Hi Husnain,
If the motor is not connected, the drain to source voltage of the enabled FET should be close to 0V.
Please place a resistor divider at an output. A 20k to VM and 10k to GND is used to determine if the output is enabled. The midpoint of the resistor is connected to the output.
Please capture the voltages at VM, and the drain, gate, and source of a high side FET when the FET is being enabled. This should be done with no load. Prior to the fault disabling the output, you should see:
drain voltage = VM
gate voltage = VM + ~11V
source voltage = ~VM
For low side FETs, you should see:
drain voltage = ~0V
gate voltage = ~11V
source voltage = 0V
Repeat with the other three outputs.
If you do not see these voltages, then you should determine the reason for this.
If the motor is not connected, the drain to source voltage of the enabled FET should be close to 0V.
Please place a resistor divider at an output. A 20k to VM and 10k to GND is used to determine if the output is enabled. The midpoint of the resistor is connected to the output.
Please capture the voltages at VM, and the drain, gate, and source of a high side FET when the FET is being enabled. This should be done with no load. Prior to the fault disabling the output, you should see:
drain voltage = VM
gate voltage = VM + ~11V
source voltage = ~VM
For low side FETs, you should see:
drain voltage = ~0V
gate voltage = ~11V
source voltage = 0V
Repeat with the other three outputs.
If you do not see these voltages, then you should determine the reason for this.