JP2006133861A - Flame sensor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame sensor unit capable of reducing overall consumption current in the flame sensor unit. <P>SOLUTION: The flame sensor unit includes an infrared sensor 1 internally consuming a drive current, an amplification means 4 for amplifying the output signal of the infrared sensor 1, a fire identification section 6 for identifying a fire based on the output signal amplified in the amplification means 4, and a power supply circuit 32 for supplying a drive voltage at least to the infrared sensor 1. In the above flame sensor unit, a zener diode 8, as a reference potential generation device, is connected in series to the infrared sensor 1, so that the drive current for both the infrared sensor 1 and the zener diode 8 is shared. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flame detector, and more particularly to a flame detector that reduces current consumption.

FIG. 4 is a circuit diagram for amplifying the sensor output of a conventional flame detector as an example.
In a conventional circuit for amplifying the sensor output of a flame detector, the sensor output of an infrared sensor 100 such as one using a pyroelectric element is input via a capacitor 101 to an amplifying unit 102 composed of an operational amplifier. It was amplified and taken into flame determination means (not shown), and flame detection was performed by the flame determination means.
As a power source, a constant voltage power source (not shown) for supplying an idling current to the infrared sensor 100 and driving the amplifying unit 102 is provided, and a reference potential for determining an operating point of the amplifying unit 102 is output. A reference voltage generation circuit 104 is provided.

In the conventional infrared detection circuit, the current signal of the infrared sensor is converted into a voltage signal by the current-voltage conversion circuit, the voltage signal is amplified by the voltage amplification circuit, output to the determination circuit, and the flame is determined by the determination circuit. I am doing so.
And as a power supply, the reference voltage source which outputs the reference voltage which sets the operating point of a voltage amplifier circuit is provided. Although not shown, an infrared sensor and a constant voltage power source for driving the amplifying unit 102 are provided (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2003-227753 (page 6, FIG. 2)

  In the circuit for amplifying the sensor output of the conventional flame detector shown in FIG. 4 and the infrared detection circuit described in Patent Document 1, the drive current is supplied to the infrared sensor and the amplification circuit by a constant voltage power supply, and separately from that, The reference voltage source for setting the operating point of the amplifier circuit also requires a drive current and consumes the current, which causes a problem that the current consumption cannot be reduced.

  The present invention has been made to solve such a problem, and an object thereof is to provide a flame detector capable of reducing current consumption of the entire flame detector.

  A flame detector according to the present invention includes an infrared sensor that consumes a drive current therein, an amplification unit that amplifies an output signal of the infrared sensor, and a fire that performs fire discrimination based on the output signal amplified by the amplification unit In a flame detector comprising a determination unit and at least a power supply circuit for supplying a driving voltage to the infrared sensor, a reference potential generating element is connected in series to the infrared sensor, and the infrared sensor and the reference potential generating element are connected. And a common drive current.

  As described above, the present invention includes at least a power supply circuit that supplies a drive voltage to the infrared sensor, and a reference potential generating element is connected in series with the infrared sensor to generate a drive current between the infrared sensor and the reference potential generating element. Since it is shared, the drive current of the infrared sensor can be used, and the current consumption of the conventional power supply for generating the reference potential is eliminated, so that the current consumption is reduced accordingly.

FIG. 1 is a block diagram showing the configuration of the flame detector according to the first embodiment of the present invention, and FIG. 2 is a circuit diagram showing a specific configuration until the output signal of the main infrared sensor of the flame detector is taken into the MPU. FIG. 3 is a circuit diagram showing the internal configuration of the infrared sensor of the flame detector.
FIG. 3 shows a main infrared sensor 1. The main infrared sensor 1 consumes a drive current, and receives pyroelectric body 1a that generates an electric charge by receiving infrared rays therein. The charge of the pyroelectric body 1a is converted into a voltage. A gate resistor 1b for conversion and an FET 1c for amplifying the voltage of the gate resistor 1b are incorporated. The sub infrared sensor 11 is the same.
The main infrared sensor 1 receives infrared rays, converts them into electrical signals, and outputs them to the amplifier 2. The signal amplified by the amplifying unit 42 via the amplifying unit 4 by the amplifier 2 and the frequency filter 3 is rectified on the lower side by the lower rectifier 5 and input to the MPU 6.

The flame detector includes a sub-infrared sensor 11 having the same configuration as the main infrared sensor 1, and the sub-infrared sensor 11 similarly receives infrared rays and outputs an electric signal, and an amplifier 12 and a frequency filter 13. The signal amplified by the amplification unit 14 via the amplification unit 14 is subjected to lower rectification by the lower rectifier 15 and input to the MPU 6.
Although not shown in detail, the MPU 6 takes in the outputs of the lower rectifiers 5 and 15 after A / D conversion and determines whether or not a flame has occurred.

The MPU 6 is connected to the fire signal generator 31. The fire signal generator 31 receives the detection signal from the MPU 6 and generates and outputs a fire signal.
A power supply unit 32 supplies power to the MPU 6 and also supplies power to the amplifiers 2 and 12. Reference numeral 33 denotes a power supply / signal line for supplying a predetermined DC voltage to the power supply section 32. Reference numeral 34 denotes a line voltage monitoring section provided on the power supply / signal line 33 for monitoring the supply of power. After confirming that the voltage of the signal line 33 is not abnormal, the MPU 6 is made to output the detection signal.

Next, a specific configuration until the output signal of the main infrared sensor of the flame detector according to Embodiment 1 of the present invention is taken into the MPU will be described with reference to FIG.
In FIG. 2, an amplifier 4 that amplifies the output of the main infrared sensor 1 that outputs a signal in the wavelength band (for example, 4.4 μm) of CO 2 resonance radiation that is a fluctuation component of a flame by an optical filter (not shown) is composed of an operational amplifier. The frequency filter 3 that passes the fluctuation component of the flame is composed of a high-pass filter 3a and a low-pass filter 3b.

The output side of the amplifying unit 4 is connected to the lower rectifier 5 via a capacitor 8. The lower rectifier 5 includes an operational amplifier 5 a, a diode 5 b and a resistor 5 c, and a resistor 5 d provided between the capacitor 8.
Since the diode 5b is arranged in the feedback path of the operational amplifier 5a, the upper side of the reference potential is almost clipped and does not become a high voltage, and the operational amplifier 5a outputs a lower side wave and is input to the MPU 6.

The power supply unit 32 includes a first constant voltage IC 32 a that supplies power to the MPU 6 and a second constant voltage IC 32 b that supplies power to each unit such as the amplifier 2 and the main infrared sensor 1. A predetermined DC voltage is supplied from the power / signal line 33 to the power supply unit 32. The second constant voltage IC 32b is a reference potential generating element connected in series to the main infrared sensor 1 and the main infrared sensor 1. It is connected to a certain Zener diode 8.
With this configuration, the output of the main infrared sensor 1 is superimposed on the reference potential, and this reference potential is set to be the midpoint of the AC amplification by the amplifier 2. Reference numeral 9 is a source resistance, and 10 is a capacitor.
Although the Zener diode 8 is used as a reference potential generating element for generating the reference potential, a shunt regulator can be used instead of the Zener diode 8.

2 shows a specific configuration until the output signal of the main infrared sensor of the flame detector is taken into the MPU. The sub-infrared sensor 11 shown in FIG. 1 also includes the amplifying unit 4 and the lower side shown in FIG. A circuit having the same configuration as that of the rectifier 5 and the like is provided.
The main infrared sensor 1 is different from the sub infrared sensor 11 in that an optical filter (not shown) outputs a signal in a wavelength band (for example, 5.0 μm) slightly shifted from the wavelength band of the flame component. It is a point that is configured.

Next, the operation of the flame detector according to the first embodiment of the present invention will be described.
The sensor outputs of the main infrared sensor 1 and the sub infrared sensor 11 are amplified by the amplifiers 4 and 14 and then input to the MPU 6 via the lower rectifiers 5 and 15.
The MPU 6 samples a signal of the lower side wave based on the main / sub infrared sensors 1 and 11 subjected to A / D conversion.
Then, the MPU 6 performs waveform data creation processing for extracting only data having a predetermined threshold value or more to create waveform data, creates waveform data, and determines whether or not a flame has occurred based on the waveform data.

  At this time, for example, when the output value of the waveform data based on the main / sub infrared sensor 1, 11 side is a predetermined ratio (for example, when the output value of the main infrared sensor 1 and the output value of the sub infrared sensor 11 are 3: 1) ) Is determined to be a fire.

  As described above, according to the first embodiment, the power supplied from the second constant voltage IC 32b, which is a power supply circuit, to the main infrared sensor 1 can drive the Zener diode 8, which is a reference potential generating element. Thus, the current consumption necessary for generating the reference potential is eliminated, and the current consumption is reduced accordingly.

  In the first embodiment, the sensor outputs of the main and sub infrared sensors 1 and 11 are input to the MPU 22 to perform fire discrimination, but the output of the main infrared sensor 1 side is input to the MPU 22. However, it goes without saying that a fire determination can be made by the MPU 22 by providing a threshold value.

The block diagram which shows the structure of the flame detector of Embodiment 1 which concerns on this invention. The circuit diagram which shows the concrete structure until it takes in the output signal of the main infrared sensor of the flame detector in MPU. The circuit diagram which shows the internal structure of the infrared sensor of the flame detector. The circuit diagram which carries out the half wave rectification of the sensor output of the conventional flame detector.

Explanation of symbols

1 main infrared sensor, 2 amplifier, 3 frequency filter, 4 amplifying unit, 5 lower rectifier, 6 MPU (fire discrimination unit), 8 Zener diode (reference potential generating element), 9 source resistance, 11 sub infrared sensor, 12 amplifier , 13 Band pass filter, 14 Amplifier, 15 Lower rectifier, 32b Second constant voltage IC (power supply circuit).

Claims (2)

An infrared sensor that consumes a drive current internally; an amplifying unit that amplifies the output signal of the infrared sensor; a fire discriminating unit that performs a fire discrimination based on the output signal amplified by the amplifying unit; and at least the infrared sensor In a flame detector comprising a power supply circuit for supplying a driving voltage,
A flame detector, wherein a reference potential generating element is connected in series to the infrared sensor to share a drive current between the infrared sensor and the reference potential generating element. The flame detector according to claim 1, wherein the reference potential generating element is a Zener diode or a shunt regulator.

Images