AMIS-30622 Datasheet, PDF (17/35 Pages) AMI SEMICONDUCTOR – I2C Microstepping Motordriver

AMIS-30622 I²C Microstepping Motordriver
Data Sheet
9.2.2.7 Motor Shutdown Mode
A motor shutdown occurs when:
1. The chip temperature rises above the thermal shutdown
threshold T_tsd (see § 5 DC-Parameters).
2. The battery voltage goes below UV2 (see § 5 DC
Parameters).
3. Flag <ElDef> = ‘1’, meaning an electrical problem is
detected on one or both coils.
4. 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 I²C 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 GetFullStatus1 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-30622.
Warning
The application should limit the number of consecutive
GetFullStatus1 commands to try to get the AMIS-30622
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 GetFullStatus1 attempts to disable
the protection of the H-bridges.
Note
The priority encoder (see § 9.2.2.11 Priority Encoder) is
describing the management of states and commands. The
table above is to be considered illustrative.
AMI Semiconductor - Rev. 2.3
www.amis.com
17