Application information

AN4243

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Doc ID 024199 Rev 1

3.1

Field oriented control driving method

The field oriented control (F.O.C.) method allows smooth and precise motor control of BLDC

motors to be provided. In this configuration (see Figure 19), three sensing resistors are

required, one for each channel.

The sensing signals, coming from the output power stage, are conditioned by external

operational amplifiers which provide the proper feedback signals to the analog-to-digital

converter and the system controller. According to the feedback signals the six input lines are

generated by the controller.

Note that some filtering and level shifting RC networks should be added between the sense

resistor and the correspondent op-amp input.

The uncommitted internal comparator with open-drain output is available.

Figure 19.

F.O.C. typical application

EN3

CP+

CP-

GND

CPOUT

POWER

GROUND

SIGNAL

GROUND

+

-

VCP

VBOOT

DIAG/EN

ENABLE

IN3

EN2

IN2

EN1

IN1

EN3

IN3

EN2

IN2

EN1

IN1

THREE-PHASE

MOTOR

M

+

-

Signal conditioning

ADC

AM16581v1