Questions tagged [powermosfet]

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MOSFET as a switch in battery management system

I am designing a BMS circuit for a 48V battery pack. For the switching mechanism, I thought of using a MOSFET as a switch. I thought I could use an N-channel enhancement MOSFET, but I am having ...
4 votes
3 answers
615 views

Switching MOSFET reacting much slower than expected on rising edge in simulation vs reality

I have the following schematic. This is a NE555 with voltage controlled by a 12 V voltage reference (TL431) providing a PWM of around 10 kHz at a 90 % duty cycle. The PWM then powers the gate of an ...
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Why is the MOSFET not behaving as per standard device characteristic curve?

A MOSFET has 3 modes of operation: 1.Vgs < Vth => Cutoff 2. Vgs > Vth and Vds < Vgs − Vth => linear region The MOSFET operates like a resistor, controlled by the gate voltage relative ...
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1 vote
1 answer
57 views

P-MOS control and capactive load

I am trying to drive an high capacitive load with a P-Mosfet. I added a PTC to limit the current, but it doesn't seen to be working. The mosfet is often killed. Can anybody help and provide a 'simple' ...
7 votes
5 answers
2k views

MOSFET keeps blowing out

I am trying to make a system that acts as a constant current/power load. At the time I am working with the power electronics, but I am having some trouble with the MOSFET in the circuit. Below is a ...
0 votes
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58 views

Bandwidth: voltage-source vs. current-source gate drivers

Why do voltage-source gate drivers provide low-to-medium bandwidth that does not work well for wide band gap devices, while current-source gate drivers provide hundreds of MHz of bandwidth?
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1 vote
2 answers
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What is the reason why thermal aging affects only the Cds capacitance but not the Cgs or Cgd capacitances?

Please take a look at the following images, experimentally obtained from a power cycling test of a power MOSFET. After the test where thermal aging is created due to repetitive power cycles, it is ...
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2 votes
1 answer
102 views

Replace an N-channel MOSFET with equivalent in chinese solar inverter

I am planning to replace the NCEP85T16 MOSFET in a Easun SV IV hybrid inverter. The blown out MOSFETs are on the 48 V battery DC boost side of the inverter. I found a possible replacement in Toshibas ...
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8 votes
5 answers
780 views

MOSFET overheating and voltage drop

I've searched on the network for days but couldn't find a solution to my problem I hope you can help me. I want to create a DC motor speed regulator using IRFZ46N as a power MOSFET and a 10k ...
2 votes
3 answers
260 views

Why doesn't the bootstrap diode in the half-bridge driver cause the high side to be driven at a lower voltage than the low side?

Taking a look at the block diagram for a half-bridge gate driver, the high-side gate voltage is run through the bootstrap diode which would cause a voltage drop, while the low side has no such diode. ...
1 vote
1 answer
64 views

Driving MOSFET with high rise time and high gate charge

My subwoofer got blown every time I got it repaired. A pair of K10A60D MOSFETS were originally installed by the manufacturer, but the service centre never found the original part and used the ...
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2 answers
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Understanding MOSFET forward-bias safe operating area

I am planning to use some power MOSFETS as simple on/off switches for a high voltage battery discharge circuit I'm designing. The circuit will consist of several parallel resistors of relatively high ...
2 votes
3 answers
87 views

What voltage will drive this MOSFET best?

I'm planning to use this MOSFET as on/off switches for various loads ranging from roughly 100 to 250VDC and 0.1 - 1A. I believe it to be more than adequately sized. I can also add quite a bit of ...
0 votes
1 answer
37 views

MOSFET On/Off Switch Power Dissipation

Basic setup: A battery is discharged using some lightbulbs wired in parallel. At various points throughout the discharge cycle, lightbulbs are switched off in order to increase the resistance of the ...
1 vote
2 answers
150 views

How does a bootstrap capacitor power the gate?

I understand this circuit for the most part, but I am still confused on something. So lets say that the bootstrap capacitor is already charged from the bottom MOSFET being on previously. Then, a logic ...
3 votes
3 answers
757 views

How is a highside gate powered with a bootstrap circuit and MOSFET driver?

I have been trying to understand this circuit, but I just don't get how the boot strapping works. Correct me if I am wrong but if I apply 400V at the drain of the high side MOSFET, the gate needs 410V ...
2 votes
1 answer
67 views

How is MOSFET gate resistor chosen?

I have been doing research on MOSFETS. I see that in a typical circuit that includes a MOSFET and a Driver IC, there is a gate resistor. I have done research on this gate resistor and I am aware that ...
1 vote
2 answers
111 views

How to choose a MOSFET driver?

What do you look for in a MOSFET driver before choosing it to switch a certain MOSFET? Am reading through the driver datasheet and cant precisely understand what is the ability limit of this driver. ...
5 votes
2 answers
166 views

Overvoltage Protection

I just destroyed my $1,500.00 wind turbine's battery charging module. I think I need a surge & overvoltage arrestor to add to my system to protect its replacement. We have a small family farm in ...
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1 vote
1 answer
62 views

Using IRF7821PbF mosfet without a gate driver

I have extracted some information from the datasheet of the IRF7821PbF and would like some confirmation on it. I calculated that if I have a 6A load, it only dissipates 0.32W and gets only 16° warmer ...
2 votes
1 answer
260 views

Mitigating FET current spikes in an SMPS buck converter

I'm currently designing an SMPS buck converter that converts 311VDC to 60VDC at 10 Amps maximum load. I'm using ESP32 for the PWM control, and IR2110 for the switching driver. The switch I'm currently ...
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0 votes
1 answer
35 views

Formula to calc Id of this IRF3205 in the linear region from this specific voltage measure point

I was doing a project of a electronic load and I bought a hall effect sensor to measure the current through the mosfets in this project. Due to some instability in the hall effect sensor, I needed to ...
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1 answer
251 views

RLD + RC Snubber for MOSFET

I'm currently making a DC-DC SMPS power supply that converts 331VDC (rectified from 240VAC) to 60VDC with a maximum output current of 10 amps. I've asked once on this forum about a general problem on ...
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1 answer
124 views

Inconsistent behavior of MOSFET gate driver

I am working on a 7-level power micro-inverter which composed mainly by power MOSFETs. These logic-level MOSFETs (IRLZ24NS) are driven by separate photovoltaic gate drivers with integrated fast turn-...
0 votes
1 answer
105 views

All Mosfet terminals internally shorted in voltage controlled resistor

I was planning on making a voltage controlled resistor using a power MOSFET in order to load one 12V lead acid battery. I tried implementing the circuit below; everything was going well for a few ...
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1 vote
2 answers
104 views

Chain MOSFETs to drive high voltage / high power signal from 3V3 GPIO?

I have a set of LED light strips (LEDs + resistors integrated) that I want to control with MCU GPIO outputs. The MCU outputs 3V3 signals. I have tested the IRBL8721 Power MOSFET and also the IRFZ44 (...
0 votes
1 answer
94 views

Solenoid valve driver circuit [closed]

Which extra protection components should i use if my solenoid valve of rating 24V 1.7A is driven by the POWER MOSFET IRF540 controlled by Arduino? (Flywheeling diode is there.)
1 vote
1 answer
67 views

Layout for MOSFETs (copper area for source vs drain)

I have a schematic. Here is a section of it: The FETS are being driven by the chip to behave as ideal diodes. Plus two FETs in series to block current path when chip is in shut down stage. I've seen ...
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1 vote
0 answers
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P-Channel MOSFET - Vsd unexpectedly high when driven on?

Using this cct with a FQP27P06 P-Channel MOSFET. I am trying to switch 12V power on the high side to a non-inductive load drawing about 3A . I am expecting 0.07 ohms x 3 A = .21V drop across the ...
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1 answer
55 views

CN3722 External MOSFET heating up

In my charging circuit, CN3722 is used as the charging controller where I'm using an external MOSFET FDS4435bz as per it's application. Earlier I was using DMG2307L-7 which was heating up(50°C). To ...
0 votes
0 answers
50 views

MOSFET heats up quickly in High power 14V DC-DC bidirectional charging circuit

I am currently design the following circuit to charge a 14V LifePO4 4 cells battery while running a high power motor at 14V 24A. There are some issues that I am currently facing: Without any diodes ...
0 votes
0 answers
35 views

Automatic multiple switch ON when power is applied

I have made a switch as shown in the schematics to turn ON/OFF 24 loads. When I apply a pulse on the ON-signal the load gets 24 V and when an OFF-signal pulse is applied the 24 V at the load gets ...
0 votes
1 answer
113 views

Sensing current into a battery while charging

I want to sense the current into a 84 V battery while charging and disconnect it when fully charged using a MOSFET. Is it advisable to use lowside current sensing? I used a noninverting opamp ...
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2 votes
0 answers
79 views

How to compute the SOA of a MOSFET?

Is there any tool to check if a MOSFET is within its SOA or not for a given operating condition?
1 vote
1 answer
91 views

Power MOSFET gate driver: voltage and current levels

Following are the doubts on the gate driver section of a forward converter. Peak drive voltage = 7.4 V (Shouldn't it be higher, say 10 V or so, usually for driving power MOSFETS?) Peak MOSFET gate ...
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101 views

UCC27211 Gate Driver High Side Output Randomly Turns Off

I am operating a half bridge. The high side gate driver output randomly turns off. I am unable to identify why this may be happening. Attached is an image (Pink: HO, Cyan: HI, Green: LI, Blue: Vgs(LO)....
1 vote
2 answers
137 views

Overheating P-CH MOSFET at Low-ish Current

I designed/had built a PCB to handle higher current draw. The P Channel MOSFET (Q1) I selected is used as a ON/OFF switch for the rest of the circuitry. R2 gets grounded through a switch when flipped ...
2 votes
2 answers
121 views

MOSFET selection for buck regulator (SOA vs thermal dissipation)

I am trying to design a buck regulator with the following specification: Vin = 24V Vout = 5V I max = 8A Fsw=228k. The load is basically a long strip of RGB LED's. Which in certain cases would be all ...
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62 views

How to use MOSFET?

I'm having trouble understanding MOSFET. There is always a voltage at the drain pin (my case: MOSFET on 5 V, MOSFET off 4.8 V). I've tried n-channel irfz44n and p-channel irf4905, but the result is ...
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2 votes
0 answers
69 views

Ringing at input of digital isolator while driving a mosfet with high voltage and current

From a rectified main 230V supply + 4x120µF 400V capacitor, I'm driving a STW40N65M2 mosfet which commutes a big coil. Gate is driven by MCP14A0304T. Gate current is limited by a 30.9 Ohm resistor. ...
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65 views

Voltage at the drain of P-channel part of IRF7319

Given the switch schematic: When I applied 5V to VCC and pressed SW1, I measured 4.8V on the drain of Q1B. With SW1 released, I measured 1.85V on the drain of Q1B. I read that power MOSFETs require ...
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1 answer
163 views

Why is a capacitor connected across the power MOSFET in the DC-DC stage of most SMPSs?

In many of the schematics of the DC-DC stage of SMPSs, there is an external capacitor connected across the MOSFET switch (across drain and source). Why is this capacitor required? MOSFETs have an ...
1 vote
2 answers
87 views

Why does the below SPICE simulation show an initial current even before the voltage source is applied?

LT-spice simulation is showing a sudden jump in MOSFET current from 0 to 5mA at t=0. What would be the explanation for this? Is it a tool issue? All the capacitor initial voltages (C2, C1 and C4) are ...
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1 answer
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Low loss method of connecting two dissimilar battery voltages together without a diode?

TLDR; Is there a simple circuit which delivers a diode's robust reverse-voltage behavior, only with an order of magnitude less heat generation? I have two lithium batteries with different chemistries ...
0 votes
1 answer
229 views

Would this be an appropriate design for interfacing high-power LEDs with an ESP32?

I am currently exploring a project that allows me to control high-power RGB LEDs using PWM from an ESP32 microcontroller. In this way, I plan to create a simple LED panel for canopy illumination that ...
0 votes
1 answer
60 views

High-Side P-Channel MOSFET for Lower Rated Toggle Switches

My goal is to add two toggle switches to high power DC lines so that I can break the circuit and stop power from being delivered to my load. This load will be using 28V, ~27A. I have an two channel ...
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0 votes
1 answer
45 views

Why does max current handling differ greatly form different MCU boards?

I had successfully controlled my power inverter using an Arduino DUE (Atmel SAM3X8E). To drive all of my six power MOSFETs (IRLZ24N) each GPIO is interfaced by a Photovoltaic MOSFET Driver (Panasonic ...
-2 votes
1 answer
60 views

FET Gate Voltage Question

What gate voltage is required to turn on a power MOSFET to the specified Rds(on) at a given drain current? Take for example, 1.5A drain current using this FET. https://www.vishay.com/docs/78092/...
-1 votes
1 answer
128 views

MOSFET Vds is too high when MOSFET turn on

Few days ago, I upload question about MOSFET driver getting too hot. That problem was solved by your help. thank you. But I have another problem. I connect 80ohm load to MOSFET like this figure. ...
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-1 votes
1 answer
92 views

Heatsink size calculation

Let's say I found a random heatsink with no name or model or anything else from which I can find a datasheet and get its thermal resistance. Therefore, simply by knowing its sizes, how can I calculate ...

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