AMIS30421C4211G ONSEMI [ON Semiconductor], AMIS30421C4211G Datasheet - Page 20

• Manufacturer Part Number: AMIS30421C4211G
• Description: Micro-Stepping Stepper Motor Bridge Controller
• Manufacturer: ONSEMI [ON Semiconductor]

Programmable Peak−Current
(I
The coil current can be calculated as next:
R
updated at the next PWM cycle.
Clear
chip. To clear the complete digital inside AMIS−30421, the
CLR−pin needs to be pulled to logic 1 for a minimum time
of t
during Sleep Mode. During a clear the charge pump remains
max
SENSE
The amplitude of the current waveform in the motor coils
A change in the coil current (<CUR[2:0]>) will be
Logic 0 on the CLR−pin allows normal operation of the
CLR
stepping mode is equal to Step 1 of half step stepping mode
) can be programmed through SPI bits <CUR[2:0]>.
Correct change to a lower stepping mode. Step 2 of 1/4
(Table 5). Clearing the motor driver can not be done
is resistor R
1/4
(see Table 7). No offset or phase shift is created.
th
Half Step
Stepping Mode
I
I
Y
Y
Step
I
max
+ <CUR[2:0}>
1
Step 2
and R
I
I
X
X
2
as given in Figure 9.
Figure 18. Changing to/from Full step Stepping Mode
Step
R
Figure 17. NXT−Step Mode Synchronization
SENSE
Half Step
Full Step
Half Step
I
I
I
Y
Y
Y
Step
Step 1
Step 3
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Step 2
DIR−pin = low
th
I
I
X
I
X
X
20
stepping mode is not shared with a step in half step stepping
active. The voltage regulator remains functional during and
after the clear action and the WDb−pin is not activated.
(see Figure 7).
Speed and Load Angle Output
level of the BEMF (Back Electro Magnetic Force) voltage
of the motor. This BEMF voltage is sampled during every
so−called ”coil current zero crossing”. Per coil, two
zero−current positions exist per electrical period, yielding in
a total of four zero−current observation points per electrical
period.
coil during current decay, the coil voltage V
mode (see Table 7). An offset or phase shift will be created!
Incorrect change to a lower stepping mode. Step 1 of 1/4
After a clear, NXT pulses can be applied after t
The SLA−pin provides an output voltage that indicates the
Because of the relatively high recirculation currents in the
1/4
th
Stepping Mode
Half Step
I
Full Step
Y
I
I
Y
Y
Step 1
Step
Step
I
X
I
X
I
X
Half Step
I
Full Step
Y
I
Y
COIL
Step
DIR pin = low
CLR_SET
shows a
th
I
X
I
X