Field effect transistor driver

tangwei8802429

Field effect transistor driver [Copy link]

I saw that other people's circuits driving IRF530 all use transistor push-pull output. Why is it designed this way? The input resistance of the field effect tube is not very large, and it can be controlled by a small voltage. Can I directly use a single chip microcomputer + a single transistor to control it?

maychang

"Can I use a single-chip microcomputer and a single transistor to control it?" If the switching frequency is below a few hundred Hz, it is feasible. If the frequency is slightly higher, it will not work.

tangwei8802429

maychang posted on 2018-1-25 22:40 "Can I use a single-chip microcomputer + a single triode control directly?" It is feasible if the switching frequency is below hundreds of Hz. It will not work if the frequency is slightly higher.

How is this power calculated? I am now giving a square wave with T=1us.

tangwei8802429

maychang posted on 2018-1-25 22:40 "Can I use a single-chip microcomputer + a single triode control directly?" It is feasible if the switching frequency is below hundreds of Hz. It will not work if the frequency is slightly higher.

How is this power calculated? I am now giving a square wave with T=1 microsecond.

maychang

tangwei8802429 posted on 2018-1-25 23:14 How is this power calculated? I am now giving you a square wave with T=1 microsecond.

It is quite difficult to drive with push-pull even with a period of 1 microsecond, not to mention single-ended drive. IRF530 is a power MOS tube, and its input capacitance is quite large (including Miller capacitance), so the driving circuit must be able to provide a considerable current at the rising and falling edges of the input to charge and discharge the MOS tube input capacitance, and the current can reach several amperes.

shipeng

I remember that when I was still in school, I had the same idea when I first came into contact with field effect tubes. At that time, I deliberately reduced the load current of the driving circuit in pursuit of low energy consumption. However, I was doing linear amplification at that time. There was no problem at a certain fixed frequency, but as the frequency increased, the signal attenuation became greater and greater and finally cut off directly. At that time, I just thought that the MOS tube I bought had problems. Now I think that I was really naive at that time.

tangwei8802429

OK, got it. Thank you, group leader.