Fast current control of inductive loads

• US 20040057183A1
• Filed: 04/18/2003
• Published: 03/25/2004
• Est. Priority Date: 10/21/2000
• Status: Active Grant

• Current Assignee: Kenneth Vincent, Peter J. Knight
• Original Assignee: Kenneth Vincent, Peter J. Knight
• Inventors: Vincent, Kenneth, Knight, Peter J.
• Granted Patent: US 7,433,171 B2
• Time in Patent Office: Days
• US Class Current: 361/118
• CPC Class Codes: H01F 7/18 Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
• CPC Class Codes: H01F 7/1811 demagnetising upon switching off, removing residual magnetism

Abstract

A circuit arrangement for the fast dissipation of the stored magnetic energy in an inductive load (4) controlled by a first switch (T1), comprising a high voltage-drop energy dissipation path (D2) disposed across the first switch (T1) and a second switch (T2) by which a constant-voltage diode drop path (D1) across the load (L1) can be selectively opened.

Claims

1. A circuit arrangement for the fast dissipation of the stored magnetic energy in an inductive load controlled by a first switch, comprising a high-voltage-drop energy dissipation path disposed across said first switch and a second switch by which a constant-voltage diode drop path across the load can be selectively opened.

2. A circuit arrangement as claimed in claim 1, wherein said first switch comprises a switching transistor and said high-voltage drop energy dissipation path comprises a voltage regulating diode in parallel with the switching path of said switching transistor.

3. A circuit arrangement as claimed in claim 2 wherein the switching transistor is a field effect transistor and the voltage regulating diode is connected between its source and drain terminals.

4. A circuit arrangement as claimed in claim 2 wherein the switching transistor is a field effect transistor and the voltage regulating diode is connected, in series with a first diode, between its drain and gate terminals.

5. A circuit arrangement as claimed in any of claims 1 to 4, wherein said second switch comprises a field effect transistor in series with a second diode across the series combination of the inductive load and a current sensing element.

6. A circuit arrangement as claimed in any of claims 1 to 5, wherein said second switch commonly controls the opening of a plurality of said constant-voltage diode drop paths across a plurality of respective inductive loads, each of which is switchable by a respective first switch across which there is disposed a respective high-voltage-drop energy dissipation path.