AMIS-30622 Datasheet, PDF (31/42 Pages) AMI SEMICONDUCTOR – I2C Microstepping Motordriver

AMIS-30622
9.2.3.4. Motor stopping phase
At the end of the deceleration phase, the currents are maintained in the coils at their actual DC level (hence
keeping the sine/cos ratio between coils) during 1/4^th of an electrical period at minimum velocity (thus 2 half-
steps). The currents are then set to the hold values, respectively Ihold × sin (TagPos) and Ihold × cos
(TagPos) as illustrated below. A new positioning order can then be executed.
I_coil
t
9.2.3.5. Charge pump monitoring
If the charge pump voltage is not sufficient for driving the high side transistors (due to a failure), an internal
HardStop command is issued. This is acknowledged to the master by raising flag <CPFail> (available with
command GetFullStatus1).
In case this failure occurs while a motion is ongoing, the flag <StepLoss> is also raised.
9.2.3.6. Electrical defect on coils, detection and confirmation
The principle relies on the detection of a voltage drop on at least one transistor of the H-bridge. Then the
decision is taken to open the transistors of the defective bridge.
This allow to detect the following short circuits:
• External coil short circuit
• Short between one terminal of the coil and Vbat or Gnd
• One cannot detect internal short in the motor
Open circuits are detected by 100% PWM duty cycle value during a long time
Pins
Yi or Xi
Yi or Xi
Yi or Xi
Y1 and Y2
X1 and X2
Xi and Yi
Fault mode
Short circuit to GND
Short circuit to Vbat
Open
Short circuited
Short circuited
Short circuited
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