JPH04143690A - Radiation identification circuit and electronic circuit used for it - Google Patents

Abstract

PURPOSE:To make possible the identification of a radiation dose to contrive the modification of redundancy of the same dose by generating an error signal when the error bit read from a memory storing specified data reaches specified number. CONSTITUTION:An address control circuit 1 increases an address according to a clock signal to supply an SRAM 3. A data control circuit 2 makes a light enable VE signal zero to make the SRAM 3 a write state to write data in each bit successively and, if they are written, the VE signal is made 1 to be in a read state. At this time the circuit 1 reads the data of the whole bit of the SRAM 3 according to the clock signal. During this time the circuit 2 detects the error bit of read data to count the number and, when the number of the generation of the error bit becomes specified predeterminated value, the error signal is generated. Further, the sensitivity of a circuit for radiation can be changed by changing the value of operating voltage Vcc. In addition, the threshold for counting the number of error bits had better be changed.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a radiation recognition circuit and an electronic circuit using the same, and particularly relates to a radiation recognition circuit suitable for use in an electronic circuit used in outer space where the amount of cosmic radiation varies greatly. be.

Conventional technology In electronic equipment used in outer space such as communication satellites,
Because the radiation dose, for example alpha radiation, varies greatly, it is necessary to assume the worst-case scenario when designing. Therefore, it is necessary to provide hardware with sufficient redundancy in the actual usage environment.

Furthermore, when a defect occurs, it is difficult to determine whether the defect is due to the α-ray dose in the usage environment or other factors, and it takes time to analyze the defect.

Purpose of the Invention The present invention has been made to solve the drawbacks of the prior art, and its purpose is to provide a radiation recognition circuit that can recognize the amount of radiation such as alpha rays. Our goal is to provide the following.

Another object of the invention is to provide an electronic circuit which allows radiation dose to be recognized and the redundancy of the circuit to be changed in response to this recognized result.

Structure of the Invention The radiation recognition circuit according to the present invention includes a memory in which predetermined data is stored in advance, read control means for sequentially reading data from the memory, and detecting error pits in the read data so that the number of error pits reaches a predetermined number. It is characterized in that it includes an error detection means that generates an error output when the radiation dose is reached, and the radiation dose is recognized based on the error output.

The electronic circuit according to the present invention includes a redundant circuit provided to improve reliability against radiation, a memory in which predetermined data is stored in advance, a read control means for sequentially reading data from the memory, and detecting error pits in the read data. a radiation detection circuit comprising an error detection means that generates an error output when the number of error pits reaches a predetermined number;
The apparatus is characterized in that it includes a control means for changing and controlling the redundancy of the redundant circuit in accordance with the error output.

Example Next, the present invention will be explained using the drawings.

FIG. 1 is a block diagram of an α-ray recognition circuit according to an embodiment of the present invention. The address control circuit 1 generates addresses of the SRAM 3 by sequentially incrementing them from an initial value "0°" in synchronization with a clock signal.

Data control circuit 2 synchronizes with the clock signal and outputs Sl? A.M.
3, and when writing data, a predetermined pig pattern (all "0" in this example) is written.

Furthermore, when reading data, the presence or absence of error pits is detected and an error signal output is generated according to the number of error pits.

SRAM (Static Random Access Memory) 3
is a memory IC whose operating power supply is Vcc, and the memory needs to be weak against alpha rays. Specifically, it is necessary to select a memory IC package that is thin and holds a small amount of charge in the cell.

In this configuration, the address control circuit 1 increments the address by 1 from "0" according to the clock signal and supplies the incremented address to the SRAM 3. The data control circuit 2 is WE(
The write enable) signal is set to “0°” to control SRAM 3 to write state, and the SRAM 3 is written according to the above address.
A "0" notator is sequentially written to each bit of 3.

Data control circuit 2 sets all bits of SRAM 3 to “0”
After writing, the WE multiplication signal is set to "1" and the state is set to read. At this time, the address control circuit 1 again sequentially increments the address by 1 from "O" according to the clock signal, and reads out data of all bits of the SRAM 3.

During this time, the data control circuit 2 detects error pits in the read data, and if "1" is detected, it means that the data in the SRAM 3 has changed, so the number of occurrences of these error pits is counted. When the number of error pits that occur reaches a predetermined value of 1 or more, it is reported to the outside as an error signal.

Since the α-ray resistance of the SRAM 3 varies greatly depending on the operating voltage Vcc, the sensitivity of the circuit to α-rays can be changed by changing the voltage value of VCC. Further, the threshold value for counting the number of error pits may be changed.

FIG. 2 is a block diagram of an electronic circuit according to an embodiment of the present invention using the α-ray recognition circuit of FIG. The electronic circuit of this embodiment includes an α-ray recognition section 10, an address control section 11, a memory IC 12゜13, and a data control section 1 shown in FIG.
It consists of 4.

When no error signal is generated by the α-ray recognition unit 10, the address control unit 11 and the data control unit 14 recognize the memory ICs 12 and 13 as memories in different address spaces, and the upper address indicates C8 (chip select ) signal can be generated to selectively access the address space of either memory IC 12 or 13.

When an error signal is generated in the α recognition unit 10, α
Since it is recognized that there are many lines, the entire circuit needs to be in high reliability mode.

Therefore, first, the contents of the memory ICl3 are transferred to an external device, and the contents of the memory IC12 are copied to the memory ICl3. Then, the address control section 11 and the data control section 14 recognize the memory ICs 12 and 13 as memories having the same address space, and perform access processing by regarding both of the C8 signals as common.

Therefore, the memory ICs 12 and 13 are in a duplex state, increasing redundancy and improving reliability. Therefore, if the data read from both memory ICs are different from each other, the data in which the error occurred is ignored due to parity,
Read the correct data to the outside. Of course, data in which an error has occurred should be rewritten.

When data is written, the same data is written to both memory ICs, and therefore, although the address space is halved compared to normal operation, reliability is doubled.

Incidentally, in the above embodiment, an example was shown in which the α-ray recognition circuit was applied to a memory device, but it is obvious that the invention can be applied to other electronic circuits. Further, although the explanation has been given using the recognition of alpha rays as an example, other radiations may be used.

Effects of the Invention As described above, according to the present invention, a memory IC is used for radiation recognition, and the radiation dose in the external environment can be recognized according to the error occurrence state of the memory bit.
This has the effect of being able to change the hardware configuration to deal with it.

In particular, if the radiation recognition section is installed outside where radiation is not shielded, and an IC with lower radiation resistance than the IC used in the electronic circuit is used in the radiation recognition section, the circuit will be activated depending on the recognition result. This makes it possible to change and control the reliability of the circuit, preventing malfunctions caused by radiation from outside the circuit, and making it easier to isolate problems caused by the external environment.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an electronic circuit using the circuit of FIG. Explanation of symbols of main parts 1... Address control circuit 2... Data control circuit 3... SRAM 10... Alpha ray recognition unit 12.13... ...Memory IC

Claims (3)

[Claims] (1) A memory that stores predetermined data in advance, a read control means that sequentially reads data from the memory, detects error bits in the read data, and generates an error output when the number of error bits reaches a predetermined number. What is claimed is: 1. A radiation recognition circuit comprising: an error detection means for detecting radiation, and recognizing radiation based on the error output. (2) Claim 1 characterized in that the operating power source of the memory is freely changeable so that the sensitivity to radiation can be freely controlled.
The radiation recognition circuit described. (3) A redundant circuit provided to improve reliability against radiation, a memory that stores predetermined data in advance, a read control means that sequentially reads data from the memory, and a system that detects error bits of this read data and detects errors. A radiation detection circuit comprising an error detection means that generates an error output when the number of bits reaches a predetermined number, and a control means that changes and controls the redundancy of the redundant circuit in accordance with the error output. electronic circuit.