CN220087520U

CN220087520U - Ultraviolet lamp tube driving circuit

Info

Publication number: CN220087520U
Application number: CN202321064718.8U
Authority: CN
Inventors: 王文迪; 邓剑峰; 钟泽强; 李海峰; 陈磊
Original assignee: Foshan Comwin Light & Electricity Co ltd
Current assignee: Foshan Comwin Light & Electricity Co ltd
Priority date: 2023-05-05
Filing date: 2023-05-05
Publication date: 2023-11-24
Anticipated expiration: 2033-05-05

Abstract

The utility model discloses an ultraviolet lamp tube driving circuit which comprises a filtering boosting module, an MCU main control module, a CLASS-D half-bridge module and a half-bridge driving control module; the filtering boosting module is electrically connected with the CLASS-D half-bridge module and the MCU main control module; the filtering boosting module is used for providing power for the CLASS-D half-bridge module; the filtering boosting module is used for transmitting sampling signals to the MCU main control module; the half-bridge driving control module is electrically connected with the MCU main control module and the CLASS-D half-bridge module; the CLASS-D half-bridge module is electrically connected with the MCU main control module; the utility model aims to provide an ultraviolet lamp tube driving circuit, which can avoid the load calculation required by the built-in operational amplifier of an L6574 driving IC chip by matching a CLASS-D half-bridge module with a half-bridge driving control module, has more visual and easier control effect on adjusting working power, and simultaneously increases the function of adjusting preheating current.

Description

Ultraviolet lamp tube driving circuit

Technical Field

The utility model relates to the technical field of lamp tube driving, in particular to an ultraviolet lamp tube driving circuit.

Background

With the rapid development of lighting engineering, general lighting has transitioned from the discharge lamp age to the LED solid-state lighting age, resulting in a full industry chain being inclined toward the LED industry chain. However, in some special fields, such as the field of UV ultraviolet lamps, the conventional electronic ballast is still required to be lighted in a matched manner, but because the whole industry chain tends to change in the LED industry chain, the special chip of the electronic ballast is almost stopped, and if the special chip of the electronic ballast is not used or the simplified electronic ballast chip is used, a preheating starting process cannot be realized for the UV ultraviolet lamp electronic ballast, and therefore, proper preheating time, preheating frequency and working frequency cannot be provided for the ultraviolet lamp ballast.

Disclosure of Invention

The utility model aims to provide an ultraviolet lamp tube driving circuit, which is matched with a CLASS-D half-bridge module and a half-bridge driving control module, so that load calculation required by built-in operational amplifier of an L6574 driving IC chip can be avoided in a circuit formed by the L6574 driving IC chip, the effect of more intuitively and easily controlling the adjusting working power is achieved, and meanwhile, the function of adjusting preheating current is added.

To achieve the purpose, the utility model adopts the following technical scheme: an ultraviolet lamp tube driving circuit comprises a filtering boosting module, an MCU main control module, a CLASS-D half-bridge module and a half-bridge driving control module;

the filtering boosting module is electrically connected with the CLASS-D half-bridge module and the MCU main control module;

the filtering boosting module is used for providing power for the CLASS-D half-bridge module and the MCU main control module;

the filtering boosting module is used for transmitting sampling signals to the MCU main control module;

the half-bridge driving control module is electrically connected with the MCU main control module and the CLASS-D half-bridge module, and is used for receiving a half-bridge driving signal of the MCU main control module and sending a half-bridge control signal to the CLASS-D half-bridge module, and the half-bridge control signal drives the CLASS-D half-bridge module to work or cut off;

the CLASS-D half-bridge module is electrically connected with the MCU main control module and is used for receiving lamp tube control signals sent by the MCU main control module, and the lamp tube control signals drive the lamp tubes to work or cut off.

Preferably, the half-bridge driving control module comprises a discharging sub-circuit and a driving chip, wherein the input end of the discharging sub-circuit is electrically connected with the MCU main control module, the output end of the discharging sub-circuit is electrically connected with the driving chip, and the driving chip is electrically connected with the CLASS-D half-bridge module; the discharging sub-circuit is used for receiving the PWM signal sent by the MCU main control module, and changing the current transmitted to the driving chip according to the PWM signal, so that the output frequency of the driving chip is changed, and the output frequency of the driving chip controls the working current of the CLASS-D half-bridge module.

Preferably, the half-bridge driving control module further comprises a preheating sub-circuit, wherein the input end of the preheating sub-circuit is electrically connected with the MCU main control module, and the output end of the preheating sub-circuit is electrically connected with the driving chip.

Preferably, the system further comprises a sampling protection module, wherein the sampling protection module is electrically connected with the CLASS-D half-bridge module and is used for collecting lamp voltage sampling signals and steady-state working lamp current sampling signals;

the sampling protection module is electrically connected with the MCU main control module and is used for receiving the detection discharge control signal sent by the MCU main control module and sending an A/D detection signal to the MCU main control module.

Preferably, the sampling protection module comprises a voltage half-wave precision rectifier circuit, a voltage full-wave precision rectifier circuit, a voltage infinite gain multipath feedback low-pass filter sub-circuit, a voltage control voltage source second-order low-pass filter sub-circuit and a lamp peak voltage overvoltage protection sub-circuit;

the voltage half-wave precise rectifier circuit is electrically connected with the voltage full-wave precise rectifier circuit and the voltage infinite gain multipath feedback low-pass filter sub-circuit, the voltage full-wave precise rectifier circuit is electrically connected with the lamp peak voltage overvoltage protection sub-circuit, the lamp peak voltage overvoltage protection sub-circuit is electrically connected with the MCU main control module, the voltage infinite gain multipath feedback low-pass filter sub-circuit is electrically connected with the MCU main control module, and the voltage control voltage source second-order low-pass filter sub-circuit is electrically connected with the MCU main control module.

Preferably, the sampling protection module further comprises a current half-wave precision rectifier circuit, a current full-wave precision rectifier circuit, a current infinite gain multipath feedback low-pass filter sub-circuit and a current voltage-controlled voltage source second-order low-pass filter sub-circuit;

the current half-wave precise rectifier circuit is electrically connected with the current full-wave precise rectifier circuit and the current infinite gain multipath feedback low-pass filter sub-circuit, the current full-wave precise rectifier circuit is electrically connected with the lamp peak current overvoltage protection sub-circuit, the lamp peak current overvoltage protection sub-circuit is electrically connected with the MCU main control module, the current infinite gain multipath feedback low-pass filter sub-circuit is electrically connected with the MCU main control module, and the current voltage-controlled voltage source second-order low-pass filter sub-circuit is electrically connected with the MCU main control module.

Preferably, the power supply further comprises a single-ended flyback switching power supply module, wherein the single-ended flyback switching power supply module is electrically connected with the filtering boosting module, and the filtering boosting module provides power for the single-ended flyback switching power supply module; the single-ended flyback switching power supply module is used for providing positive 5V voltage, positive 15V voltage and negative 15V voltage to supply power for the circuit element.

Preferably, the system further comprises a boost control module, wherein the boost control module is electrically connected with the MCU main control module and the filtering boost module;

the boost control module is used for receiving a switch control signal from the MCU main control module, receiving a sampling signal of the filtering boost module, and sending a boost control signal, wherein the boost control signal drives the filtering boost module to work or cut off.

The technical scheme of the utility model has the beneficial effects that: through the cooperation of the CLASS-D half-bridge module and the half-bridge drive control module, load calculation required by the built-in operational amplifier of the L6574 drive IC chip can be avoided in a circuit formed by the L6574 drive IC chip, the effect of more intuitively and easily controlling the adjustment of working power is achieved, and meanwhile, the function of adjusting the preheating current is added.

Drawings

FIG. 1 is a schematic diagram of a circuit connection of one embodiment of the present utility model;

FIG. 2 is a schematic circuit diagram of a filter boost module according to one embodiment of the present utility model;

FIG. 3 is a schematic circuit diagram of an MCU master control module according to an embodiment of the utility model;

FIG. 4 is a schematic circuit diagram of a CLASS-D half-bridge module according to one embodiment of the utility model;

FIG. 5 is a schematic circuit diagram of a half-bridge drive control module according to one embodiment of the utility model;

FIG. 6 is one of the circuit schematic diagrams of the sample protection module of one embodiment of the present utility model;

FIG. 7 is a second schematic circuit diagram of a sample protection module according to an embodiment of the present utility model;

FIG. 8 is a schematic circuit diagram of a single-ended flyback switching power supply module according to one embodiment of the present utility model;

fig. 9 is a schematic circuit diagram of a boost control module in accordance with one embodiment of the present utility model.

Wherein: the device comprises a filtering boosting module 1, an MCU main control module 2, a CLASS-D half-bridge module 3, a half-bridge driving control module 4, a sampling protection module 5, a single-ended flyback switching power supply module 6 and a boosting control module 7.

Detailed Description

The technical scheme of the utility model is further described below by the specific embodiments with reference to the accompanying drawings.

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

Referring to fig. 1 to 9, an ultraviolet lamp tube driving circuit includes a filtering boosting module 1, an MCU main control module 2, a CLASS-D half-bridge module 3 and a half-bridge driving control module 4;

the filtering boosting module 1 is electrically connected with the CLASS-D half-bridge module 3 and the MCU main control module 2;

the filtering boosting module 1 is used for providing power for the CLASS-D half-bridge module 3 and the MCU main control module 2;

the filtering boosting module 1 is used for transmitting sampling signals to the MCU main control module 2;

the half-bridge driving control module 4 is electrically connected with the MCU main control module 2 and the CLASS-D half-bridge module 3, and the half-bridge driving control module 4 is used for receiving a half-bridge driving signal of the MCU main control module 2 and sending a half-bridge control signal to the CLASS-D half-bridge module 3, wherein the half-bridge control signal drives the CLASS-D half-bridge module 3 to work or cut off;

the CLASS-D half-bridge module 3 is electrically connected with the MCU main control module 2, and the CLASS-D half-bridge module 3 is used for receiving a lamp control signal sent by the MCU main control module 2, and the lamp control signal drives a lamp to work or cut off.

The utility model relates to an ultraviolet lamp tube driving circuit, which adopts a CLASS-D half-bridge structure, wherein the control of the circuit takes an L6574 or IR2166 driving IC chip as a core, the L6574 driving IC chip and the IR2166 driving IC chip are driving ICs commonly adopted on current ballasts, and the driving ICs refer to a main control IC used in a lamp tube driving control circuit, and the main function of the driving IC is to output PWM voltage required by MOS conduction. The lighting of the ultraviolet lamp comprises preheating, ignition and operation, and the adjustment of the power of the ultraviolet lamp tube is completed in operation.

According to the utility model, the CLASS-D half-bridge module 3 is matched with the half-bridge drive control module 4, so that load calculation required by built-in operational amplifier of the L6574 drive IC chip can be avoided in a circuit formed by the L6574 drive IC chip, the effect of more intuitively and easily controlling the adjustment of working power is achieved, and meanwhile, the function of adjusting the preheating current is added. For the circuit formed by using the IR2166 drive IC chip, the capability of adjusting the preheating circuit and the working current is increased.

The ultraviolet lamp tube driving circuit is a part of a ballast and specifically refers to a circuit part for converting bus voltage into alternating voltage to drive a lighting lamp tube.

The filtering boost module 1 is used for filtering to inhibit current mutation and filtering current clutter, and the boost circuit boosts the input voltage to the bus voltage required by the lamp tube driving circuit. The filtering boosting module 1 is used for boosting the direct current voltage input in the direct current range of 50V-120V to 200V or 300V for the following CLASS-D half-bridge module 3, and the NTC100 is used for monitoring the temperature of the magnetic ring and MOS. The filtering boosting module 1 is provided with voltage sampling and current sampling, and double-loop control is realized.

The CLASS-D half-bridge module 3 is used as a driving circuit for the lamp. The CLASS-D half-bridge module 3 finishes operations such as preheating, ignition, running and the like by inputting power into the ultraviolet lamp tube. The capacitor CpA and the capacitor Cp are resonance capacitors and provide voltage required by lamp tube breakdown and current on the lamp filament, wherein the capacitor CpA is connected through a relay, the current of the lamp filament is increased during preheating, the voltage at two sides of the lamp tube is reduced to prevent glow, the consumed electronic powder is unfavorable for the service life of the lamp tube, the lamp tube is disconnected after being lighted, the current on the lamp filament is reduced, and the lamp filament is consumed unfavorable for the service life due to overlarge current of the lamp filament. The current transformer detects the current on the main loop, the preheating current filament current is the preheating current in the preheating process, and the lamp tube current plus the filament current is the running process. The lamp tube is provided with a resistor for sampling the voltage of the lamp tube.

The half-bridge driving control module 4 is used for controlling the CLASS-D half-bridge module 3 to provide complementary PWM waveforms required by alternate conduction of the half-bridge MOS transistors. The MCU master control module 2 is used for controlling the whole ballast. The half-bridge driving control module 4 outputs complementary PWM driving waveforms to control the high-low end MOS of the half bridge to be alternately conducted, preheating time is controlled through the capacitors C250, C250A and C250B, and the triode Q250 controls whether the capacitor C250A and the capacitor C250B are connected or not, so that preheating time is controlled. The capacitor C251 is an oscillating capacitor, the resistor R250 and the resistor R251 are preheating resistors, the resistor R252 and the resistor R253 are operating resistors, the preheating frequency is determined by the preheating resistors and the operating resistors together, and the operating frequency is determined by the operating resistors. The resistor R254, the resistor R254A and the diode D250 form a discharge circuit, and the other end may input a filtered PWM signal, or a level signal lower than 2V, and when the duty ratio of the PWM signal or the level signal is changed, the discharge current at the 4 pins of the driving IC chip may be changed, thereby changing the output frequency. When the duty ratio is smaller/the level signal is smaller, the discharge current is increased, the output frequency is increased, and the preheating current/the running current of the lamp tube are reduced; conversely, the duty ratio is increased/the level signal is increased, the discharge current is reduced, the output frequency is reduced, and the preheating current/the running current of the lamp tube are increased. The resistor R254 and the resistor R254A are current limiting resistors, and limit the discharge current, so as to control the output frequency variation range. The diode D250 functions to prevent the external signal current from flowing backward into the 4 pins of the driving IC chip to damage the chip. Isolation between the external signal and diode D250 is considered using optocouplers.

The MCU main control module 2 is used for detecting external signals and internal signals of the ballast, including lamp voltage and current, power input voltage, control relay to control the power supply of the half-bridge driving circuit and the protection circuit and the access of the resonance capacitor, whether the booster circuit works or not, and sending a blocking and restarting signal and a PWM dimming signal to the half-bridge driving control circuit.

The MCU master control module 2 comprises a CA51F252L2 singlechip chip, and the singlechip chip outputs signals to other circuits through program judgment after receiving external signals.

The four branches of the voltage stabilizing diodes Z410 to Z413 are used as ADC detection to detect the voltage and current of the lamp tube from the sampling circuit.

The voltage stabilizing tubes Z414-Z415 are used for detecting ADC and detecting voltage signals sampled by input voltage.

The branch where the resistor R422 is located is a button circuit, and after the button is pressed, the singlechip receives a low level to react, so that the capacitor C422 plays a role in filtering for the total working time recorded by the reset singlechip.

The branch where the resistor R423 is located is used for receiving the lamp tube signal short-circuit signal, the singlechip receives a low level to react, the ballast is turned off, and the capacitor C423 plays a role in filtering.

The two branches where the resistor R420 and the resistor R421 are located are used as input of a sampling circuit, when the sampling circuit detects abnormality, a low-level interrupt is generated when a signal is output to the sampling circuit, and the singlechip receives the low-level interrupt to react, so that the ballast is turned off.

The branch where the resistor R450 is positioned is a relay control circuit, and the relay is responsible for supplying power to the sampling circuit and the lamp tube driving control circuit.

DP400 is a dial switch, changing the working mode of the SCM.

CN400 is the program recording entry.

BOOST switch control refers to controlling the operation of the BOOST control circuit.

The branch where the resistor R430 is located sends out PWM signals, and after passing through the filter, the PWM signals are sent to the lamp tube driving control circuit to provide reference voltages required by power adjustment.

The control of the L6574 driving IC chip is used for sending out a signal to block or restart the lamp driving control circuit to work, the resistor R432 is used for blocking, and the resistor R434 is used for restarting.

And the running state LED is used for controlling the LED to be lightened according to the working state of the ballast and indicating the state of the ballast.

The branch where the resistor R448 is located is used as an optocoupler control circuit, when the fault occurs, the singlechip outputs a high level to enable the triode to be conducted, the primary side of the optocoupler flows current, and the secondary side is cut off to be in an on state.

Specifically, the half-bridge driving control module 4 includes a discharging sub-circuit and a driving chip, the input end of the discharging sub-circuit is electrically connected with the MCU main control module 2, the output end of the discharging sub-circuit is electrically connected with the driving chip, and the driving chip is electrically connected with the CLASS-D half-bridge module 3; the discharging sub-circuit is used for receiving the PWM signal sent by the MCU main control module 2, and changing the current transmitted to the driving chip according to the PWM signal, so that the output frequency of the driving chip is changed, and the output frequency of the driving chip controls the working current of the CLASS-D half-bridge module 3.

The existing ultraviolet lamp tube driving circuit adopts an integrated APFC driving and protecting circuit formed by IR2166 driving IC chips, and the circuit does not have a dimming function. Meanwhile, a circuit formed by an L6574 driving IC chip or an IR2166 driving IC chip does not have the function of adjusting the preheating current, but the preheating current greatly affects the service life of the ultraviolet lamp tube, the preheating current is different from the length of the lamp tube wiring due to the difference of components, the parameters of the components need to be manually modified to compensate due to the difference of the components, and the problem that the different lengths of the lamp tube wiring cannot be solved.

Therefore, a discharging circuit is added on the frequency control peripheral circuit of the driving chip, and the discharging circuit controls the discharging current in the driving IC chip, so that the output frequency of the driving IC chip is controlled, and the power of the ultraviolet lamp tube and the aim of preheating the ultraviolet lamp tube are adjusted through the CLASS-D half-bridge module 3.

Preferably, the half-bridge driving control module 4 further includes a preheating sub-circuit, an input end of the preheating sub-circuit is electrically connected with the MCU main control module 2, and an output end of the preheating sub-circuit is electrically connected with the driving chip.

When the ballast starts the ultraviolet lamp tube, the ultraviolet lamp tube is divided into quick start and preheating start, the preheating start has different time requirements, a general analog circuit can only select one starting mode, the preheating start can only select fixed time, and the existing circuit cannot adapt to the starting mode which needs to be used under special conditions.

The circuit for controlling the preheating time is matched with the triode Q250, the capacitor C250A and the capacitor C250B, and the quick start or the preheating start and the preheating time are controlled by controlling the on-off of the triode Q250.

The preheating sub-circuit is composed of a triode Q250, a capacitor C250A, a capacitor C250B, a resistor R257 and a capacitor C250, when no signal is sent to the base electrode of the triode Q250, the triode Q250 is cut off, only the capacitor C250 is connected with an L6574 driving IC chip, the total capacitance is low, and the preheating time is short; when a signal is sent to the base electrode of the triode Q250, the triode Q250 is conducted, the capacitor C250A and the capacitor C250B are connected to the L6574 driving IC chip, the total capacity of the capacitor is high, and the preheating time is long.

Specifically, the system further comprises a sampling protection module 5, wherein the sampling protection module 5 is electrically connected with the CLASS-D half-bridge module 3 and is used for collecting lamp voltage sampling signals and steady-state working lamp current sampling signals;

the sampling protection module 5 is electrically connected with the MCU main control module 2, and is used for receiving a detection discharge control signal sent by the MCU main control module 2 and sending an A/D detection signal to the MCU main control module 2.

Preferably, the sampling protection module 5 comprises a voltage half-wave precision rectifier circuit, a voltage full-wave precision rectifier circuit, a voltage infinite gain multipath feedback low-pass filter sub-circuit, a voltage-controlled voltage source second-order low-pass filter sub-circuit and a lamp peak voltage overvoltage protection sub-circuit;

the voltage half-wave precise rectifier circuit is electrically connected with the voltage full-wave precise rectifier circuit and the voltage infinite gain multipath feedback low-pass filter sub-circuit, the voltage full-wave precise rectifier circuit is electrically connected with the lamp peak voltage overvoltage protection sub-circuit, the lamp peak voltage overvoltage protection sub-circuit is electrically connected with the MCU main control module 2, the voltage infinite gain multipath feedback low-pass filter sub-circuit is electrically connected with the MCU main control module 2, and the voltage control voltage source second-order low-pass filter sub-circuit is electrically connected with the MCU main control module 2.

Preferably, the sampling protection module 5 further comprises a current half-wave precision rectifier circuit, a current full-wave precision rectifier circuit, a current infinite gain multipath feedback low-pass filter sub-circuit and a current voltage-controlled voltage source second-order low-pass filter sub-circuit;

the current half-wave precise rectifier sub-circuit is electrically connected with the current full-wave precise rectifier sub-circuit and the current infinite gain multipath feedback low-pass filter sub-circuit, the current full-wave precise rectifier sub-circuit is electrically connected with the lamp peak current overvoltage protection sub-circuit, the lamp peak current overvoltage protection sub-circuit is electrically connected with the MCU main control module 2, the current infinite gain multipath feedback low-pass filter sub-circuit is electrically connected with the MCU main control module 2, and the current voltage-controlled voltage source second-order low-pass filter sub-circuit is electrically connected with the MCU main control module 2.

The sampling protection module 5 is used for collecting current and voltage of the lamp tube and the driving circuit, protecting the lamp tube and the driving circuit, and feeding the current and voltage back to the MCU main control module 2.

The sampling protection module 5 obtains the average value of the positive half cycle of the voltage and the current of the lamp tube by constructing a half-wave precise rectifier circuit, a full-wave precise rectifier circuit, an infinite gain multipath feedback low-pass filter sub-circuit and a voltage-controlled voltage source second-order low-pass filter sub-circuit, and sends the average value of the full wave to the MCU for judgment, and the difference value of the positive half cycle of the voltage and the average value of the full wave is used for judging whether the lamp tube has a rectifying effect or not; the peak value of the voltage and the current of the lamp tube is obtained by using a comparator to form a peak value holding circuit, and the peak value is sent to the rear end of the protection circuit for protection and turn-off. And the comparison circuit is built through the operational amplifier, and when the sampled voltage and current of the lamp tube, the current sampling value under the half-bridge driving MOS and the voltage on the temperature monitoring NTC exceed the set reference value, a high level is output. Through the SCR340, the SCR350, the SCR360, and the SCR370 in each branch, when receiving the high level, the corresponding SCR is turned on and locked, outputs the low level, sends the signal to the logic gate 74LS00 or the singlechip, and the logic gate 74LS00 outputs the high level to the half-bridge control circuit for blocking, and sends the signal to the singlechip for interruption. The locked state of the thyristor may be cleared by the relay turning off the power. U390 is a voltage reference chip that provides a reference voltage for the comparison circuit. The capacitors such as C300 are ceramic capacitors and are used for filtering power supply of each operational amplifier. The circuit has the advantages that the voltage and the current of the lamp tube and the current on the MOS can be sampled and obtained, and the circuit has a quick response speed to the overvoltage and overcurrent of the lamp tube and the overheat inside the ballast.

Specifically, the device further comprises a single-ended flyback switching power supply module 6, wherein the single-ended flyback switching power supply module 6 is electrically connected with the filtering boosting module 1, and the filtering boosting module 1 provides power for the single-ended flyback switching power supply module 6; the single-ended flyback switching power supply module 6 is used for providing positive 5V voltage, positive 15V voltage and negative 15V voltage to supply power for the circuit elements.

The single-ended flyback switching power supply module 6 is used for providing positive 5V voltage, positive 15V voltage and negative 15V voltage for power supply voltage required by each control circuit. The single-ended flyback switching power supply module 6 adopts a DC-DC working mode, directly inputs power supply voltage, outputs +/-15V and 5V voltage, and respectively supplies power to the drive IC chip, the protection circuit and the singlechip.

Preferably, the system further comprises a boost control module 7, wherein the boost control module 7 is electrically connected with the MCU main control module 2 and the filtering boost module 1;

the boost control module 7 is configured to receive a switch control signal from the MCU main control module 2, and simultaneously receive a sampling signal of the filtering boost module 1, and send a boost control signal, where the boost control signal drives the filtering boost module 1 to work or cut off.

The boost control module 7 controls the filtering boost module 1 and detects voltage and current feedback of the filtering boost module 1. The boost control module 7 mainly comprises a UC2843 chip, boost is controlled by controlling the conduction of an MOS tube through output PWM, 8 pins of the UC2843 chip output reference voltage, and output frequency is controlled through a circuit composed of a resistor R150, a capacitor C151 and the like. The capacitor C154, the capacitor C155 and the resistor R153 form an integrating circuit, so that the response of the voltage sampling is controlled. The resistor R154, the capacitor C156 and the triode Q150 control the reference voltage in the 1 pin of the UC2843 chip, the PNP tube conduction degree is controlled through slow charging, the boosting speed is controlled, the current is prevented from being too large due to too fast boosting, and the soft switching effect is achieved. The resistor R155 and the triode Q151 achieve the aim of turning off and boosting by pulling down the reference voltage of the pin 1 of the UC2843 chip. The current sample is sent to 3 pins of UC2843 chip through differential amplifying circuit composed of operational amplifier to control the on time of driving waveform.

In the description herein, reference to the term "embodiment," "example," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The technical principle of the present utility model is described above in connection with the specific embodiments. The description is made for the purpose of illustrating the general principles of the utility model and should not be taken in any way as limiting the scope of the utility model. Other embodiments of the utility model will be apparent to those skilled in the art from consideration of this specification without undue burden.

Claims

1. The ultraviolet lamp tube driving circuit is characterized by comprising a filtering boosting module, an MCU main control module, a CLASS-D half-bridge module and a half-bridge driving control module;

2. The ultraviolet lamp tube driving circuit according to claim 1, wherein the half-bridge driving control module comprises a discharging sub-circuit and a driving chip, wherein an input end of the discharging sub-circuit is electrically connected with the MCU main control module, an output end of the discharging sub-circuit is electrically connected with the driving chip, and the driving chip is electrically connected with the CLASS-D half-bridge module; the discharging sub-circuit is used for receiving the PWM signal sent by the MCU main control module, and changing the current transmitted to the driving chip according to the PWM signal, so that the output frequency of the driving chip is changed, and the output frequency of the driving chip controls the working current of the CLASS-D half-bridge module.

3. The ultraviolet lamp tube driving circuit according to claim 2, wherein the half-bridge driving control module further comprises a preheating sub-circuit, an input end of the preheating sub-circuit is electrically connected with the MCU main control module, and an output end of the preheating sub-circuit is electrically connected with the driving chip.

4. The ultraviolet lamp tube driving circuit according to claim 1, further comprising a sampling protection module electrically connected to the CLASS-D half-bridge module for collecting lamp tube voltage sampling signals and steady state operating lamp tube current sampling signals;

5. The ultraviolet lamp tube driving circuit according to claim 4, wherein the sampling protection module comprises a voltage half-wave precision rectifier circuit, a voltage full-wave precision rectifier circuit, a voltage infinite gain multi-path feedback low-pass filter sub-circuit, a voltage-controlled voltage source second-order low-pass filter sub-circuit and a lamp tube peak voltage overvoltage protection sub-circuit;

6. The ultraviolet lamp tube driving circuit according to claim 5, wherein the sampling protection module further comprises a current half-wave precision rectifier circuit, a current full-wave precision rectifier circuit, a current infinite gain multi-path feedback low-pass filter sub-circuit and a current voltage-controlled voltage source second-order low-pass filter sub-circuit;

7. The ultraviolet lamp tube driving circuit according to claim 1, further comprising a single-ended flyback switching power supply module, wherein the single-ended flyback switching power supply module is electrically connected with the filtering boost module, and the filtering boost module provides power for the single-ended flyback switching power supply module; the single-ended flyback switching power supply module is used for providing positive 5V voltage, positive 15V voltage and negative 15V voltage to supply power for the circuit element.

8. The ultraviolet lamp tube driving circuit according to claim 1, further comprising a boost control module, wherein the boost control module is electrically connected with the MCU main control module and the filtering boost module;