How does IR2110's HIGH-SIDE Internal Circuity work ?

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How does IR2110's HIGH-SIDE Internal Circuit work ?

I think i understand how this driver work with only high-side configuration for buck converter.

i'm trying to understand how the high-side section works internally.



haven't found anything on the web so far.

experts? :roll:

Gary
 

Dear Gray
Hi
Are you referring to the boot strap section ? is your problem with understanding how it can drive h side mosfet ? or you are referring tot he internal sections ?
If internal section is your mean :
At first it will have two mosfet as voltage multiplier and then an under voltage lockout . this section is prepared to control dissipations due to the low gate drive supply . if your gate supply ( GS ) be lower than 15 volts , your mosfet will be at linear region that means dissipative region . this section will shut down your IC , if your supply isn't as much as enough .
Best Wishes
Goldsmith
 


Hi my friend,

i did looked for understanding the internal secions.
thank you for your explanation.

Are you referring to the boot strap section ? YES
Is your problem with understanding how it can drive h side mosfet ? YES

Of course these questions i would also ask...

I do want to understand how this bootstrap section works. For my understanding, here it consists of a capacitor and diode ? yes ?
this bootstrap thing always made me confused. sure i can also tell that this source connection to Vs HIGH SIDE OFFSET voltage also adds to the confusion.

will be happy to understand how it works in this circuit:




Thank you

Gary
 

Hi again My friend
At first the circuit that you attached has a big problem ! this mosfet can't be turn on ! never ! because boot strap capacitor won't have any path to be full of charge . hence you should use another mosfet which has an internally anti parallel diode instead of the diode in out put section .
Anywhere , Wait for some minutes , please , i'll write some paper for you , and i'll attach them for you , . just some minutes .
Best Wishes
Goldsmith
 

i'm sorry to disturb you while you make some papers,

but actually i simulated it in pspice and it works. are you sure with your claims ?
the topology i attached earlier was taken from a datasheet.

here's the pspice schematic:



VDD Supply voltage is 12vdc.

Gary
 
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Well i came back , see below , please :
View attachment IMG_0969.pdf
View attachment IMG_0970.pdf
You can also , remove negative supply and use ground instead of it for your aim . and i saw it's datasheet and then i told this to you . if you read things that i wrote i think you'll understand my meaning . and nother thing is , that simulation can't show you all things !
BTW : sorry if my hand writing is bad !
Best Wishes
Goldsmith
 

Dear goldsmith,

Thank you very much for your dedication!

Here's a question: won't the hexfet IRF540N should with be sufficient applying according to the datasheet schematics without the need of another moset? I just need it for buck converter and not for implanting any kind of bridges, using only HIN input, and high-side outputs...

Update: btw, the buck's vin should be anything between 1v and 41v approx.
 
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Cubano,

Thank you for those links.

The application note an-978 I did try to read. It was mister-rf who supplied me with that link on another thread, but the boot strap explanation was too complicated that I couldn't get it's general purpose.

The other application note you recommend seems to have planty explanations in depth. Hope that I could understand its usage.

I will try to look into it.
 

Hi again
I'm glad because i could help you .
But , it is a usual term to use a mosfet instead of diode or a mosfet in parallel with diode . however there are some float drivers that designed just for H side . but majority of drivers need two mosfet , too . such as IR21XX (2113 /2110 /2130 .... )
Good luck
Goldsmith

- - - Updated - - -

By the way , i'm glad too , because you could read my bad hand writing !
 

So I didn't understand...is the IRF540N sufficient without the need for another MOSFET? It had an internally schotkey diode connected between the source and drain. The driver I'm using is IR2110
 

oh sorry i forgot to answer this question !
At first , what do you mean by : it has internally diode ? pf course it has but what is the benefit of this diode in driving process ? nothing !
Can you attach it's datasheet , please ? IS2110 ?
 

I'm sorry, it was a typo... I meant IR2110 Driver. Already corrected it in my reply.


Gary
 

Gary , of course you'll need low side mosfet too , ( for this driver ) but don't forget to create enough dead time . if you create enough dead time , the low side mosfet can be a low power mosfet and then you can use a high power diode in parallel because the low side mosfet in your aim , is just to supply bootstrap capacitor ( creating a path up to ground )
Good luck
Goldsmith
 
Okay, i understand now, thank you very much !

i tried to take a look on the application notes regarding the bootstrap topology and still can't understand why the hell do we need it at all ?
what happens if we dont apply bootstrap configuration to high-side drive circuit ?

Gary
 

Hi again dear Gary
Ha ha ! i see ! i know exactly what is in your mind ! listen carefully ! we will have a PWM or SPWM . which has a ground ( reference point ) . and we will have a high power power supply . . and as you probably know we have to put +15 volts across the GS junction of each mosfet to turn it on . you understand ?
So for low side , we won't have any problem because we can connect or signal ground ( ground of PWM section ! ) to the source of low side . but we can't connect it to the source of H side too . because if we do it , in fact , we should see a big explosion ! because the DS of l side short circuited if we do it !
So we should create a float supply to drive h side .
Clear ? if you don't understand it , tell me , please i can simplify it for you .
Good luck
Goldsmith
 

Consider a high side NMOS switch. To drive the output to postive supply (fully on), what's the required gate voltage referred to positive supply? What are your options to generate the gate-drive voltage?
 

yes i read that the gate voltage must be 10-15 volts higher than the source voltage. so are you saying the that the bootstrap capacitor solves it by charging itself to VDD-Vf(Bootstrap Diode)
so the gate's peak voltage would be VIN(Buck)+VDD-Vf(Bootstrap Diode) like said on other topic ?
 

the gate voltage should be around +HV+15 ! the GS voltage is +15 volts !

- - - Updated - - -

e.g your VDC is around 500 volts ! the voltage from gate up to ground , will be 515 volts . but GS voltage will be 15 volts !
 

2 questions:

1. if i tied together my PWM outputs via diodes to have the whole duty cycle range (using SG3525A), instead two outputs with 180 degree phase difference.
i understand that now two mosfets need to be used on the output to fully charge the bootstrap capacitor (VCC to groun) i see LIN has to be used as well.
BUT - in my schematic i used only HIN connectivity. LIN is grounded. what do i connect to LIN in my driver?

2. is using two mosfets with an external diode equal to using two hexfets with their internal diodes ? so no need for external diode ?


Gary
 

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