60 votes

How to design the gate resistor value?

Understanding The Gate Of A MOSFET MOSFETs are remarkable devices which provide many benefits when driving various loads. The fact that they are voltage driven and that, when on, they have very low ...
user avatar
  • 45.7k
20 votes
Accepted

How to design the gate resistor value?

If you selected this driver, which has huge output current (7A) then I presume you need this gate drive current to switch a very large FET very fast. The gate resistor will only slow things down by ...
user avatar
  • 60.1k
18 votes
Accepted

Bootstrap circuit for high-side MOSFET driver

simulate this circuit – Schematic created using CircuitLab Note 1: The input voltages are only \$V_{cc}\$ and \$V_\text{High Voltage}\$. You don't apply anything at the \$V_{BS}\$ node. It is ...
user avatar
  • 13.5k
17 votes
Accepted

Driving highly inductive loads destroys mosfet driver

Holy Carp! You're trying to do 10's of nsec switching on a solderless breadboard? And you don't have a flyback diode on your transformer? If you're going to do this stuff, you've got to learn to ...
user avatar
17 votes
Accepted

Proper way of connecting logic GND / power GND on MOSFET driver

I've answered a question very similar to this here (How do I design correctly ground plane separation for Texas Instruments TPS63060 IC?), but I'll tweak a reply for you here. IRF is asking you to ...
user avatar
  • 6,106
17 votes
Accepted

p-channel MOSFET switch

First off, the rules of the site do state not to ask for recommendations of products, so I will skip that bit. Just read the datasheets as everything will be explained in there. If there is something ...
user avatar
  • 11.5k
17 votes

Is paralleling MOSFETs a good or a bad idea?

I see no problem with it. It is also best for them to share the same heat sink and be switched at a reasonable speed and proper gate voltage. If one starts conduction more than the others it will get ...
user avatar
  • 2,994
17 votes
Accepted

Why can't an MCU's GPIO pins directly control power MOSFETs?

Sometimes they can. But when they can't there are two main reasons- not enough voltage and/or not enough current. The voltage is required to get many MOSFETs to turn on so they have low resistance. ...
user avatar
16 votes

Is paralleling MOSFETs a good or a bad idea?

It is perfectly fine and frequently done. Even if the devices didn't turn on (or off) simultaneously, the (possibly) higher current for a brief time won't cause any damage. Note that it is better to ...
user avatar
  • 13.9k
15 votes
Accepted

Why doesn't shoot-through occur on totem-pole structure?

These transistors don't conduct unless Vbe>0.6V for the NPN, Vbe<-0.6V for the PNP. And as the bases and emitters are tied together, it is impossible for both these conditions to be true at the ...
user avatar
15 votes
Accepted

Why do I keep burning my mosfet?

Lose the diode. I can't even guess what you think it does, but it will prevent the FET from being turned off quickly. The FET driver will drive the gate high quickly, which turns on the motor. ...
user avatar
15 votes

p-channel MOSFET switch

The trouble with using a high side P channel MOSFET driven from a signal that doesn't get close (less than 0.5 volts) to the high side voltage is that there is a decent probability that it will appear ...
user avatar
  • 385k
14 votes
Accepted

Designing a *linear* MOSFET driver stage

This is indeed an interesting problem, because of the variation of effective load capacitance with the load resistance due to Mr. Miller, and your need to not overcompensate it. I suspect a biased ...
user avatar
14 votes
Accepted

Is it better to use a MOSFET with a gate driver IC or a MOSFET with a lower VGS,on?

which is best for fast switching do I need to use MOSFET driver IC such as ICL766 with IRFZ44n or is it better to use lower VGS MOSFET such as AO3400 You don't want fast switching to drive LED strips!...
user avatar
  • 60.1k
14 votes

Is paralleling MOSFETs a good or a bad idea?

The PTC characteristics of most FETs make this a valid application for digital or fast dVgs/dt switching, but not slow switching in the linear high power region as commonly ignored due to parallel ...
user avatar
13 votes

Resistors getting hot in this MOSFET driver circuit

Here is your circuit being discussed: R3 and R5 should not be getting "hot". Do the math. Even if Q1 were a perfect switch, there would only be 5 V across R3. (5 V)2(1 kΩ) = 25 mW. Unless ...
user avatar
12 votes

Why doesn't shoot-through occur on totem-pole structure?

In a true totem pole configuration, shoot thru usually does occur for a very short time during switching. However, what you have is not a totem pole configuration. You have two emitter followers ...
user avatar
12 votes

Resistors getting hot in this MOSFET driver circuit

Figure 1. When Q1 is off both Q2 and Q3 are forward biased (green) and will turn on. The result will be shoot-through the two transistors (red). If the supply voltage doesn't collapse (1) will be at ...
user avatar
  • 160k
12 votes

Can you drive a P-MOSFET as a high side switch directly from a microcontroller?

If I use a GPIO configured as open drain output, not push-pull, and use a pullup resistor between the gate and source of the P-MOSFET and It this OK to do so ? Am I correct, or am I missing ...
user avatar
  • 385k
11 votes

p-channel MOSFET switch

Here is another approach that uses an N-MOSFET in a level shifter configuration that does not invert the control signal polarity. simulate this circuit – Schematic created using CircuitLab You ...
user avatar
  • 45.7k
10 votes

Designing a *linear* MOSFET driver stage

Outcome Report Okay, the short story is: adding a discrete buffer worked! That said, I don't think I'll design my circuit this way, rather I'll go with the recommendation of @Spehro and @...
user avatar
  • 6,842
10 votes

Power MOSFET gets hot while driving Peltier by step-down buck voltage converter

To protect against possible future edits, here is the circuit we're talking about: Major problem are: There are no component designators in the schematic, making the circuit hard to talk about. The ...
user avatar
10 votes
Accepted

Why does my MIC4605 keep blowing up?

On your layout the decoupling cap (finger-painted red) is very far away from the chip, there is a 5R resistor in series (purple) and the current loop area (highlighted in yellow) is quite large. This ...
user avatar
  • 60.1k
10 votes

MOSFETs on Motor Controller died

They got destroyed due to inductive kickback. The TVS diode is not a correct choice, you should use a schottky diode at that position. When the MOSFETs were switched off, the motor induced a high ...
user avatar
10 votes
Accepted

Can I drive a low-voltage MOSFET gate directly from a microcontroller?

The answer is yes, and no. I mean it depends on what you need to do with the load. For simple and relatively slow on/off switching you can do it provided that… Your MCU has sufficient output level: ...
user avatar
10 votes

Why can't an MCU's GPIO pins directly control power MOSFETs?

The MOSFET gate turn-on voltage may be higher than what an MCU I/O pin can provide. A driver circuit can translate the I/O logic output voltage into a strong 'on' gate voltage. A MOSFET drive circuit ...
user avatar
  • 17.9k
9 votes

Driving highly inductive loads destroys mosfet driver

A combination of the IRF840's reverse transfer capacitance (120pF), the dv/dt of the drain voltage and the rather weak driver (MCP1402) is my best guess. Starters, read the data sheet on the driver - ...
user avatar
  • 385k
9 votes
Accepted

Drive a MOSFET via BJT?

This is called "push pull output configuration" and provides unity voltage gain but significantly low output impedance and high output current. This makes push/pull output ideal for driving high ...
user avatar

Only top scored, non community-wiki answers of a minimum length are eligible