SLA7070M, SLA7071M,

SLA7072M, and SLA7073M

Motor Driver ICs

9

www.allegromicro.com

Stepper Motor

Coil Short Circuit

Coil Short Circuit

Normal Operation

Output Disable

+V

0

t

RSInt

Figure 4. Motor coil short circuit protect circuit operation. Overcurrent that flows with-

out passing the sense resistor is undetectable. To recover the circuit after protection oper-

ates, VDD must be cycled and started up again.

Protection Functions: PR Types

The PR types of the SLA7070M series include a motor coil

short-circuit protection circuit and a motor coil open protection

circuit. They are described in this section.

• Motor Coil Short-Circuit Protection (Load Short) Circuit

This protection circuit, embedded in the SLA7070M series,

begins to operate when the device detects an increase in the volt-

The voltage at which motor coil short-circuit protection

put is disabled at the time the protection circuit starts.

In order for the motor coil short-circuit protection circuit to

Overcurrent that flows without passing the sense resistor

is undetectable. To resume the circuit after protection operates,

VDD must be cycled.

• Motor Coil Open Protection

Details of this functions is not disclosed yet due to our pat-

ent policy.