I'm looking to make a driver to control power mosfet with a pwm signal (20-40KHz) approximately. I searched on the internet and recommend settings "Totem Pole" as shown in the diagram. The LM317 I've added is because I think power loads 12V-32V so a greater than 20V voltage on the gate would damage the mosfet so I have regulated 10V
Tell me if it's okay or that arrangement would recommend ...
Or if they know of circuits of this type ...
Well, you make it yourself very difficult, the circuit can be way more easy.
Give me a few minutes and i will send you the easy circuit that i use mostly.
Here is the circuit i am using, if you want to isolate the mosfet from the pwm, then you can place before the resistor a diode (1N4141 or something like that) extra. For bigger powers you can use as mosfet a IRFP260N.
gabojrb:
I'm looking to make a driver to control power mosfet with a pwm signal (20-40KHz) approximately. I searched on the internet and recommend settings "Totem Pole" as shown in the diagram. The LM317 I've added is because I think power loads 12V-32V so a greater than 20V voltage on the gate would damage the mosfet so I have regulated 10VTell me if it's okay or that arrangement would recommend ...
Or if they know of circuits of this type ...
We really need to know the current draw of the load too in order to suggest something. If you are driving a mosfet with big gate charge ( greater than 50nC) then a totem pole is a suitable way to attain the switch frequency you need (20-40khz) unless you use a driver IC.
If you are only switching a small load and can use a mosfet with a small gate charge ( <20nC) then you might be able to use a single LOGIC LEVEL mosfet. The buz11 and irfp260N are not logic level. They both won't turn on properly at 5v gate drive and the irfp260N will not switch fast enough without a totem pole driver because it will take to long to charge the gate. The flyback diode should be across the load too.
The circuit that you have isn't a bad start. I would change the resistor before the led to 150-300Ohm and have some more decoupling around the voltage regulator ( see datasheet). A 10k pulldown at the mosfet gate to ground isn't a bad idea either. There may be more suggestions, I didn't look over it that thoroughly.
The current draw of the load and type of load is the key. With that we can recommend a suitable mosfet and a system to drive it.
I use the BUZ11 and irfp260N at 80kHz with 5V gate source and it works fine for me.
Dece:
I use the BUZ11 and irfp260N at 80kHz with 5V gate source and it works fine for me.
Are we talking about the same mosfet? this one? http://www.irf.com/product-info/datasheets/data/irfp260n.pdf
The irfp260N has a gate charge of 234nC at 10 volts!
At 5 volts it would have a charge of 117nC ( is this right?), anyway lets say 117nC for an example.
If you charge this with the arduino's safe current limit of 40mA. it would take 2.925us to charge or discharge the gate. So close to 6us just to turn on and back off.
80kHz has a period of 12.5us, 6us is spent just switching the fet. The switching time of this mosfet at 80kHz is almost 1/2 the period !
Single chip MOSFET drivers are definitely the way to go here, much simpler and easier and
have built-in schmitt-trigger on the input.
MIC4420 or MIC4422 I've used before, available in DIP and SOIC packages, handle even the
largest MOSFETs easily. Remember solid decoupling is absolutely necessary in any MOSFET driver
circuit, 10uF ceramic would be my choice, not a wimpish 0.1uF, gate drivers can pull an amp or more straight
from their decoupling cap.
