Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: DaemonToad3 on October 03, 2010, 07:58:09 AM

Title: Replacement dual H bridge
Post by: DaemonToad3 on October 03, 2010, 07:58:09 AM
I am busy trying to build this:
http://www.robotroom.com/Joystick2.html (http://www.robotroom.com/Joystick2.html)

What is a suitable and cheap replacement for the FAN8200? It still needs to handle a 9v motor. Help would be much appreciated.
Title: Re: Replacement dual H bridge
Post by: DUKELancelot on October 03, 2010, 10:12:49 AM
An L298?
Title: Re: Replacement dual H bridge
Post by: Soeren on October 03, 2010, 10:21:58 AM
Hi,


Why not just use the FAN8200?
Can be bought here as a non-Fairchild replacement:
http://www.wrighthobbies.net/catalog/product_info.php?products_id=65&osCsid=157 (http://www.wrighthobbies.net/catalog/product_info.php?products_id=65&osCsid=157)


L293 is close, slightly more powerfull, different pinout, DIP package, L293D has got diodes built-in.
Title: Re: Replacement dual H bridge
Post by: DaemonToad3 on October 03, 2010, 10:54:20 AM
I live in South Africa and none of my local suppliers stock the FAN8200 so inporting it will cost around $30 which is an option that I would prefer to avoid.

Which is the better alternative between the fan8100 or the L298?
Title: Re: Replacement dual H bridge
Post by: Soeren on October 03, 2010, 11:23:06 AM
FAN8100 is fine.
You need to start getting datasheets for the chips that you wanna compare and for how they should be mounted.
Title: Re: Replacement dual H bridge
Post by: blackbeard on October 03, 2010, 09:06:22 PM
what about the lm293d? i got 4 for $1
Title: Re: Replacement dual H bridge
Post by: DaemonToad3 on October 04, 2010, 07:32:20 AM
what about the lm293d?
That's a dual comparator I think. Thanks for the input anyway.

The cheapest chip I have found so far is the ROHM BA6845FS. Datasheet: http://tinyurl.com/33esvao (http://tinyurl.com/33esvao)

With the FAN8200 it has an enable pin and a single input. To run it in the circuit in my first post I just had to power up the enable and give a current to the input for the motor to use.

With the BA6845FS it has 2 "logic inputs", how would I connect this chip in the diagram? And what are the N.C. pins?
Title: Re: Replacement dual H bridge
Post by: pic16f628 on October 04, 2010, 08:47:17 AM
Hi

The L293 may work if the motor does not draw more than 600mA.
You can order it from Rabtron in SA for R31.07 
see http://shop.rabtron.co.za/catalog/ (http://shop.rabtron.co.za/catalog/)

I am currently trying to make an H-bridge to drive a motor from a PIC using TIP122 and TIP127 Darlington pairs but I am a newbie, wannabie roboteer and struggling. It should be simple, since they each only have 3 leads (bce) like normal transistors.  But no matter whether I put a + voltage or - voltage across the TIP127 base lead,  (which is PNP), a current still flows from c to e and the base does not seem to switch it off.  Ahh well, I am probably doing something stupid.
Title: Re: Replacement dual H bridge
Post by: Soeren on October 08, 2010, 08:55:21 PM
Hi,

what about the lm293d?
That's a dual comparator I think. Thanks for the input anyway.
No, it's a motor driver.


The cheapest chip I have found so far is the ROHM BA6845FS. Datasheet: http://tinyurl.com/33esvao (http://tinyurl.com/33esvao)
Dead link?


With the BA6845FS it has 2 "logic inputs", how would I connect this chip in the diagram? And what are the N.C. pins?
N.C. is short for "No Connection".
The datasheet have a full explanation.
Title: Re: Replacement dual H bridge
Post by: Webbot on October 10, 2010, 02:59:55 PM
what about the lm293d?
That's a dual comparator I think. Thanks for the input anyway.
No, it's a motor driver.
The L293D is a motor driver but the LM293D is a ....?
Title: Re: Replacement dual H bridge
Post by: Soeren on October 10, 2010, 05:11:59 PM
Hi,

The L293D is a motor driver but the LM293D is a ....?
Ahh, good catch - an easy mistype to make for blackbeard and not something you'd expect, so easy to overlook the "m".
Well, I allready mentioned the L293D, but it didn't seem to interrest the OP.