L298 made with general parts - Page 1
Forum section: electronics / projects

author: asad111
author_rank: Newbie
timestamp: December 05, 2016, 11:32:29 am
content: I want to create L297,L298 bipolar stepper driver but I want to use L298 (made of general parts) to drive motor at higher ampinstead ofL298 chip becuase it limits the current to 2amp.There is circuit same like L298:This circuit has power transistors but I want to use mosfets in this circuit. Please guide me how to replace transistors with mosfets here.I have available IRFZ44 and its equivalent p-mosfet in my stock.

author: eugenenine
author_rank: Frequent Contributor
timestamp: December 05, 2016, 11:51:16 am
content: The L298 is just an h bridge motor driver, look up that and build one. I used IRF511's from Radio Shack in college to drive stepper motors from old dot matrix printers/

author: danadak
author_rank: Super Contributor
timestamp: December 05, 2016, 12:34:04 pm
content: The IRFZ44 requires a 10V Vgs to get low Rdson, so circuit is more involved than justreplacing bipolar ion the schematic you show. Plus you have no thermal protection. in thatbasic circuit.http://www.st.com/content/ccc/resource/technical/document/application_note/68/cd/c6/ab/ef/17/41/06/CD00003900.pdf/files/CD00003900.pdf/jcr:content/translations/en.CD00003900.pdfhttps://en.wikipedia.org/wiki/Gate_driverhttps://www.fairchildsemi.com/application-notes/AN/AN-6069.pdfYou might want to consider an integrated solution as drivers are challenging.Also board layout becomes critical due to high gate drive currents, as wellas the currents from the H Bridge.https://www.dropbox.com/s/ruaf9booe17jk8n/PCB%20Layout.zip?dl=0Regards, Dana.

author: Jeroen3
author_rank: Super Contributor
timestamp: December 05, 2016, 12:39:23 pm
content: Just get the L298 without any transistors. Like the MC33883.QuoteOr build it yourself out of discretes if you're in for a challange.

author: technix
author_rank: Super Contributor
timestamp: December 06, 2016, 11:42:46 am
content: You can also check out IR2110 and IR2101 high-side and low-side gate drivers with a pair of N-channel MOSFETs or IGBTs. You will need a 12V gate drive rail though. Those high-side drivers requires a non-zero low side conduction time to work properly.

author: TheAdmiralty
author_rank: Contributor
timestamp: December 06, 2016, 10:21:12 pm
content: Read some datasheets on half-bridge drivers or high-side FET drivers, I think that's what you're looking for; I've done designs for 15A+ using two IR2183 ICs and four decent FETs:http://www.infineon.com/dgdl/ir2183.pdf?fileId=5546d462533600a4015355c9490e16d1Something like the IR21xx series or the MC33883 will work well; I personally prefer the IR21xx since I've been able to run it down to a 5V single supply with logic level FETs and still have decent results for designs operating on a slow PWM frequency for brushless DC motors.If you're doing a motor driver, I'd put a freewheeling diode across each of the FETs too, since I've had a few of them get surly when letting the body diode try to handle it alone. Technically speaking you shouldn't 'need' this, but ten cents of diode is worth the time IMO.

author: technix
author_rank: Super Contributor
timestamp: December 07, 2016, 01:18:51 am
content: Quote from: TheAdmiralty on December 06, 2016, 10:21:12 pmSince you are already using a gate driver IC, you might as well run a +12V gate drive rail and use cheaper, 10V gate drive MOSFETs. Also I don't think there are any logic-level IGBTs if you want to tackle a LOT of amps.