Browse Prior Art Database

FAST TURN-ON SOLENOID CURRENT BOOST

IP.com Disclosure Number: IPCOM000005746D
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2001-Nov-01
Document File: 1 page(s) / 59K

Publishing Venue

Motorola

Related People

Jeffrey Barylak: AUTHOR [+2]

Abstract

To accomplish the initial turn-on (peak or pull-in) mode of a solenoid, the current needed is greater than when it is already on in the sustain or hold current level mode. In some solenoid control systems, the impedance of the solenoid current path is so high that the normal system supply voltage is not capable of supplying enough current to accomplish the initial peak mode of the solenoid, but could provide enough current to keep the solenoid on once the solenoid is in the on position. The present system provides boost current required for the initial turn-on (peak or pull-in) mode of the solenoid. This is accomplished such that the present invention provides a fast solenoid turn-on and high current availability into a high impedance load at low voltage levels. The pre- sent invention allows solenoids requiring high currents to be used in applications where the nominal voltage source is not high enough to provide the desired turn-on current, and the present invention will also turn on normal loads faster than otherwise possible.

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MOlYlROLA Technical Developments Volume a October 1988

FAST TURN-ON SOLENOID CURRENT BOOST

by Jeffrey Barylak and Jeffrey Kotowski

   To accomplish the initial turn-on (peak or pull-in) mode of a solenoid, the current needed is greater than when it is already on in the sustain or hold current level mode. In some solenoid control systems, the impedance of the solenoid current path is so high that the normal system supply voltage is not capable of supplying enough current to accomplish the initial peak mode of the solenoid, but could provide enough current to keep the solenoid on once the solenoid is in the on position. The present system provides boost current required for the initial turn-on (peak or pull-in) mode of the solenoid. This is accomplished such that the present invention provides a fast solenoid turn-on and high current availability into a high impedance load at low voltage levels. The pre- sent invention allows solenoids requiring high currents to be used in applications where the nominal voltage source is not high enough to provide the desired turn-on current, and the present invention will also turn on normal loads faster than otherwise possible.

   In the present invention, before the solenoid L2 is to be turned on, inductor Ll must be "charged" to a given current level. This is accomplished with signal Vcontroll. At (or just before) the desired cpening time of the solenoid, transistor Ql is turned off. This causes Q2 to turn off and Vx to go negati...