I am trying to make a motor drive using L298N
But when I try it in Proteus it won't work
any Idea ?
Thank you.

 

I am trying to make a motor drive using L298N
But when I try it in Proteus it won't work
any Idea ?
Thank you.

The four inputs require high and low logic levels to work correctly. Your inputs have no path to ground when the input switches are opened so they never receive a low signal. Connect a 10Kohm resistor between each input and ground, then it should work..

 

Pins IN1, IN2, IN3 & IN4 - do they need pull-up resistors and pull down switches?

 

The four inputs require high and low logic levels to work correctly. Your inputs have no path to ground when the input switches are opened so they never receive a low signal. Connect a 10Kohm resistor between each input and ground, then it should work..

Result is same it doesn't move
T^T

 

Pins IN1, IN2, IN3 & IN4 - do they need pull-up resistors and pull down switches?

It could well be. I have only used them connected to TTL inputs.

 

I just don't understand when I use PWM as input signal it run but not the DC input

 

I just don't understand when I use PWM as input signal it run but not the DC input

You see pin5 is red, meaning high. somehow the input pin to go below 1.5V, what is the voltage of that DC input?
And when you connected the 10kohm to ground, what color did the input pins have?
What if you connect them straight to ground.
What if you connect them with 10kohm to VCC and put the switch to ground?

 

What if you connect them with 10kohm to VCC and put the switch to ground?

That should work, but if you want to keep the switches as pull-ups to Vcc then you need pull-down resistors with a maximum value of ~2k to satisfy the logic-low requirements of TTL circuits.

 

That should work, but if you want to keep the switches as pull-ups to Vcc then you need pull-down resistors with a maximum value of ~2k to satisfy the logic-low requirements of TTL circuits.

Why 2k? why didn't it work with 10k then? only explantation would be if the inputs or the open switch are low (30k ish) impedance.

 

Why 2k? why didn't it work with 10k then?

It should.
The low level input current is only 10μA, not the higher TTL level.

 

You see pin5 is red, meaning high. somehow the input pin to go below 1.5V, what is the voltage of that DC input?
And when you connected the 10kohm to ground, what color did the input pins have?
What if you connect them straight to ground.
What if you connect them with 10kohm to VCC and put the switch to ground?

1) The DC input is 5V when I try 2.4999V it turn to gray and If i try 2.5V it turn to red agian
But If I turn to 0.8V it turn to blue and Motor will run and if 0.801V it turn to gray and it will not run

2) With or without 10kohm if input 5V connect to ground it will turn to blue
So if both pin5 and pin7 connect to ground motor will not run cause booth input pins turn to blue

3) Same result as 2)

4) IT WORK!!!!! But why??? I don't Understand
(But If I don't connect it with 10kohm when switch is ON the input pins will turn to Yellow why?????)

Please help me explain this. Thank you T^T

Is this problem happen in proteus only?
I have never try this circuit in real life before.
If I do can I use the circuit in the first image?

 

You cannot use the first image, the inputs require a defined voltage below 0.8 or above 2.5 in any situation. That's why it turns grey in between.

"2) With or without 10kohm if input 5V connect to ground it will turn to blue
So if both pin5 and pin7 connect to ground motor will not run cause booth input pins turn to blue"
This is logical, as the voltage will be close to GND potential and 5 and 7 need to have a an opposite that for the motor to turn.

"4) IT WORK!!!!! But why??? I don't Understand"
Because the pin is high when switch is open (due to 10k to VCC) and low when connected to gnd due to the switch.
This is how pull-up and pull-down circuits are supposed to work. try too google that "pull-up resistor".

"(But If I don't connect it with 10kohm when switch is ON the input pins will turn to Yellow why?????)"
This i dont understand, can you check the on and off internal resistance of the switch?

 

It should.
The low level input current is only 10μA, not the higher TTL level.

This thread may be of interest.

 

This thread may be of interest.

That discusses an actual TTL gate which does have a significant input current.
The L298N is designed to respond to TTL voltage levels, but does not have the TTL input current, as its data sheet shows.

 

Hi

Maybe this will help.
SW is a center-off switch.
When top contact closes, motor turns in forward direction.
When bottom contact closes, motor reverses direction.
When SW is in center position, motor stops.

eT