IR2104 MOSFETs are heating

[amitkatheria91]

I am using a 50kHZ PWM signal to run the 24V20A motor but after some time Q3 and Q1 MOSFETs are heating up. I am using the below circuit to drive the motor.
Please help me to fix it.


Circuit

 

[KlausST]

Hi,

We don´t know:
* VIN
* IN1, IN2 , SD_Bar levels and duty cycle range
* R6 type
* PCB-layout
* which MOSFET becomes hot
* exact motor type

Klaus

 

[danadakk]

The dead time supplied by 2104 is 650 nS at 1000 pf load.

Have you done a scope capture of actual timing looking at gates of
Q1 and Q3 ? Your deadtime may not be sufficient. Hopefully if thats
the case your PWM outputs allow you to also control and set additional
dead time.

This example shows 16 clocks of deadband (ph1 and ph2 as a result never on
at same time) -

Regards, Dana.

 

[abc_de]

Why your running you dc motor at 50khz
It should be less then 16khz

 

[Easy peasy]

the type of gate drive you are using may well be a factor - as well as the freq ...

 

[amitkatheria91]

Hi,

We don´t know:
* VIN
* IN1, IN2 , SD_Bar levels and duty cycle range
* R6 type
* PCB-layout
* which MOSFET becomes hot
* exact motor type

Klaus

Sorry for the late reply,
VIN is 24V, IN1 is PWM has frequency 50K and Duty is 50%, SD-Bar Is 0V, MOSFETs Q1 and Q3 are heating, the Motor rating is 24V20A

 

[amitkatheria91]

The dead time supplied by 2104 is 650 nS at 1000 pf load.

Have you done a scope capture of actual timing looking at gates of
Q1 and Q3 ? Your deadtime may not be sufficient. Hopefully if thats
the case your PWM outputs allow you to also control and set additional
dead time.

This example shows 16 clocks of deadband (ph1 and ph2 as a result never on
at same time) -

View attachment 171024


Regards, Dana.

Yes, Q1 and Q3 are heating. So, how can I control or generate enough deadtime?. Please guide me

 

[KlausST]

Hi,

You say:
VIN = 24V ... but this is connected to VCC of the IR2104, which is rated for 20V only.
SD_BAR = 0V .. this means the driver is disabled.

What MOSFET type are you using? Link to datasheet.

What about your "secrets"? I guess you have your reason not to show them.
* IN2 information, complete
* IN1, IN2 voltage levels
* and all the other items.....
But without them it´s really hard to give useful help.

Klaus

 

[danadakk]

Yes, Q1 and Q3 are heating. So, how can I control or generate enough deadtime?. Please guide me

What is the HW/Processor/Part Number you are using to generate the PWM signal that
drive the 2104's ?


Regards, Dana.

 

[amitkatheria91]

What is the HW/Processor/Part Number you are using to generate the PWM signal that
drive the 2104's ?


Regards, Dana.

processor is dsPIC30f4012

 

[danadakk]

The motor control PWM in this part has dead time programmable control, from the datasheet -

Regards, Dana.

 

[Easy peasy]

Also - if your mosfets are too small or not well heatsunk - they may well overheat ....

 

[amitkatheria91]

Hi,

You say:
VIN = 24V ... but this is connected to VCC of the IR2104, which is rated for 20V only.
SD_BAR = 0V .. this means the driver is disabled.

What MOSFET type are you using? Link to datasheet.

What about your "secrets"? I guess you have your reason not to show them.
* IN2 information, complete
* IN1, IN2 voltage levels
* and all the other items.....
But without them it´s really hard to give useful help.

Klaus

No, the VCC of the IR2104 is 15V this is the mistake

 

[Easy peasy]

Where is the de-coupling for the mosfets ... ?