I currently have about 20 MTP3055V MOSFETs from eBay. In order for them to be fully "on", they need a Vgs of about 10V, from my understanding. To do this, I used a TC427 MOSFET driver, since the signal was coming from a 5V PIC. However, I accidently miswired one of the drivers, and it broke. I'm using them to control a stepper motors.
This thread is to ask the best way to proceed. What I am doing is making a stepper controller for my PCB mill. I basically just need to drive MOSFETS with a +5VDC signal. From what I've read, I can get HEXFETs that will be fully "on" with a logic level signal. Is this true for all HEXFETs? What the in the datasheet should I be looking for to find the minimum on voltage for Vgs? If I don't buy logic level HEXFETs, I can always buy more motor drivers. It's too bad these things take a week to get here from digikey! (Any recommendations on where else to get this stuff?)
I think I'm in favor of switching to logic level HEXFETs, since that'll reduce the number of components on the board. I'm just not sure which HEXFETs to buy.
Here is maybe one option? http://www.jameco.com/Jameco/Products/ProdDS/669901IR.pdf
My stepper motors are rated at 2.583V, 2.1A,1.23 ohms. According to my calculations, if I run these off a +5V source (from a PC power supply), I need to put a ~1 ohm power resistor.
V=IR => V=(5V - 2.583V), I=2.1A ==> R = V/I = (5V - 2.583V)/(2.1A) = 1.165 ohm.
Power: P=IV: 2.1A*(5V-2.583V)=5W. I should probably get a 10W resistor just in case.
Any recommendations on resistors? They need to be non-inductive, and 10W. I'm a student, so cost is also a concern (Altho I assure you this is not a school assignment, I'm actually studying mechanical engineering). I should also consider the resistance of the HEXFET, but if it's fully on then the resistance should be low. Are my calculations about correct?
Thanks for any help,
Matt
This thread is to ask the best way to proceed. What I am doing is making a stepper controller for my PCB mill. I basically just need to drive MOSFETS with a +5VDC signal. From what I've read, I can get HEXFETs that will be fully "on" with a logic level signal. Is this true for all HEXFETs? What the in the datasheet should I be looking for to find the minimum on voltage for Vgs? If I don't buy logic level HEXFETs, I can always buy more motor drivers. It's too bad these things take a week to get here from digikey! (Any recommendations on where else to get this stuff?)
I think I'm in favor of switching to logic level HEXFETs, since that'll reduce the number of components on the board. I'm just not sure which HEXFETs to buy.
Here is maybe one option? http://www.jameco.com/Jameco/Products/ProdDS/669901IR.pdf
My stepper motors are rated at 2.583V, 2.1A,1.23 ohms. According to my calculations, if I run these off a +5V source (from a PC power supply), I need to put a ~1 ohm power resistor.
V=IR => V=(5V - 2.583V), I=2.1A ==> R = V/I = (5V - 2.583V)/(2.1A) = 1.165 ohm.
Power: P=IV: 2.1A*(5V-2.583V)=5W. I should probably get a 10W resistor just in case.
Any recommendations on resistors? They need to be non-inductive, and 10W. I'm a student, so cost is also a concern (Altho I assure you this is not a school assignment, I'm actually studying mechanical engineering). I should also consider the resistance of the HEXFET, but if it's fully on then the resistance should be low. Are my calculations about correct?
Thanks for any help,
Matt
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