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US 4,059,844 AGranted
Solenoid driver circuit
AssigneeNCR Corporation
InventorJohn W. Stewart
Life of this patent
Estimating the term…
Abstract
A driver circuit for limiting the magnitude of current flowing through a solenoid wherein the level of the current flowing through the solenoid is sensed and fed back to a driving switch. A level of current above a set level cuts off the drive voltage allowing the current in the solenoid to decay. A timing means fixes the time that the driving switch is off. During off times a conserving voltage is applied to the solenoid to prevent the rapid decay of the solenoid current.
Claims10
A solenoid drive circuit comprising:
- a solenoid;
- switch means for operatively connecting a source of drive voltage in circuit with said solenoid;
- and
- means for cycling said switch means in response to the level of current in said solenoid to disconnect the source of drive voltage from said solenoid for fixed periods of time so as to maintain the level of current in said solenoid below a selected level.
1 more element
A solenoid drive circuit comprising:
- a solenoid;
- a switch means having an open and a closed state for operatively connecting a source of drive voltage in circuit with said solenoid;
- a current sense means for providing a sense signal the level of which is indicative of the level of current in said solenoid;
- means for enabling said switch means to a closed state in response to a solenoid actuate signal;
- and
- means for cycling said switch means between said open and said closed state in response to the level of the sense signal, and for maintaining said switch means in said open state for a fixed period of time during each cycle.
3 more elements
Dependencies are inferred from the claim text.