DRV10963 Datasheet, PDF (7/14 Pages) Texas Instruments – 5-V, THREE PHASE, SENSORLESS BLDC MOTOR DRIVER

DRV10963
www.ti.com
SLAS955 – MARCH 2013
MOTOR DIRECTION CHANGE
FR (Forward Reverse) pin is used to change the direction of motor rotation as shown in Table 1.
Motor direction
Table 1. Motor Direction Phase Sequencing
FR = 1
U→V→W
FR = 0
U→W→V
MOTOR STATUS INDICATOR (SPEED)
During operation of the DRV10963, the FG status pin indicates the speed of the motor. Using Table 2, the status
of the motor can be determined.
Table 2. Motor Status Speed Indicator Configuration
Motor Condition
DRV10963DSNR Normal operation
Locked Rotor
FG (FGS = 1)
Toggles once per electrical cycle
Remains at high level
FG (FGS = 0)
Toggles once every 2 electrical cycles
Remains at high level
The FG pin is used to indicate the speed of the motor, and can be configured by use of the FGS pin to toggle
either once per electrical cycle or twice per electrical cycle as described in the preceding figure. Using this
information and the number of pole pairs are in the motor, the mechanical speed of the motor can be determined.
The formula to determine the speed of the motor is:
If FGS = 1, RPM = (FREQ_FG × 60)/ number of pole pairs
If FGS = 0, RPM = (FREQ_FG × 120)/ number of pole pairs
The FG pin has built in short circuit protection, which limits the current in the event the pin is shorted to V_CC. The
current will be limited to I_{SC_FG}.
SPIN UP SETTINGS
DRV10963 starts the motor using a procedure which is illustrated in Figure 2.
The motor start profile includes open loop to close loop transition threshold, align time and accelerate rate as
described in Table 3.
DRV10963DSNR
Table 3. Motor Status Speed Indicator Configuration
ALIGN TIME (t_align)
(ms)
350
ACCELERATION RATE (R_acc)
(Hz/S)
80
THRESHOLD (H_offth)
(Hz)
100
In order to align the rotor to the motor acceleration profile the DRV10963 applies a 50% duty cycle on phases V
and W while holding phase U at GND. This condition is maintained for t_align seconds. When the align phase
completes the motor is accelerated by stepping through the commutation sequence at an increasing rate
described by R_acc until the rate of commutation reaches H_offth Hz. When this threshold is reached the
commutation drive sequence is determined by the internal control algorithm and the applied voltage is
determined by the PWM input duty cycle.
The graphical illustration of the spin up procedure is shown in Figure 2:
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