3. But thats not enough to open the mosfet's gate(IRFP250N). Now I want to amplify the voltage. I do not have op-amp right now. But I tried to use LM393P comparator but its seems too slow. So if I put LED direct to PWM output I can see it blinking but if I put
Your circuit has several issues. Worst of all, 35 V gate voltage will immediately kill the mosfet. You need a voltage limiting means for the gate voltage. Secondly, the relative large load resistor R1 will only slowly discharge the gate capacitance. For fast switching a lower resistance or preferably a push-pull driver circuit is necesary.
Somebody help me? I want to simulate a paper but it does not similar paper I download transistor model (mosfet32n h/k and finfet32n) from the site. Ptm., But I do not know what changes should do it on both: w=100n l=32 vin=0.5 My result with this models: Avgpwr mosfet was better than finfet. but
Hello forum I am trying to switch mosfet. I am using 1 ohm resistor. My aim is heating or cooling resistor. First, ı tried basic common source configuration. I used 1 ohm resistor as a drain resistor. My gate voltage is either 3.3 v or 0 v. With this configuration, mosfet cant enter triode region. So how can ı swi
The N-mos gate is referenced to its source terminal (more negative). The source terminal needs to see a definite path to ground, in order for the mosfet to operate. A mosfet and its controller U1 ought to have the same ground connection. Q1 is at the high side so its gate may need extremes of voltage. Make sure it is turning fully off and fully o
Dear all. Recently I have started designing a radio frequency amplifier based on dual-gate mosfet BF998. I have simulated it in HSPICE simulation software, designed input and output matching networks. Unfortunately, This is a four-parameter problem which is suitable to be solved by optimization technique. I need to optimize three inductors and one
Hi Finally, the mosfet warming problem was solved. I think this problem was caused by the L6599 and they resolve it by producing the newer generation of resonant controller(L6699). I set the maximum frequency to 200khz and F-start=190khz and F-min=60khz . CF=330pf( due to table6 of L6699 datasheet ) Resonance capacitor=110nF Ls(series (...)
Hi All, May I ask for NMOS gate driving method with isolation using IR2110 and IR2117? For IR2110, without low side mosfet, the bootstrap capacitor cannot be charged. How can i solve the problem on driving isolation NMOS with high side driver only? Second, can I use IR2117 directly to achieve my goal? Does the bootstrap capacitor charging
I think you should try a mosfet e.g. 2N7000 with source at 'E' and drain at 'C' of Q2. *are you sure R3 is connected to Ground? Allen