JPH06273481A - Latch-up detection circuit - Google Patents

Abstract

PURPOSE:To detect a latch-up in any IC accurately by connecting the cathode of a diode to the power supply terminal of each IC, connecting an anode to one resistor, and then connecting the detection terminal of the resistor to the power supply with the connection point as the detection terminal. CONSTITUTION:When all ICs 1 operate normally, the power supply terminal of the ICs 1 is nearly equal to a power supply voltage +Vcc and the voltage of a detection terminal 6 is also equal to the power supply voltage. When the ICs 1 receive a high energy radiation and at least one ICs 1 result in latch-up, the ICs are short-circuited and the power supply terminal of the ICs 1 are connected to the ground potential. Therefore, a forward voltage is applied to a diode 5, thus allowing current to flow and the potential of the detection terminal 6 to be also connected to the ground potential. Therefore, the voltage of the detection terminal 6 changes from the high level of the power supply voltage to the low level of the ground potential and then is output as a latch-up detection signal. Also, even if the voltage of the detection terminal 6 is reduced to a low level, the power supply terminal voltage of other ICs 1 where no latch-up is generated, us not reduced and continues normal operation since an inverse voltage is applied to the diode connected to the ICs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a single event upset (SE) in which an integrated circuit is in a radiation failure mode.
Of U), it relates to a latch-up detection circuit for detecting a latch-up in which a power supply pin of an integrated circuit is in a short circuit mode.

[0002]

2. Description of the Related Art Integrated circuits (ICs)
Is widely used as a space electronic device. Radiation is much stronger in outer space than on the ground. When an integrated circuit such as a CMOS IC receives high-energy radiation, it fails and malfunctions. One of the failure modes is a latch-up in which a short circuit occurs and a large current flows.

[0003]

When latch-up occurs, a large current flows in the integrated circuit and destroys it. Therefore, each integrated circuit is provided with a resistor for preventing overcurrent in series with the power supply to protect the integrated circuit. There is. However, when latch-up occurs, the integrated circuit malfunctions, but in the past, because the integrated circuit was only protected and the occurrence of latch-up was not detected, the cause could be recognized even if the integrated circuit malfunctioned. No
Appropriate protection was not provided for the entire circuit.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a latch-up detection circuit capable of detecting latch-up of a plurality of integrated circuits with a simple circuit.

[0005]

To achieve the above object, the present invention provides a plurality of integrated circuits each having a power supply terminal connected in parallel to a power supply via a first resistor and having a ground terminal grounded, and a power supply. The anti-power supply end of the second resistor connected to the detection end is used as a detection end, and the cathode side is connected to the power supply terminal of each integrated circuit from this detection end, and the diode connecting the anode side to this detection end is connected. is there.

[0006]

When the integrated circuit receives high-energy radiation and latch-up occurs, the integrated circuit is short-circuited to the ground,
Although a large current flows, a voltage drop occurs due to the first resistance and the power supply terminal voltage of the integrated circuit becomes zero. Then, a voltage is applied in the forward direction to the diode connecting the cathode side to the power supply terminal of the integrated circuit, a current flows through the diode, and the voltage at the detection end becomes low level. The voltage at the detection end when no short circuit occurs in any of the integrated circuits is at the same high level as the power supply voltage, so that when the voltage at the detection end becomes lower than the high level, it is output as a latch-up detection signal. As a result, the detection circuit can detect that latchup has occurred in any of the connected integrated circuits.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a latch-up detection circuit diagram of an embodiment of the present invention. The integrated circuit 1 such as a CMOS IC has its power supply terminal connected to the resistor 2 (R1) and its ground terminal grounded. The resistor 2 protects the integrated circuit 1 by limiting the current flowing from the power source (+ Vcc) when the integrated circuit 1 is short-circuited due to latch-up. Each integrated circuit 1 is connected in parallel via a resistor 2 to a power source (+ Vcc). A capacitor 3 is connected between the power supply terminal and the ground terminal of the integrated circuit 1 to reduce high frequency noise generated by the integrated circuit during normal operation and protect the entire circuit from noise. A resistor 4 (R2) is connected to the power source (+ Vcc), and the opposite power source end of the resistor 4 is connected to the detection end 6
Between the detection terminal 6 and the power supply terminal of each integrated circuit 1,
The diodes 5 are connected with the cathodes on the power supply terminal side.

Next, the operation will be described. When all the integrated circuits 1 are operating normally, the power supply terminal of the integrated circuit 1 is almost the power supply voltage (+ Vcc), and the voltage of the detection terminal 6 is also the power supply voltage. When the integrated circuit 1 receives high-energy radiation and one or more integrated circuits 1 are latched up, a short circuit occurs in the integrated circuit 1 and the power supply terminal of the integrated circuit 1 becomes the ground potential. Therefore, a forward voltage is applied to the diode, a current flows, and the potential of the detection end 6 also becomes the ground potential. As a result, the detection terminal 6 changes from the high level of the power supply voltage to the low level of the ground potential, and this is output as the latch-up detection signal. Even if the detection terminal 6 becomes low level, the voltage of the power supply terminal of the other integrated circuit 1 in which latch-up does not occur does not decrease because the reverse voltage is applied to the diode connected to this integrated circuit 1. Normal operation can be continued.

Although latch-up occurs due to radiation, there are some integrated circuits that cause latch-up even without radiation, and the circuit of the present invention can be applied to such cases as well. In addition, this circuit can monitor a plurality of integrated circuits with one latch-up detection circuit, and only one resistor (R2) and the same number of diodes 5 as the integrated circuits 1 can be used as circuit components, so that low cost and high reliability are achieved. Can be realized.

[0010]

As is apparent from the above description, according to the present invention, the cathode side of the diode is connected to the power supply terminal of each integrated circuit, and the anode side is connected to one resistor. Since the anti-detection end of this resistor is connected to the power supply to form the latch-up detection circuit, it is possible to accurately detect which latch-up occurs in which integrated circuit. Further, since the circuit configuration is simple, the reliability is high and the cost is low.

[Brief description of drawings]

FIG. 1 is a latch-up detection circuit diagram of an embodiment of the present invention.

[Explanation of symbols]

 1 Integrated circuit 2, 6 Resistance 3 Capacitor 5 Diode 6 Detection end

Claims (1)

[Claims] 1. A plurality of integrated circuits each having a power supply terminal connected in parallel to a power supply via a first resistor and having a ground terminal grounded, and an anti-power supply end of a second resistor connected to the power supply as a detection end. A latch-up detection circuit is characterized in that a cathode side is connected to a power supply terminal of each of the integrated circuits from the detection end, and a diode that connects an anode side to the detection end is connected.