UM0580

Board architecture

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7.2

Gate driving

As mentioned previously, gate driving of the switches is performed through the latest L6390

family of devices. Refer to Section 8.1 for detailed information on the gate driving circuit and

dead time insertion. A fault signal is also fed back to the J5 connector if an overcurrent is

detected.

7.3

Amplifying network

The voltages across the three shunt resistors are amplified by K to correctly condition the

current feedback signals and optimize the output voltage range for a given phase current

range and A/D converter input dynamics. Refer to Section 8.3 for more detailed information

on how to dimension the op-amp conditioning network depending on your needs.

7.4

Brake feature

The brake feature performs a motor brake by switching simultaneously to the low side power

MOSFET, thus shortening the motor phases.

Warning:

This feature is mandatory in applications that require the

motor to operate in a flux-weakening region. In these

conditions, the back-EMF generated by the rotor’s spinning is

greater than the bus voltage and the brake feature prevents

the motor from acting as a generator destructively charging

the bus capacitance. Refer to Section 8.4 for additional

information.

7.5

Temperature feedback

Temperature feedback is performed by way of an NTC. It enables you to monitor the power

stage temperature so as to prevent any damage to the inverter caused by over temperature.