Brownout protection circuit in embedded systems

Hello , everyone .

I'm Shailakadesh Pandey , and welcome to my YouTube channel .

Today's topic is Brown node protection circuit in the embedded systems .

Okay .

So let's get started with the topic .

So basically , what is this Brown node protection circuit ?

See , every processor or controller is having a specified operating voltage that it operates at a particular voltage range .

Okay .

And if , the voltage falls below the specified voltage , then there's a possibility that processor may under undergo unexpected program execution or abnormal behavior .

To avoid this unexpected program execution and abnormal behavior , we are having the brownout hornet protection circuit when it is useful only when the , supply voltage of the processor falls below the threshold value that is specified voltage range .

Okay .

So let's get to the next point .

Battery power devices .

See , this brownout protection circuit , this works on the , devices which operate on the battery .

Okay .

Miss , which are battery powered devices because there's a possibility that battery voltage might drop and during such a situation we will require the brownout protection circuit .

Okay .

Fine .

Now , what does this Brown or protection do ?

Okay .

This Brown or protection , how how does it work ?

See whenever the voltage of the controller or processor falls below the specified voltage .

When it falls below the specified voltage to avoid the unexpected program execution , it resets that processor .

Means when the voltage falls below the threshold value value , it resets that processor .

Okay .

And the processor remains in the reset state till the voltage reaches the value which is above the threshold value or threshold value .

Okay .

And , the reset state , after it when the processor reaches the , specified voltage range , the reset is stopped .

Okay .

It gets back to normal working state .

So to avoid this unexpected abnormal behavior of a processor during the , low power , situations or low voltage situations , we have ground mount protection circuit .

Okay .

Now let's see the working of it .

Now , there are some devices .

There are some , controllers or processors which are having built in ground on protection circuit .

And these built in ground out protection circuit monitors the internal supply voltage of the processor or the controller .

Okay .

There is a supply voltage to every processor of controller to monitor that supply voltage we're having the protection circuit .

Okay .

Now , see , you can see the diagram on the right side .

Okay .

This circuit diagram is of the Brownout protection circuit .

Okay .

Where vcc is the supply voltage , Vbe is the voltage across the transistor and vz is the voltage across the Zener diode .

Okay .

So these are the 3 voltages and according to the values of these 3 voltages , the Brownout circuit protection works .

Okay .

Fine .

Now here , Zener diode transistor .

See .

This is the Zener diode and this is the transistor .

These form the heart of your , Brownian protection circuit .

Zener diode transistor are heart of the Brownian protection circuit .

Now working when we get into the working of this Brown Hall protection circuit .

When the value of the VCC , that is the supply voltage , is greater than the sum of vb and vz , that is the sum of voltage across transistor plus this voltage across diode , okay , then the transistor starts conducting .

See , I've written here .

Vcc greater than bb plus vz transistor conducting .

Okay .

So the transistor starts conducting , and when the transistor is conducting , the voltage drop across it is 0 indicating conducting .

What does that mean ?

When the supply voltage VCC is conducting .

What does that mean ?

When the supply voltage VCC is lesser than the voltage across transistor and voltage across the Zener diode .

Okay .

Then it is less than the sum .

It stops conducting .

Okay .

And when it stops conducting , the voltage develops across the transistors .

Low current is flowing through it .

And when the voltage drop develops across the transistor , it indicates the active high .

So what are we getting initially ?

There was active low , then there was active high .

So we will get the reset ones like this .

Okay .

So this is the working of the Brownian protection circuit .

Now , there are , components in this circuit , resistor 1 , 2 , and 3 .

Now what are the values of these resistances ?

Values of the resistance r 1 , r 2 , and r 3 depends on the electrical characteristics of the transistor .

Electrical characteristics of the transistor .

What is the electrical characteristics of the transistor ?

It's , voltage and current ratings .

Okay .

Voltage and current ratings of the transistor .

So , voltage and current ratings , we can get from the datasheet of the transistor .

Okay .

And according to those ratings , we have the value of r 1 , r 2 , and r 3 .

Okay .

We are selecting the values according to the transistor .

Fine .

So , what are the examples of this Brownian protection circuit ?

See , this Brownian protection circuit is also called as a microprocessor supervisor IC .

An example of it is from Maxim Delas , IC DS 123 2 .

IC DS 12 32 from Maxim Delas is example of the Browner protection circuit .

I see .

So it is very important part .

Okay .

I hope you have understood this Browner protection circuit and you have liked this video .

So please like , share and subscribe my channel .

Thank you for watching .