SPMD150STP

Function description and application information

Doc ID 17160 Rev 1

19/23

Figure 20.

Microstepping

4.6

Non-dissipative overcurrent protection

The SPMD150STP integrates an overcurrent protection circuit.

This circuit provides protection against a short circuit to ground or between two phases of

the bridge.

To implement the over current detection, a sensing element that delivers a small but precise

fraction of the output current is implemented with each high side power MOSFET.

Since this current is a small fraction of the output current, there is very little additional power

dissipation.

This current is compared with an internal reference, when the output current reaches the

detection threshold (typically 5.6A) the OCP comparator signals a fault condition.

If a fault condition is detected, the EN pin is pulled below the turn off threshold (1.3V typical)

by an internal open drain MOSFET with a pull down capability of 4mA.