Hello everyone,

I have a simulair circuit like this. But i have some trouble with an blown up L298N IC sometimes. 9 of the 10 times i have no problem but sometime i get back some defective IC's.

When an output is enabled, and the motor is going to be reversd there is an current spike. Now the diodes D1 to D8 (SK86) wil take care of that. But when the output is switched to quickly then the IC gets damaged.

The motor draws arround 150-200mA at 24v. But when the motor is engaged the inrush current goes over 4A.

How do i protect the IC even better? Should i use pwm to similate an ramp up and down situation?

I hope someone gan give me some advise, tips and tricks.

Kindly regards.

 

From when you say " When an output is enabled, and the motor is going to be reversd there is an current spike. Now the diodes D1 to D8 (SK86) wil take care of that." Your undestanding of the function of the diodes is wrong. They will NOT protect against current spikes. They protect against voltage spikes when the current though the motor windings is switched off.
You do not say if this is driving two motors or two windings on a single stepper motor stepper motor.

Les.

 

From when you say " When an output is enabled, and the motor is going to be reversd there is an current spike. Now the diodes D1 to D8 (SK86) wil take care of that." Your undestanding of the function of the diodes is wrong. They will NOT protect against current spikes. They protect against voltage spikes when the current though the motor windings is switched off.
You do not say if this is driving two motors or two windings on a single stepper motor stepper motor.

Les.

Hello Les,

Thank you for pointing out that the diodes are for the voltage spikes. I learning everyday new things.

There are two motors one for each channel. The Hbridge is currently only used for left and right controller. So ena_A an ena_B is pulled high.

How can i protect the IC against current spikes?

 

One thing I would add is a much larger electrolytic capacitor than the 220uF shown. Try a couple of 4700uF caps.
But the L298 is probably not the chip to use. It is pretty old now and there are a lot better chips to use.
The max current for the L298 is 3A and you are seeing 4A. Look for an H bridge that can handle 10A at least.
These maybe worth looking at...
https://www.infineon.com/dgdl/BTS79...90004&fileId=db3a304412b407950112b43945006d5d

https://www.ebay.com/itm/3943156200...EIXkSYfi6LsOO+cWsaPSFY6kGw==|tkp:BFBMsPyT3aZj

 

One thing I would add is a much larger electrolytic capacitor than the 220uF shown. Try a couple of 4700uF caps.
But the L298 is probably not the chip to use. It is pretty old now and there are a lot better chips to use.
The max current for the L298 is 3A and you are seeing 4A. Look for an H bridge that can handle 10A at least.
These maybe worth looking at...
https://www.infineon.com/dgdl/BTS79...90004&fileId=db3a304412b407950112b43945006d5d

https://www.ebay.com/itm/394315620005?hash=item5bcf0adea5:g:Y6EAAOSwwBBjYcVV&amdata=enc:AQAIAAABIGIH6E/TG+3i3KpH0gitQw8La/u4jD2tCnpzEKGmQjwXtHQ+yDZbAQTx6FC2r4Wjb1xpIBAmIYMBuzP3KaA7iJvM+r0qBCzeBmUrW+smdhYXIOZAAP/TmbNkWBS+4UbwoZP9GgUP05zTiz4KBkGHhVwv6eNBJAzTdfKQfCJ4S0aP1kCSqsdVfAkBAW0wQ32HJJTKwmK71zZIOv+dCF27WL0EqUh5c2sfLWzeUt8BPor6AzKG5cNu7WbZzS8H86mdnFa4yv84siCf+vaZyEdQ06UUX6bHuWdAgBfiS9dEC7Vht96MjwSMFqg55relc59VNri1wSOjSmDOs8v1LHSuxl1SNMpUZTxYNH/0x43lEIXkSYfi6LsOO+cWsaPSFY6kGw==|tkp:BFBMsPyT3aZj

Hello Dendad,

Thank you for the information. I wil look in to your suggestions.

 

Perhaps you could use the IC's current-sense feature (pins 1 and 15) to control a current-limiter arrangement for reducing the inrush current?

 

You are using two motors but current sense pin 15 shows open?
As per @Alec_t use the current sense, as is done when using the L297.