AMIS-30621 datasheet(35/43 Pages) AMI

35 / 43 page

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 1/4th of an

electrical period at minimum velocity (thus 2 half-steps). The

currents are then set to the hold values, respectively Ihold x

sin(TagPos) and Ihold x cos(TagPos) as illustrated below. A

new positioning order can then be executed.

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

GetFullStatus

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

Fault Mode

Yi or Xi

Short circuit to GND

Yi or Xi

Short circuit to Vbat

Yi or Xi

Open

Y1 and Y2

Short circuited

X1 and X2

Short circuited

Xi and Yi

Short circuited

AMI Semiconductor - Rev. 1.4

www.amis.com

AMIS-30621 LIN Microstepping Motordriver

Data Sheet

AMIS-30621 Datasheet(PDF) 35 Page - AMI SEMICONDUCTOR

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