ATA6830 ATMEL Corporation, ATA6830 Datasheet - Page 13

• Manufacturer Part Number: ATA6830
• Description: Intelligent Stepper Motor Driver
• Manufacturer: ATMEL Corporation

Step Operation
Bridge Current Control
4575C–BCD–05/03
If the chip temperature exceeds the overtemperature warning threshold, the step speed
is reduced to 300 Hz. If the chip temperature rises further the output driver is shut off.
Table 4. Maximum Step Frequency
The stepping motor is operated in halfstep-compensation mode. The current for both
coils is shown in Figure 12. The current levels are increased when the temperature is
below 0 ° C to secure operation. For final tests at the end of the application production
line the currents are reduced.
Figure 12. Compensated Halfstep Operation
The bridge current is controlled by a chopper current control, shown in Figure 13. The
current is turned on every 40 µs (25 kHz chopper frequency). The current flow in the H-
bridge is shown in Figure 14a. After a blanking time of 2.5 µs to suppress turn-on peaks
the current is measured via the shunt voltage. As soon as the current has reached its
nominal value it is turned off again. The current flow in this state is shown in Figure 14b.
V
< 9 V
9 V to 9.5 V
9.5 V to 10 V
10 V to 10.5 V
10.5 V to 11 V
> 11 V
> 20 V
BAT
coil B
coil A
-500mA
-700mA
-500mA
-700mA
700mA
500mA
700mA
500mA
1
Maximum Step Frequency
at Rising Voltage
No operation
No operation
No operation
No operation
850 Hz (1.17 ms)
1000 Hz (1 ms)
No operation
2
3
4
5
6
7
Maximum Step Frequency
(V
No operation
300 Hz (3.33 ms)
500 Hz (2.03 ms)
680 Hz (1,47 ms)
850 Hz (1.17 ms)
1000 Hz (1 ms)
No operation
BAT
once > 10.5 V)
8
half steps
half steps
ATA6830
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