Group,

I've recently inherited a college student team competing in the Shell Eco-m=
arathon competition which is held April 9th (short fuse) in Detroit.  As pa=
rt of this competition, students are required to custom design their own Mo=
tor Controller to, in our case, control a 36V, ~600W BLDC wheel hub motor. =
 Previous semesters of students built a circuit card assembly, around Alleg=
ro's A3938 chip (http://www.allegromicro.com/en/Products/Motor-Driver-And-I=
nterface-ICs/Brushless-DC-Motor-Drivers/A3938.aspx), that unfortunately doe=
sn't work.  This semester's students have been trying to make the previous =
design function, and they're making progress but have so far been unsuccess=
ful.  As I'm a mechanical engineer (with some EE experience), I haven't bee=
n all that much help.

Has anyone else used this A3938 MC IC before and have any suggestions on ho=
w to proceed?

Right now, their latest symptom involves the A3938's truth table (hall sens=
or input vs. gate drive/phase output).  The table shows with any given hall=
 sensor input combination, only one high side and one low side gate drive s=
hould be on.  Upon reading the outputs of the gate drives, the students saw=
 exclusively two high side and two low side gate drives on with any given h=
all sensor input combination (they checked about 10 combinations), and all =
of the gate drives read odd voltages (between 6V and 25V).

Any help is greatly appreciated!
Gary

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