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well eventually I would like to use 15v at 2 amps, so that h-bridge might to be ideal for now.
To follow your idea on using MOSfet, I found a web site talking about the IRF540, which is very similar to the one I have IRFZ44N., Except they use Pmos also, I guess I can use 4 Nmos and using an inverter instead of using 2 Nmos and 2 Pmos.
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what about driving one L298 per motor instead of two motors ?
will it be creating less heat ?
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You got it, for the most part. In the end, you get 2 control lines, one for on/off, and one for direction. But, you will have to use 2 N's and 2 P's and an inverter (which you can also use a couple of small MOSFETs and a couple of resistors and make your own inverter from components rather than a 7404), N channel on top, P channel on bottom. Remember (in basic terms), N channel MOSFETs work by applying a ground to a circuit, P channel's apply power to the circuit.Originally Posted by lerameur
And yes, some snubber caps and protection diodes, just in case. Motors are ugly in some ways...
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I put back the circuit together with one L298.
added caps, Its really hard to make them stick onto the motors, any thoughts?
Also it was not working at first, I realized that my Pic chip was not putting some pins at high. I changed the program so the pin output went from portC to portD and it worked. I reprogrammed the chip a few times, those couple of pins on PortC are not working no more. Can I revived them ? what happened..
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Post your circuit, otherwise it's hopeless...
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basically I am driving the h_bridge directly from microcontroller. Some one told me to use an opto coupler. BUt the output of the microcontroller is hooked up to the enable of the h-bridge, how can that fry my pins. I just fried my ccp pin..
Also, would it be better to use a seperate power supply for the controlelr and h-bridge?
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Like I said, post the circuit! We can hook you up with good info much quicker that way.
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ok, i need to draw it
any software has a 40 pin chip ?
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Under normal circumstances, it shouldnt.
Having said that, you have already destroyed on H-Bridge which is being fed from your 12V supply. When that chip died it is possible that the 12v supply got fed back to your PIC.
One phone system that I used to work on had ULN2803 drivers for the relays. The phone system CPU was running on a 5v power supply but the relays were running off 47v. When systems were hit by lightning the power supply would normally die and sometimes the ULN2803s would be damaged. If you didnt find the damaged ones and replace them they would fail shortly after the system was powered up and stuff the 47v supply into the CPU killing it and the new PSU
I think you need to read up more on the basics of electronics as to date in this thread you have
Toasted an LCD
Cooked an H-Bridge
Fried a PIC
.... maybe a job in the catering trade would be more suitable based on the above
A picture is worth a thousand words so as Skimask suggested, a look at your schematic may give us the chance to help you resolve your problems. We have all been down the road of killing components, its how you build up experience. Expensive but it forces you to learn quickly !!!!
Keith
www.diyha.co.uk
www.kat5.tv
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as for the lCd that is entirely my fault,
but are you saying opto couplers are not necessary?
when should they be used. ?
i just read a few reports of similar problem that where resolved this way.
pic:
http://www3.sympatico.ca/lerameur/PDR_0141.jpg
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