Transformer coupled semiconductor bridge igniter for low voltage ignition from a high voltage source.

摘要

Some missile systems have high voltage, short (< 1 (mu)s) current pulses available for ignition of the missile's rocket motor. Such high voltage systems are desirable for enhanced safety considerations. However, application of high voltage firing pulses to conventional 1-(Omega) bridgewire igniters can result in a detonation in the igniter rather than a well controlled burn. We present in this paper a concept proposed by Eglin Air Force Base for converting the high voltage (2 kV) firing signal pulse to the appropriate low voltage (<50 V) and low energy (approximately 1.5 mJ) input required for semiconductor bridge, SCB, igniters. The Eglin concept makes use of a pot core transformer to step down the input voltage. Our transformer Ferroxcube pot core (10 mil air gap) with a 50-turn primary and 1-turn secondary. In our prototype design, the 1-turn secondary is a Kapton-laminated copper loop with the SCB directly bonded to the ends of the copper loop. The igniter assembly consist of the primary spool and secondary loop mounted in the pot core transformer with a hole, which serves as the charge holder for the igniter material, drilled in one of the pot core halves and positioned directly over the SCB. The igniter material is pressed into the charge holder against the SCB. Application of a 2 kV (<1 (mu)s) pulse to the primary, produces a 40-V signal in the secondary that functions the SCB and ignites the explosive material. In addition to the 2-kV all-fire ignition requirement, the ignition system must be able to withstand 500-V no-fire signals and electrostatic discharge, ESD, inputs. We will discuss in this paper various design configurations of this component and their output and also the ability of this concept to successfully withstand the no-fire and ESD inputs. 7 refs., 5 figs., 1 tab.