Patent Number: 6,297,568

Title: Inductive ignition circuit

Abstract: An inductive ignition circuit (10) especially adapted for use withmicro-turbine and other small-sized turbine engines such as are used inelectric generators. The inductive ignition circuit (10) includes aflyback transformer (14), a drive circuit (16) for energizing the primary(22) of the transformer (14), and a control circuit (18) that temporarilydisables the drive circuit (16) once the transformer primary (22) has beensufficiently energized. The drive circuit includes a switching transistor(20) which is biased on to draw current through the primary (22). Thecontrol circuit (18) includes two feedback circuits (42,44), one of whichinitiates disabling of the transistor (20) to cause the transformerflyback and the second of which sets the spark rate. The first feedbackcircuit (42) monitors the primary current and disables the transistor (20)once the current exceeds a pre-selected level. The second feedback circuit(44) uses a portion of the flyback energy obtained via a feedback winding(30) to maintain the transistor disabled for a period of time that can beselected over a wide range of values. The feedback winding (30) is used toprovide positive bias to the transistor (20) during switching on of thetransistor and is used by the second feedback circuit (44) during flybackto provide charging current to an RC timer circuit (64) in the secondfeedback circuit. This timer circuit (64) includes a capacitor (68) whichis used to hold the transistor (20) off until the capacitor (68) hasdischarged below a pre-selected level.

Inventors: Kempinski; Steve J. (Seneca, SC)


International Classification:

Expiration Date: 10/02/2013