JPS5815838B2 - Kasaikantiki - Google Patents

Description

[Detailed description of the invention] FIELD OF THE INVENTION The present invention relates to a fire detector.

Conventionally, with this type of fire detector, it is usually unknown whether or not the detector will operate normally in an abnormal situation.Therefore, during testing, abnormal conditions were created and the detector was activated to investigate.

The present invention improves the above-mentioned drawbacks, and the fire detector normally uses an oscillation element that oscillates, but when an abnormality occurs, the oscillation element switches to detect a fire, making inspection easier. This is what I did.

Next, the present invention will be explained with reference to examples.

Fig. 1 shows a fire detector of the present invention. 1 is a silicon n-type substrate, 2 is a P+ layer doped with a P-type impurity on a part of 1, and 3 is a P+ layer doped with an n-type impurity on P+2. A heavily doped n+ layer, 4 is an n+ layer heavily doped with n-type impurities on the other part of the n1 substrate, and 5 is a P layer on the other side of the n1 substrate.
This is a P+ layer doped with type impurities at a high concentration.

Electrodes 6, 7 and 8 are attached on these 3, 4 and 51, respectively.

9 is an output resistor, and 10 is a temperature sudden change resistance element such as v02 or a thermistor.

Vl is the main power supply, and ■2 is the auxiliary power supply.

Direction 2 may be omitted; in other words, the main power supply V1 and the resistor 9 are connected in series between the electrodes 6 and 7, and the sudden temperature change resistance element 10 and the auxiliary power supply 2 are connected between the electrodes 8 and 7. Connect in series.

When the temperature is low and the temperature sensor 10 has a high resistance, the potential of the P+5 layer increases due to the injection of holes from the outside, and when the potential of the P5 layer becomes higher than that of the n1 layer+, P+5, nl.

P2. The cyrisk structure of n+3 conducts and the output + A current flows through the force resistor 9.

Then, the potential of the P+5 layer decreases to approximately the potential of the n+3 layer.

Since the resistance value of the sensor 10 is so high that it is less than the holding current of Cyrisk, holes will not come out from the P+5 layer, and when electrons from n3 enter the P+5 layer, the potential of the P+5 layer will increase. When the current decreases, the current flow in the cyrisk structure stops.

However, the n1-P2 junction remains forward biased until these carriers are exhausted due to excess carriers accumulated in the P''-2 layer.
Since the transistor structure of n 4 , nl , P+2 tn+3 is in a saturated state, a saturation current 8 flows where the resistance of element 9 is R.

When these excess carriers disappear, the current stops completely.

The potential of the P+5 layer remains low, but it gradually rises due to the injection of holes from the outside, and the potential of the P+5 layer remains low.
When the potential of the layer rises above the potential of the n1 layer, the cyrisk structure switches.

Oscillation is performed by repeating the above steps. Then, as the temperature increases, the resistance of the temperature sensor 10 decreases and therefore the cyrisk structure p+5. When nLP 2tn+3 is turned on, the current becomes higher than the holding current, and Cyrisk continues to conduct.

Then, this sirisk current and the saturation current (8) due to the transistor structure continue to flow.

As described above, according to the device of the present invention, in a normal state, the output is represented by an oscillating waveform, and at high temperatures, a large constant current flows due to switching of the device.

In addition, when an element fails, no output is output, so it is possible to detect a fire etc. by the difference in the output waveform, and if the oscillation output is output during normal operation,
Since it is known that the sensor is operating without any abnormality, there is no need to check the operation, and inspection can be performed extremely easily.

[Brief explanation of drawings]

FIG. 1 shows a fire detector of the present invention. 1... N-type substrate, 2... P+ layer, 3...
...Layer by layer, 4...n+ layer, 5...
...P+ layer, 6,7,8...electrode, 9...
...output resistance, 10...temperature sudden change element, vl,
v2...Power supply.

Claims (1)

[Claims] 1. An impurity layer 2 of a conductivity type opposite to that of the conductivity type semiconductor substrate 1 is provided on a part of one side of the conductivity type semiconductor substrate 1. Furthermore, a substrate 1 is provided on the impurity layer 2.
An impurity layer 3 of the same conductivity type as the substrate 1 is provided, an impurity layer 4 of the same conductivity type as the substrate 1 is provided on the other side of the substrate 1, an impurity layer 5 of the opposite conductivity type is provided on the opposite side of the substrate 1, In the oscillation element in which electrodes 6, 7 and 8 are provided on 3, 4 and 5, respectively,
A fire detector in which a temperature sensor is connected between electrodes 7 and 8, and a power source 1 is connected through an output resistor 9 in series between electrodes 6 and 7 so that electrode 7 is in the positive direction.