In the last tutorial H-bridge with P-channel and N-channel MOSFETs for Arduino Robotics we showed one form of H-bridge circuit design with P and N channel mosfet transistor. Here I wanted to show another form of H-bridge which also uses the structure as the previous ones but now this one includes extra inverting mosfet which are both N-type.
So below is the circuit diagram of this H-bridge.
The h-bridge used previously is reshown below:
%20and%20two%20N-channel(IRF540N)%20MOSFETs.gif "mosfet h-bridge driver circuit diagram")
As previously said, the difference between these two mosfet is the use of the extra two 2N7000 N-channels. Their purpose is to invert the signal. The pwn signal applied to the base junction of the h-bridge on one side goes to low side IRF540N n-channel mosfet while the same invertedsignal is applied to high side IRF9540N p-channel mosfet. So if the input pwm signal is high, then the lower nmos transistor is turned on while the upper pmos transistor is off. Similar action happens on the other side of the H-bridge. To for the rotation of the motor, each side of the h-bridge must be applied voltage signal of opposite polarity. So when input signal is high, then Q3 and Q2 are turned on and when the input pwm signal is low, Q1 and Q4 are turned on.
H-bridge can also be constructed with BJT transistors which was illustrated in the tutorials DC Motor with BJT H-bridge motor driver and also in the guide driving DC motor with BJT based H-bridge.
