MCT8317A datasheet(144/161 Pages) TI1

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Table 9-3. Recommended Default Values (continued)

GD_CONFIG2

0x000000AE

0x00000000

Once the device EEPROM is programmed with the desired configuration, device can be operated stand-alone

and I2C serial interface is not required anymore. Speed can be commanded using SPEED pin.

Below are the two essential parameters that are required to spin the motor in closed loop.

1. Maximum motor speed.

2. Cycle by cycle (CBC) current limit.

9.2.1 Application curves

9.2.1.1 Motor startup

Figure 9-2 shows the phase current waveforms of various startup methods in MCT8317A such as align, double

align, IPD and slow first cycle.

Figure 9-2. Motor phase current waveforms of all startup methods

9.2.1.2 120o and variable commutation

In 120° commutation scheme, each motor phase is driven for 120° and Hi-Z for 60° within each half electrical

cycle, resulting in six different commutation states for a motor. Figure 9-3 shows the phase current and current

waveform FFT in 120° commutation mode. In variable commutation scheme, MCT8317A device switches

dynamically between 120° and 150° trapezoidal commutation depending on motor speed. The device operates

MCT8317A

SLLSFQ2 – JANUARY 2023

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MCT8317A Datasheet(PDF) 144 Page - Texas Instruments