Regarding my babies:
I managed to get them powered and communicating (this is the L6480 chip). As soon as I give it a move command it reports that there is a over current condition. It’s method of detecting over current is by measuring the voltage drop between the Motor Supply Voltage and the Output. If its more than 1V (I’ve configured it for 1 volt) then it triggers and shuts down the bridge.
When I disable that protection I am able to get it to run and to a position. It however does not turn a single motor that I have. Judging by the vibrations coming from the motor, I would say that it is not providing enough current to drive the motor (in my experience). When I scope the outputs and use the measure function, the Rigol reports that the max voltage is 10 volts (min is 2V). The supply voltage is 12Volts!
The driver IC uses external dual mosfets: SQJQ910EL-T1_GE3. I have blank PCBs from the manufacturer so that I can test any net for continuity. So far everything check out. I’ve looked over the pcb layout in cad, and can’t find any obvious problem with the output stage. I have checked the resistance between the output pins and GND/VS; the resistance is approaching 1 MOhm, except in one case where I think the multimeter was turning the mosfet gate on, because it was reading 7KOhm with the black lead on GND and the red lead on the pin but not when I reversed them.
How would I go about determining what is wrong with driver, given my available tools? (The scope, the meter and the blank pcbs).
Any vauge advice would be helpful.