Hello Everyone,
So this goes along with my scooter project that I have been working on. I have been going back and forth with LSD design and had some issues. Initially I was using a BJT to drive a NMOS on the High side of both but that would result in a battery short if I plugged the motor in before the controller since there was always a voltage on it. So that is why I am at my current design.
The current design is to use a PMOS to pull the NMOS gate to the 12V signal. The PMOS is controlled by a PWM signal from the arduino. I have attached a drawing of the circuit. Now the problem is that no matter what the load is on when I turn the switch on. I am not understanding why this is happening. I have a 10K pull up resistor to keep the PMOS off when not in use. I alter the PWM with a pot to control the voltage to the NMOS gate. No matter what I do the load is on. I am using a simple LED to verify control before I use the motor. I am unable to change the brightness of the LED by altering the PWM. Can someone please look over my schematic and verify I have the right intention and maybe give me an idea of what might be wrong? When I get home I am going to scope the signals of the PWM and check the voltages but for now we will go on theory of what I have setup.
So this goes along with my scooter project that I have been working on. I have been going back and forth with LSD design and had some issues. Initially I was using a BJT to drive a NMOS on the High side of both but that would result in a battery short if I plugged the motor in before the controller since there was always a voltage on it. So that is why I am at my current design.
The current design is to use a PMOS to pull the NMOS gate to the 12V signal. The PMOS is controlled by a PWM signal from the arduino. I have attached a drawing of the circuit. Now the problem is that no matter what the load is on when I turn the switch on. I am not understanding why this is happening. I have a 10K pull up resistor to keep the PMOS off when not in use. I alter the PWM with a pot to control the voltage to the NMOS gate. No matter what I do the load is on. I am using a simple LED to verify control before I use the motor. I am unable to change the brightness of the LED by altering the PWM. Can someone please look over my schematic and verify I have the right intention and maybe give me an idea of what might be wrong? When I get home I am going to scope the signals of the PWM and check the voltages but for now we will go on theory of what I have setup.
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