motor driver

[engkeat]

i have tried using L298N to control a 12V DC motor which required to drive 1.44A, but i found that the output of L298N that generate to the motor tend to drops to half of the voltage that i supplied to input pin of L298N, and the maximum voltage that manage to supplied to the motor is only achieve around 3V, while i required 7~8V for the motor to lift certain load...anyone have any idea on it???

 

[colin55]

You have a REAL problem. You say the motor needs 1.5A. This is the "running" or operating current when no-load is applied to the motor. When the motor is starting, the current taken by the motor can be 4 times the running current. If the motor is starting under load, this current can be even higher. The bridge you are using has a voltage drop across each of the output transistors that can be as high as 2.7v for a 2 amp current. There are 4 transistors in the bridge and almost all the voltage of the supply (12v) is lost across these transistors. That's why you are seeing almost no voltage delivered to your motor. You need to build your own H-bridge with high-power transistors or buy an "H-bridge-chip" capable of delivering 10A.

 

[audioguru]

i have tried using L298N to control a 12V DC motor which required to drive 1.44A, but i found that the output of L298N that generate to the motor tend to drops to half of the voltage that supplied to input pin of L298N, and the maximum voltage that manage to supplied to the motor is only achieve around 3V, while i required 7~8V for the motor to lift certain load...anyone have any idea on it???

You did not post your schematic so I am just guessing.
The typical voltage drop of one L298 at 1.5A is about 1.7V and the max saturation voltage loss at 1.5A is 2.2V.

Its input voltage must be at least 2.3V at a low current.