CN204315027U

CN204315027U - Smoke detector

Info

Publication number: CN204315027U
Application number: CN201420869673.6U
Authority: CN
Inventors: 刘伟吉
Original assignee: Shanghai Beiling Co Ltd
Current assignee: Shanghai Beiling Co Ltd
Priority date: 2014-12-26
Filing date: 2014-12-26
Publication date: 2015-05-06
Anticipated expiration: 2024-12-26

Abstract

The utility model provides a kind of smoke detector, comprise luminotron and luminotron driving circuit, it is characterized in that, also comprise the capacitor be connected in series between described luminotron and ground, described capacitor is electrically connected with at least one module in the chip of described smoke detector, with at least one module for power supply described.Smoke detector of the present utility model, gets up the power scavenging that luminotron is wasted, and is supplied to other circuit and uses, thus reduce total current significantly, extend the serviceable life of smoke detector.

Description

Smoke detector

Technical field

The utility model relates to a kind of smoke detector, the photoelectric smoke detector of particularly a kind of low-power consumption.

Background technology

With reference to Fig. 1, it is the basic block diagram of smoke detector in prior art.Control circuit wherein every the set time (such as, 10 seconds) start luminotron driving circuit, luminotron driving circuit output level makes power tube Q1 conducting, thus drives luminotron D1 luminescence (can be such as, that infraluminescence pipe sends infrared light).Receiving tube D0 receives the scattered light in smoke detection chamber, and its photocurrent produced is received by current detection circuit (this circuit can have part of devices and circuit to be positioned at outside chip) and amplified, and then gives alarm decision circuit.

If smoke detection has smoke particle in chamber, the infrared light that receiving tube D0 receives is just many, and the photocurrent of generation is just large.When smoke particle concentration acquires a certain degree, when the photocurrent namely produced exceedes certain threshold value, alarm drive circuit starts, and sends corresponding sound, optical, electrical alerting signal.

Under all circuit of this circuit are all operated in 9V voltage VCC, be characterized in, when luminotron D1 is luminous, pressure drop major part drops on resistance Re and power tube Q1, and therefore its efficiency driven is very low.Such as, when luminotron D1 is luminous, the pressure drop of place path is: VRe+Vce_Q1+Von_D1=9V, and Vce_Q1+Von_D1 is wherein about 7.5V, and Von_D1 is about 1.5V, and therefore, its efficiency driven only has 17%.

This smoke detector is when standby, and the total current of this circuit is about 4 ~ 7uA.Wherein, the average current of luminotron D1 is (200mA ~ 400mA) * 100uS/10S=2 ~ 4uA, and the summation of the standby current of other circuit is 3 ~ 5uA.Therefore, needed for the average current of luminotron D1 and other circuit, the summation of electric current is suitable.If use the common carbon powered battery of a 270mAH, then this smoke detector approximately can with 3 years.

Utility model content

In order to make the power consumption of smoke detector lower, the utility model provides a kind of smoke detector, comprise luminotron and luminotron driving circuit, also comprise the capacitor be connected in series between described luminotron and ground, described capacitor is electrically connected with at least one module in the chip of described smoke detector, with at least one module for power supply described.

Further, also comprise the first switch being controlled its break-make by described luminotron driving circuit, described first switch is connected in series between described luminotron and power supply, and described luminotron driving circuit is positioned at the side of the close described power supply of described luminotron.

Further, also comprise low-tension supply charging circuit and charging control circuit, when described charging control circuit detects the voltage of described capacitor lower than first threshold voltage, described charging control circuit controls described low-tension supply charging circuit to start to charge to described capacitor.Preferably, described low-tension supply charging circuit comprises the second switch be connected in series between described power supply and described capacitor; Described charging control circuit comprises the first voltage comparator, and two input end connects the voltage of described first threshold voltage and described capacitor respectively, and its output terminal is electrically connected with described second switch, for controlling the break-make of described second switch.

Further, also comprise low-tension supply discharge circuit and charge/discharge control circuit, when described charge/discharge control circuit detects the voltage of described capacitor higher than Second Threshold voltage, described charge/discharge control circuit controls described low-tension supply discharge circuit to start described capacitor discharge.Preferably, described low-tension supply discharge circuit comprises the 3rd switch and the resistor be connected in series, and one end of described low-tension supply discharge circuit is connected to the positive pole of described capacitor, other end ground connection; Described charge/discharge control circuit comprises the second voltage comparator, and two input end connects the voltage of described capacitor and described Second Threshold voltage respectively, and its output terminal is electrically connected with described 3rd switch, for controlling the break-make of described 3rd switch.

Smoke detector of the present utility model, gets up the power scavenging that luminotron is wasted, and is supplied to other circuit and uses, thus reduce total current significantly, extend the serviceable life of smoke detector.

Accompanying drawing explanation

Fig. 1 is the structural representation of the smoke detector of prior art;

Fig. 2 is the structural representation preferred embodiment of smoke detector of the present utility model.

Embodiment

Below in conjunction with the drawings and specific embodiments, smoke detector of the present utility model is described in further detail, but not as to restriction of the present utility model.

With reference to Fig. 2, smoke detector of the present utility model, comprise luminotron D1 and luminotron driving circuit, also comprise the capacitor Cpower be connected in series between luminotron D1 and ground, capacitor Cpower is electrically connected with at least one module in the chip of smoke detector, with to this at least one module for power supply.The electric current that luminotron D1 flows out is collected by capacitor Cpower and stores, and Cpower powers to control circuit, current detection circuit, alarm decision circuit and other observation circuits as low-tension supply VDD_LOW simultaneously.The size of low-tension supply VDD_LOW is determined by chip technique used, is generally 1.8 ~ 3.3V.

This smoke detector also comprises the first switch S 1, first switch S 1 controlling its break-make by luminotron driving circuit and is connected in series between luminotron D1 and power supply VCC.The type of drive of this luminotron D1 is, control circuit opens luminotron driving circuit every the set time, and luminotron driving circuit controls the first switch S 1 and opens, thus drives luminotron D1 luminous.Smoke detector of the present utility model compared with prior art, eliminates power tube Q1 and resistance Re, saves cost and the space of peripheral components, and improves the reliability of product; Further, smoke detector of the present utility model, produces the drive current of luminotron D1, improves precision, so that temperature compensation and photoelectricity compensation of ageing at chip internal.

Especially, luminotron driving circuit is positioned at the side of the close power supply VCC of luminotron D1.In prior art, luminotron driving circuit is positioned at the side closely of luminotron D1, as shown in Figure 1; And in smoke detector of the present utility model, luminotron driving circuit is positioned at the side of the close power supply VCC of luminotron D1, as shown in Figure 2.After the position of luminotron driving circuit changes nearly mains side into, be convenient to insert capacitor Cpower in the side of near-earth and collect the electric current flowing through luminotron D1, if luminotron driving circuit is still in side closely, the capacitor Cpower then inserted can only relative to power source charges, the ground of now control circuit then can be caused to be floating ground, circuit and the more difficult realization of technique.

For the ease of the voltage of low-tension supply VDD_LOW that control capacitor Cpower is formed, this smoke detector also comprises low-tension supply charging circuit and charging control circuit and low-tension supply discharge circuit and charge/discharge control circuit.

With reference to Fig. 2, low-tension supply charging circuit comprises the second switch S2 be connected in series between power supply VCC and capacitor Cpower.Charging control circuit comprises the first voltage comparator, and two input end connects the voltage VDD_LOW of first threshold voltage and low-tension supply respectively, and its output terminal is electrically connected with second switch S2, for controlling the break-make of second switch S2.When charging control circuit detects the voltage VDD_LOW of low-tension supply lower than first threshold voltage, charging control circuit controls second switch S2 and opens to charge to capacitor Cpower.

Low-tension supply discharge circuit comprises the 3rd switch S 3 and resistor Rd that are connected in series, and one end that the 3rd switch S 3 is not connected with resistor Rd is connected to the positive pole of capacitor Cpower, one end ground connection that resistor Rd is not connected with the 3rd switch S 3.Charge/discharge control circuit comprises the second voltage comparator, and two input end connects voltage VDD_LOW and the Second Threshold voltage of low-tension supply respectively, and its output terminal is electrically connected with the 3rd switch S 3, for controlling the break-make of the 3rd switch S 3.When charge/discharge control circuit detects the voltage VDD_LOW of low-tension supply higher than Second Threshold voltage, charge/discharge control circuit controls the 3rd switch S 3 and opens to discharge to capacitor Cpower.

Above-mentioned charging control circuit and charge/discharge control circuit can be respectively two entity circuit, also can be entity circuit, such as, as shown in Figure 2, can be low-tension supply control circuits.

The course of work of this smoke detector is described in detail referring to Fig. 2.

Process one: when this smoke detector powers on, charging control circuit controls second switch S2 and opens, and charge/discharge control circuit controls the 3rd switch S 3 and closes, now, by IIRED, capacitor Cpower is charged, make low-tension supply VDD_LOW charge to required voltage.Wherein, IIRED can be drive current source, the resistance or short-circuit line etc. of multiplexing luminotron D1.After low-tension supply VDD_LOW is stable, chip just can carry out smoke detection and monitoring, namely carries out process two.

Process two: when this smoke detector carries out smoke detection, capacitor Cpower collects the electric current flowing through luminotron D1, improves the voltage VDD_LOW of low-tension supply.If the voltage VDD_LOW of low-tension supply is too high, charge/discharge control circuit can control the 3rd switch S 3 and open, and too much electric charge is bled off, to reduce the voltage VDD_LOW of low-tension supply.

Process three: when not carrying out smoke detection, if the voltage VDD_LOW of low-tension supply is too low, charging control circuit controls second switch S2 and opens, and charges to capacitor Cpower, supplements electricity to improve the voltage VDD_LOW of low-tension supply.

Smoke detector of the present utility model, the power scavenging that luminotron is wasted is got up, be supplied to other circuit to use, due to the multiplexing drive current of luminotron, thus make the total current of system reduce 30% ~ 50%, thus further increase the service time of battery, extend the serviceable life of smoke detector.

Above embodiment is only illustrative embodiments of the present utility model, can not be used for limiting the utility model, and protection domain of the present utility model is defined by the claims.Those skilled in the art can in essence of the present utility model and protection domain, and make various amendment or equivalent replacement to the utility model, these are revised or be equal to replacement and also should be considered as dropping in protection domain of the present utility model.

Claims

1. a smoke detector, comprise luminotron and luminotron driving circuit, it is characterized in that, also comprise the capacitor be connected in series between described luminotron and ground, described capacitor is electrically connected with at least one module in the chip of described smoke detector, with at least one module for power supply described.

2. smoke detector according to claim 1, it is characterized in that, also comprise the first switch being controlled its break-make by described luminotron driving circuit, described first switch is connected in series between described luminotron and power supply, and described luminotron driving circuit is positioned at the side of the close described power supply of described luminotron.

3. smoke detector according to claim 1, it is characterized in that, also comprise low-tension supply charging circuit and charging control circuit, when described charging control circuit detects the voltage of described capacitor lower than first threshold voltage, described charging control circuit controls described low-tension supply charging circuit to start to charge to described capacitor.

4. smoke detector according to claim 3, is characterized in that,

Described low-tension supply charging circuit comprises the second switch be connected in series between described power supply and described capacitor;

Described charging control circuit comprises the first voltage comparator, and two input end connects the voltage of described first threshold voltage and described capacitor respectively, and its output terminal is electrically connected with described second switch, for controlling the break-make of described second switch.

5. smoke detector according to claim 3, it is characterized in that, also comprise low-tension supply discharge circuit and charge/discharge control circuit, when described charge/discharge control circuit detects the voltage of described capacitor higher than Second Threshold voltage, described charge/discharge control circuit controls described low-tension supply discharge circuit to start described capacitor discharge.

6. smoke detector according to claim 5, is characterized in that,

Described low-tension supply discharge circuit comprises the 3rd switch and the resistor be connected in series, and one end of described low-tension supply discharge circuit is connected to the positive pole of described capacitor, other end ground connection;

Described charge/discharge control circuit comprises the second voltage comparator, and two input end connects the voltage of described capacitor and described Second Threshold voltage respectively, and its output terminal is electrically connected with described 3rd switch, for controlling the break-make of described 3rd switch.