Electronics > Electronics

New H-bridge for my Robotic Car!

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TrickyNekro:
Hallo guys,

itīs seriously been sometime, since I last posted here, but my time with my job and studies is rather limited.
I ordered some days ago some free samples from Analog Devices and along with them, a leaflet came for
iCouplers. I was trying to build almost since forever a very good H-bridge for my project so I guessed it would
be nice to revive the idea of the project, with these new product that I found to be quite "matching" for what
I want to achieve so...

Here is my final board, unfortunately yet to be tested but that will come very soon ;-)



I will try to post schematics and stuff as soon as I have some more spare time!
For now I would love to have your feedback!

Best Regards,
Lefteris, Greece

jwatte:
Home-made surface mount board; pretty interesting!
Which iCoupler are you using? AD1410? And, as they are magnetic, how do they work close to a big inductor like a motor?

TrickyNekro:
I just add the schematics here, remember the board is NOT tested yet, might work perfectly might not.
Most of the circuit should work like a trip but I am not sure about the two TS12A44513 part. They are
responsible for switching the polarity at the output by choosing which half bridge is going to receive the
two PWM signals. Normally it should be ok, I double checked it, triple checked it and so on, before
materializing the PCB, but we donīt live in a perfect world... :-/

Note that the design is implementing the boot-strap method to drive the high side mosfet, allowing for
all the mosfets to be the same, but on the other hand means that the high side mosfet canīt be 100%
of the duty cycle on. It must be off and the low side mosfet on to charge the capacitors which are used
for providing power to the high side driver.

This bottleneck can be countered by isolated high side DC power supplies, but they are one hell on their
own and usually expensive so preferably the boot-strap method is used.





Iīve recorded the process of building the PCB (or at least most of it, havenīt shot soldering time,
but then again SMD soldering is not a big deal, you will find many tutorials out there).
Kinda shot it like itīs a tutorial, but I need to compose the final video now, this will take time,
itīs a lot of footage.

TrickyNekro:

--- Quote from: jwatte on March 07, 2013, 11:14:04 AM ---Home-made surface mount board; pretty interesting!
Which iCoupler are you using? AD1410? And, as they are magnetic, how do they work close to a big inductor like a motor?

--- End quote ---

I used the ADUM4223A (six versions of this IC exist 3223 and 4223, they have 3kV and 5kV of input output isolation respectively,
then there are 3 combinations of each A, B and C, having high side low voltage drop-out of 4.1V, 7V and 11.(something if I am correct) V respectively. I am not sure about these values check them in the site, just wanna give you the general idea).

I havenīt tested the device yet, thatīs the only truth and a motor is supposed to be close enough ( less than 10cm ), but they claim that they are quite noise immune both because they are shielded and cause of the technique the use to send the signal through. I shielded them in my design with some ground plane as good as I could, normally the type of environment I am going to have this is enough, but you can never know... can you? ;-)

Best Regards, Lefteris
Greece

waltr:
Why did you connect the A and B grounds on the ACUM isolator?

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