Help me find out why L298 gets so hot

[tictac]

Hi all
I make a circuit to control the rpm of a dc motor with L298 and atmega16.I use pwm for control the speed of the motor.L298 is getting hot at duty cycle below 40% but have a normal temprature at duty cycle 50% and higher .I use 4 diode shottky at to side of motor.
motor work at 500ma normally.
please help me.
by regards

 

[bungee-]

hot l298

How did you connect the diodes? And what is the frequency that you drive PWM with?

I have design with single Mosfet and I can put on motors that "suck" 5 amps and FET doesn't even get warm.

 

[funnynypd]

transistor type used in l298

MOSFET does generate less heat when used in the switch mode.
Just Wonder: do you have any cap before the transistor? Somehow your transistor is not working in the switch mode.

 

[tictac]

l298 application note

I use 470uf cap on tow side of motor
Is it make the problem??

Added after 4 minutes:

hi bungee-
can you send me your h-bridge with mosfet,please??

 

[funnynypd]

l298 very hot

The cap probably is the reason putting the transistor on the low efficient amplify zone, which makes the device very hot.

 

[tictac]

why l298 get hot?

thank you.
I remove the cap.I also have a self (100uH)at the way of motor.is it make trouble?

 

[bungee-]

Re: why l298 get hot?

I'm using IRF7455 and IRF7416 because you can drive them with logic level (5V).
I read a lot of Microchip application notes and I found them helpful.

Classic H bridge

Here are some links, that could be helpful:
https://ww1.microchip.com/downloads/en/AppNotes/00906B.pdf
**broken link removed**
https://ww1.microchip.com/downloads/en/DeviceDoc/41233C.pdf

Hope this help.

 

[funnynypd]

Re: why l298 get hot?

thank you.
I remove the cap.I also have a self (100uH)at the way of motor.is it make trouble?

Is it a inductor filter?

 

[tictac]

why l298 get hot?

I use it for noise and make a slow change in current

 

[Fernando Vasquez]

why l298 get hot?

L298 could be damaged, 500mA is a very low current, it can support it without getting hot. Try to change it, measure the current of on the motor, maybe it is not 500mA.

 

[glenjoy]

why l298 get hot?

Check the load of the motor also, maybe it is too heavy that is why it sucks too much current.