An initiator including a housing adapted to be received in an igniter or rocket motor, at least one charge at a distal end of the housing, an electro-explosive device behind the charge for detonating the charge when subject to a voltage HV, and a pressure bulkhead behind the electro-explosive device. An electronic subsystem in the housing is connected to the electro-explosive device through the bulkhead and includes a lead for providing the voltage HV to the electro-explosive device to initiate it, and a switch in the lead which does not conduct if errant voltages are present on the lead to prevent initiation of the electro-explosive device until the correct voltage HV is present.
1. An initiator comprising:
an over voltage protection circuitry housing;
an over voltage protection circuitry configured to be received within the over voltage protection circuitry housing comprising:
a first lead configured to charge a main charge capacitor above an EFI threshold voltage;
a solid state switch connected to the main charge capacitor and a gate driver, the solid state switch configured to be off until driven to conduction by the gate driver; and
the gate driver connected to a second lead,
wherein the gate driver is configured to not drive the solid state switch to conduction if voltage less than a gate driver operating voltage is present on the second lead, and the charge voltage on the capacitor is at or above the predetermined switching voltage of greater than 500 volts;
an electro-explosive device comprising a first charge and an exploding foil initiator (EFI) in electrical communication with the solid state switch and the main charge capacitor at a distal end of the over voltage protection circuitry housing, the EFI configured to initiate the first charge when subject to a voltage above the EFI threshold voltage; and
an igniter comprising an igniter housing wall separating the electro-explosive device from an igniter charge disposed within the igniter,
wherein the gate driver is configured to switch the solid state switch to discharge the main charge capacitor through the solid state switch and subject the EFI to a voltage above the EFI threshold voltage causing detonation of the first charge by the EFI, and a shock wave resulting from the detonation of the first charge is configured to detonate the igniter charge through the igniter housing wall.
2. The initiator of claim 1 further including a housing having threads configured to be received in the igniter or rocket motor.
3. The initiator in claim 1 in which the igniter charge includes two charges in a distal end of the initiator.
4. The initiator of claim 3 in which one charge of the two charges is the pyrotechnic material and the other charge is a detonating material.
5. The initiator of claim 4 in which the pyrotechnic material includes BKNO 3 and the detonating material includes HNS-IV.
6. The initiator of claim 1 in which the solid state switch is a MOS Controlled Thyristor (MCT).
7. The initiator of claim 1 , wherein:
the electro-explosive device further comprises a pair of electrical pins; and
the electronic subsystem further comprises a pair of sockets configured to receive the pair of electrical pins.
8. The initiator of claim 7 , wherein the pair of sockets are configured to receive the pair of electrical pins through a pressure bulkhead.