Inductive load drive control circuit with semiconductor switch protection function

摘要

A control/drive circuit for an inductive load includes a semiconductor switch for connecting the load to a driving voltage and for isolating the load from the driving voltage. Also included is a switch-off function for protecting the semiconductor switch against negative voltages induced by the switching process. The switch-off function is formed by a first voltage limiting circuit (diode and zener diode) (D2,ZD2) connected between a control (gate) terminal of the semiconductor switch (T1) (MOSFET) and earth potential. More specifically, the first voltage limiting circuit is formed by a second zener diode (ZD2), in which a second diode (D2) lies between the second zener diode and the gate terminal of the MOSFET (T1) and prevents discharge of the gate terminal.