High-voltage generating circuit of ultraviolet tube for flame detection

Abstract

The utility model relates to the technical field of electronic circuits, in particular to a high-voltage generating circuit of an ultraviolet tube for flame detection, which comprises an input module, an output module, an energy conversion and storage module and a control module. The control module is connected with the energy conversion and storage module, and the control module adjusts the voltage output from the input module to the output module through the energy conversion and storage module; the energy conversion and storage module comprises a transformer, a switch element and a voltage stabilizing circuit, the transformer is respectively connected with the switch element and the voltage stabilizing circuit, and the input module is connected with the output module through the transformer and the voltage stabilizing circuit in sequence; the control module is connected with the transformer through the switch element. According to the utility model, the technical problems of insufficient control stability and accuracy of the high-voltage generating circuit in the design and application of the flame detector are solved, and the stable and reliable work of subsequent sensing elements is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a high-voltage generating circuit of an ultraviolet tube for flame detection. Background Art

[0002] The high-voltage generating circuit plays a vital role in the red and ultraviolet flame detector. This circuit is generally integrated on the internal circuit board of the detector. Its main task is to generate and stably maintain the high-voltage output to effectively drive the key sensing elements in the detector (such as the ultraviolet phototube), thereby achieving efficient and accurate flame detection.

[0003] Traditional high-voltage generation circuits primarily consist of an input module, a step-up transformer, an energy storage capacitor, and an output module. The input module receives and transmits low-voltage power to the step-up transformer, which converts the input low voltage to a preset high voltage based on electromagnetic induction. This high voltage is then transmitted to the energy storage capacitor, which begins charging. When a sensor element, such as a UV phototube, needs to be activated to detect a flame, the high-voltage generation circuit controls the energy storage capacitor to release its stored high-voltage energy into the sensor element. This ensures that the sensor element can quickly and reliably perform flame detection tasks efficiently at critical moments, enabling sensitive perception and timely response to the presence of a flame.

[0004] The design of traditional high-voltage generating circuits is often based on a relatively simplified circuit structure and preset fixed control parameters to achieve the boost function. However, when faced with a complex and changeable flame detection environment, the accuracy and stability of its output voltage and current are relatively insufficient. It may be difficult to provide stable and reliable signal input for the sensor elements in the subsequent circuit, thereby affecting the accuracy and reliability of the flame detection results. In addition, traditional high-voltage generating circuits have obvious shortcomings in protection mechanisms and lack necessary protection measures such as overvoltage and overcurrent. Once an abnormal situation occurs, the circuit and equipment are easily damaged, which poses a threat to the reliability and safety of the entire system.

[0005] Therefore, in the application of flame detectors, how to solve the problem of insufficient control stability and accuracy of high-voltage generation circuits is of great significance. Utility Model Content

[0006] The purpose of this application is to provide a high-voltage generating circuit for an ultraviolet tube for flame detection, which solves the technical problems of insufficient control stability and accuracy of the high-voltage generating circuit in the design and application of flame detectors, and ensures that subsequent sensing elements work stably and reliably.

[0007] In order to solve the above technical problems, the solution adopted by this application is as follows:

[0008] The utility model provides a high-voltage generating circuit for an ultraviolet tube for flame detection, comprising an input module, an output module, and an energy conversion and storage module, wherein the input module is connected to the output module via the energy conversion and storage module; and is characterized in that the utility model further comprises a control module, wherein the control module is connected to the energy conversion and storage module, and the control module adjusts the voltage output from the input module to the output module via the energy conversion and storage module.

[0009] In some embodiments, the control module includes a signal generating module and a peripheral circuit, the peripheral circuit is connected to the signal generating module, the output end of the signal generating module is connected to the energy conversion and storage module; the output module is connected to the signal generating module through the peripheral circuit.

[0010] In some embodiments, the peripheral circuit includes a slope compensation circuit, which includes a transistor and a resistor; the base, emitter, and collector of the transistor are respectively connected to different pins of the signal generating module; the base of the transistor is also connected to the emitter of the transistor through a resistor, and the connection is grounded; the energy conversion and storage module is connected to the collector of the transistor through a resistor.

[0011] In some embodiments, the signal generating module is a PWM controller.

[0012] In some embodiments, the energy conversion and storage module includes a transformer, a switching element, and a voltage stabilizing circuit. The transformer is connected to the switching element and the voltage stabilizing circuit respectively. The input module is connected to the output module in turn through the transformer and the voltage stabilizing circuit; the control module is connected to the transformer through the switching element.

[0013] In some embodiments, the voltage stabilizing circuit includes a diode and a capacitor, and one end of the secondary coil of the transformer is connected to the other end of the secondary coil of the transformer through the diode and the capacitor in sequence to form a closed loop; an output end is set at the connection between the diode and the capacitor, and this output end is connected to the output module; the connection between the secondary coil and the capacitor is grounded.

[0014] In some embodiments, the input module is grounded through the primary coil of the transformer and the switching element in sequence.

[0015] In some embodiments, the input module includes a peak absorption circuit, which includes a resistor, a capacitor, and a diode. One end of the resistor and capacitor in parallel is connected in series with the cathode of the diode, and the other end of the resistor and capacitor in parallel and the anode of the diode are respectively connected to one end of the primary coil of the transformer and the other end of the primary coil of the transformer.

[0016] In some embodiments, the switching element is a field effect transistor.

[0017] In some embodiments, the output module includes a voltage feedback sampling circuit, which includes a diode and a resistor. The diode and the resistor are connected in parallel, the anode of the diode is grounded, and the cathode of the diode is connected to the control module.

[0018] The technical solution of this application has at least the following advantages and beneficial effects:

[0019] 1. This utility model uses a signal generation module to send PWM signals to control the on and off time of the switching element. This not only ensures precise control of the energy storage and release process within the transformer, but also effectively suppresses noise interference, reduces voltage fluctuations, and achieves precise fine-tuning of the output voltage, thereby significantly improving the accuracy and reliability of flame detection.

[0020] 2. The signal generating module in the present invention is closely connected to the peripheral circuit. The peripheral circuit not only provides reliable operating conditions for the signal generating module and ensures the stable operation of the signal generating module, but also can dynamically adjust the control parameters according to the real-time voltage feedback of the output module and the energy conversion and storage module, so as to further optimize energy consumption and ensure accurate and correct adjustment of the output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the overall circuit diagram of the utility model. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not require further definition or explanation in subsequent figures. Terms such as "center," "upper," "lower," "inner," and "outer" indicate positions or locations based on the positions or locations shown in the figures, or the positions or locations in which the product is typically placed when in use. These terms are used solely for ease of description and simplification of the present application. They do not indicate or imply that the device or component referred to must have a specific position, be constructed, or operate in a specific orientation, and are not to be construed as limiting the present application. It should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "mounted," and "connected" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct connections or indirect connections through an intermediary; or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this application in specific contexts.

[0024] Example 1

[0025] Please refer to Figure 1 The utility model provides a high-voltage generating circuit for an ultraviolet tube for flame detection, which is the same as the prior art and includes an input module, an output module, and an energy conversion and storage module. The input module is connected to the output module through the energy conversion and storage module.

[0026] The energy conversion and storage module includes a transformer and a voltage stabilizing circuit. The primary coil of the transformer is connected to the input module, and the secondary coil of the transformer is connected to the output module through the voltage stabilizing circuit. The transformer converts the received low-voltage power into high-voltage electrical energy. The voltage stabilizing circuit stores the converted high-voltage electrical energy and outputs the high-voltage electrical energy to the output module.

[0027] The voltage stabilizing circuit includes a diode and a capacitor. One end of the secondary coil of the transformer is connected to the other end of the secondary coil of the transformer through a diode and a capacitor in sequence to form a closed loop. An output end is set at the connection between the diode and the capacitor, and this output end is connected to the output module. The connection between the secondary coil and the capacitor is grounded.

[0028] In the present invention, the energy storage and conversion module further includes a switching element, and the input module is connected to ground in sequence through the primary coil of the transformer and the switching element;

[0029] It should be noted that, in this embodiment, the switching element is a field effect transistor.

[0030] It should be noted that the energy storage and conversion module further includes a current sampling resistor, and the switch element is grounded via the current sampling resistor.

[0031] The input module is used to receive external low-voltage power and transmit the low-voltage power to the energy conversion and storage module;

[0032] In this embodiment, the input module includes a spike absorption circuit to suppress the spike voltage generated by the transformer leakage inductance when the switching element is turned off. The spike absorption circuit includes a resistor, a capacitor, and a diode. One end of the resistor and capacitor connected in parallel is connected in series with the cathode of the diode. The other end of the resistor and capacitor connected in parallel and the anode of the diode are connected to one end of the transformer's primary coil and the other end of the transformer's primary coil, respectively.

[0033] The output module is used to transmit the received high-voltage electrical energy to the external load.

[0034] Different from the prior art, the invention further comprises a control module, which is connected to the energy conversion and storage module, and the control module adjusts the voltage output from the input module to the output module through the energy conversion and storage module;

[0035] It should be explained that the control module is connected to the transformer through the switching element to control the transformer to perform the power conversion task.

[0036] The control module includes a signal generating module and a peripheral circuit. The peripheral circuit is connected to the signal generating module. The output end of the signal generating module is connected to the energy conversion and storage module. The output module is connected to the signal generating module through the peripheral circuit.

[0037] The peripheral circuit includes a slope compensation circuit, which is used to suppress subharmonic oscillations in the current control mode. The slope compensation circuit includes a transistor and a resistor. The base, emitter, and collector of the transistor are respectively connected to different pins of the signal generation module. The base of the transistor is also connected to the emitter of the transistor through a resistor, and the connection is grounded. The energy conversion and storage module is connected to the collector of the transistor through a resistor.

[0038] Specifically, the connection point between the field effect tube and the current sampling resistor is connected to the collector of the transistor through the resistor.

[0039] It should be noted that the current sampling resistor provides a real-time feedback voltage, and the control module performs overcurrent protection based on the feedback voltage, thereby ensuring the safe and stable operation of the control module.

[0040] The peripheral circuit also includes a feedback loop compensation network and a filter circuit, and the feedback loop compensation network and the filter circuit are respectively connected to different pins of the signal generation module;

[0041] The feedback loop compensation network is used to enhance the stability of the signal generation module, reduce overshoot and oscillation, and improve the dynamic response speed of the signal generation module. The filter circuit is used to filter out the spike voltage generated on the current sampling resistor when the switching element is turned on, ensuring that the signal generation module does not accidentally enter the overcurrent protection mode due to false triggering.

[0042] It should be noted that the filter circuit is an RC filter circuit.

[0043] It should be noted that in this embodiment, the output module includes a voltage feedback sampling circuit, which is used to feed the resulting signal back to the signal generation module, thereby controlling the PWM duty cycle output by the signal generation module and implementing closed-loop control to achieve voltage stabilization. The voltage feedback sampling circuit includes a diode and a resistor connected in parallel, with the anode of the diode grounded and the cathode of the diode connected to the control module.

[0044] In this embodiment, the signal generating module is a PWM controller.

[0045] Furthermore, the high voltage generating circuit includes a PWM controller U1, a transistor Q1, diodes D1, D2, D3, D4, and D5, a field effect transistor Q2, a transformer T1, a polarized capacitor C4, ordinary capacitors C1, C2, C3, C5, C6, C7, C8, C9, C10, and C11, and resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, and R19;

[0046] It should be noted that the spike absorption circuit includes resistor R5, capacitor C8, and diode D2; the slope compensation circuit includes transistor Q1, resistors R1 and R2; the voltage feedback sampling circuit includes resistors R15, R16, R17, R18, R19, and diode D5; the feedback loop compensation network includes resistors R3 and R4, and capacitor C3; the filter circuit includes resistor R11 and capacitor C7; and the current sampling resistor includes resistors R9 and R10.

[0047] It should be explained that, in this embodiment, the model of the PWM controller U1 is UC2843BD1; the field effect tube Q2 is an NMOS tube, and its model is HSU18N20; the transistor Q1 is an NPN type, and its model is S8050;

[0048] Specifically, the negative electrode of the polar capacitor C4 is grounded, the positive electrode of the polar capacitor C4 is connected to the positive electrode of the diode D1 and is connected to the low-voltage power supply here; the negative electrode of the diode D1, one end of the resistor R5, one end of the ordinary capacitor C8, and pin 2 of the transformer T1 are connected, the other end of the resistor R5, the other end of the ordinary capacitor C8, and the negative electrode of the diode D2 are connected, the positive electrode of the diode D2, the pin 3 of the transformer T1, and the drain of the field-effect transistor Q2 are connected, the source of the field-effect transistor Q2, one end of the resistor R9, one end of the resistor R10, and one end of the resistor R11 are connected, the other end of the resistor R9, the other end of the resistor R10, one end of the ordinary capacitor C7, and one end of the resistor R8 are connected. , pin 5 of the PWM controller U1 and grounded; the other end of resistor R8, the gate of the field effect tube Q2, one end of resistor R7, and the anode of diode D4 are connected, the cathode of diode D4, the other end of resistor R7, and one end of resistor R6 are connected, and the other end of resistor R6 is connected to pin 6 of the PWM controller U1; pin 7 of the PWM controller U1, one end of ordinary capacitor C5, and one end of ordinary capacitor C6 are connected and connected to a low-voltage power supply; the other end of ordinary capacitor C5 and the other end of ordinary capacitor C6 are connected and grounded; the other end of resistor R11, the other end of ordinary capacitor C7, one end of resistor R1, and pin 3 of the PWM controller U1 are connected. The other end of the resistor R1 is connected to the collector of the transistor Q1, the base of the transistor Q1, one end of the resistor R2, pin 4 of the PWM controller U1, and one end of the ordinary capacitor C2 are connected, and the other end of the ordinary capacitor C2 is grounded; the other end of the resistor R2, the emitter of the transistor Q1, one end of the ordinary capacitor C1, and pin 8 of the PWM controller U1 are connected, and the other end of the ordinary capacitor C1 is grounded; pin 1 of the PWM controller U1, one end of the resistor R3, and one end of the ordinary capacitor C3 are connected, the other end of the ordinary capacitor C3, the other end of the resistor R3, pin 2 of the PWM controller U1, and one end of the resistor R4 are connected; the other end of the resistor R4, The cathode of diode D5, one end of resistor R19, and one end of resistor R18 are connected. The other end of resistor R19 is connected to the anode of diode D5 and grounded. The other end of resistor R18 is connected to one end of resistor R17, the other end of resistor R17 is connected to one end of resistor R16, the other end of resistor R16 is connected to one end of resistor R15. The other end of resistor R15, one end of common capacitor C9, one end of common capacitor C10, one end of common capacitor C11, and the cathode of diode D3 are connected, and the VHI output terminal is provided there. The other end of common capacitor C10, the other end of common capacitor C11, and pin 5 of transformer T1 are connected and grounded.Pin 8 of transformer T1, one end of resistor R13, and the anode of diode D3 are connected. The other end of resistor R13 is connected to one end of resistor R14. The other end of resistor R14 is connected to one end of resistor R12. The other end of resistor R12 is connected to the other end of common capacitor C9.

[0049] It should be noted that, in this embodiment, the low-voltage power supply is a positive 12V power supply; the high-voltage electric energy converted by the utility model ranges from DC325V to DC490V, the purpose of which is to provide a stable operating voltage for the sensor elements in the subsequent circuit.

[0050] It should be noted that, in this embodiment, the diode D4 is a Schottky diode, and its model is 1N5819WS; the diode D5 is a Zener diode, and its model is MMSZ5222BT1G.

[0051] The utility model adopts a flyback topology, and its working principle is:

[0052] After the circuit is powered on, pin 6 of the PWM controller U1 outputs a PWM signal with a certain frequency and duty cycle to drive the field effect transistor Q1;

[0053] When the FET is turned on, the input module transmits a positive 12V DC voltage to the primary coil of transformer T1. At this time, the primary coil of transformer T1 acts as an inductor, and energy is stored in it in the form of magnetic energy. The primary coil is positive at the top and negative at the bottom, and the secondary coil is negative at the top and positive at the bottom. The diode D3 in the storage circuit is cut off, and capacitors C10 and C11 both supply power to the load.

[0054] When the switching element is turned off, magnetic energy is transferred from the primary coil of transformer T1 to the secondary coil. The primary coil is negative at the top and positive at the bottom, and the secondary coil is positive at the top and negative at the bottom. Diode D3 is turned on, charging capacitors C10 and C11 while supplying power to the load.

[0055] Thus far, various embodiments of the present invention have been described in detail. To avoid obscuring the concept of the present invention, some details known in the art have been omitted. Based on the above description, those skilled in the art will fully understand how to implement the technical solutions of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A high-voltage generating circuit for an ultraviolet tube for flame detection, comprising an input module, an output module, and an energy conversion and storage module, wherein the input module is connected to the output module via the energy conversion and storage module; characterized in that: It also includes a control module, which is connected to the energy conversion and storage module. The control module adjusts the voltage output from the input module to the output module through the energy conversion and storage module.

2. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 1, characterized in that: The control module includes a signal generating module and a peripheral circuit. The peripheral circuit is connected to the signal generating module. The output end of the signal generating module is connected to the energy conversion and storage module. The output module is connected to the signal generating module through the peripheral circuit.

3. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 2, characterized in that: The peripheral circuit includes a slope compensation circuit, which includes a transistor and a resistor; the base, emitter, and collector of the transistor are respectively connected to different pins of the signal generating module; the base of the transistor is also connected to the emitter of the transistor through a resistor, and the connection is grounded; the energy conversion and storage module is connected to the collector of the transistor through a resistor.

4. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 3, characterized in that: The signal generating module is a PWM controller.

5. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 1, characterized in that: The energy conversion and storage module includes a transformer, a switching element, and a voltage stabilizing circuit. The transformer is connected to the switching element and the voltage stabilizing circuit respectively. The input module is connected to the output module through the transformer and the voltage stabilizing circuit in turn; the control module is connected to the transformer through the switching element.

6. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 5, characterized in that: The voltage stabilizing circuit includes a diode and a capacitor. One end of the secondary coil of the transformer is connected to the other end of the secondary coil of the transformer through the diode and the capacitor in sequence to form a closed loop. An output end is set at the connection between the diode and the capacitor, and this output end is connected to the output module. The connection between the secondary coil and the capacitor is grounded.

7. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 5, characterized in that: The input module is grounded through the primary coil of the transformer and the switch element in sequence.

8. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 7, characterized in that: The input module includes a peak absorption circuit, which includes a resistor, a capacitor, and a diode. One end of the resistor and capacitor connected in parallel is connected in series with the cathode of the diode, and the other end of the resistor and capacitor connected in parallel and the anode of the diode are respectively connected to one end of the primary coil of the transformer and the other end of the primary coil of the transformer.

9. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 7, characterized in that: The switching element is a field effect tube.

10. The high voltage generating circuit of the ultraviolet tube for flame detection according to claim 1, characterized in that: The output module includes a voltage feedback sampling circuit, which includes a diode and a resistor. The diode and the resistor are connected in parallel, the anode of the diode is grounded, and the cathode of the diode is connected to the control module.

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