Browse Prior Art Database

Inductor Driver Circuitry

IP.com Disclosure Number: IPCOM000096649D
Original Publication Date: 1963-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Donner, EF: AUTHOR

Abstract

Fast decay of load current is realized by a two-stage circuit. This has a Schmitt trigger 10 and an inductor driver transistor 12.

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Inductor Driver Circuitry

Fast decay of load current is realized by a two-stage circuit. This has a Schmitt trigger 10 and an inductor driver transistor 12.

Transistor 12 is blocked and no current flows in the inductive load, such as solenoid 14, in the presence of relatively positive signal voltage at input terminal
16. Such holds Schmitt trigger 10 with an input transistor 16 blocked and an output transistor 18 conducting. This applies a slightly positive signal voltage resulting from the opposing voltage drops across collector resistor 20 and emitter resistor 22 on the base of transistor 12.

A relatively negative signal at input 16 reverses conduction of the transistors. Transistor 16 conducts to apply slightly positive voltage on the base of transistor
18. This blocks transistor 18 and turns on transistor 12 by applying a negative potential to the base electrode.

When transistor 12 is then blocked by the application of relatively positive signal at input 16, high transient energy is developed in solenoid 14. This energy is applied by capacitor 24 to a low impedance sink circuit comprising load resistor 20 now connected in parallel with emitter resistor 22 due to conduction of transistor 18.

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