Questions tagged [gate-driving]

MOSFET and IGBT gate driving

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4
votes
3answers
6k views

Driving high and low inputs of a MOSFET driver with a single PWM signal

(A typical circuit from FAN7390 datasheet.) I have high-side and low-side MOSFETs to drive. I read dozens of MOSFET driver datasheets, all of them have two separate inputs for controlling high and ...
2
votes
1answer
2k views

What must be rated maximum voltage of the boot-strap capacitor of a high-side MOSFET driver?

What is the maximum voltage that appears on a boot-strap capacitor? For example, in this circuit, does \$C_B\$ ever charge to a voltage level near \$600V \pm V_{cc}\$ ? Or does it charge to \$V_{cc}\$ ...
1
vote
0answers
498 views

Why are the dead-time in IRF boot-strap gate driver ICs relatively long?

Why are the dead-time in IRF gate-driver ICs like IR2109 relatively long?1 I can be interpreting the data-sheet wrong too. The IR2109 has a dead-time of 540ns. For IGBTs that dead-time are not ...
3
votes
2answers
2k views

AC coupled gate drive

I am trying to get a MOSFET/IGBT driver to work for almost a year. The last efforts utilizing a bipolar Totem pole driver failed without mercy. For some time I studied alternatives and came to AC ...
5
votes
2answers
8k views

Is it possible to use P-MOSFET at the floating high side of a MOSFET driver?

I need to use a MOSFET driver in my circuit. I have read some MOSFET driver datasheets. As far as I have seen, always an N-MOSFET is used at the high side. For example, consider FAN7842. Typical ...
4
votes
2answers
8k views

Internal structure of MOSFET gate driver integrated circuts

As far as I know, a typical MOSFET is driven by a circuit like below. I read several MOSFET driver IC datasheets. It looks like they have a more complicated internal structure. For example, the ...
2
votes
1answer
3k views

High side N-Channel IGBT/Mosfet drive methods

According to this paper http://www.fairchildsemi.com/an/AN/AN-9742.pdf "However, a transformer may cause half bridge crossconduction due to the offset voltage of gatepulse deadtime stage." ...
12
votes
2answers
9k views

What is MOSFET gate drive capability and why do I care about it?

Someone told me that this circuit has "poor gate drive capability": simulate this circuit – Schematic created using CircuitLab What exactly does that mean? I tested it with an LED as a load ...
6
votes
2answers
1k views

Should I gate SCRs on when reverse-biased?

I've been told that it's a bad idea to gate SCRs on when reverse-biased. Is that accurate? I'm reasonably confident that the SCRs won't actually conduct reverse-biased whether gated or not; are there ...
1
vote
1answer
1k views

HIP4082 input & bootstrap problem

Concerning the HIP4082 IC from intersil. I was asking about the input to the IC. Pins (ALI,BLI), can I use a very low frequency input on these pins for example to control a stepper motor, so the ...
24
votes
2answers
34k views

Criteria behind selecting pwm frequency for speed control of a dc motor?

I'm working on a speed control circuit for a brushed dc motor (24v, 500rpm, 2A, 4kgcm). The main components that I plan to use are PIC16f873, 4n25 optocoupler, IRFZ44N MOSFET, BY 500 - 800 diode(for ...
1
vote
2answers
2k views

Design Considerations for a dc motor drive circuit?

I'm planning to develop a control circuit for a 24V, 500 RPM (@no load), 2A, 4 kg-cm brushed DC motor. Motor has to run only in one direction. I plan to use IRF44ZN MOSFET with a proper driver to ...
5
votes
2answers
1k views

Does this use of IR2183 as high-side n-channel gate driver work?

I'm building a switching power supply taking 12V to 19V at 3A max out. I've already built one of these using a Schottky diode for the rectifier, but this time I'm thinking of trying a high-side-...
4
votes
3answers
17k views

Bootstrap circuit function

I had some question about the bootstrap capacitor on gate driver. First, the bootstrap capacitor is used because the voltage on the high side drivers gate need to be about 10-15 volts higher than the ...
2
votes
3answers
1k views

Why gate drive transformer is not connected directly to the gates in this App Note?

Here’s a circuit from TI App Note SLUA323, which shows a synchronous rectification in a current doubler circuit. U2 is a gate driver. Transformer T2, which looks very much like a gate drive ...