DRV10975_15 Datasheet, PDF (18/57 Pages) Texas Instruments – DRV10975 12-V, Three-Phase, Sensorless BLDC Motor Driver

DRV10975
SLVSCP2 – JANUARY 2015
www.ti.com
DIR pin
change
Power on
ISDen
N
Y
ISD
Y
Forward
N
Y
Speed >
RvsDrThr
N
RvsDrEn
Y
RvsDr
N
Speed <
ISDThr
Y
BrkEn
N
Y
N
Brake
Speed >
Y
BrkDoneThr
N
Accelerate
IPDEn
Y
N
Align
IPD
N
Speed >
Op2CIsThr
ClosedLoop
Y
Figure 9. Motor Starting-Up Flow
Power-On State This is the initial power-on state of the motor start sequencer (MSS). The MSS starts in this
state on initial power-up or whenever the DRV10975 comes out of either standby or sleep modes.
ISDen Judgment After power-on, the DRV10975 MSS enters the ISDen Judgment where it checks to see if the
Initial Speed Detect (ISD) function is enabled (ISDen = 1). If ISD is disabled, the MSS proceeds
directly to the BrkEn Judgment. If ISD is enabled, the motor start sequence advances to the ISD
state.
ISD State The MSS will determine the initial condition of the motor (see ISD).
Speed<ISDThr Judgment If the motor speed is lower than the threshold defined by ISDThr[1:0], then the motor
is considered to be stationary and the MSS proceeds to the BrkEn judgment. If the speed is greater
than the threshold defined by ISDThr[1:0], the start sequence proceeds to the Forward judgment.
Forward Judgment The MSS determines whether the motor is spinning in the forward or the reverse direction.
If the motor is spinning in the forward direction, the DRV10975 executes the resynchronization (see
Motor Resynchronization) process by transitioning directly into the ClosedLoop state. If the motor is
spinning in the reverse direction, the MSS proceeds to the Speed>RvsDrThr.
Speed>RvsDrThr Judgment The motor start sequencer checks to see if the reverse speed is greater than the
threshold defined by RvsDrThr[2:0]. If it is, then the MSS returns to the ISD state to allow the motor
to decelerate. This prevents the DRV10975 from attempting to reverse drive or brake a motor that
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