I would expect the high impedance input of the fet would then be susceptible to noise. The output voltage tracks the input voltage therefore if you only have 0V to 5V input to the totem pole, it will only give you 0V to 5V on output (Not quite 5V as it is a. Some key points about using NPN-PNP totem pole are: 1. For example, you want to drive gate of MOSFET with the help of microcontroller output pin.The microcontroller output pin is generating a square wave of voltage level 5 volt and to fully drive mosfet gate of P-channel mosfet you need. Click this link for the Power Tip 42 (Part 1): Discrete devicesa good alternative to integrated MOSFET drivers. After the cap discharges, though, the common node at the emitter of the two bipolar transistors is floating (isn't it?).this is not a good thing, in my opinion. Totem pole basically an output driver circuit use to convert one level of voltage into another level of voltage. However, when the PWM output is low, the upper transistor is off, but so is the bottom transistor (except perhaps while the charge stored in the FET's gate capacitance serves to provide the vbe for the bottom pnp transistor to turn on, briefly. When the output from the PWM controller is high, the upper transistor is an emitter follower, so I expect to see Vout-vbe at the gate of the FET (assume no Rg for the sake of argument) -fine. I for the life of me cannot understand how this is a good circuit. In a lot of the literature out there, they make reference to the totem pole topology for driving Mosfets (as in an H-bridge) as shown in the figure attached.
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