H Bridge Driver IC

This H bridge driver ic will solve most of your problems in dealing with a full H-bridge control of motor.

Generally what we do when we want to control a motor in bidirectional?

An H-bridge is one of the simplest method available as shown in below figure.

h bridge driving

A connection of H bridge with motor


You have to give four pulses by microcontroller device to make the bridge operate.

thats right and affordable also, we can do this.

But what about “Vgs” for every mosfet to turn on you have to give some voltage on gate with reference to source.

mosfet across voltage

Vgs applied to a mosfet.This seems right for one mosfet.

This seems right, its fine you can do it right?

But what about the H bridge we were talking about?
H bridge has 4 mosfets. 2 of them have source connected to ground and other two have source connected to “Load” that is floating.


So how can you apply Vgs to the top two Mosfets ?
There is also a solution. you can have each power supply separate so no need to worry about the top two Mosfets, their power supply will be different and their ground may be different than actual ground as you can see here. but that is a very lengthy process as you have to derive four power supplies for all Mosfets.

Instead of this you can use a H bridge driver IC. This IC will take care of almost everything.

You just have to apply Two pulses to the Driver IC and all the other things are generated internally.

Here is the block diagram of a typical H bridge driver IC from Freescale Semiconductor.

internal diagram of h bridge drieer ic

As you can see there is internal 5V power supply so you don’t need to worry about separate power supply for each mosfet gate voltage.

All you need to do is give input according to the truth table shown in data sheet to achieve positive or negative current from load.

Here is the data sheet for MC33186 H bridge driver IC from Freescale Semiconductor.

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