AMIS-30621 Datasheet, PDF (19/59 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

Condition
DriveLS
R2 VBAT
Tsw = 1024 ms
DriveHS
Tsw_on = 64 ms
AMIS−30621
OPEN
R2 VBAT
R2 GND
t
t
t
“R”−Comp
R_th
t
HW2_Cmp
t
State
t
Figure 11. Timing Diagram Showing the Change in States for HW2 Comparator
R2VBAT
A resistor is connected between VBAT and HW2. Every
1024 ms S_BOT is closed and a current is sensed. The output
of the I → R converter is low and the HW2_Cmp output is
high. Assuming the previous state was floating, the internal
logic will interpret this as a change of state and the new state
will be high (see also Table 15). The next time S_BOT is
closed the same conditions are observed. The previous state
was high, so based on Table 15 the new state remains
unchanged. This high state will be interpreted as HW2
address = 1.
OPEN
In case the HW2 connection is lost (broken wire, bad
contact in connector) the next time S_BOT is closed, this will
be sensed. There will be no current, the output of the
corresponding I → R converter is high and the HW2_Cmp
will be low. The previous state was high. Based on Table 15
one can see that the state changes to float. This will trigger
a motion to secure position.
R2GND
If a resistor is connected between HW2 and the GND, a
current is sensed every 1024 ms when S_TOP is closed. The
output of the top I → R converter is low and as a result the
HW2_Cmp output switches to high. Again based on the
stated diagram in Table 15 one can see that the state will
change to Low. This low state will be interpreted as HW2
address = 0.
External Switch SWI
As illustrated in Figure 12 the SWI comparator is almost
identical to HW2. The major difference is in the limited
number of states. Only open or closed is recognised leading
to respectively ESW = 0 and ESW = 1.
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