Other Parts Discussed in Thread: INA240
Hello Ti,
i’m developing a new motor control board and wanted to ask if you could please take a look at it.
Board specs (10cmx10cm) (Top: red, Layer 2: yellow, Layer 3: green, Bottom: blue):
4 Layer, 2oz other layer, 0.5oz inner layer
Stackup power section: top=gnd, bottom=vdd, layer 2=gate traces, layer 3=current sense traces
Stackup control section: top=pwr/signal, layer 2=gnd, layer 3= pwr/signal, bottom=gnd
Rated voltage: 50V (all caps on vdd will be rated to 100v)
Rated current: 60A (not sure if I get thermal problems with the pcb, I will see)
Switching frequency: 10kHz-40kHz
All ceramic caps will be double the rated voltage what is needed.
Gate driver: DRV8300 with external diodes (the gate traces are 70miles wide because of 0.5oz in inner layer). I will start with 30 ohm gate resistors and later I try to tune it (slla385a.pdf). the bootstrap caps will be around 200nf-300nf (calculated from the datasheet equations), is this ok? There are one 100nF and 2.2uF on the supply pin(12V) and an elko with 100uF a bit away.
Mosfets: IRFB4110PBF, 130A, 100V, 4mOhm Rdson, 150nC qg, 43nC qgd, 50ns trr bodydiode.
Caps: 9x330uF vdd-gnd, 3x2.2uF (double stacked) vdrain-gnd and 3x1uF vdrain-source(LS-FET)
All ceramic caps will be double the rated voltage what is needed.
Snubber: 2x between ground and vdd on all three phases (if I need them)
For current sensing, the ina240 are used with 1mohm shunt resistors. What do you think about the cut-out of the analog section, is this ok or should I use a pure ground plane?
What I’m really unsure about is the ground connection from power section to the control section. Normally I would put it on the left side (picture below where de vias are) but I’m a little bit concerned about the gate return currents from the low side fets. Therefore, I made 4 ground connections near the gate traces (picture below). I’m not sure if this is a good idea, what would you do?
Here are the layout and schematic (the microcontroller board is plugged onto the two headers on the left and right):
GND Planes:
VDD Plane:
All Planes:
Without Planes:
3D:
Power Stage (Phase A, B and C similar):
Gate Drive:
Current Sensing:
Supply:
Hall/QEB Sensors:
Voltage regulators: