AMIS-30621 LIN Micro-stepping Motor Driver
Data Sheet
Table 21: Electrical Defect Detection
Pins
Fault Mode
Yi or Xi
Short circuit to GND
Short circuit to Vbat
Open
Yi or Xi
Yi or Xi
Y1 and Y2
X1 and X2
Xi and Yi
Short circuited
Short circuited
Short circuited
14.3.7. 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 Under-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 Iholdmode. 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’
GetFullStatusor
GetStatusframe
GetFullStatusor
GetStatusframe
SetPosition
frame
↓
↑
↑
↑…
- The circuit is driven in - The position set-point - The application is
- Possible confirmation
motor shutdown
mode
is updated by the
LIN Master
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
- The application is not - Motor shutdown
aware of this
mode ⇒ no motion
- The application is still
unaware
<StepLoss> or <ElDef> or <CPFail>
again at ‘1’
Figure 22: Example of Possible Sequence Used to Detect and Determine Cause of Motor Shutdown
AMI Semiconductor – Sept. 2007, Rev 1.5
www.amis.com
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