Manual

14
ATA6830
4575B–BCD–01/03
Figure 13. Chopper Current Control
Figure 14. Current Flow in Halfbridge
Exception Handling During operation, different exceptional states or errors can arise to which the circuit
must correspondingly react. These are described below:
• Supply voltage below 9 V
Travel operation is suspended for the duration of the undervoltage. The output current
will be set to zero. When the supply voltage rises above 10.5 V, travel operation
restarts.
• Supply voltage above 20 V
Travel operation is suspended for the duration of the undervoltage. The output current
will be set to zero. When the supply voltage falls below 20 V, travel operation restarts.
•Overtemperature warning
The maximum stepping speed is reduced to 300 Hz. This ensures a safe shut-off proce-
dure if the temperature increases to shut-off temperature.
• Overtemperature shut-off
coil current
turn on signal
flyback
comparator
shunt resistor
voltage
Imax
blanking time
ON
OFF
ON
OFF ON
OFF OFF
ON
a) b)