Browse Prior Art Database

Solenoid Driver Circuit

IP.com Disclosure Number: IPCOM000091537D
Original Publication Date: 1968-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Schaefer, WC: AUTHOR

Abstract

This solenoid driver circuit has controlled rise- and fall-time periods that maximize reliability. The junction temperatures of the driver transistors and power supply line noise generation are minimized. Solenoid 10 is picked up and held in response to voltage pulses applied between ground and input terminal 12. Input transistor 14 drives a pick channel Inverter transistor 16 and a hold channel driver transistor 18. Capacitor 20 controls the rise- and fall-time periods at the inputs of both transistors 16 and 18. Interaction between these transistors is prevented by isolating resistors 22 and 24.

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Solenoid Driver Circuit

This solenoid driver circuit has controlled rise- and fall-time periods that maximize reliability. The junction temperatures of the driver transistors and power supply line noise generation are minimized. Solenoid 10 is picked up and held in response to voltage pulses applied between ground and input terminal 12. Input transistor 14 drives a pick channel Inverter transistor 16 and a hold channel driver transistor 18. Capacitor 20 controls the rise- and fall-time periods at the inputs of both transistors 16 and 18. Interaction between these transistors is prevented by isolating resistors 22 and 24.

Transistor 26 is connected in a single-shot circuit turned on by transistor 16. Timing of the single-shot circuit is governed by the values of capacitor 28 and resistor 29. The rise- and fall-time periods of the output of the single-shot are controlled by capacitor 30. Emitter-follower 32 provides sufficient current gain to energize two parallel-connected driver transistors 34 and 36 which pick up solenoid 10. Emitter resistors 38 and 39 prevent transistors 34 and 36 from turning on abruptly and equalize collector current flow. The transitions from cutoff to saturation and saturation to cutoff of the driver transistors are gradual. The pick up driver output current is of the order of an ampere. Transistor 18 also has a gradual transition in turning on and off due to emitter resistor 42. The hold transistor output current is of the order of a quar...