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H Bridge configuration is commonly used in electrical applications where the load needs to be driven in either direction. A typical H-Bridge structure is shown below; Figure-1 : Wikimedia Commons - Cyril BUTTAY The current flows through the load M - Motor in one direction when S1 and S4 switches are closed and current flows in the other direction when S2 and S3 switches are closed. The components that realize the switching action are commonly transistors. Two types of transistors, NPN and PNP for BJTs, N-Channel and P-Channel for MOSFETs are needed for the proper biasing where the high side is P-type and the low side is N-type.
In this project, we use MOSFETs because of their high switching speed and low RDS(on) resistance for low heat dissipation. H-Bridge configuration requires both P and N type MOSFETs but since N-type MOSFETs have improved electrical characteristics, using only N-type for four of the transistors will be ideal. IR2110 half bridge MOSFET and IGBT driver IC allows us to do this. By using a boost-up capacitor, it can bias the high side N-type MOSFETs so we get rid of the P-type. Component List
C1, C5, C6 : 100uF/16V Electrolytic Capacitor
C3, C4, C7, C8: 10uF/16V Electrolytic Capacitor
C2 : 100nF Polyester Capacitor
Con1, Con2, Con3, Con4 : 2x4 Terminal
D1 : 1N4001 Diode
D2, D3, D4, D5, D6 : 1N5818 Schottky Diode
Q1, Q2, Q3, Q4 : IRF3205 Power MOSFET
R1, R2, R3, R4 : 1/4W Resistor
U1, LM7805CV Linear +5V Voltage Regulator
U2, U3 : IR2110 High and Low Side Driver
When one current way is off, namely its control signal is low, the boost up capacitor is charged up. When this way turns on, the boost up capacitor starts to bias the high side MOSFET until it fully discharges.So it is not possible to drive the motor in one way continuously without a PWM control signal. By using PWM control signals you can easily adjust the speed of motor and continuously run the load in one way. Same is also valid for the other way of current.
The MOSFETs used in this project are International Rectifier’s IRF3205 which can handle up to 115A drain current and 55V Drain to Source voltage. It has 0.008 Ohm RDS(on) resistance. For lower currents (~0-5A) heat dissipation will be too low. But if you will use this board for high current applications you should connect a heatsink. On the other hand you can choose a different MOSFET that suits your needs. As it is shown in the schematic, we input +12V DC supply voltage to the board. +12V is used for gate driving of MOSFETs. A LM7805 linear voltage regulator converts +12V to +5V DC for the logical supply of IR2110 which is suitable for microcontroller applications. The board has 8 terminal connections. From left to right; 1 and 2 : Load connection
3 : Ground
4 : +12V DC
5 : Load Supply ground
6 : Load Supply positive voltage
7 – 8 : PWM signals The construction of the circuit board is easy. The PCB file is provided in pdf format. You can apply it to the board by using the ironing method.
Click here to download the PCB files.
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