TLE4728G Datasheet, PDF (24/25 Pages) Infineon Technologies AG – 2-Phase Stepper-Motor Driver

TLE 4728 G
during that time. To achieve maximum current accuracy such glitches at the phase
inputs should be avoided by proper control signals.
To lower EMI a ceramic capacitor of max. 3 nF is advisable from each output to GND.
Thermal Shut Down
To protect the circuit against thermal destruction, thermal shut down has been
implemented.
Error Monitoring
The error outputs signal corresponding to the logic table the errors described below.
Logic Table
Kind of Error
a) No error
b) Short circuit to GND
c) Open load ¹⁾
d) b) and c) simultaneously
e) Temperature pre-alarm
Error 1
H
H
L
H
L
Error Output
Error 2
H
L
H
L
L
1) _{Also possible: short circuit to + VS or short circuit of the load.}
Overtemperature is implemented as pre-alarm; it appears approximately 20 K before
thermal shut down. To detect an open load, the recirculation of the inductive load is
watched. If there is no recirculation after a phase change-over, an internal error flipflop
is set. Because in most kinds of short circuits there won’t flow any current through the
motor, there will be no recirculation after a phase change-over, and the error flipflop for
open load will be set, too. Additionally an open load error is signaled after a phase
change-over during hold mode.
Only in the case of a short circuit to GND, the most probably kind of a short circuit in
automotive applications, the malfunction is signaled dominant (see d) in logic table) by a
separate error flag. Simultaneously the output current is disabled after 30 µs to prevent
disturbances.
A phase change-over or putting both current control inputs of the affected bridge on high
potential resets the error flipflop. Being a separate flipflop for every bridge, the error can
be located in easy way.
Data Sheet
24
2004-03-01