GB1154072A - Electronic Circuit Arrangement for Generating High Power Pulses. - Google Patents

Abstract

1,154,072. Semi-conductor pulse circuits. GENERAL DYNAMICS CORP. 1 Sept., 1966 [27 Sept., 1965], No. 39166/66. Heading H3T. In a pulse generator of the type in which a capacitor 22 is charged via a thyristor 20 and later discharged into a pulse forming network 52 under control of a thyristor 40 and saturable transformer 38, the voltage across capacitor 22 is sensed by a circuit such as 24 arranged to turn off thyristor 20 and terminate each charging cycle of capacitor 22. Thyristor 20 is retriggered at a time after thyristor 40 determined by a delay circuit including silicon controlled switch 86. The energy of pulses provided by discharging the pulse forming network 52 into a magnetron 56 is thus maintained constant. Capacitor 22 is preferably arranged to charge resonantly via transformer 18 to twice the voltage of a high voltage rectifier 10, each time thyristor 20 is triggered by a circuit 42. Thyristor 40 is then triggered by circuit 70, saturating reactor 34 and allowing capacitor 22 to transfer its charge to the pulse forming network 52. When capacitor 22 is discharged, thyristor 40 becomes non conductive. A current from PFN 52 now builds up, saturating transformer 38 and allowing 52 to discharge via transformer 54 into a magnetron load 56. Trigger circuits for thyristors 40, 20, 26.- Thyristor 40 is triggered by a pulse fed to the base of transistor 72, the output of which is coupled via transformer 74 to thyristor 40. Capacitor 22 is recharged after each pulse by thyristor 20, triggered from an output of transistor 72 after delay in a circuit comprising a four-terminal silicon controlled switch 86 and unijunction transistor 102. The voltage across capacitor 22 is sensed by a circuit 24 in which transistor 130 becomes conductive when the voltage on 22 reaches a predetermined level (set by potentiometer 128) turning on transistor 138 and Shockley diode 140, the pulse so generated being amplified by transistor 148 and used to turn on thyristor 26 which provides a turn-off voltage via transformer 18 to charging thyristor 20, thus terminating the charging of capacitor 22. Protection circuits.-Shockley diode 50 and Zener diode 126 respectively protect circuits 40, 24.