The difference between push-pull circuit drive and totem pole drive

        Sometimes when considering the cost of driver chips , We will consider using a triode to build the drive circuit , So we need to be clear about the usage of commonly used drive circuits .

1、 Push pull drive .

The circuit structure is shown in the figure below , When the input is high, the upper triode is on , When the input is low, the following triode is on , No matter how slow the rising and falling edges of the input are , There is no problem that the upper and lower tubes are connected at the same time .

Precautions for push-pull drive applications ： If your input Driver The signal is MCU Output , The general range is 3.3v, The push-pull supply voltage has 12v, Then there will be a problem with the driver .

1> Because it was given MOS The gate voltage of the tube is only 2.7V about , May not be able to make the following MOS Completely conductive .

2> At this time, the voltage drop of the triode is 9.3v, If the driving current is large , Then the power consumption of the triode will be very large .

The correct usage is ： The amplitude of the push-pull input signal should be the same as that of the supply voltage , For example, push-pull power supply is 12v, Then the high level of the drive signal you input should also be 12v.

2、 Fake push-pull circuit

If the input end of this circuit is simply considered as 0v,12v There is no problem , Input 0v The upper tube is connected , Input 12v Lower the conduction tube , But from 0v To 12v Between time , For example, when the rising edge is very slow, the input is 6v when , The upper tube is connected , The lower pipe is also conductive , This is what we don't want to see . The main problem with this circuit is that the input voltage is 0.7~11.3v This voltage range , The upper and lower tubes are conductive .

 3、 Totem pole drive circuit

I think totem pole circuit is a different name for push-pull circuit .TI The push-pull circuit is also called in the Application Manual of Totem-Pole.