Im using a IRF540N mosfet as switch for my boost converter using arduino...im thinking of using a gate driver ic for switching@25khz.since the mosfet is not a logic level type,i have to connect the pwm of arduino to the driver ic...can anyone help me out on how to connect the arduino pwm to driver ic pins and mosfet gate terminals
Connect the Arduino pin to the gate driver input, the gate driver output(s) to the MOSFET gate, common the
grounds and supply 12V to the driver. Add 10uF ceramic decoupling to the gate driver as close
as physically possible to its supply/ground pins.
Also be sure to read the datasheet for the chip you use, they give example circuits, pcb layout information
and so forth.
The path between driver and MOSFET gate/source should be as low inductance as possible, note, which
means running twisted pair (or overlying PCB traces) from the driver to the gate+source terminals of the
MOSFET. Do not common the source wire with the main load circuit, its a separate connection commoned
right at the MOSFET leg. You want to keep the gate-source input circuit separate from the drain-source
output circuit as much as possible.
Can i give 6-9Volt supply to driver instead of 12volts?? And should i connect the 10uF capacitor in between gate pin of mosfet and o/p of driver ?????
Ansuman1994:
Can i give 6-9Volt supply to driver instead of 12volts?? And should i connect the 10uF capacitor in between gate pin of mosfet and o/p of driver ?????
Read the datasheet!
It tells you everything you need to know.
// Per.
As others have said, read the datasheet. However I know from experience reading the datasheet is not an easy task.
To give you an answer to get you started. No you cannot provide the driver with 6 - 9Volts. The FET needs at least 10V to be fully "ON". 12 volts is even better.
Regarding the bypass capacitor. I think MarkT may have meant 1µf ceramic. A 10µf ceramic capacitor is a rare bird. I personally prefer 0.1µF with leads as short as possible.
What does the capacitor do..? When the driver is switching the FET it will momentarily draw high currents 2 amps .... 10 amps (depends on the driver). The need is very short, the capacitor provides energy for this short "spike" of load to keep the switching working properly.
Why does the value matter? Good question! Capacitors have some built in inductance (not on purpose but it exists due to physical limitation). At high frequencies the inductance starts to reduce the effectiveness of the capacitor. The higher the capacitance value the lower the frequency where this occurs.
As long as I'm on a capacitor rant you might ask "..why not an electrolytic? I can easily get a 100 µF..." The reason is that electrolytics are notorious poor at high frequencies. And although they have plenty of energy stored, they cannot provide it as fast as the driver requires it.
Likely this whole discussion on capacitors will have little effect for your circuit. I just thought you should know there is some logic behind the value choice.
Good luck
JohnRob
Ansuman1994:
Can i give 6-9Volt supply to driver instead of 12volts?? And should i connect the 10uF capacitor in between gate pin of mosfet and o/p of driver ?????
NO!
and
NO!
read what I said, gate drivers use 12V supply, the capacitor is decoupling for the driver chip, between 12V and ground.