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408 Threads found on Mosfet Problem
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.
sir i hav design different voltage level by mosfet as resister for my adc. but when i give this to my circuit the voltage will reduce to .8 volt from 1.68v or 1.56 v how can i solve this problem. i think there is loading effect there
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
you have to actually connect up the bottom mosfet and run both hi and lo in order for the upper gate drive to work......!
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.
I'm trying to turn of my mosfet using 555 and transistor but when I try to trun off it, I get 1 Volt at low state . I posted my circuit diagram
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.
i want to drive 10 irfp460 mosfet that parallel and using ir2110 to drive them.but ir2110 cant.can i use bjt totem pole or i Must use jfet totem pole to driving mosfet? the Threshold Voltage of irfp460 is 4 volt and I'm afraid to use bjt totem pole when driver voltage below 4 volt and in this area Linear acts Can someone help me?
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
i am using ir 2110 for mosfet driver but i am not getting the high side pwm untill unless i connect the output of ic to mosfet gate ? is it necessary to always connect , cant we check the pwm seperately? why is it so?
You see the mosfet substrate diode in forward bias, due to unsuitable transistor connection.
Lets leave apart the the solenoid, motor etc. etc. The problem is if the mosfet is overloaded, only the mosfet should blow, not the driver! Destruction of the driver insists something else... 1. I don't see any series gate resistor to limit the inrush sink/source current from the driver. 1R2110 can handle only 2A current. First and (...)
You must quick charge and disharge capacitenca on FETs gate: It is often stated that transistors such as mosfets with isolated gate electrodes can be driven without a power source, which is not correct. In contrast to bipolar transistors, mosfets do not require constant power input, as long a
Hi all, I am building a dc-dc boost converter with a UCC27254 (up to 5A peak current source/sink) to drive the low side mosfet. My input voltage is 20V at minimum, and switching frequency is 100khz. I am using an LM7815 linear regulator directly connected to the input voltage, to generate a fixed 15V to power the mosfet driver. I have attached t
Hi, Pls find the attached motor testing bipolar stepper driver circuit which has A4989 driver with IRLR024NPbf mosfet .. Motor runs smoothly upto 2KHz in full step mode only if step input duty cycle set to below 20% & the current through each coil shows 1.3A. if i increase the duty cycle slightly above 20% ..motor is not rotating p
hello i am trying to make a double gate mosfet 32nm through atlas i have made the code and i am getting basic current equation but i am facing problems in extracting the subthreshold slope can anyone help me please i really need some guidance whatever i have made i have done it with help of examples
Hi! I want to simulate AND operation using mosfet's in Proteus. I have attached a screenshot of the design. But I'm not getting the necessary output. (when A and B is logic 1 Z should be logic 1) What is the mistake? 105092
I have designed a three phase pure sine wave inverter with spwm unipolar scheme. I am using a three phase rectifier to supply 200 Vdc on the dc bus of the inverter. Upon connecting a low pass LC filter i am able to get a 100Vrms pure sine wave across all three phase and the inverter is working fine on 100W load per phase. All the mosfets in this co
Guys, I need some help with my circuit which I have attached circuit is intended to be a very cheap solution of a transmitter-receiver channel - the receiver is comprised of R1 and D1 and the rest components are the transmitter. The problem is with the gate voltag
Delay is CV/I, so if you know all these values and current equation of a mosfet (I), figuring out delay should be easy, right? Since this is an inverter, you want to make sure that the current through the NMOS and PMOS are the same, so essentially, size the PMOS so that you get the same current. There are better approximations given in textbooks, b
From the netlist, there are no connections to M2. So, perhaps the problem is not with the resistor but with the mosfet which does not appear in the netlist. Perhaps check your library and make sure M2 is found and it is correct.
IR2110 getting demaged in full bridge inverter with mosfet and Arduino Hi everyone! I've been in the forum for a while, reading and analysing the posts much more than posting, trying to find threads were the solved problems are similar to mine... In many situations I've found answers to my questions, but this time it didn't happened, so I'm
You need to give 12 V as supply and there has to be a low value resistor between the mosfet gate and the driver transistor in series.