AMIS-30621 Datasheet, PDF (17/43 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS-30621 LIN Microstepping Motordriver
Data Sheet
9.2.2.8 Motor Shutdown Mode
A motor shutdown occurs when:
- The chip temperature rises above the thermal shutdown
threshold Ttsd (see § 5)
- The battery voltage goes below UV2 (see § 5)
- Flag <ElDef> = ‘1’, meaning an electrical problem is
detected on one or both coils, e.g. a short circuit
- Flag <CPFail> = ‘1’, meaning there is a charge pump
failure
A motor shutdown leads to the followings:
- H-bridges in high impedance mode
- The TagPos register is loaded with the ActPos (to avoid
any motion after leaving the motor shutdown mode)
The LIN interface remains active, being able to receive
orders or send status.
The conditions to get out of a motor shutdown mode are:
- Reception of a GetStatus or GetFullStatus command
AND
- The four above causes are no more detected
Which leads to H-bridges in Ihold mode. Hence the circuit is
ready to execute any positioning command.
This can be illustrated in the following sequence given as an
application tip. The Master can check whether there is a
problem or not and decide which application strategy to
adopt.
Important
While in shutdown mode, since there is no hold current in
the coils, the mechanical load can cause a step loss, which
indeed cannot be flagged by the AMIS-30621.
Warning
The application should limit the number of consecutive
GetStatus or GetFullStatus commands to try to get the
AMIS-30621 out of Shutdown mode when this proves to be
unsuccessful, e.g. there is a permanent defect. The reliability
of the circuit could be altered since Get(Full)Status
attempts to disable the protection of the H-bridges.
Note
(0) The priority encoder (see § 9.2.2.12) is describing the
management of states and commands. The note below is
to be considered illustrative.
(1) If the LIN communication is lost while in shutdown mode,
the circuit enters the sleep mode immediately.
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