Electronic contactless load switching device esp. for optical proximity switch - uses DC=DC converter controlled by output of switching amplifier and coupled to control electrode of power MOSFET

摘要

The switching device is coupled via an external lead to one terminal of a voltage source and via a second lead to the switched load which is coupled on the other side to the second voltage source terminal. It uses a proximity indicator (1) employing an oscillator, coupled via a switching amplifier (2) to a controlled electronic switch (3), e.g. a MOSFET. A DC/DC converter (5) is coupled at its input (7) to a control output (8) of the switching amplifier (2), its output (10) coupled to the control electrode of the switch (3). Pref. the DC/DC converter (5) uses a Clapp oscillator. ADVANTAGE - Reduced voltage drop in conductive state of switching device.