JPS5811675B2 - magnetic switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the circuit configuration of a smoke detector, and although the current consumption is kept to the same level as conventional circuits during alarm, the logic circuit ensures high reliability and no malfunction. This is an attempt to create a smoke detector with a high level of functionality.

A conventional smoke detector circuit has a configuration as shown in FIGS. 2 and 3, for example.

The former circuit has a structure in which the output of the sensor is amplified by an amplifying port, and when the output reaches a certain level, the switching circuit C is activated. With smoke detectors, the sensor output is small and the gain of the amplifier needs to be high, so they are susceptible to noise, and with ion-type smoke detectors, the impedance of the sensor is high, so they are susceptible to induced noise. Both photoelectric smoke detectors and ion smoke detectors have low current consumption, so they have high circuit impedance, which makes them susceptible to inductive noise, which makes them more likely to malfunction. .

In addition, the latter circuit has a configuration in which the output of the sensor is amplified by an amplifying port and the output is processed by logic circuit 2 to operate switching circuit C, so there are fewer malfunctions. However, logic circuit 2 generally includes many transistors, FETs, and other elements.
The drawback is that the current consumption is large, which limits its applications.

In view of the problems of conventional circuits, the smoke detector according to the present invention includes a sensor, an amplifier for amplifying the output of the sensor, a switching circuit operated by the output of the amplifier, and a switching circuit for the sensor. A logic circuit to which current is supplied by the amplifier, a switching circuit operated by the output from the logic circuit, and a circuit configured to supply an input signal to the logic circuit from the output of the amplifier. This relates to smoke detector circuits.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a smoke detector circuit according to the present invention will be specifically described with reference to the drawings.

1 is a sensor, 2 is an amplifier, 3 and 4 are switching circuits,
5 is a logic circuit.

Sensor 1 - Amplifier 2 - Switching circuit 3
The output of the switching circuit 3 is amplified by the amplifier 2 to operate the switching circuit 3, but this type of circuit is susceptible to noise even if the current consumption is low.

By processing the output signal of the amplifier 2, the logic circuit 5 is configured to transmit a signal to the switching circuit 4 only when there is a pattern peculiar to a fire, or a counter circuit for canceling single-shot noise, etc. It has become.

The switching circuit 3 acts as a power switch to the logic circuit 5, and when the levels of the sensor 1 and amplifier 2 reach a certain level or higher (in other words,
Although it cannot be determined that a fire has occurred, some kind of signal is detected by the amplifier 2.
(when it is determined that there is a possibility of a fire occurring), the switching circuit 3 operates to supply current to the logic circuit 5, and the logic circuit 5 determines whether or not an alarm should be generated. It is something to judge again.

Therefore, in a normal state, that is, a state in which the switching circuit 3 is not operating, current consumption is low, and even if the switching circuit 3 operates due to noise, malfunctions are unlikely to occur due to the logic circuit 5.

As described above, the smoke detector circuit according to the present invention has a low current consumption during normal operation, and even in the event of a fire or malfunction due to noise, the circuit generates an alarm after checking again with the logic circuit. It has the advantage of providing highly reliable functions with fewer false alarms.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit of a smoke detector according to the present invention, and FIGS. 2 and 3 are block diagrams of circuits of a conventional smoke detector corresponding to the present invention. 1 is a sensor, 2 is an amplifier, 3 and 4 are switching circuits,
5 is a logic circuit.

Claims (1)

[Claims] 1 a sensor and an amplifier that amplifies the output of the sensor;
A switching circuit operated by the output of the amplifier, a logic circuit supplied with current by the switching circuit,
1. A smoke detector circuit comprising a switching circuit operated by an output from the logic circuit and a circuit configured to supply an input signal to the logic circuit from the output of the amplifier.