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Fast Inductive Load Current Switch Circuit

IP.com Disclosure Number: IPCOM000052407D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Schillinger, WE: AUTHOR

Abstract

This driver circuit for electromagnetic actuators and the like is arranged for automatically increasing the energizing potential during a slewing mode and lowering it in steady-state mode with the addition of only a transistor, a diode and two resistors.

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Fast Inductive Load Current Switch Circuit

This driver circuit for electromagnetic actuators and the like is arranged for automatically increasing the energizing potential during a slewing mode and lowering it in steady-state mode with the addition of only a transistor, a diode and two resistors.

The actuator is indicated in Fig. 1 as an inductor 10. A direct current source 12 and a transistor 14 are found in prior-art switch circuits where the transistor 14 is turned on by a positive logical signal at input terminals 16, 18 causing the current to rise exponentially through the inductor 10, as shown by a curve 20 in Fig. 2.

A diode 22 and a resistor 24 are interposed in the prior-art circuit arrangement along with the addition of a transistor 26 a resistor 28 and additional potential by way of a source 32 for increasing the possible current rise, as indicated by the curve 30 in Fig. 2.

A positive logical signal applied across the input terminals 16, 18 will turn on the transistor 14 and saturate it since most of the potential appears across the inductor 10. The low potential appearing at the junction 34 causes the transistor 26 to turn on and add the potential of the source 32 to the circuit in series with the potential of the source 12. The potential of the source 32 is preferably very much larger than that of the source 12, whereby the current rises faster by a factor (P(12)+P(32))/P(12). As the current increases the potential at the junction will increase and...