[moved] Gate driver for mosfets

[curious#01]

Hello everyone,

I am planning to use a totem pole arrangement for driving a mosfet from the PWM pin of a stm32f series(3.3V) microcontroller. The mosfet i am planning to use is: VISHAY SILICONIX - SIE810DF-T1-E3 - MOSFET, N, POLAR PAK.

I want to know how to decide the values of the transistors and the resistors that have to be employed in the totem pole arrangement.

I have attached a totem pole circuit for your reference.The VClk input comes from the PWM pin and the VGS output goes to the base of a mosfet.

Thankyou.

 

[BrunoARG]

Both totem-pole transistors must be able to allow all that current pass through them. The maximum emitter current (for a very very short time) will be (Vclk-VBE)/Rg. Make sure the current you will supply by the base will polarize the transistor correctly, It should not be so small that it make the transistor cut.

 

[FvM]

Your description doesn't fit the schematic. The transistor circuit needs a high level drive signal, e.g. 0..12V, but you want to drive it with a 3.3V level processor output. This can't work without an additional level converter.

For lowest part count, use an industry standard (low side) gate driver IC like TC427.

 

[crutschow]

As FvM noted you need an added stage to drive the MOSFET from a 3.3V processor signal.
You can connect R2 to 12V and add a transistor with the collector connected to the junction of R2 and the transistor bases, and the emitter to ground. Add a resistor in series with the base. Connect the other end of the transistor to the processor output.

The value of R2 depends upon the capacitance of the MOSFET gate and how fast you want he MOSFET to switch on (fall time).

Note that adding this stage will invert the PWM signal polarity.