DRV10987 Datasheet, PDF (23/69 Pages) Texas Instruments – DRV10987 12- to 24-V, Three-Phase, Sensorless BLDC Motor Driver

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DRV10987
SLVSE89 – AUGUST 2017
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.
IPDEn Judgment The MSS checks to see if IPD has been enabled (IPDCurrThr[3:0] ≠ 0000). If the IPD is
enabled, the MSS transitions to the IPD state. Otherwise, it transitions to the align state.
IPD State The DRV10987 device performs the IPD function. The IPD function is described in IPD. After the
IPD completes, the MSS transitions to the accelerate state.
ISD State The MSS determines the initial condition of the motor (see Initial Speed Detect).
ISDen Judgment After power-on, the DRV10987 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.
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 DRV10987 device comes out of standby mode.
RvsDrEn Judgment The MSS checks to see if the reverse drive function is enabled (RvsDrEn = 1). If it is, the
MSS transitions into the RvsDr state. If the reverse drive function is not enabled, the MSS
advances to the BrkEn judgment.
RvsDr State The DRV10987 device drives the motor in the forward direction to force it to rapidly decelerate (see
Reverse Drive). When it reaches zero velocity, the MSS transitions to the Accelerate state.
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.
Speed>Op2ClsThr Judgment The motor accelerates until the drive rate exceeds the threshold configured by
the Op2ClsThr[4:0] settings. When this threshold is reached, the DRV10987 device enters into the
ClosedLoop state.
Speed>RvsDrThr Judgment The motor start sequencer checks to see if the reverse speed is greater than the
threshold defined by RvsDrThr[1:0]. If it is, then the MSS returns to the ISD state to allow the motor
to decelerate. This prevents the DRV10987 device from attempting to reverse drive or brake a
motor that is spinning too quickly. If the reverse speed of the motor is less than the threshold
defined by RvsDrThr[1:0], then the MSS advances to the RvsDrEn judgment.
Time>BrkDoneThr Judgment The MSS applies brake for a time configured by BRKDoneThr[2:0]. After brake
state, the MSS advances to the IPDEn judgment.
8.4.3.1 Initial Speed Detect
The ISD function is used to identify the initial condition of the motor. If the function is disabled, the DRV10987
device does not perform the initial speed detect function and treats the motor as if it is stationary.
Phase-to-phase comparators are used to detect the zero crossings of the motor BEMF voltage while it is
coasting (motor phase outputs are in the high-impedance state). Figure 14 shows the configuration of the
comparators.
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