AMIS-30623 LIN Microstepping Motordriver
Data Sheet
15.3.8. Motor Shutdown Mode
A motor shutdown occurs when:
•
The chip temperature rises above the thermal shutdown threshold Ttsd (see
Thermal Shutdown Mode)
•
The battery voltage goes below UV2 (see
Battery voltage management)
•
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 following:
•
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.
Tj
≥
Tsd or
Vbb
≤
UV2 or
<ElDef> = ‘1’ or
<CpFail> = ‘1’
SetPosition
frame
GetFullStatus
or
GetStatus
frame
GetFullStatus
or
GetStatus
frame
↓
-
The circuit is driven in
motor shutdown
mode
-
The application is not
aware of this
↑
-
The position set-point
is updated by the
LIN Master
-
Motor shutdown
mode
⇒
no motion
-
The application is still
unaware
↑
↑…
-
The application is
-
Possible confirmation
aware of a problem
of the problem
-
Reset <TW> or <TSD> or <UV2> or <StepLoss>
or <ElDef> or <CPFail> by the application
-
Possible new detection of over temperature or
low voltage or electrical problem
⇒
Circuit
sets <TW> or <TSD> or <UV2> or
<StepLoss> or <ElDef> or <CPFail>
again at ‘1’
Figure 23:Example of Possible Sequence used to Detect and Determine Cause of Motor Shutdown
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-30623.
Warning:
The application should limit the number of consecutive
GetStatus
or
GetFullStatus
commands to try to get the AMIS-
30623 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.
Notes
(0) The
Priority Encoder
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
AMI Semiconductor
– June 2006, Rev 3.0
38
www.amis.com
AMI [ AMI SEMICONDUCTOR ]
