Clocked Magnet Driver
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
A clocked magnet driver circuit is proposed which, owing to its preselected initial attraction and holding currents, is well suited for driving magnets, relays, or the like. The circuit (Fig. 1) consists of a push-pull power output stage with driver transistors Q1, Q2, two flip-flops 1, 2, two comparators 3, 4, and an oscillator 5 of preferably 16 kHz. The special feature of this circuit is that it automatically switches from a relatively high initial attraction current IA to a lower holding current IH. The values of the initial attraction (peak) current IA and the holding (steady-state) current IH are determined as follows by suitably selecting the sense resistor RS and the reference resistors R1, R2, R3, where VCC is the supply voltage: (Image Omitted) The circuit and its function are described in detail by means of Figs.