PMOS And NMOS H-Bridge Motor Drive Demo
Category: Miscellaneous
Designer: RANA MUHAMMAD ADNAN KHALIL
Notes
In this circuit you will learn how a) H-Bridge is made using P and N type MOSFETS. b) To select up side (A & D) and down side (B & C) mosfets. c) To drive NMOS. d) To drive PMOS. e) To drive DC motor. f) To change direction of DC motor. Working of this circuit is given below. 1. To turn ON mosfet, the difference between voltage of gate and source (Vgs = Vg - Vs) should be greater than threshold voltage. 2. MOSFET will turn OFF if Vgs is zero. 3. NPN transistors are used to turn ON and OFF MOSFET. 4. There must be some logic at Vgs, either 1 or 0. The gate of MOSFET should not be floating. 5. By default all switches (A, B, C & D) are open. 6. The Q1 and Q2 are P-type, while Q3 and Q4 are N-type mosfets. 7. The P-type mosfets will turn ON on zero logic and turn off at 1 logic, while N-type mosfets will turn ON on 1 logic and turn off at zero logic. 8. Therefore, Q1 and Q2 are configured for 1 logic and Q3 and Q4 are configured for zero logic at gates. 9. At high side, it is easy to make zero logic, and at low side it is easy to make 1 logic. 10. Therefore, at high side PMOS and at low side NMOS are selected. 11. When switch A and C are closed, the motor will rotate in clockwise direction. 12. When switch B and D are closed, the motor will rotate in anti-clockwise direction. Applications: 1. This circuit is used to change the polarity of DC power supply. 2. This circuit can be used to understand the DC motor direction control. 3. This circuit is used to understand the working of H-Bridge. Note: 1. This circuit is designed and simulated in proteus 7.10. 2. More circuits will be added in near future.