Fire detector transmitting tube voltage-multiplying driving circuit and control method thereof

Abstract

The invention relates to the technical field of fire detectors, and provides a fire detector transmitting tube voltage-multiplying driving circuit and a control method thereof, and the fire detector transmitting tube voltage-multiplying driving circuit comprises a battery, a capacitor, a switching tube, a switching tube driving circuit, a transmitting tube and a transmitting tube driving circuit. The battery is electrically connected with the capacitor, the capacitor is further electrically connected with the switch tube and the transmitting tube, the switch tube is further electrically connected with the switch tube driving circuit, and the transmitting tube is further electrically connected with the transmitting tube driving circuit; the battery outputs a first fixed voltage to the capacitor, and the switching tube driving circuit drives the switching tube to output a second fixed voltage to the capacitor; the first fixed voltage is the same as the second fixed voltage; the capacitor superposes the first fixed voltage and the second fixed voltage to form double voltage so as to discharge to the transmitting tube, and the transmitting tube is driven to be started through the transmitting tube driving circuit; the whole circuit is simple in design, does not occupy too much circuit board area, is low in manufacturing cost, and has a better driving effect and electromagnetic compatibility.

Description

Technical Field

[0001] The present application relates to the technical field of fire detectors, and more specifically, to a voltage doubling driving circuit for a fire detector transmitting tube and a control method thereof. Background Art

[0002] Photoelectric smoke fire detectors use photoelectric smoke devices and excellent production technology. They have stable operation, beautiful appearance, simple installation and no need for debugging. Therefore, they are widely used in public places such as shopping malls and residences for fire safety monitoring.

[0003] Existing stand-alone photoelectric smoke detectors are generally powered by 3V lithium-ion batteries. When driving a transmitter with a conduction voltage drop greater than 3V, the battery voltage needs to be boosted first. At least more than 5.5V can drive the transmitter to work properly. The traditional boosting method is to use a switching DC converter, and form a boost chopper circuit through electronic devices such as switching tubes, inductors and capacitors to boost 3V to above 5.5V. The switching tube needs to be driven by a square wave signal, and the overall circuit is relatively loaded. Although most of the current solutions make the square wave signal generation circuit and the switching tube into an integrated chip, the cost is still high. In addition, the driving current of the transmitting tube may reach hundreds of milliamperes, and the power consumption is large. In most cases, the inductor can only be external, resulting in the entire boost circuit occupying a large area of ​​the circuit board. Since the switch tube drive requires high-frequency pulses, it is easy to generate electromagnetic radiation. In the use environment with high signal integrity requirements, additional means are needed to reduce or shield radiation interference, and the electromagnetic compatibility is poor.

[0004] Application Contents

[0005] The technical problem to be solved by the present application is to provide a fire detector transmitting tube voltage doubling driving circuit and a control method thereof in view of the above-mentioned defects of the prior art.

[0006] The technical solution adopted by this application to solve its technical problem is:

[0007] On the one hand, the present application provides a fire detector transmitting tube voltage doubling drive circuit, including a battery, a capacitor, a switch tube, a switch tube drive circuit, a transmitting tube and a transmitting tube drive circuit; the battery is electrically connected to the capacitor, the capacitor is also electrically connected to the switch tube and the transmitting tube respectively, the switch tube is also electrically connected to the switch tube drive circuit, and the transmitting tube is also electrically connected to the transmitting tube drive circuit; the battery outputs a first fixed voltage to the capacitor, and the switch tube drive circuit drives the switch tube to output a second fixed voltage to the capacitor; the first fixed voltage and the second fixed voltage are the same; the capacitor superimposes the first fixed voltage and the second fixed voltage to form a double voltage to discharge to the transmitting tube, and drives the transmitting tube to turn on through the transmitting tube drive circuit.

[0008] In some embodiments, a first resistor is electrically connected between the battery and the capacitor, and the capacitor is also electrically connected to a second resistor. The battery charges the capacitor through the first resistor and forms a loop with the second resistor.

[0009] In some embodiments, one end of the first resistor is electrically connected to the battery, and the other end of the first resistor is electrically connected to the positive electrode of the capacitor, and the positive electrode of the capacitor is also electrically connected to the positive electrode of the transmitting tube; one end of the second resistor is electrically connected to the negative electrode of the capacitor, and the other end of the second resistor is grounded.

[0010] In some embodiments, the switch tube driving circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a first transistor; one end of the third resistor is electrically connected to the circuit control end, the other end of the third resistor is electrically connected to one end of the fourth resistor and the base of the first transistor respectively, the other end of the fourth resistor and the emitter of the first transistor are both grounded; the collector of the first transistor is electrically connected to one end of the fifth resistor, the other end of the fifth resistor is electrically connected to one end of the sixth resistor and the gate of the switch tube respectively, the other end of the sixth resistor and the source of the switch tube are both electrically connected to the voltage input source, the drain of the switch tube is electrically connected to the negative electrode of the capacitor; the positive electrode of the capacitor is also electrically connected to the voltage output source.

[0011] In some embodiments, the transmitting tube driving circuit includes a seventh resistor, an eighth resistor, a ninth resistor and a second triode; one end of the seventh resistor is electrically connected to the circuit enable end, and the other end of the seventh resistor is electrically connected to one end of the eighth resistor and the base of the second triode respectively; the emitter of the second triode is electrically connected to one end of the ninth resistor, the other end of the ninth resistor and the other end of the eighth resistor are both grounded, and the collector of the second triode is electrically connected to the negative electrode of the transmitting tube.

[0012] In some embodiments, the switch tube is a P-type MOS tube.

[0013] In some embodiments, the transmitting tube is a light emitting diode.

[0014] On the other hand, the present application also provides a method for controlling a voltage doubling driving circuit of a fire detector transmitting tube, which is applied to a photoelectric smoke fire detector, wherein the photoelectric smoke fire detector comprises any of the above-mentioned voltage doubling driving circuits for the fire detector transmitting tube, and the method comprises the following steps:

[0015] Step 1: connect the photoelectric smoke fire detector to a battery, power it up and initialize it, and output a first fixed voltage to the capacitor through the battery to charge the capacitor;

[0016] Step 2: Control the switch tube driving circuit to drive the switch tube to output a second fixed voltage to the capacitor, and superimpose the first fixed voltage and the second fixed voltage through the capacitor to form a double voltage;

[0017] Step three, control the capacitor to discharge to the transmitting tube, and collect the voltage doubler output signal of the capacitor, and when the voltage doubler output signal is stable, control the transmitting tube drive circuit to work to light up the transmitting tube.

[0018] The beneficial effects of the present application are as follows: different from the prior art, in the fire detector transmitting tube voltage doubling driving circuit of the present application, the battery is electrically connected to the capacitor, the capacitor is also electrically connected to the switch tube and the transmitting tube respectively, the switch tube is also electrically connected to the switch tube driving circuit, and the transmitting tube is also electrically connected to the transmitting tube driving circuit; the battery outputs a first fixed voltage to the capacitor, and the switch tube driving circuit drives the switch tube to output a second fixed voltage to the capacitor; the capacitor superimposes the first fixed voltage and the second fixed voltage to form a double voltage to discharge to the transmitting tube, and drives the transmitting tube to turn on through the transmitting tube driving circuit; based on the principle that the voltage at both ends of the capacitor cannot change suddenly when charging and discharging, a transmitting tube voltage doubling driving circuit with good driving effect and electromagnetic compatibility is designed, the overall circuit design is simple, no large-volume devices such as inductors, filter capacitors and oscillation signal generators are required, it will not occupy too much circuit board area, and the manufacturing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a principle block diagram of a voltage doubling driving circuit for a fire detector transmitting tube in an embodiment of the present application;

[0020] Figure 2 1 is a circuit structure diagram of a voltage doubling driving circuit of a fire detector transmitting tube in an embodiment of the present application;

[0021] Figure 3 is a control flow chart of a voltage doubling driving circuit of a fire detector transmitting tube in an embodiment of the present application;

[0022] Names and numbers in the figure: battery-1; capacitor-2; switch tube-3; switch tube drive circuit-4; transmitting tube-5; transmitting tube drive circuit-6. DETAILED DESCRIPTION

[0023] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] "Multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0026] Moreover, the terms "up, down, front, back, left, right, upper end, lower end" and the like indicating directions are all based on the posture and position of the device or equipment described in this solution during normal use.

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the following will be described clearly and completely in combination with the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present application.

[0028] Example 1: This application is implemented as follows Figure 1 and Figure 2As shown in, a fire detector transmitting tube voltage doubling drive circuit includes a battery 1, a capacitor 2, a switch tube 3, a switch tube drive circuit 4, a transmitting tube 5 and a transmitting tube drive circuit 6; the battery 1 is electrically connected to the capacitor 2, the capacitor 2 is also electrically connected to the switch tube 3 and the transmitting tube 5 respectively, the switch tube 3 is also electrically connected to the switch tube drive circuit 4, and the transmitting tube 5 is also electrically connected to the transmitting tube drive circuit 6; the battery 1 outputs a first fixed voltage to the capacitor 2, the switch tube drive circuit 4 drives the switch tube 3 to output a second fixed voltage to the capacitor 2; the first fixed voltage and the second fixed voltage are the same; the capacitor 2 superimposes the first fixed voltage and the second fixed voltage to form a double voltage to discharge to the transmitting tube 5, and drives the transmitting tube 5 to turn on through the transmitting tube drive circuit 6.

[0029] The core principle of the voltage doubling driving circuit of the fire detector transmitting tube of this embodiment is: after the fire detector is powered on, the battery 1 outputs a fixed voltage to charge the capacitor 2 first. After a certain period of time, when the capacitor 2 is fully charged, the voltage difference between the two ends of the capacitor 2 is U. Through the switch tube driving circuit 4, the switch tube 3 is controlled to instantaneously connect a fixed voltage that is the same as the fixed voltage output by the battery 1 to the negative electrode of the capacitor 2. According to the principle that the voltage of the capacitor 2 cannot change suddenly, at this time, the output voltage of the positive electrode of the capacitor 2 will be based on the original voltage U, and then superimposed with U, that is, 2 times U, so as to realize the voltage doubling function. Then, by selecting an appropriate voltage, the output can be made greater than 5.5V. The positive electrode of the capacitor 2 is connected to the positive electrode of the transmitting tube 5. When the driving signal of the transmitting tube 5 is turned on, the capacitor 2 discharges to the transmitting tube 5, so that the transmitting tube 5 is turned on.

[0030] In this embodiment, a first resistor R9 is electrically connected between the battery 1 and the capacitor 2, and the capacitor 2 is also electrically connected to a second resistor R5. The battery 1 charges the capacitor 2 through the first resistor R9 and forms a loop with the second resistor R5. Specifically, one end of the first resistor R9 is electrically connected to the battery 1, and the other end of the first resistor R9 is electrically connected to the positive electrode of the capacitor 2, and the positive electrode of the capacitor 2 is also electrically connected to the positive electrode of the transmitting tube 5; one end of the second resistor R5 is electrically connected to the negative electrode of the capacitor 2, and the other end of the second resistor R5 is grounded.

[0031] In this embodiment, the switch tube driving circuit 4 includes a third resistor R1, a fourth resistor R2, a fifth resistor R4, a sixth resistor R3 and a first transistor Q1; one end of the third resistor R1 is electrically connected to the circuit control end (Control), the other end of the third resistor R1 is electrically connected to one end of the fourth resistor R2 and the base of the first transistor Q1 respectively, and the other end of the fourth resistor R2 and the emitter of the first transistor Q1 are both grounded; the collector of the first transistor Q1 is electrically connected to one end of the fifth resistor R4, the other end of the fifth resistor R4 is electrically connected to one end of the sixth resistor R3 and the gate of the switch tube 3 respectively, the other end of the sixth resistor R3 and the source of the switch tube 3 are both electrically connected to the voltage input source (VIN), the drain of the switch tube 3 is electrically connected to the negative electrode of the capacitor 2; the positive electrode of the capacitor 2 is also electrically connected to the voltage output source (VO). Among them, the switch tube 3 is a P-type MOS tube Q2. The capacitor 2 is C1.

[0032] In this embodiment, the transmitting tube driving circuit 6 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R6 and a second triode Q3; one end of the seventh resistor R7 is electrically connected to the circuit enable terminal (EN), and the other end of the seventh resistor R7 is electrically connected to one end of the eighth resistor R8 and the base of the second triode Q3 respectively; the emitter of the second triode Q3 is electrically connected to one end of the ninth resistor R6, the other end of the ninth resistor R6 and the other end of the eighth resistor R8 are both grounded, and the collector of the second triode Q3 is electrically connected to the negative electrode of the transmitting tube 5. Among them, the transmitting tube 5 is a light emitting diode LED1.

[0033] The fire detector transmitting tube voltage-doubling driving circuit of this embodiment is designed to be a transmitting tube 5-fold voltage-doubling driving circuit with good driving effect and electromagnetic compatibility based on the principle that the voltage at both ends of capacitor 2 cannot change suddenly when charging and discharging. The overall circuit design is simple, and there is no need to use large-volume devices such as inductors, filter capacitors and oscillation signal generators. It will not take up too much circuit board area and has low manufacturing cost.

[0034] Embodiment 2: The embodiment of the present application also provides a method for controlling a voltage-doubler driving circuit of a fire detector transmitting tube, which is applied to a photoelectric smoke fire detector. The photoelectric smoke fire detector includes the voltage-doubler driving circuit of the fire detector transmitting tube in the above embodiment 1. The method specifically includes the following steps:

[0035] Step 1: connect the photoelectric smoke detector to the battery 1, power it up and initialize it, and output a first fixed voltage to the capacitor 2 through the battery 1 to charge the capacitor 2;

[0036] Step 2: Control the switch tube driving circuit 4 to drive the switch tube 3 to output a second fixed voltage to the capacitor 2, and superimpose the first fixed voltage and the second fixed voltage through the capacitor 2 to form a double voltage;

[0037] Step three, control the capacitor 2 to discharge to the transmitting tube 5, and collect the voltage-doubled output signal of the capacitor 2. When the voltage-doubled output signal is stable, control the transmitting tube driving circuit 6 to work to light up the transmitting tube 5.

[0038] Among them, the photoelectric smoke fire detector is specifically an independent photoelectric smoke fire detector, which has the characteristics of high sensitivity, stability and reliability, low power consumption, beautiful appearance and durability, and easy use.

[0039] Figure 3 The specific control flow of the voltage doubling driving circuit of the fire detector transmitting tube is shown. The working principle and control flow of the specific implementation are described below in combination with the voltage doubling driving circuit of the fire detector transmitting tube in Example 1:

[0040] 1) The detector is connected to the battery and powered on. VIN is the battery voltage. The controlled signals Control and EN are initially low level when powered on. VO is the output voltage of C1.

[0041] 2) After power-on, VIN charges C1 through the first resistor R9 and forms a loop with the second resistor R5. The charging time constant of C1 is τ=(R5+R9)*C1, that is, after at least 3τ, VO≈VIN. The negative electrode of C1 is pulled down to the reference ground by the second resistor R5, and its voltage is 0, so the voltage drop across C1 is VIN, recorded as V1.

[0042] 3) When the detector needs to turn on LED1 for smoke detection, the Control signal is first set to a high level, the switch tube drive circuit 4 controls Q2 to turn on, the voltage drop of Q2 is close to 0, VIN is instantly connected to the negative pole of C1, and the voltage of the negative pole of C1 is VIN. According to the principle that the voltage across C1 cannot change suddenly, the positive pole voltage of C1 will also increase with the negative pole voltage, that is, VO=VIN+V1=2VIN. When the battery voltage VIN is 3V, VO=6V, which is greater than 5.5V, and can drive LED1 with a high conduction voltage drop.

[0043] 4) The function of the third resistor R1 and the fourth resistor R2 is to divide the control signal Control to limit the current, so that Q1 is in a saturated state, and the fifth resistor R4 is pulled down to the reference ground. The function of the fifth resistor R4 and the sixth resistor R3 is to divide the voltage of VIN and act on the gate of Q2 to control the Q2 switch. When Q1 is turned off, the gate of Q2 is VIN, and Q2 is not turned on; when Q1 is turned on, the gate voltage of Q2 VG=R4 / (R3+R4)*VIN, select the appropriate fifth resistor R4 and sixth resistor R3, so that the gate of Q2 is less than the turn-on voltage VGTH, and Q2 is turned on.

[0044] 5) By collecting the voltage of VO, it is determined that the VO voltage is stable, and the VO voltage is applied to the positive electrode of LED1. When smoke sampling is required, the EN signal is set to a high level, and the seventh resistor R7, the eighth resistor R8 and the ninth resistor R6 divide the voltage and limit the current, so that Q3 is turned on and in the amplification state, C1 discharges to LED1, and LED1 is turned on to emit light. At this time, the driving current of LED1 is estimated to be I=β(EN-0.6) / (R6+R7).

[0045] 6) After the smoke sampling is completed, the signal EN is set to a low level, LED1 is turned off, and C1 no longer discharges; then the signal Control is set to a low level, VIN charges C1 again, and the process of step 2) is repeated until the voltage difference across C1 returns to VIN, and this cycle is repeated.

[0046] The fire detector transmitting tube voltage doubling driving circuit of the present embodiment can drive a high conduction voltage drop transmitting tube, which is simpler than the traditional DC chopper boost circuit, has fewer components, and lower cost, and does not require the use of large-volume components such as inductors, filter capacitors, and oscillation signal generators. In addition, the fire detector transmitting tube voltage doubling driving circuit of the present embodiment does not require the use of an oscillation circuit, and has better electromagnetic compatibility than the traditional DC chopper boost circuit. Combined with the control method of the fire detector transmitting tube voltage doubling driving circuit, the core component capacitor can work continuously, and the voltage is doubled only when the voltage is required to be boosted. Compared with the traditional boost circuit, the stabilization rate is fast, the power consumption is small, and the energy consumption ratio is high, which effectively solves the problems of high electronic cost, complex circuit, high power consumption, large electromagnetic interference, and difficult maintenance caused by the existing photoelectric smoke fire detector using a switching DC boost circuit to drive a high conduction voltage drop transmitting tube.

[0047] It should be understood that ordinary technical workers in the field can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A fire detector transmitting tube voltage doubling driving circuit, characterized in that: It includes a battery, a capacitor, a switch tube, a switch tube driving circuit, a transmitting tube and a transmitting tube driving circuit; the battery is electrically connected to the capacitor, the capacitor is also electrically connected to the switch tube and the transmitting tube respectively, the switch tube is also electrically connected to the switch tube driving circuit, and the transmitting tube is also electrically connected to the transmitting tube driving circuit; the battery outputs a first fixed voltage to the capacitor, and the switch tube driving circuit drives the switch tube to output a second fixed voltage to the capacitor; the first fixed voltage and the second fixed voltage are the same; the capacitor superimposes the first fixed voltage and the second fixed voltage to form a double voltage to discharge to the transmitting tube, and drives the transmitting tube to turn on through the transmitting tube driving circuit.

2. The fire detector transmitting tube voltage doubling driving circuit according to claim 1, characterized in that: A first resistor is electrically connected between the battery and the capacitor, and the capacitor is also electrically connected to a second resistor. The battery charges the capacitor through the first resistor and forms a loop with the second resistor.

3. The fire detector transmitting tube voltage doubling driving circuit according to claim 2 is characterized in that: One end of the first resistor is electrically connected to the battery, and the other end of the first resistor is electrically connected to the positive electrode of the capacitor, and the positive electrode of the capacitor is also electrically connected to the positive electrode of the transmitting tube; one end of the second resistor is electrically connected to the negative electrode of the capacitor, and the other end of the second resistor is grounded.

4. The fire detector transmitting tube voltage doubling driving circuit according to claim 3 is characterized in that: The switch tube driving circuit includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a first transistor; one end of the third resistor is electrically connected to the circuit control end, the other end of the third resistor is electrically connected to one end of the fourth resistor and the base of the first transistor respectively, and the other end of the fourth resistor and the emitter of the first transistor are both grounded; the collector of the first transistor is electrically connected to one end of the fifth resistor, the other end of the fifth resistor is electrically connected to one end of the sixth resistor and the gate of the switch tube respectively, the other end of the sixth resistor and the source of the switch tube are both electrically connected to the voltage input source, and the drain of the switch tube is electrically connected to the negative electrode of the capacitor; the positive electrode of the capacitor is also electrically connected to the voltage output source.

5. The fire detector transmitting tube voltage doubling driving circuit according to claim 3, characterized in that: The transmitting tube driving circuit includes a seventh resistor, an eighth resistor, a ninth resistor and a second triode; one end of the seventh resistor is electrically connected to the circuit enable end, and the other end of the seventh resistor is electrically connected to one end of the eighth resistor and the base of the second triode respectively; the emitter of the second triode is electrically connected to one end of the ninth resistor, the other end of the ninth resistor and the other end of the eighth resistor are both grounded, and the collector of the second triode is electrically connected to the negative electrode of the transmitting tube.

6. The fire detector transmitting tube voltage doubling driving circuit according to any one of claims 1 to 5, characterized in that: The switch tube is a P-type MOS tube.

7. The fire detector transmitting tube voltage doubling driving circuit according to any one of claims 1 to 5, characterized in that: The transmitting tube is a light emitting diode.

8. A control method for a voltage-doubling driving circuit of a fire detector transmitting tube, applied to a photoelectric smoke fire detector, characterized in that: The photoelectric smoke fire detector comprises a fire detector transmitting tube voltage doubling driving circuit as claimed in any one of claims 1 to 7, and the method comprises the following steps: Step 1: connect the photoelectric smoke detector to a battery, power it up and initialize it, and output a first fixed voltage to the capacitor through the battery to charge the capacitor; Step 2: Control the switch tube driving circuit to drive the switch tube to output a second fixed voltage to the capacitor, and superimpose the first fixed voltage and the second fixed voltage through the capacitor to form a double voltage; Step three, control the capacitor to discharge to the transmitting tube, and collect the voltage doubler output signal of the capacitor, and when the voltage doubler output signal is stable, control the transmitting tube drive circuit to work to light up the transmitting tube.

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