Other Parts Discussed in Thread: UCC21750
My design is a 3-phase inverter with 3 Half-bridge devices. Each Half-bridge will be driven by 2 UCC21750 drivers.
For the NTC conenction
a) I am assuming it will be better to use the AIN pin of the lower Driver ( i.e. the one with a connection to the DC Bus) and not the upper driver
whose common is connected to the connection of the upper gate source and lower gate drain.
b) I would like clarification on the following:
Section 9.2.2.7.1 (Isolated Temperature Sensing ) of the UC21750 data sheet SLUSDH9B shows the NTC connected to an R-C lowpass filter,
with the R,C junction going to AIN.
However the EVM schematic (SLUUBX2B) shows the NTC should be connected to TR+ which is in parallel with C29 (0.01uF) and R42 ( 6.19kohm).
which means TR+ is the same as AIN .
Which option is the one to use? I will connect the other end of the NTC to the driver COM pin.
I will use an R-C filter for the APWM output as in Fig 56 of SLUSDH9B.
Thanks
David Nyarko