A driving device and driving method of UV lamp tube

Abstract

A driving device for a UV lamp and a driving method thereof, the driving device for the UV lamp comprises a power supply circuit, a driving circuit, a boost circuit and a UV lamp, and is characterized in that it also comprises a current feedback circuit and an MCU single chip computer, wherein the power supply circuit is electrically connected to the MCU single chip computer and the driving circuit respectively, the MCU single chip computer, the driving circuit, and the boost circuit are electrically connected in sequence and then connected to one end of the UV lamp, and the other end of the UV lamp is electrically connected to the boost circuit through the current feedback circuit. The operating method of the driving device for the UV lamp comprises the following steps: Step 1, at each power-on startup, the first transistor Q1 and the second transistor Q2 are driven by the PWM port of the MCU single chip computer, so that the first transistor Q1 and the second transistor Q2 are turned on in turn, thereby generating a high-voltage sine wave at the secondary of the transformer T1, and the sine wave is coupled through the first capacitor C1. The present invention has the characteristic of long service life.

Description

Technical Field

[0001] The invention relates to a driving device of a UV lamp tube and a driving method thereof. Background Art

[0002] UV lamps are commonly used disinfection devices and are widely used in various health disinfection industries such as life and medical treatment. Due to the limitations of UV lamp production technology, the consistency of the starting voltage of UV lamps varies greatly during mass production.

[0003] At present, UV lamps generally use traditional Royer topology UV driving circuits. This Royer topology UV driving circuit is a self-oscillating structure. Due to its simple structure, mature technology, and price advantage, it is widely used. However, due to the influence of component parameter deviation, it is not easy to achieve strict lamp frequency and lamp current control, both of which will affect the brightness of the lamp. In addition, when the Royer topology UV driving circuit is used to match the lamp, it is easy to have a poor matching degree, resulting in an increase in defective products, increasing the product scrap rate and the test cycle of the detection and matching process. Summary of the invention

[0004] The object of the present invention is to provide a driving device and a driving method of a UV lamp with a long service life, so as to overcome the shortcomings of the prior art.

[0005] A UV lamp driving device designed for this purpose includes a power supply circuit, a drive circuit, a boost circuit and a UV lamp. Its structural feature is that it also includes a current feedback circuit and an MCU single-chip computer, wherein the power supply circuit is electrically connected to the MCU single-chip computer and the drive circuit respectively, the MCU single-chip computer, the drive circuit and the boost circuit are electrically connected in sequence and then connected to one end of the UV lamp, and the other end of the UV lamp is electrically connected to the boost circuit through the current feedback circuit.

[0006] Wherein, the driving circuit includes a first triode Q1, a second triode Q2, a fourth resistor R4 and a fifth resistor R5, the emitter of the first triode Q1 and the emitter of the second triode Q2 are respectively grounded GND, the collector of the first triode Q1 is electrically connected to one end of the primary of the transformer T1, the collector of the second triode Q2 is electrically connected to the other end of the primary of the transformer T1, the base of the first triode Q1 is electrically connected to the first pin of the MCU microcontroller through the fourth resistor R4, and the base of the first triode Q1 is electrically connected to the second pin of the MCU microcontroller through the fifth resistor R5;

[0007] The boost circuit includes a transformer T1 and a first capacitor C1, and one end of the secondary of the transformer T1 is electrically connected to one end of the UV lamp tube through the first capacitor C1;

[0008] The current feedback circuit includes a first resistor R1, a second resistor R2, a third capacitor R3, a first diode D1 and a second capacitor C2, one end of the first resistor R1 is electrically connected to the other end of the secondary of the transformer T1, the other end of the first resistor R1 is electrically connected to the positive electrode of the first diode D1, the negative electrode of the first diode D1 is electrically connected to one end of the second resistor R2, the other end of the second resistor R2 is electrically connected to the third pin of the MCU microcontroller, one end of the second capacitor C2 is connected between the negative electrode of the first diode D1 and one end of the second resistor R2, the other end of the second capacitor C2 is grounded GND, one end of the third resistor R3 is grounded GND, and the other end of the third resistor R3 is connected between the other end of the second resistor R2 and the third pin of the MCU microcontroller;

[0009] The other end of the UV lamp is connected between the other end of the first resistor R1 and the anode of the first diode D1.

[0010] Furthermore, the power supply circuit is a battery power supply circuit.

[0011] Furthermore, the battery is a primary battery or a secondary battery.

[0012] An operating method of a driving device of a UV lamp tube is characterized by comprising the following steps:

[0013] Step 1: At each power-on startup, the MCU microcontroller first detects and records the current voltage value of the battery in the power supply circuit, and marks it as the initial voltage value of the battery. Then, the first transistor Q1 and the second transistor Q2 are driven through the PWM port of the MCU microcontroller, so that the first transistor Q1 and the second transistor Q2 are turned on in turn, thereby generating a high-voltage sine wave at the secondary of the transformer T1. The sine wave is coupled through the first capacitor C1 and loaded onto the UV lamp tube; the MCU microcontroller gradually adjusts the output frequency of PWM, and the output frequency gradually increases from 10KHz to 80KHz; at the same time, the voltage value fed back from the second resistor R2 end is detected, and the MCU microcontroller records the voltage value fed back in each frequency band; and a corresponding table of the frequency band and the voltage value is formed;

[0014] Step 2: When the output frequency of the PWM adjusted by the MCU microcontroller is close to or equal to the resonant frequency formed by the secondary of the transformer T1, the first capacitor C1 and the UV lamp, the UV lamp undergoes ionization breakdown and is lit. The output frequency of the PWM when lit is recorded as the maximum operating frequency of this power-on startup; at the same time, the MCU microcontroller records the voltage value corresponding to the maximum operating frequency of this power-on startup and the current voltage value of the battery in the current power supply circuit;

[0015] Step three, the MCU actively lowers the current output frequency of PWM, so that the current output frequency of PWM is 60% to 100% of the maximum operating frequency, and the UV lamp tube works at a stable brightness.

[0016] Furthermore, the operating method of the driving device of the UV lamp tube further includes the following steps:

[0017] Step 4, when the UV lamp is working, the MCU microcontroller timely records the current voltage value of the battery in the power supply circuit, and compares the current voltage value of the battery with the initial voltage value of the battery. When the difference between the current voltage value of the battery and the initial voltage value of the battery decreases by 0.1V, the MCU microcontroller actively reduces the current output frequency of PWM by 0-10%.

[0018] The power supply circuit in the present invention is electrically connected to the MCU single chip and the driving circuit respectively. The MCU single chip, the driving circuit and the boost circuit are electrically connected in sequence and then connected to one end of the UV lamp. The other end of the UV lamp is electrically connected to the boost circuit through a current feedback circuit. Each time the power is turned on and started, the MCU single chip will re-scan the frequency, which can not only start the resonance and play a role in rapid ignition, but also avoid the resonant frequency drift caused by the drop of battery voltage, and can also neutralize the parameter changes of the UV lamp caused by the change of temperature and humidity environment, so as to keep the brightness of the UV lamp consistent each time.

[0019] The battery in the present invention is a primary battery or a secondary battery; the secondary battery includes a lithium battery. The present invention is very suitable for circuits driven by a single lithium battery. Since the voltage operating range of the lithium battery is from 4.2V to 2.8V, the above technical solution can completely avoid the failure to start due to the reduction of the battery voltage.

[0020] After the UV lamp tube in the present invention is lit, the MCU single chip actively lowers the current output frequency of PWM, so that the current output frequency of PWM is 60-100% of the maximum operating frequency, and the operating current of the UV lamp tube is kept constant in a balanced state; thus, it can prevent the UV lamp tube from being very bright in the early stage and from being dim or even not bright in the later stage, thereby greatly extending the service life of the UV lamp tube.

[0021] The invention can be quickly matched with a UV lamp tube and is suitable for UV lamp tubes with various ignition voltages, thereby reducing the scrap rate of the lamp tube and the production cost of the UV lamp tube.

[0022] In summary, the present invention has the characteristics of easy matching and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. 4 is a circuit connection block diagram of an embodiment of the present invention.

[0024] Figure 2 It is a circuit connection schematic diagram of the present invention.

[0025] In the figure: 1 is the power supply circuit, 2 is the drive circuit, 3 is the boost circuit, 4 is the MCU microcontroller, 5 is the current feedback circuit, and 6 is the UV lamp. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0027] See also Figure 1-Figure 2 The driving device of the UV lamp tube includes a power supply circuit 1, a driving circuit 2, a boost circuit 3 and a UV lamp tube 6, and also includes a current feedback circuit 5 and an MCU single chip computer 4, wherein the power supply circuit 1 is electrically connected to the MCU single chip computer 4 and the driving circuit 2 respectively, and the MCU single chip computer 4, the driving circuit 2, and the boost circuit 3 are electrically connected in sequence and then connected to one end of the UV lamp tube 6, and the other end of the UV lamp tube 6 is electrically connected to the boost circuit 3 through the current feedback circuit 5.

[0028] Wherein, the driving circuit 2 includes a first transistor Q1, a second transistor Q2, a fourth resistor R4 and a fifth resistor R5, the emitter of the first transistor Q1 and the emitter of the second transistor Q2 are grounded GND respectively, the collector of the first transistor Q1 is electrically connected to one end of the primary of the transformer T1, the collector of the second transistor Q2 is electrically connected to the other end of the primary of the transformer T1, the base of the first transistor Q1 is electrically connected to the first pin of the MCU microcontroller 4 through the fourth resistor R4, and the base of the first transistor Q1 is electrically connected to the second pin of the MCU microcontroller 4 through the fifth resistor R5; the boost circuit 3 includes a transformer T1 and a first capacitor C1, one end of the secondary of the transformer T1 is electrically connected to one end of the UV lamp 6 through the first capacitor C1; the current feedback circuit 5 includes a first resistor R1, a second resistor R2, a third capacitor R3, a first diode D1 and a second capacitor C2, one end of the first resistor R1 is electrically connected to the other end of the secondary of the transformer T1, the other end of the first resistor R1 is electrically connected to the positive electrode of the first diode D1, the negative electrode of the first diode D1 is electrically connected to one end of the second resistor R2, the other end of the second resistor R2 is electrically connected to the third pin of the MCU single chip (4), one end of the second capacitor C2 is connected between the negative electrode of the first diode D1 and one end of the second resistor R2, the other end of the second capacitor C2 is grounded GND, one end of the third resistor R3 is grounded GND, the other end of the third resistor R3 is connected between the other end of the second resistor R2 and the third pin of the MCU single chip 4; the other end of the UV lamp 6 is connected between the other end of the first resistor R1 and the positive electrode of the first diode D1.

[0029] In this embodiment, the power supply circuit 1 is a power supply circuit powered by a battery.

[0030] The battery is a primary battery or a secondary battery, wherein the primary battery includes a dry cell, and the secondary battery includes a lead storage battery and a lithium battery.

[0031] A method for operating a driving device of a UV lamp tube comprises the following steps:

[0032] Step 1, at each power-on startup, the MCU single-chip computer 4 first detects and records the current voltage value of the battery in the power supply circuit 1, and marks it as the initial voltage value of the battery, and then drives the first transistor Q1 and the second transistor Q2 through the PWM port of the MCU single-chip computer 4, so that the first transistor Q1 and the second transistor Q2 are turned on in turn, thereby generating a high-voltage sine wave at the secondary of the transformer T1, and the sine wave is coupled through the first capacitor C1 and loaded onto the UV lamp 6; the MCU single-chip computer 4 gradually adjusts the output frequency of PWM, and the output frequency gradually increases from 10KHz to 80KHz; at the same time, the voltage value fed back from the second resistor R2 end is detected, and the MCU single-chip computer 4 records the voltage value fed back in each frequency band; and forms a corresponding table of the frequency band and the voltage value.

[0033] When the MCU single chip computer detects the current voltage value of the battery in the power supply circuit 1, the voltage of VDD is reversely calculated through the built-in 1.4V reference voltage of the MCU single chip computer.

[0034] Since the voltage cannot be detected when the UV lamp 6 is not lit, it does not need to be recorded; when the UV lamp is lit, its voltage will rise rapidly, and the program built into the MCU will record the frequency value corresponding to the voltage after the frequency retrace when performing frequency retrace.

[0035] In the following test table, what is recorded are the frequency corresponding to when the UV lamp 6 is lit, and the battery voltage corresponding to the frequency.

[0036] By detecting the voltage value fed back from the second resistor R2, the corresponding current is calculated; the larger the current, the larger the corresponding voltage.

[0037] Step 2: When the output frequency of the PWM adjusted by the MCU microcontroller 4 is close to or equal to the resonant frequency formed by the secondary of the transformer T1, the first capacitor C1 and the UV lamp 6, the UV lamp 6 undergoes ionization breakdown, and the UV lamp 6 is lit. The output frequency of the PWM when lit is recorded as the maximum operating frequency of this power-on startup; at the same time, the MCU microcontroller 4 records the voltage value corresponding to the maximum operating frequency of this power-on startup and the current voltage value of the battery in the current power supply circuit 1;

[0038] The voltage value corresponding to the maximum operating frequency refers to the voltage value provided by the second resistor R2, and the current voltage value of the battery refers to the voltage value of the VDD power supply.

[0039] Step three, the MCU 4 actively lowers the current output frequency of PWM, so that the current output frequency of PWM is 60% to 100% of the maximum operating frequency, and the UV lamp 6 works at a stable brightness.

[0040] Since the maximum energy efficiency can only be achieved after the secondary of the transformer T1, the first capacitor C1 and the UV lamp 6 form resonance, the UV lamp 6 is activated to light up. At this time, the peak voltage recorded by the MCU microcontroller 4 is the best effect of the UV lamp 6; however, in order to increase the service life of the UV lamp, after the UV lamp 6 is started and lit up, the MCU microcontroller 4 will adjust the output frequency of the PWM at the same time according to the recorded voltage value and the current power supply voltage value, so that the working current of the UV lamp is constant in a balanced state.

[0041] After this power-on startup, when the UV lamp 6 first stably works, the MCU single-chip computer 4 has adjusted the current output frequency of PWM to 60-100% of the maximum operating frequency; as the working time increases, that is, if the UV lamp 6 is lit for a long time, causing the battery voltage to change, the MCU single-chip computer 4 will actively compare the current power supply voltage value with the power supply voltage value when the UV lamp 6 first stably works, and then operate according to the following technical solution, as follows.

[0042] The operating method of the driving device of the UV lamp tube further includes the following steps:

[0043] Step 4, when the UV lamp 6 is working, the MCU microcontroller 4 timely records the current voltage value of the battery in the power supply circuit 1, and compares the current voltage value of the battery with the initial voltage value of the battery. When the difference between the current voltage value of the battery and the initial voltage value of the battery decreases by 0.1V, the MCU microcontroller 4 actively reduces the amplitude of the current output frequency of PWM to 0-10%.

[0044] For example, the maximum operating frequency of the UV lamp 6 when it is lit is 50KHz, and the current power supply voltage value corresponding to the maximum operating frequency of 50KHz is 4.8V; then, according to the technical solution provided by the present invention, the MCU single chip 4 actively adjusts the current output frequency of PWM to 74% of the maximum operating frequency, that is, 50KHz*74.06%=37.03KHz, and 37.03KHz exists in the corresponding table of frequency band and voltage value recorded by the MCU single chip 4, then, the UV lamp 6 actually works in an environment with a voltage of 3.7V and an operating frequency of 37KHz, until the MCU single chip 4 detects a new value of the power supply voltage value. See the fifth row of data in the test table No. 1 for details.

[0045] For another example: the maximum operating frequency of the UV lamp 6 when it is lit is 50KHz, and the current power supply voltage value corresponding to the maximum operating frequency of 50KHz is 4.8V; then, according to the technical solution provided by the present invention, the MCU single chip 4 actively adjusts the current output frequency of PWM to 83.32% of the maximum operating frequency, that is, 50KHz*83.32%=41.66KHz, and 41.66KHz exists in the corresponding table of frequency band and voltage value recorded by the MCU single chip 4, then, the UV lamp 6 actually works in an environment with a voltage of 3.7V and an operating frequency of 37KHz, until the MCU single chip 4 detects that the power supply voltage value has a new value. See the fifth row of data in the test table No. 5 for details.

[0046] In practice, after comparing the matching results of UV lamps using the technical solution provided by the present invention with the matching results of UV lamps using the traditional Royer topology UV driving circuit, it can be clearly concluded that the technical solution provided by the present invention can indeed reduce the difficulty of matching and prolong the service life.

[0047] The following is a test table of UV lamps using variable frequency startup.

[0048] Test Table

[0049]

[0050]

[0051]

[0052] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0053] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for operating a UV lamp driving device, comprising a power supply circuit (1), a driving circuit (2), a boost circuit (3) and a UV lamp (6), wherein the method is characterized in that: It also includes a current feedback circuit (5) and an MCU single chip computer (4), wherein the power supply circuit (1) is electrically connected to the MCU single chip computer (4) and the drive circuit (2) respectively, the MCU single chip computer (4), the drive circuit (2) and the boost circuit (3) are electrically connected in sequence and then connected to one end of the UV lamp tube (6), and the other end of the UV lamp tube (6) is electrically connected to the boost circuit (3) via the current feedback circuit (5); The drive circuit (2) comprises a first transistor Q1, a second transistor Q2, a fourth resistor R4 and a fifth resistor R5, the emitter of the first transistor Q1 and the emitter of the second transistor Q2 are respectively connected to the ground GND, the collector of the first transistor Q1 is electrically connected to one end of the primary of the transformer T1, the collector of the second transistor Q2 is electrically connected to the other end of the primary of the transformer T1, the base of the first transistor Q1 is electrically connected to a first pin of the MCU single chip computer (4) through the fourth resistor R4, and the base of the first transistor Q1 is electrically connected to a second pin of the MCU single chip computer (4) through the fifth resistor R5; The boost circuit (3) comprises a transformer T1 and a first capacitor C1, and one end of the secondary of the transformer T1 is electrically connected to one end of the UV lamp (6) via the first capacitor C1; The current feedback circuit (5) comprises a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1 and a second capacitor C2, one end of the first resistor R1 is electrically connected to the other end of the secondary of the transformer T1, the other end of the first resistor R1 is electrically connected to the positive electrode of the first diode D1, the negative electrode of the first diode D1 is electrically connected to one end of the second resistor R2, the other end of the second resistor R2 is electrically connected to the third pin of the MCU single chip (4), one end of the second capacitor C2 is connected between the negative electrode of the first diode D1 and one end of the second resistor R2, the other end of the second capacitor C2 is grounded GND, one end of the third resistor R3 is grounded GND, and the other end of the third resistor R3 is connected between the other end of the second resistor R2 and the third pin of the MCU single chip (4); The other end of the UV lamp (6) is connected between the other end of the first resistor R1 and the positive electrode of the first diode D1; The operation includes the following steps: Step 1: At each power-on start-up, the MCU single-chip computer (4) first detects and records the current voltage value of the battery in the power supply circuit (1), and marks it as the initial voltage value of the battery. Then, the first transistor Q1 and the second transistor Q2 are driven through the PWM port of the MCU single-chip computer (4), so that the first transistor Q1 and the second transistor Q2 are turned on in turn, thereby generating a high-voltage sine wave at the secondary of the transformer T1. After the sine wave is coupled through the first capacitor C1, it is loaded onto the UV lamp (6); the MCU single-chip computer (4) gradually adjusts the output frequency of the PWM, and the output frequency gradually increases from 10KHz to 80KHz; at the same time, the voltage value fed back from the second resistor R2 end is detected, and the MCU single-chip computer (4) records the voltage value fed back in each frequency band; and a corresponding table of the frequency band and the voltage value is formed; Step 2: When the PWM output frequency adjusted by the MCU single chip computer (4) is close to or equal to the resonance frequency formed by the secondary of the transformer T1, the first capacitor C1 and the UV lamp tube (6), the UV lamp tube (6) is ionized and broken down, and the UV lamp tube (6) is lit. The PWM output frequency when lit is recorded as the maximum operating frequency of this power-on startup; at the same time, the MCU single chip computer (4) records the voltage value corresponding to the maximum operating frequency of this power-on startup and the current voltage value of the battery in the current power supply circuit (1); Step three, the MCU (4) actively lowers the current output frequency of PWM so that the current output frequency of PWM is 60% to 100% of the maximum operating frequency, and the UV lamp (6) operates at a stable brightness.

2. The operating method of the driving device of the UV lamp according to claim 1, characterized in that The following steps are involved: Step 4: When the UV lamp (6) is working, the MCU single chip computer (4) timely records the current voltage value of the battery in the power supply circuit (1), and compares the current voltage value of the battery with the initial voltage value of the battery. When the difference between the current voltage value of the battery and the initial voltage value of the battery decreases by 0.1V, the MCU single chip computer (4) actively reduces the amplitude of the current output frequency of PWM by 0 to 10%.

3. The operating method of the driving device of the UV lamp according to claim 1, characterized in that The power supply circuit (1) is a battery power supply circuit.

4. The operating method of the driving device of the UV lamp according to claim 3, characterized in that The battery is a primary battery or a secondary battery.

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