RU2589350C1 - Device for protection of electronics exposed to pulsed ionising radiation - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering and can be used for protection of electronics from impact of pulse ionising radiation. Device for protection of radio-electronic equipment (REE) when exposed to pulsed ionising radiation sources is based on disconnecting power to REE upon exceeding potentially critical level effect of ionising radiation sources on REE and is characterised by that it comprises detector of pulse ionising radiation, buffer stage-emitter follower and pulse generator - multivibrator, and as a detector of pulse ionising radiation a collector p-n junction of a n-p-n transistor with shorted emitter to base.

EFFECT: technical result is faster operation of protection device and simplification of protection circuit.

1 cl, 2 dwg

Description

The invention relates to the field of radio engineering and can be used to protect electronic equipment (CEA) containing CMOS chips and exposed to factors of pulsed ionizing radiation (III).

A device for protecting integrated circuits from exposure to radiation, is presented in the patent [1] (prototype). The known device comprises a radiation detector, an amplifier for detector signals, a power control command issuing unit, a forward protection switching unit, a secondary power source, a pulse power transistor, first and second resistors. The disadvantage of this device is the presence in the advanced protection circuit of the master oscillator, which reduces the response speed of the device. Another disadvantage is the need for effective shielding of the device elements.

The aim of the present invention is the protection of CEA containing CMOS chips from catastrophic failures caused by the thyristor effect (TE), when exposed to the equipment III.

This is achieved by the fact that at the moment of exposure to the REA III, the protection device (US) gives an impulse to turn off the power of the REA. Turning off the power of the REA prevents the development of the thyristor effect in the REA equipment.

The technical result of the invention is to increase the response speed of the ultrasound and simplify the protection circuit.

The technical result is achieved by the fact that the ultrasonic device contains a buffer cascade — an emitter follower and a pulse shaper — a one-shot, and a collector pn junction of a large area of a powerful npn transistor, for example, 2T866A, with a shorted emitter with a base (Fig. 1), is used as an III detector.

All elements of ultrasound are selected with a level of resistance for all types of exposure, significantly exceeding the level of resistance of the protected CEA.

The pulse to turn off the power of the REA is given by the ultrasound when the potentially critical level of the influence of the III on the REA recorded by the III detector is exceeded.

In FIG. Figure 2 shows a block diagram of ultrasonic testing, which includes an III detector (1), a buffer cascade — an emitter follower (2), and a pulse former — a single-shot (3).

UZ works as follows.

The amplitude of the primary photocurrent flowing through the pn junction of the transistor when exposed to an III, is described by the following expression [2]:

I = G · P _γ · S · (W _t + L _n + L _p ) = G · P _γ · V _eff ,

where G is the volumetric rate of current generation (for [Si] equal to 6.4 μA · rad / (cm ³ · s));

P _γ is the dose rate for ionization, rad / s;

S is the area of the pn junction;

W _t is the thickness of the combined region of the pn junction, cm;

L _n , L _p - diffusion length of minority carriers in n and p regions, respectively, cm;

V _eff is the effective carrier collection volume, cm ³ .

At the input resistor of the emitter follower connected in series with the p-n junction, when a current passes, a voltage pulse is generated.

From the emitter follower, the pulse is supplied to the pulse shaper. The shape and duration of the pulse supplied to the input of a single vibrator repeats the shape and duration of the pulse of the acting III. A single-shot converts the input pulse into a rectangular pulse with a duration determined by the RC chain. The output pulse generated by the single-vibrator is supplied to the REA key power supply circuit. The leading edge of this pulse disables the CEA, while the trailing edge provides its inclusion.

The described device allows you to turn off the CEA when the impact of III and thereby prevent the occurrence of catastrophic failures CEA caused by the influence of III.

Literature

1. Patent RU No. 2323275 C1, IPC Н03К 17/08, application No. 2006135561 dated 10.10.2006.

2. F. Larin, Radiation effects in semiconductor devices, New York: John Wiley and Sons, Inc., 1968.

Claims (1)

A device for protecting electronic equipment when exposed to pulsed ionizing radiation, comprising a pulsed ionizing radiation detector, characterized in that it contains a buffer cascade — an emitter follower and a pulse shaper — a one-shot, and a collector pn junction of the npn transistor is used as a detector of pulsed ionizing radiation shorted emitter with base.

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