Driving 5phase step motor with 10 mosfet

Hi
I use five TC4428 for driving ten IRFZ44N. I want to use it for 5phase step motor.

VDD of TC4428 =12v
Input voltage for TC4428 from Micro controller is 5 volts and 0 .
voltage of motor is 12 volts.

My problem is that the high side mosfet get so hot but the low side mosfet is normal. Step motor can turn .

I think that high side mosfet doesnt turn on completely and there is some drain-source resistance and it cause more losses.
How can I improve my circuit?


Its my driver schematic.
https://s2.picofile.com/file/7712512896/stepmotorDriver.pdf.html


Regards

Hi
I use five TC4428 for driving ten IRFZ44N. I want to use it for 5phase step motor.

VDD of TC4428 =12v
Input voltage for TC4428 from Micro controller is 5 volts and 0 .
voltage of motor is 12 volts.

My problem is that the high side mosfet get so hot but the low side mosfet is normal. Step motor can turn .

I think that high side mosfet doesnt turn on completely and there is some drain-source resistance and it cause more losses.
How can I improve my circuit?


Its my driver schematic.
**broken link removed**


Regards

Click to expand...

Hi tictac !
Where your driving signal is came from ?
i think the problem is simple . you didn't drive your mosfet in on/ off mode . you've drived it in linear region . it is why hside is being so warm and the low side is just fine . don't forget for a usual mosfet you'll need 15 volts across the GS junction to guarantee that it is turned on as well just like a key with low value of rdson .
so what you need is a float driver ( boot strap driver ) like : IR2113 or IR2110 or anything else .
Best Wishes
Goldsmith

Hi goldsmith
Driving signal is came from Mega32.
Can I use TC4428 with more supply voltage , for example 15v . Is it correct that I use the same voltage for step motor driving(15v) ?
Should I use float driver or it may be worked with TC4428?

Thanks you for your response.
Regards
Tictac

Hi goldsmith
Driving signal is came from Mega32.
Can I use TC4428 with more supply voltage , for example 15v . Is it correct that I use the same voltage for step motor driving(15v) ?
Should I use float driver or it may be worked with TC4428?

Thanks you for your response.
Regards
Tictac

Click to expand...

Hi TicTac !
Ok , if it coming from the mega 32 it means your signal level is between zero and +5 volts . so you'll need to change it's level from zero up to +15 volts . so you can use an ICL7667 or what you've used before , but of course it is not enough for your aim . the reason is you'll need to put +15 volts across the GS junction of your mosfet , exactly as i've mentioned before . and you should use a boot strap driver for that . do you know the reason behind this ? or how a boot strap driver does work ?
Best Wishes
Goldsmith

Hi Goldsmith.

I study a little about bootstrap and understand the need of this technique.
My problem is with the nodes labeld "G" for gate and "S" for source. The parameter of interest in turning on an N-channel MOSFET is called "Vgs(th)" . In the case of the IRF540 for example this parameter from the data sheet is a minimum of 2.0 Volts to a maximum of 4.0 Volts. This means that in order for the IRF540 to conduct any appreciable current, the Gate must be 2.0 to 4.0 Volts above the Source.
If the Drain is connected to +12 Volts and some small amount of current begins to flow the Source will be some tens of millivolts below +12 Volts. In order for this to happen the voltage at the Gate needs to be 14.0 to 16.0 Volts. If I want the IRF540 to really turn on hard then I need a Vgs of 10V. This means I need to get the gate to 22.0 Volts or so. Vgs = Vg - Vs = 22 - 12 = 10 Volts. Is it true?
another question : Can I use one P-channel mosfet at the high side of my circuit instead of IRZ44N? is it solve my problem ? I want to know that if it works so I dont change my pcb .

Thanks you so much for your answer.
Regards
Tictac

P-channel mosfet at high side will reduce loses in steady states, but you will have big (and for components dangerous) high current pulses
through both mosfets during transition time. The best way is using appropriate driver e.g. ir2110 or similar

Hi Goldsmith.

I study a little about bootstrap and understand the need of this technique.
My problem is with the nodes labeld "G" for gate and "S" for source. The parameter of interest in turning on an N-channel MOSFET is called "Vgs(th)" . In the case of the IRF540 for example this parameter from the data sheet is a minimum of 2.0 Volts to a maximum of 4.0 Volts. This means that in order for the IRF540 to conduct any appreciable current, the Gate must be 2.0 to 4.0 Volts above the Source.
If the Drain is connected to +12 Volts and some small amount of current begins to flow the Source will be some tens of millivolts below +12 Volts. In order for this to happen the voltage at the Gate needs to be 14.0 to 16.0 Volts. If I want the IRF540 to really turn on hard then I need a Vgs of 10V. This means I need to get the gate to 22.0 Volts or so. Vgs = Vg - Vs = 22 - 12 = 10 Volts. Is it true?
another question : Can I use one P-channel mosfet at the high side of my circuit instead of IRZ44N? is it solve my problem ? I want to know that if it works so I dont change my pcb .

Thanks you so much for your answer.
Regards
Tictac

Click to expand...

Hi Tictac !
Do you know what is Vgs(th ) ? it is shorted form of threshold gate to source voltage which means your mosfet will be off if your GS voltage is below that range . if you increase it a bit above than it , then it will start the conduction . but of course in linear mode . which is pretty dissipative region .
So you'll need to give it , it's maximum required voltage to guarantee that it has been turned on just like a key . according to the datasheet of IRF450 you'll need something around 15 voltag across the GS junction to guarantee that it is somewhere around the maximum conduction mode . and as it mentioned it will be safe till +-20 volts across it . but 15 will be enough .

the Gate needs to be 14.0 to 16.0 Volts. If I want the IRF540 to really turn on hard then I need a Vgs of 10V. This means I need to get the gate to 22.0 Volts or so. Vgs = Vg - Vs = 22 - 12 = 10 Volts. Is it true?

Click to expand...

When your circuit is working with any voltage , for example 500 volts , then you'll need 515 volts as VG to guarantee that VGS is 15 volts . ok ?

another question : Can I use one P-channel mosfet at the high side of my circuit instead of IRZ44N? is it solve my problem ? I want to know that if it works so I dont change my pcb

Click to expand...

P channel mosfets can be used to make your driver more simpler but in fact you'll have some problems . you must not expect very good precision because both of your mosfets are not exactly the same together . and also P channels will have more dissipation and more limitations in comparison with n channels . it is why many of the power circuits that you can see have used only one type of mosfet . just p or just n . to be sure about the precision and some of the probable problems .

P-channel mosfet at high side will reduce loses in steady states, but you will have big (and for components dangerous) high current pulses

Click to expand...

I afraid but i'm disagree with you ! P channels are more dissipative . and there is no relation between p and n and inrush current of gate . as far as i know inrush current depends on Ciss .

Best Wishes + Good Luck
Goldsmith

Hi Goldsmith.
Thanks you so much for answer in detail.
I am designing another schematic with IR2104 and as soon as possible I put it here for your suggestion.
I have another question:
1- what is a application of TC4428 or TC4420 in driving mosfet? where can I use them?
2- I think about the correctness of the digital pulse that come from Mega32. I use the below link for giving correct pulse to the 5phase step motor.
https://homepage.cs.uiowa.edu/~jones/step/types.html
https://www.eca.ir/forum2/index.php?action=dlattach;topic=53616.0;attach=7862 (page 33 about 5phase step motor driving)

=======================================================================================
With a 5-phase motor, there are 10 steps per repeat in the stepping cycle, as shown below:

Terminal 1 +++-----+++++-----++
Terminal 2 --+++++-----+++++---
Terminal 3 +-----+++++-----++++
Terminal 4 +++++-----+++++-----
Terminal 5 ----+++++-----+++++-
time --->
========================================================================================
"+" --> '1' = 5 volt on each pin "-" --> '0' = 0 volt on each pin
========================================================================================
I use PORTA(PIN0 TO PIN4) of Mega32 for generating pulses for excitation of step motor.
unsigned char out[10]={0xed,0xe9,0xeb,0xea,0xfa,0xf2,0xf6,0xf4,0xf5,0xe5};

--------------------------------------- PORTA.4------- PORTA.3------PORTA.2--------PORTA.1-------PORTA.0
-------------------------------------------------------------------------------------------------------------------------
for example 0xed=1 , 1 , 1-------- ,----- 0-------------,1-------------,1-----------------, 0---------------, 1
for example 0xe9=1 , 1 , 1-------- ,----- 0-------------,1-------------,0-----------------, 0---------------, 1

Is it true?

Regards.
Tictac

Hi Goldsmith.
I have another question: " Can I drive IR2110 with 0 volts and 5 volts(Excitation sequence) that come from Mega32 ? "

Regards.
Tictac

what is a application of TC4428 or TC4420 in driving mosfet? where can I use them?

Click to expand...

It's a pure low side driver, not suited for driving high-side transistors respectively push-pull power stages.

Can I drive IR2110 with 0 volts and 5 volts(Excitation sequence) that come from Mega32?

Click to expand...

Yes. But the bootstrap circuit doesn't work at low-speed respectively static motor control.

You'll possively want to use pwm controlled constant current stepper operation at lower speed, then IR2110 can work.

Hi FvM

You'll possively want to use pwm controlled constant current stepper operation at lower speed, then IR2110 can work.

Click to expand...

I want to use IR2104 or IR2110 for driving gate of the Mosfets at each half-bridge branch. (there are 5 half-bridge for driving step motor)

"3.3V, 5V and 15V input logic compatible" ===>Its one of the IR2104 's specification . So I think I can give the digital pulses from ATMega32. But as I understand from the IR2110's datasheet that the VIH=10 volt. so I cant connect Mega32 directly to IR2110. Is it correct?

Yes. But the bootstrap circuit doesn't work at low-speed respectively static motor control.

Click to expand...

The maximum step motor speed is about 100 RPM. It means that the time of one complete rotation is about 600 ms.
500 step per one complete rotation ==> one step =1.2ms ==> so the frequency of mosfet switching is about 1 khz. Is it low frequency for boot strap circuit?

Regards.
Tictac

But as I understand from the IR2110's datasheet that the VIH=10 volt. so I cant connect Mega32 directly to IR2110. Is it correct?

Click to expand...

Apparently you didn't read the datasheet completely, e.g. figures 12B and 13B. Although the chip is specified to work at 3.3V Vdd, you should be aware of increased delays which might be a problem for fast applications (PWM frequencies > 50k). 5V is always fine.

The maximum step motor speed is about 100 RPM. It means that the time of one complete rotation is about 600 ms.
500 step per one complete rotation ==> one step =1.2ms ==> so the frequency of mosfet switching is about 1 khz. Is it low frequency for boot strap circuit?

Click to expand...

You don't have to very about maximum speed. The problem is low speed and hold. I presume you want to operate the motor in a typical stepper application rather than at constant speed. Consider that even without a hold state motor speed is always ramped up from zero.

Is it true?

Click to expand...

Hi Tictac
and sorry for the delayed answer . well , as we can see FvM answered you as well .
About the program that you've asked me is that true or not , i can't say anything because i'm not a programmer . programming is out of my field .
Good Luck with your designs
Goldsmith

Hi goldsmith
As you say before I can use Ir2110 for driving mosfet.
But fvm said that :"But the bootstrap circuit doesn't work at low-speed respectively static motor control.""
As I say , the maximum speed of stepmotor is about 100 rpm. Can I use it for driving stepmotor? Please describe it for me.
Regards.
Tictac

But fvm said that :"But the bootstrap circuit doesn't work at low-speed respectively static motor control.""

Click to expand...

Hi Tictac
of course FvM is absolutely right and i agree with him . because every boot strap driver needs to store energy in a capacitor and then put it across the GS of h side to turn it on . and when speed is low you'll need a high capacity capacitor which won't be trustful . and many of the problems would be occurred with that .
So one of the best ways for this case is using a floated ground supply . which will handle your aim as well .
If you need your circuit be simple and then you could use a boot strap driver , you need to increase frequency of your PWM for instance till 20 KHZ or perhaps 50 KHZ . thus it will work as well too
Best Wishes
Goldsmith

Hi goldsmith
If I increase the frequency of the pulses that come from mega32 ,so the speed of step motor increases above 100 rpm. So it cant rotate at that speed. What can I do? Do you know another solution?
Regards
Tictac

Hi again
No ! i think you are trying to design a velocity control circuit ( controlling speed of a simple DC motor ) so it doesn't make any sense with frequency . do you know what PWM is doing in such circuits ?
PWM is used to play role of a variable DC power supply with this difference that the efficiency has been increased in compare with a linear circuit .
So when you are varying the duty cycle , it means you're varying the average of that signal so the DC voltage will be changed easily . so you can easily increase the frequency . frequency doesn't to anything with average voltage . i've designed many speed controllers with 500 KHZ too so there won't be any problem if you increase the frequency up to several KHZ like 50 KHZ .
Best Luck
Goldsmith

Hi Goldsmith and thanks for your answering

No ! i think you are trying to design a velocity control circuit ( controlling speed of a simple DC motor ) so it doesn't make any sense with frequency

Click to expand...

I just want to rotate the step motor with fixed speed and as you know my problem is warming the high-side mosfet.
As I mentioned before, I have one 5phase STEP-MOTOR with 5 wire(five coil). I must excite all of these magnet coil at the same time according to the below table


Terminal 1 + + + - - - - - + + + + + - - - - - + +
Terminal 2 - - + + + + + - - - - - + + + + + - - -
Terminal 3 + - - - - - + + + + + - - - - - + + + +
Terminal 4 + + + + + - - - - - + + + + + - - - - -
Terminal 5 - - - - + + + + + - - - - - + + + + + -

I know about PWM and its application.I dont want to change the DC value of voltage with pwm for changing the speed of step motor(It doesnt possible for step motors) . I want to change the time of each pulses that be given to the coils. If I decrease the time between of each pulses that be given to five magnet coils , so they cant store enough energy for magnetizing and so they cant rotate properly and step motor lost some steps and start to vibrating. I want to use one simple 12 volts DC for each half-bridge branch and switch each of coils proper to pulses that come from Mega32.
Please help me to correct my circuit to work fine without warming at low speed and low frequency.

Regards
Tictac

Easy (but not cheap) way to use IR2110 for your purpose is to supply high side of IR2110 with small isolated DC/DC converter like IF0515S.

I want to use one simple 12 volts DC for each half-bridge branch and switch each of coils.

Click to expand...

Generally speaking, most high performance stepper motors are specifying constant I rather than constant V operation. But you didn't tell anything about the involved motor so we can't know it's specification.

Constant V means that the phase current is decreasing at higher step rates, resulting in a low torque respectively restricted step rate. Constant I is usually achieved by (sufficient high frequent) PWM, in contrast to your assumptions in post #18. Even if your application doesn't require PWM operation, it could be a workaround to allow bootstrap operation of IR2110. Otherwise your high side gate drivers must be suited for static operation, e.g. by adding DC/DC converters. The quiescent current of the high side driver is rather low, so it could be supplied by a small current source or series resistor, combined with a zener diode voltage limiter for the bootstrap voltage. A single auxilary supply on top of the DC bus voltage is required, but still better than implementing five DC/DC converters.