What did you see on the data sheets that lead you to think there MOSFETS would not get hot?Paul
Hi all,I have problems with controlling my Nema 23 steppermotor with a mosfet h-bridge and a micro controller.First of all my p-channel mosfets are heating up, but following the datasheet it shouldn't. i use a logic 3.3v microcontroller that is connected to a level shifter (3.3v -->5.0v) those pins of the 5v output of thelevelshifter goes to the gates of the mosfets.
I use for P channel mosfets (FQP27p06) and for theN channel mosfets (IRF540N). I want to use 12v ,4amp to control the steppermotor.
I have spent many time on tutorials and forums , hopefully the arduino forum will have a solution.thank you !
On the datasheet of the p-channel FQP27p06: R.JA = 62.5 degrees/Watt RDSon = 0.07 ohm Max junction temperature = 175 degrees Current from powersupply = 4 AmpSo this is how i calculated that they shouldn't get hot: (175 degrees - 25 degrees)/62.5 degrees/Watt = 2.4 0.07 ohm *4*4 = 1.12So 2.4 > 1.12 So i don't have to use a heatsink ? But the mosfets are getting so hot that i can't even touch it.I don't know what i have to do or change with my circuit ? thank you for your reply !
The datasheet clearly says it will heat up in that situation, as the gate drive voltage is 10V minimum and youuse 5V.IRF540 is not logic level and will also fail to work or heat up. You said 5V, now you're saying 12V - you needto clarify, the pFETs will be happy at 12V.In that case you'll know most steppers are current driven, not voltage driven. So tell us full details ofthe stepper motor and we can proceed to chose a suitable driver for it.
I have no problems with the irf540N
You will have problems at 4A draw. Use a logic level MOSFET instead.If you want to discuss a circuit, post a circuit diagram. Hand drawn is fine.[/quotQuote from: jremington on Jul 26, 2019, 07:59 pmYou will have problems at 4A draw. Use a logic level MOSFET instead.If you want to discuss a circuit, post a circuit diagram. Hand drawn is fine.I build my circuit according to this link : https://en.wikibooks.org/wiki/Practical_Electronics/Stepper_MotorsDo you know logic level mosfet types that can handle 4A current ? And how can you determine the logic levelmosfets ? Thank you !
You will have problems at 4A draw. Use a logic level MOSFET instead.If you want to discuss a circuit, post a circuit diagram. Hand drawn is fine.
...but the required current to my stepper motor is 4 Amps.
At what voltage.1) Post_a_link_to_your_stepper_motor.2) Steppers_need_to_be_current_driven,_not_voltage_driven.Which part of those sentences don't you understand.Even if your H-bridges would work (they don't), then a simple H-bridge is NOT suited to drive low impedance steppers.Leo..
Stroomsterkte: 4.0Voltagesterkte: 3.0VInductantie: 5.04 ohmSeems that this datasheet has been written by the same noob.The numbers don't make sense (to me).3volt and 5.04ohm works out to 600mA, not 4Amp.Wise to measure the resistance of the coils, and see if they are actually 5 ohms.Leo..