An electronic ballast for monitoring dual lamp power balance

Abstract

The application discloses an electronic ballast for monitoring double-lamp power balance, and relates to the technical field of electronic ballasts, which comprises an MCU, a power conversion circuit, a single-double lamp state machine, a double-lamp tube voltage detection circuit, a single-lamp tube voltage detection circuit, a tube current sampling circuit and a tube current detection circuit; the MCU is used for controlling the single-double lamp state machine to perform single-double lamp state judgment according to a double-lamp tube voltage signal collected by the double-lamp tube voltage detection circuit and a single-lamp tube voltage signal collected by the single-lamp tube voltage detection circuit, and outputting a PWM pulse signal according to a judgment result; the power conversion circuit performs power conversion after receiving the PWM pulse signal to control the electronic ballast to realize double-lamp power balance work. The electronic ballast for monitoring double-lamp power balance can ensure that the working power of two ultraviolet lamp tubes is balanced when the two ultraviolet lamp tubes work at the output end of the electronic ballast.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic ballast, in particular to an electronic ballast for monitoring double lamp power balance. BACKGROUND

[0002] In the field of ultraviolet sterilization, electronic ballast is mainly used to drive ultraviolet lamp to emit light for sterilization. When the output end of the electronic ballast is connected to two ultraviolet lamps, the actual power of the single ultraviolet lamp cannot be detected whether the electronic ballast is in constant current output mode or constant power output mode. In this case, once the pressure of any one of the two ultraviolet lamps is too high due to air leakage, the ultraviolet lamp will overheat due to over-power operation, thereby affecting the service life of the ultraviolet lamp and even causing safety problems such as burning of the ultraviolet lamp. SUMMARY

[0003] The purpose of the present application is to provide an electronic ballast for monitoring double lamp power balance, which can ensure the balance of the working power of the two ultraviolet lamps when the output end of the electronic ballast is connected to two ultraviolet lamps.

[0004] To achieve the above purpose, the present application provides the following solutions:

[0005] In a first aspect, the present application provides an electronic ballast for monitoring double lamp power balance, comprising: an MCU, a power conversion circuit, a single / double lamp state machine, a double lamp tube voltage detection circuit, a single lamp tube voltage detection circuit, a lamp tube current sampling circuit and a lamp tube current detection circuit.

[0006] The lamp voltage output end of the power conversion circuit is connected with the input end of the single-double lamp state machine, the double-lamp lamp voltage output end of the single-double lamp state machine is connected with the input end of the double-lamp lamp voltage detection circuit, and the output end of the double-lamp lamp voltage detection circuit is connected with the double-lamp voltage input end of the MCU; the single-lamp lamp voltage output end of the single-double lamp state machine is connected with the input end of the single-lamp lamp voltage detection circuit, and the output end of the single-lamp lamp voltage detection circuit is connected with the single-lamp voltage input end of the MCU; the lamp current output end of the power conversion circuit is connected with the input end of the lamp current sampling circuit, the output end of the lamp current sampling circuit is connected with the input end of the lamp current detection circuit, and the output end of the lamp current detection circuit is connected with the current input end of the MCU; the MCU is used for controlling the single-double lamp state machine to perform single-double lamp state judgment according to the double-lamp lamp voltage signal collected by the double-lamp lamp voltage detection circuit and the single-lamp lamp voltage signal collected by the single-lamp lamp voltage detection circuit, and outputting a PWM pulse signal according to the judgment result; the output end of the MCU is connected with the driving signal input end of the power conversion circuit, and the power conversion circuit is used for performing power conversion to control the electronic ballast to realize double-lamp power balance work after receiving the PWM pulse signal.

[0007] Optionally, the PB14 pin and the PB15 pin of the MCU are used as the output end of the MCU, the PA00 pin of the MCU is used as the double-lamp voltage input end of the MCU, the PB12 pin of the MCU is used as the single-lamp voltage input end of the MCU, and the PA01 pin of the MCU is used as the current input end of the MCU.

[0008] Optionally, the power conversion circuit specifically comprises: a resistor R304, a resistor R305, a resistor R317, a resistor R302, a resistor R303, a resistor R306, a resistor R308, a resistor RCS1, a diode D302, a gate starting chip U301, a capacitor C303, a capacitor C304, a capacitor C305, a field effect transistor Q301, a field effect transistor Q302, a resonant inductor L301A, and an ultraviolet lamp LAMP.

[0009] The HIN pin of the gate starting chip U301 is connected with one end of the resistor R304, and the other end of the resistor R304 is connected with the PB15 pin of the MCU; the LIN pin of the gate starting chip U301 is connected with one end of the resistor R305, and the other end of the resistor R305 is connected with the PB14 pin of the MCU; the COM pin of the gate starting chip U301 is grounded; the VCC pin of the gate starting chip U301 and the anode of the diode D302 are connected with 12V voltage; the cathode of the diode D302 is connected with one end of the resistor R317; the VB pin of the gate starting chip U301 and the other end of the resistor R317 are connected with one end of the capacitor C304; the HO pin of the gate starting chip U301 is connected with one end of the resistor R302; the other end of the resistor R302 is connected with the gate of the field effect transistor Q301 and one end of the resistor R303 respectively; the LO pin of the gate starting chip U301 is connected with one end of the resistor R306; the other end of the resistor R306 is connected with the gate of the field effect transistor Q302 and one end of the resistor R308 respectively; the source of the field effect transistor Q302 is grounded; the drain of the field effect transistor Q301 is connected with voltage Vdc1; the source of the field effect transistor Q301, the other end of the resistor R303, the other end of the capacitor C304, the VS pin of the gate starting chip U301 and the drain of the field effect transistor Q302 are connected with one end of the resonant inductor L301A; the other end of the resonant inductor L301A is connected with one end of the capacitor C303; the other end of the capacitor C303 is connected with one end of the capacitor C305 and one end of the ultraviolet lamp LAMP respectively; the other end of the ultraviolet lamp LAMP is connected with one end of the resistor RCS1; the other end of the resistor RCS1 and the other end of the capacitor C305 are grounded; the common end of the capacitor C303, the capacitor C305 and the ultraviolet lamp LAMP is the lamp voltage output end of the power conversion circuit; the common end of the ultraviolet lamp LAMP and the resistor RCS1 is the lamp current output end of the power conversion circuit.

[0010] Optionally, the double-lamp lamp voltage detection circuit specifically comprises: resistors R101, R102, R103, R104, R105, R106, R107, R109, a double-channel diode D1, an operational amplifier U1C and a voltage stabilizing tube ZD1.

[0011] One end of the resistor R101 is connected with the double lamp tube voltage output end of the single-double lamp state machine as the input end of the double lamp tube voltage detection circuit; the other end of the resistor R101 is connected with one end of the resistor R103 and one end of the resistor R102 respectively; the other end of the resistor R103 is connected with one end of the resistor R104 and the negative electrode of the Zener diode ZD1 respectively; the positive electrode of the Zener diode ZD1 and the other end of the resistor R102 are grounded; the other end of the resistor R104 is connected with the positive input end of the operational amplifier U1C; the reverse input end of the operational amplifier U1C is connected with one end of the resistor R105 and one end of the resistor R106 respectively; the other end of the resistor R105 is grounded; the other end of the resistor R106 is connected with one end of the resistor R107 and the output end of the operational amplifier U1C respectively; the other end of the resistor R107 is connected with the common end of the double diode D1 and one end of the resistor R109 respectively; the other end of the resistor R109 is grounded; the negative electrode end of the double diode D1 is connected with the voltage VCC; the positive electrode end of the double diode D1 is grounded; the common end of the double diode D1, the resistor R107 and the resistor R109 is the output end of the double lamp tube voltage detection circuit.

[0012] Optionally, the single lamp tube voltage detection circuit specifically comprises: a resistor R101A, a resistor R102A, a resistor R103A, a resistor R104A, a resistor R105A, a resistor R106A, a resistor R107A, a resistor R109A, a double diode D1A, an operational amplifier U2C and a Zener diode ZD1A.

[0013] One end of the resistor R101A is connected with the single lamp tube voltage output end of the single-double lamp state machine as the input end of the single lamp tube voltage detection circuit; the other end of the resistor R101A is connected with one end of the resistor R103A and one end of the resistor R102A respectively; the other end of the resistor R103A is connected with one end of the resistor R104A and the negative electrode of the Zener diode ZD1A respectively; the positive electrode of the Zener diode ZD1A and the other end of the resistor R102A are grounded; the other end of the resistor R104A is connected with the positive input end of the operational amplifier U2C; the reverse input end of the operational amplifier U2C is connected with one end of the resistor R105A and one end of the resistor R106A respectively; the other end of the resistor R105A is grounded; the other end of the resistor R106A is connected with one end of the resistor R107A and the output end of the operational amplifier U2C respectively; the other end of the resistor R107A is connected with the common end of the double diode D1A and one end of the resistor R109A respectively; the other end of the resistor R109A is grounded; the negative electrode end of the double diode D1A is connected with the voltage VCC; the positive electrode end of the double diode D1A is grounded; the common end of the double diode D1A, the resistor R107A and the resistor R109A is the output end of the single lamp tube voltage detection circuit.

[0014] Optionally, the single-double lamp state machine specifically comprises: a relay A, a relay B, a relay C, a relay D, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R1A, a resistor R2A, a resistor R3A, a resistor R4A, a resistor R5A, a resistor R6A and a resistor R7A.

[0015] The first terminal of the single-double lamp state machine is connected with the first ultraviolet lamp tube, the first terminal introduces four filaments including filament 1, filament 2, filament 3 and filament 4; the second terminal of the single-double lamp state machine is connected with the second ultraviolet lamp tube, the second terminal introduces four filaments including filament 5, filament 6, filament 7 and filament 8; the filament 1 is connected with one end of the relay A; the filament 2 is connected with one end of the resistance R5 and one end of the relay B respectively; the other end of the resistance R5 is connected with one end of the resistance R4, the other end of the resistance R4 is connected with one end of the resistance R3, the other end of the resistance R3 is connected with one end of the resistance R2 and one end of the resistance R7 respectively, the other end of the resistance R2 is connected with one end of the resistance R1, the other end of the resistance R7 is connected with one end of the resistance R6, the other end of the resistance R1 and the other end of the resistance R6 are grounded; the common end of the resistance R6 and the resistance R7 is the double lamp tube voltage output end of the single-double lamp state machine; the filament 3 is connected with the other end of the relay B; the filament 4 is connected with the other end of the relay A, one end of the relay D and the filament 5 respectively; the filament 6 is connected with one end of the resistance R5A and one end of the relay C respectively; the other end of the resistance R5A is connected with one end of the resistance R4A, the other end of the resistance R4A is connected with one end of the resistance R3A, the other end of the resistance R3A is connected with one end of the resistance R2A and one end of the resistance R7A respectively, the other end of the resistance R2A is connected with one end of the resistance R1A, the other end of the resistance R7A is connected with one end of the resistance R6A, the other end of the resistance R1A and the other end of the resistance R6A are grounded; the common end of the resistance R6A and the resistance R7A is the single lamp tube voltage output end of the single-double lamp state machine; the filament 7 is connected with the other end of the relay C; the filament 8 is connected with the other end of the relay D; the common end of the relay A and the filament 1 is the input end of the single-double lamp state machine.

[0016] Optionally, the lamp tube current sampling circuit specifically comprises: resistance R8 and capacitor C1.

[0017] One end of the resistance R8 is connected with the lamp tube current output end of the power conversion circuit as the input end of the lamp tube current sampling circuit; the other end of the resistance R8 is connected with one end of the capacitor C1; the other end of the capacitor C1 is grounded; the common end of the resistance R8 and the capacitor C1 is the output end of the lamp tube current sampling circuit.

[0018] Optionally, the lamp current detection circuit specifically comprises: a resistor R201, a resistor R202, a resistor R203, a resistor R204, a resistor R205, a two-way diode D2, an operational amplifier U1A, and a voltage stabilizing tube ZD2.

[0019] One end of the resistor R201 is connected with a negative electrode of the voltage stabilizing tube ZD2, serving as an input end of the lamp current detection circuit and an output end of the lamp current sampling circuit; a positive electrode of the voltage stabilizing tube ZD2 is grounded; the other end of the resistor R201 is connected with a positive input end of the operational amplifier U1A; a negative input end of the operational amplifier U1A is connected with one end of the resistor R203 and one end of the resistor R202 respectively; the other end of the resistor R202 is grounded; the other end of the resistor R203 is connected with one end of the resistor R204 and an output end of the operational amplifier U1A respectively; the other end of the resistor R204 is connected with one end of the resistor R205 and a common end of the two-way diode D2 respectively; the other end of the resistor R205 is grounded; a negative electrode end of the two-way diode D2 is connected with a voltage VCC; a positive electrode end of the two-way diode D2 is grounded; the common end of the two-way diode D2, the resistor R204, and the resistor R205 is an output end of the lamp current detection circuit.

[0020] Optionally, if the judgment result is that the first ultraviolet lamp tube and the second ultraviolet lamp tube are both connected to the electronic ballast or only the first ultraviolet lamp tube is connected to the electronic ballast, the MCU calculates the actual power by using a difference operation method according to the double-lamp lamp voltage signal collected by the double-lamp lamp voltage detection circuit and the lamp current signal collected by the lamp current detection circuit; if the judgment result is that only the second ultraviolet lamp tube is connected to the electronic ballast, the MCU calculates the actual power by using a difference operation method according to the single-lamp lamp voltage signal collected by the single-lamp lamp voltage detection circuit and the lamp current signal collected by the lamp current detection circuit.

[0021] Optionally, the actual power is compared with a power threshold value preset by the MCU; if the actual power is greater than or equal to the power threshold value, the MCU increases the frequency of the output PWM pulse signal; if the actual power is less than the power threshold value, the MCU decreases the frequency of the output PWM pulse signal.

[0022] According to the specific embodiments provided in the application, the following technical effects are disclosed:

[0023] The application provides an electronic ballast for monitoring double lamp power balance, which is connected between an MCU, a power conversion circuit, a single / double lamp state machine, a double lamp tube voltage detection circuit, a single lamp tube voltage detection circuit, a tube current sampling circuit and a tube current detection circuit, when two ultraviolet tubes are connected at the output end of the electronic ballast, the MCU arranged in the electronic ballast accurately calculates the actual power of any one ultraviolet tube in real-time work according to the double lamp tube voltage signal collected by the double lamp tube voltage detection circuit, the single lamp tube voltage signal collected by the single lamp tube voltage detection circuit and the tube current signal collected by the tube current detection circuit, and controls the frequency of the output PWM pulse signal according to the calculated actual power, so as to ensure that the working power of the two ultraviolet tubes is balanced, and the safe and reliable work of the electronic ballast itself and the ultraviolet tube is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0025] Figure 1 The power conversion circuit structure schematic diagram provided by the present application is provided.

[0026] Figure 2 The MCU structure schematic diagram provided by the present application is provided.

[0027] Figure 3 The double lamp tube voltage detection circuit structure schematic diagram provided by the present application is provided.

[0028] Figure 4 The single lamp tube voltage detection circuit structure schematic diagram provided by the present application is provided.

[0029] Figure 5 The single / double lamp state machine structure schematic diagram provided by the present application is provided.

[0030] Figure 6 The tube current sampling circuit structure schematic diagram provided by the present application is provided.

[0031] Figure 7 The tube current detection circuit structure schematic diagram provided by the present application is provided. DETAILED DESCRIPTION

[0032] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0033] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0034] As shown in Figures 1 to 7 , the electronic ballast for monitoring double lamp power balance disclosed by the present application comprises: an MCU, a power conversion circuit, a single / double lamp state machine, a double lamp tube voltage detection circuit, a single lamp tube voltage detection circuit, a tube current sampling circuit and a tube current detection circuit. The lamp tube voltage output end of the power conversion circuit is connected with the input end of the single / double lamp state machine, the double lamp tube voltage output end of the single / double lamp state machine is connected with the input end of the double lamp tube voltage detection circuit, and the output end of the double lamp tube voltage detection circuit is connected with the double lamp voltage input end of the MCU. The single lamp tube voltage output end of the single / double lamp state machine is connected with the input end of the single lamp tube voltage detection circuit, and the output end of the single lamp tube voltage detection circuit is connected with the single lamp voltage input end of the MCU. The lamp tube current output end of the power conversion circuit is connected with the input end of the tube current sampling circuit, the output end of the tube current sampling circuit is connected with the input end of the tube current detection circuit, and the output end of the tube current detection circuit is connected with the current input end of the MCU. The output end of the MCU is connected with the driving signal input end of the power conversion circuit.

[0035] As shown in Figure 1 , the power conversion circuit specifically comprises: a resistor R304, a resistor R305, a resistor R317, a resistor R302, a resistor R303, a resistor R306, a resistor R308, a resistor RCS1, a diode D302, a gate start-up chip U301, a capacitor C303, a capacitor C304, a capacitor C305, a field effect transistor Q301, a field effect transistor Q302, a resonant inductor L301A and an ultraviolet lamp tube LAMP. The gate start-up chip U301 is used to drive the field effect transistor Q301 and the field effect transistor Q302, and the field effect transistor Q301 and the field effect transistor Q302 are MOSFET tubes. The capacitor C303 and the capacitor C305 are both high-voltage thin-film capacitors. The resistor RCS1 is a working current sampling resistor of the ultraviolet lamp tube LAMP, and is used to sample the working current of the ultraviolet lamp tube LAMP.

[0036] As shown in Figure 2As shown, the PB14 pin and the PB15 pin of the MCU are used as the output end of the MCU, the PA00 pin is used as the double lamp voltage input end of the MCU, the PB12 pin is used as the single lamp voltage input end of the MCU, and the PA01 pin is used as the current input end of the MCU. The PB14 pin and the PB15 pin are used to output PWM pulse signals, that is, a PWM pulse signal PWMH and a PWM pulse signal PWML, and the two PWM pulse signals are transmitted to the HIN pin and the LIN pin of the gate starting chip U301 in Figure 1 . In addition, the relay signal Relay1, the relay signal Relay2 and the relay signal Relay3 are respectively connected to the PA07 pin, the PA08 pin and the PA09 pin of the MCU. The relay signal Relay1 is used to control the relay A, the relay signal Relay2 is used to control the relays B and C, and the relay signal Relay3 is used to control the relay D. When the PA07 pin, the PA08 pin and the PA09 pin of the MCU output a 3.3V voltage, the corresponding relay of each pin is closed, and when the PA07 pin, the PA08 pin and the PA09 pin of the MCU output a 0V voltage, the corresponding relay of each pin is opened.

[0037] Specifically, the HIN pin of gate enable chip U301 is connected to one end of resistor R304, the other end of which is connected to pin PB15 of the MCU. The LIN pin of gate enable chip U301 is connected to one end of resistor R305, the other end of which is connected to pin PB14 of the MCU. The COM pin of gate enable chip U301 is grounded. The VCC pin of gate enable chip U301 and the positive electrode of diode D302 are both connected to a 12V voltage H12V, which is used to drive gate enable chip U301 and serves as the power supply voltage. The negative electrode of diode D302 is connected to one end of resistor R317. The VB pin of gate enable chip U301 and the other end of resistor R317 are both connected to one end of capacitor C304. The HO pin of gate enable chip U301 is connected to one end of resistor R302. The other end of resistor R302 is connected to the gate of field effect transistor Q301 and one end of resistor R303, respectively. The LO pin of the gate enable chip U301 is connected to one end of resistor R306. The other end of resistor R306 is connected to the gate of field-effect transistor Q302 and one end of resistor R308, respectively. The source of field-effect transistor Q302 and the other end of resistor R308 are both grounded. The drain of field-effect transistor Q301 is connected to voltage Vdc1, which is a 400V DC voltage. The source of field-effect transistor Q301, the other end of resistor R303, the other end of capacitor C304, the VS pin of the gate enable chip U301, and the drain of field-effect transistor Q302 are all connected to one end of resonant inductor L301A. The other end of resonant inductor L301A is connected to one end of capacitor C303. The other end of capacitor C303 is connected to one end of capacitor C305 and one end of the ultraviolet lamp LAMP, respectively. The other end of the ultraviolet lamp LAMP is connected to one end of resistor RCS1. The other end of resistor RCS1 and the other end of capacitor C305 are both grounded. The common end of capacitors C303, C305, and the UV lamp LAMP serves as the lamp voltage output of the power conversion circuit, outputting lamp voltage VLAMP. The common end of the UV lamp LAMP and resistor RCS1 serves as the lamp current output of the power conversion circuit, outputting lamp current ILAMP.

[0038] like Figure 3 As shown in FIG, the dual-lamp voltage detection circuit specifically includes: resistors R101, R102, R103, R104, R105, R106, R107, R109, a dual-path diode D1, an operational amplifier U1C, and a voltage regulator ZD1. The dual-path diode D1 is mainly used to clamp the analog voltage V2_ADC amplified by the operational amplifier U1C to prevent the voltage from being too high or too low and causing damage. Figure 2 The analog voltage V2_ADC is the output of the dual-lamp tube voltage detection circuit.

[0039] Specifically, one end of the resistor R101 serves as the input end of the dual lamp tube voltage detection circuit ( Figure 3 V2 in the figure) is connected to the dual-lamp tube voltage output terminal of the single-dual-lamp state machine. The other end of resistor R101 is connected to one end of resistor R103 and one end of resistor R102 respectively. The other end of resistor R103 is connected to one end of resistor R104 and the negative terminal of Zener diode ZD1 respectively. The positive terminal of Zener diode ZD1 and the other end of resistor R102 are both grounded. Zener diode ZD1 is mainly used to clamp the voltage at pin 10 of operational amplifier U1C to prevent damage caused by excessive voltage. The other end of resistor R104 is connected to the positive input terminal of operational amplifier U1C. The negative input terminal of operational amplifier U1C is connected to one end of resistor R105 and one end of resistor R106 respectively. The other end of resistor R105 is grounded. The other end of resistor R106 is connected to one end of resistor R107 and the output terminal of operational amplifier U1C respectively. In addition, the power supply terminal of operational amplifier U1C is connected to the 12V voltage and ground GND respectively. The other end of resistor R107 is connected to the common terminal of dual-path diode D1 and one end of resistor R109. The other end of resistor R109 is grounded. The cathode of dual-path diode D1 is connected to voltage VCC. The anode of dual-path diode D1 is grounded. The common terminal of dual-path diode D1, resistor R107, and resistor R109 forms the output terminal of the dual-lamp voltage detection circuit.

[0040] The specific structure of the single lamp tube voltage detection circuit of this application is the same as the specific structure of the dual lamp tube voltage detection circuit. Figure 4 As shown in FIG. 1 , the single-lamp voltage detection circuit specifically includes: resistors R101A, R102A, R103A, R104A, R105A, R106A, R107A, R109A, a dual-path diode D1A, an operational amplifier U2C, and a voltage regulator diode ZD1A. The dual-path diode D1A is primarily used to clamp the analog voltage V1_ADC amplified by the operational amplifier U2C, preventing damage caused by excessively high or low voltages. Figure 2 The analog voltage V1_ADC is the output of the single lamp tube voltage detection circuit.

[0041] Specifically, one end of the resistor R101A serves as the input end of the single lamp tube voltage detection circuit ( Figure 4(V1 in the figure) is connected to the single-lamp tube voltage output terminal of the single-lamp and dual-lamp state machine. The other end of resistor R101A is connected to one end of resistor R103A and one end of resistor R102A. The other end of resistor R103A is connected to one end of resistor R104A and the negative electrode of Zener diode ZD1A. The positive electrode of Zener diode ZD1A and the other end of resistor R102A are both grounded. The other end of resistor R104A is connected to the positive input terminal of operational amplifier U2C. The negative input terminal of operational amplifier U2C is connected to one end of resistor R105A and one end of resistor R106A. The other end of resistor R105A is grounded. The other end of resistor R106A is connected to one end of resistor R107A and the output terminal of operational amplifier U2C. The other end of resistor R107A is connected to the common terminal of dual-path diode D1A and one end of resistor R109A. The other end of resistor R109A is grounded. The cathode of the dual diode D1A is connected to the voltage VCC. The anode of the dual diode D1A is grounded. The common terminal of the dual diode D1A, resistor R107A, and resistor R109A is the output terminal of the single lamp voltage detection circuit.

[0042] like Figure 5 As shown, the single and double lamp state machine specifically includes: relay A, relay B, relay C, relay D, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R1A, resistor R2A, resistor R3A, resistor R4A, resistor R5A, resistor R6A and resistor R7A.

[0043] Specifically, terminal 1 of the single / double lamp state machine is connected to the first ultraviolet lamp tube, and four filaments are introduced into terminal 1, including filament 1 (P1), filament 2 (P2), filament 3 (P3), and filament 4 (P4). Terminal 2 of the single / double lamp state machine is connected to the second ultraviolet lamp tube, and four filaments are introduced into terminal 2, including filament 5 (P5), filament 6 (P6), filament 7 (P7), and filament 8 (P8). Filament 1 is connected to one end of relay A. Filament 2 is respectively connected to one end of resistor R5 and one end of relay B. The other end of resistor R5 is connected to one end of resistor R4, the other end of resistor R4 is connected to one end of resistor R3, the other end of resistor R3 is respectively connected to one end of resistor R2 and one end of resistor R7, the other end of resistor R2 is connected to one end of resistor R1, the other end of resistor R7 is connected to one end of resistor R6, and the other end of resistor R1 and the other end of resistor R6 are both grounded. The common end of resistor R6 and resistor R7 is the voltage output end of the double lamp tube of the single and double lamp state machine ( Figure 5V2 in the output, the dual-lamp tube voltage collected by the resistor divider is used. Filament 3 is connected to the other end of relay B. Filament 4 is respectively connected to the other end of relay A, one end of relay D and filament 5. Filament 6 is respectively connected to one end of resistor R5A and one end of relay C. The other end of resistor R5A is connected to one end of resistor R4A, the other end of resistor R4A is connected to one end of resistor R3A, the other end of resistor R3A is respectively connected to one end of resistor R2A and one end of resistor R7A, the other end of resistor R2A is connected to one end of resistor R1A, the other end of resistor R7A is connected to one end of resistor R6A, and the other end of resistor R1A and the other end of resistor R6A are both grounded. The common end of resistor R6A and resistor R7A is the single-lamp tube voltage output end of the single-dual lamp state machine ( Figure 5 Filament 7 is connected to the other end of relay C. Filament 8 is connected to the other end of relay D. The common terminal of relay A and filament 1 is the input terminal of the single and double lamp state machine.

[0044] like Figure 6 As shown, the lamp current sampling circuit specifically includes: resistor R8 and capacitor C1. This application collects the current through the filter circuit composed of resistor R8 and capacitor C1. Figure 1 The lamp current ILAMP is at the lamp current output terminal of the power conversion circuit.

[0045] Specifically, one end of the resistor R8 serves as the input end of the lamp current sampling circuit and is connected to the lamp current output end of the power conversion circuit. The other end of the resistor R8 is connected to one end of the capacitor C1. The other end of the capacitor C1 is grounded. The common end of the resistor R8 and the capacitor C1 serves as the output end of the lamp current sampling circuit ( Figure 6 V3 in the figure).

[0046] like Figure 7 As shown, the lamp current detection circuit specifically includes: a resistor R201, a resistor R202, a resistor R203, a resistor R204, a resistor R205, a dual-path diode D2, an operational amplifier U1A and a voltage regulator diode ZD2.

[0047] Specifically, one end of the resistor R201 is connected to the negative electrode of the voltage regulator ZD2, serving as the input end of the lamp current detection circuit ( Figure 7V3 in the figure) is connected to the output of the lamp current sampling circuit. The positive terminal of the voltage regulator ZD2 is grounded. The voltage regulator ZD2 is mainly used to clamp the voltage at pin 3 of the operational amplifier U1A to prevent the voltage from being too high. The other end of resistor R201 is connected to the positive input of the operational amplifier U1A. The negative input of the operational amplifier U1A is connected to one end of resistor R203 and one end of resistor R202 respectively. The other end of resistor R202 is grounded. The other end of resistor R203 is connected to one end of resistor R204 and the output of the operational amplifier U1A respectively. In addition, the power supply terminal of the operational amplifier U1A is connected to the 12V voltage H12V and ground GND respectively. The other end of resistor R204 is connected to one end of resistor R205 and the common terminal of the dual-path diode D2 respectively. The other end of resistor R205 is grounded. The negative terminal of the dual-path diode D2 is connected to the voltage VCC. The positive terminal of the dual-path diode D2 is grounded. The common end of the dual diode D2 , the resistor R204 , and the resistor R205 is the output end of the lamp current detection circuit, and the output is the analog current ILAMP_ADC.

[0048] In the electronic ballast of this application, the MCU is used to control the single-lamp and dual-lamp state machine to determine the single-lamp and dual-lamp status based on the dual-lamp voltage signal collected by the dual-lamp voltage detection circuit and the single-lamp voltage signal collected by the single-lamp voltage detection circuit, and output a PWM pulse signal based on the determination result. The power conversion circuit is used to perform power conversion after receiving the PWM pulse signal to control the electronic ballast to achieve dual-lamp power balancing.

[0049] Specifically, the realization of the dual-lamp power balancing of the electronic ballast of the present application is based on the collection of Figure 2 The ADC values ​​of the three pins PA00, PA01 and PB12 of the MCU in the middle, namely the single-chip microcomputer U2, of which the PA00 pin collects Figure 3 The voltage value of the analog voltage V2_ADC in the PB12 pin is collected Figure 4 The voltage value of the analog voltage V1_ADC in the PA01 pin is collected Figure 7 The current value of the analog current ILAMP_ADC is converted into the actual lamp voltage and lamp current value through interpolation. Then a single or double lamp judgment is performed through the single or double lamp state machine: when the output end of the electronic ballast is connected to a double lamp or a single lamp No. 1 (only the first UV lamp is connected), Figure 2 The microcontroller U2 uses the analog voltage V2_ADC collected by the PA00 pin and the analog current ILAMP_ADC collected by the PA01 pin to multiply and calculate the power of the dual lamps or the single lamp No. 1. When the electronic ballast is only connected to the single lamp No. 2 (only the second UV lamp is connected), Figure 2The single-chip microcomputer U2 multiplies the voltage value of the analog voltage V1_ADC collected by the PB12 pin and the current value of the analog current ILAMP_ADC collected by the PA01 pin to calculate and obtain the power of the No. 2 single lamp. The single-double lamp state machine has three judgment processes, i.e. double-lamp judgment, No. 1 single-lamp judgment and No. 2 single-lamp judgment.

[0050] Figure 2 After the single-chip microcomputer U2 is initialized and powered on, the voltage value of the analog voltage V2_ADC collected by the PA00 pin is first judged. When the voltage value of the analog voltage V2_ADC is greater than the threshold voltage VREF pre-set in the single-chip microcomputer, it indicates that the filaments at the No. 1 terminal and the No. 2 terminal of the single-double lamp state machine are in good contact, and the single-double lamp state machine enters the double-lamp judgment process; otherwise, it indicates that the filaments at the No. 1 terminal and the No. 2 terminal are not connected well, and it is considered that there is no No. 1 single lamp in the circuit, and the No. 2 single-lamp judgment process is entered; the No. 1 single-lamp judgment process is after the double-lamp judgment process; the specific implementation of each process is briefly described below.

[0051] The double-lamp judgment process is as shown in Figure 5 First, the relays A and D are disconnected, and the relays B and C are closed. When the voltage value of the analog voltage V2_ADC is less than or equal to the threshold voltage VREF, it is considered that the filaments in the single-double lamp state machine are all connected, and it is a double-lamp circuit, and the double-lamp lighting process is started; otherwise, when the voltage value of the analog voltage V2_ADC is greater than the threshold voltage VREF, it indicates that the filaments 3, 4, 5, 6, 7 and 8 in the single-double lamp state machine are not connected well, and the No. 1 single-lamp judgment process is entered.

[0052] The No. 1 single-lamp judgment process is as shown in Figure 5 First, the relays B and C are kept closed, and the relay D is closed. Figure 2 The single-chip microcomputer U2 detects the voltage value of the analog voltage V2_ADC of the PA00 pin. If the voltage value of the analog voltage V2_ADC is less than or equal to the threshold voltage VREF, it is determined that the filaments 3 and 4 in the single-double lamp state machine are in good contact. Since it is confirmed in the double-lamp judgment process that there is only one lamp or no lamp in the circuit, it is determined that the No. 1 single lamp is connected correctly, and the No. 2 single lamp is connected incorrectly. After the No. 1 single-lamp lighting process is started, the judgment is ended. Otherwise, if the voltage value of the analog voltage V2_ADC is greater than the threshold voltage VREF, it is determined that the filaments 3 and 4 in the single-double lamp state machine are not in good contact, and it is determined that the No. 1 single lamp is also not connected well, and then the No. 2 single-lamp judgment process is entered.

[0053] The No. 2 single-lamp judgment process is as shown in Figure 5As shown, first disconnect the relay B, C, D, and close the relay A, detect the voltage value of analog voltage V1_ADC. If the voltage value of analog voltage V1_ADC is less than or equal to the threshold voltage VREF, then infer the filament 5, 6 in the single-double lamp state machine contact is poor, indicating that the 2 single lamp wiring problem, identified in the circuit without any lamp, the end of the judgment process. Otherwise, if the voltage value of analog voltage V1_ADC is greater than the threshold voltage VREF, then determine the filament 5, 6 in the single-double lamp state machine contact is good. Keep the relay A closed while closing the relay B, C, again detect the voltage value of analog voltage V1_ADC. If the voltage value of analog voltage V1_ADC is greater than the threshold voltage VREF, indicating that the filament 7, 8 in the single-double lamp state machine contact is poor, indicating that the 2 single lamp wiring problem, identified in the circuit without any lamp, the end of the judgment process. Conversely, if the voltage value of analog voltage V1_ADC is less than or equal to the threshold voltage VREF, indicating that the filament 7, 8 in the single-double lamp state machine contact is good, identified 2 single lamp wiring is normal, start 2 single lamp lighting process, the end of the judgment process.

[0054] Power calculation: after determining the state of the lamp connected through the single-double lamp state machine, if the double lamp or 1 single lamp is connected, the analog voltage V2_ADC and analog current ILAMP_ADC value are multiplied, and the actual power of the double lamp or 1 single lamp is obtained through the interpolation operation method inside the single-chip microcomputer; if the 2 single lamp is connected, the analog voltage V1_ADC and analog current ILAMP are multiplied, and the actual power of the 2 single lamp is obtained through the interpolation operation method inside the single-chip microcomputer.

[0055] Constant power: after calculating the actual power, whether the single lamp or the double lamp is connected, the MCU will perform the PID algorithm to perform constant output of power. After calculating the actual power, it will be compared with Figure 2 the power threshold set in the single-chip microcomputer, when the calculated actual power is greater than the set power threshold, the MCU will increase the frequency of the PWM pulse signal, which is to reduce Figure 2 the frequency of the PWM pulse signal output by the PB15 and PB14 pins of the single-chip microcomputer U2, and the PWM pulse signal will pass through Figure 1Resistors R304 and R305 transmit the PWM pulse signal to pins 2 and 3 of gate-enabling chip U301. After isolation and amplification within gate-enabling chip U301, the PWM pulse signal is output from pins 5 and 7 to control the operation of field-effect transistors Q301 and Q302, reducing the operating current of the UV lamp and thus adjusting the real-time power of the UV lamp. When the actual power of the UV lamp falls below the set power threshold, the MCU reduces the output frequency of the PWM pulse signal, thereby increasing the UV lamp current and ultimately improving the real-time power of the UV lamp. By dynamically adjusting the PWM pulse signal frequency in real time, the actual operating power of the UV lamp can be dynamically adjusted.

[0056] In summary, the electronic ballast for monitoring the power balance of dual lamps in this application mainly includes a hardware circuit part and a software part. Among them, the hardware circuit part mainly includes Figure 1 The power conversion circuit, an LCC resonant half-bridge circuit, performs power conversion, primarily converting input energy into the energy required for UV lamp operation. Since the input energy refers to AC power, and since this input AC power is a low-frequency 47-63Hz, it cannot be directly used by the UV lamp. The function of the electronic ballast is to convert the input AC power into the high-frequency AC power required for UV lamp operation, and the LCC resonant half-bridge circuit is the circuit that performs this conversion. The conversion principle is to use the PWM pulse signals PWMH and PWML to drive the switching MOSFET at high speed, generating high-frequency AC power.

[0057] Figure 2 It is the logic control unit of the single chip microcomputer, which mainly controls the working sequence of the entire circuit and realizes various protections, such as heartbeat, preheating, starting and operation. In the heartbeat stage, Figure 2 The microcontroller U2 will output a PWM signal with a frequency of 50KHz and a duty cycle of 5% through the PB14 and PB15 pins. Figure 1 The resistors R304 and R305 transmit the signal to the pins 2 and 3 of the gate start chip U301. After being isolated and amplified inside the gate start chip U301, the signal is output from pins 5 and 7 to control the operation of the field effect transistors Q301 and Q302, thereby outputting the electronic ballast current. Then the preheating stage begins. Before preheating, the microcontroller U2 will output a 3.3V voltage through the PA08 pin to control Figure 5 The relay B in the circuit is closed, and then the PB14 and PB15 pins of the microcontroller U2 output the PWM of the preheating frequency and duty cycle. The PWM output signal circuit principle is the same as the heartbeat stage, generating a working current to preheat the lamp. After the preheating is completed, the lamp is ignited. Before ignition, the microcontroller U2 will turn off the voltage output by the PA08 pin, so that Figure 5The relay is disconnected, and then the PWM signal of the ignition frequency and the duty cycle is outputted to light the lamp. Finally, the ignition is completed and enters the running stage, and the PWM signal of the running frequency and the duty cycle is outputted to maintain the normal work of the lamp tube.

[0058] Figure 3 、 Figure 4 and Figure 5 The circuit is mainly used for collecting and operating the lamp tube voltage of two ultraviolet lamp tubes. Figure 6 and Figure 7 The circuit is mainly used for collecting and operating the lamp tube current of two ultraviolet lamp tubes. Through the above hardware circuit and the software control, a circuit capable of collecting the data of the working voltage and the working current of the ultraviolet lamp in real time is provided, and the real-time power of the lamp tube is judged to realize and guarantee the high efficiency and reliable work of the ballast and the lamp tube.

[0059] Therefore, the electronic ballast for monitoring the power balance of double lamps can accurately detect the real-time working power of any ultraviolet lamp when the two ultraviolet lamp tubes work at the output end of the electronic ballast, ensure the working power balance of the two ultraviolet lamp tubes, accurately control and adjust the working power of the two ultraviolet lamp tubes, ensure the safe and reliable work of the electronic ballast itself and the ultraviolet lamp tube, and thus ensure that the two ultraviolet lamp tubes do not work in overload, and the service life of the ultraviolet lamp tube can be improved.

[0060] The technical features of the above embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0061] The principles and implementation modes of the present application are described by using specific examples in this paper, and the above embodiment description is only used to help understand the method and the core idea of the present application; meanwhile, for the general technical personnel in the art, according to the idea of the present application, the specific implementation mode and the application range will be changed. In conclusion, the content of the present application should not be understood as the limitation of the present application.

Claims

1. An electronic ballast for monitoring power balance of two lamps, characterized in that: include: MCU, power conversion circuit, single and dual lamp state machine, dual lamp tube voltage detection circuit, single lamp tube voltage detection circuit, lamp tube current sampling circuit and lamp tube current detection circuit; The lamp tube voltage output end of the power conversion circuit is connected to the input end of the single-dual lamp state machine, the dual-lamp lamp tube voltage output end of the single-dual lamp state machine is connected to the input end of the dual-lamp lamp tube voltage detection circuit, and the output end of the dual-lamp lamp tube voltage detection circuit is connected to the dual-lamp voltage input end of the MCU; the single-lamp lamp tube voltage output end of the single-dual lamp state machine is connected to the input end of the single-lamp lamp tube voltage detection circuit, and the output end of the single-lamp lamp tube voltage detection circuit is connected to the single-lamp voltage input end of the MCU; the lamp tube current output end of the power conversion circuit is connected to the input end of the lamp tube current sampling circuit, the output end of the lamp tube current sampling circuit is connected to the input end of the lamp tube current detection circuit, and the output end of the lamp tube current detection circuit is connected to the current input end of the MCU; The MCU is used to control the single-lamp and dual-lamp state machine to perform single-lamp and dual-lamp state judgment based on the dual-lamp tube voltage signal collected by the dual-lamp tube voltage detection circuit and the single-lamp tube voltage signal collected by the single-lamp tube voltage detection circuit, and output a PWM pulse signal based on the judgment result; the output end of the MCU is connected to the drive signal input end of the power conversion circuit, and the power conversion circuit is used to perform power conversion after receiving the PWM pulse signal to control the electronic ballast to achieve dual-lamp power balancing; The single and double lamp state machine specifically includes: relay A, relay B, relay C, relay D, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, resistor R1A, resistor R2A, resistor R3A, resistor R4A, resistor R5A, resistor R6A and resistor R7A; The first terminal of the single / double lamp state machine is connected to the first ultraviolet lamp tube, and the first terminal introduces four filaments, including filament 1, filament 2, filament 3 and filament 4; the second terminal of the single / double lamp state machine is connected to the second ultraviolet lamp tube, and the second terminal introduces four filaments, including filament 5, filament 6, filament 7 and filament 8; the filament 1 is connected to one end of the relay A; the filament 2 is respectively connected to one end of the resistor R5 and one end of the relay B; the other end of the resistor R5 is connected to the resistor R4 One end is connected, the other end of the resistor R4 is connected to one end of the resistor R3, the other end of the resistor R3 is respectively connected to one end of the resistor R2 and one end of the resistor R7, the other end of the resistor R2 is connected to one end of the resistor R1, the other end of the resistor R7 is connected to one end of the resistor R6, and the other end of the resistor R1 and the other end of the resistor R6 are both grounded; the common end of the resistor R6 and the resistor R7 is the dual lamp tube voltage output end of the single and dual lamp state machine; the filament 3 is connected to The other end of the relay B is connected; the filament 4 is respectively connected to the other end of the relay A, one end of the relay D and the filament 5; the filament 6 is respectively connected to one end of the resistor R5A and one end of the relay C; the other end of the resistor R5A is connected to one end of the resistor R4A, the other end of the resistor R4A is connected to one end of the resistor R3A, the other end of the resistor R3A is respectively connected to one end of the resistor R2A and one end of the resistor R7A, the other end of the resistor R2A is connected to one end of the resistor R1A, the other end of the resistor R7A is connected to one end of the resistor R6A, and the other end of the resistor R1A and the other end of the resistor R6A are both grounded; the common end of the resistor R6A and the resistor R7A is the single lamp tube voltage output end of the single and double lamp state machine; the filament 7 is connected to the other end of the relay C; the filament 8 is connected to the other end of the relay D; the common end of the relay A and the filament 1 is the input end of the single and double lamp state machine.

2. The electronic ballast for monitoring power balance of two lamps according to claim 1, characterized in that: The PB14 and PB15 pins of the MCU serve as the output terminals of the MCU, the PA00 pin of the MCU serves as the dual-lamp voltage input terminal of the MCU, the PB12 pin of the MCU serves as the single-lamp voltage input terminal of the MCU, and the PA01 pin of the MCU serves as the current input terminal of the MCU.

3. The electronic ballast for monitoring dual lamp power balance according to claim 2, characterized in that: The power conversion circuit specifically includes: resistor R304, resistor R305, resistor R317, resistor R302, resistor R303, resistor R306, resistor R308, resistor RCS1, diode D302, gate start chip U301, capacitor C303, capacitor C304, capacitor C305, field effect transistor Q301, field effect transistor Q302, resonant inductor L301A and ultraviolet lamp LAMP; The HIN pin of the gate startup chip U301 is connected to one end of the resistor R304, and the other end of the resistor R304 is connected to the PB15 pin of the MCU; the LIN pin of the gate startup chip U301 is connected to one end of the resistor R305, and the other end of the resistor R305 is connected to the PB14 pin of the MCU; the COM pin of the gate startup chip U301 is grounded; the VCC pin of the gate startup chip U301 and the positive electrode of the diode D302 are both connected to a 12V voltage; the negative electrode of the diode D302 is connected to a 12V voltage. The VB pin of the gate startup chip U301 and the other end of the resistor R317 are both connected to one end of the capacitor C304; the HO pin of the gate startup chip U301 is connected to one end of the resistor R302; the other end of the resistor R302 is respectively connected to the gate of the field effect transistor Q301 and one end of the resistor R303; the LO pin of the gate startup chip U301 is connected to one end of the resistor R306; the other end of the resistor R306 is respectively connected to the gate of the field effect transistor Q301 and one end of the resistor R303. The gate of the field effect transistor Q302 and one end of the resistor R308 are connected; the source of the field effect transistor Q302 and the other end of the resistor R308 are grounded; the drain of the field effect transistor Q301 is connected to the voltage Vdc1; the source of the field effect transistor Q301, the other end of the resistor R303, the other end of the capacitor C304, the VS pin of the gate start chip U301 and the drain of the field effect transistor Q302 are all connected to one end of the resonant inductor L301A; the other end of the resonant inductor L301A is connected to one end of the capacitor C303 The other end of the capacitor C303 is respectively connected to one end of the capacitor C305 and one end of the ultraviolet lamp LAMP; the other end of the ultraviolet lamp LAMP is connected to one end of the resistor RCS1; the other end of the resistor RCS1 and the other end of the capacitor C305 are both grounded; the common end of the capacitor C303, the capacitor C305 and the ultraviolet lamp LAMP is the lamp voltage output end of the power conversion circuit; the common end of the ultraviolet lamp LAMP and the resistor RCS1 is the lamp current output end of the power conversion circuit.

4. The electronic ballast for monitoring power balance of two lamps according to claim 1, characterized in that: The dual-lamp tube voltage detection circuit specifically includes: resistor R101, resistor R102, resistor R103, resistor R104, resistor R105, resistor R106, resistor R107, resistor R109, dual-path diode D1, operational amplifier U1C and voltage regulator diode ZD1; One end of the resistor R101 serves as the input end of the dual-lamp tube voltage detection circuit and is connected to the dual-lamp tube voltage output end of the single-dual-lamp state machine; the other end of the resistor R101 is respectively connected to one end of the resistor R103 and one end of the resistor R102; the other end of the resistor R103 is respectively connected to one end of the resistor R104 and the negative electrode of the voltage-stabilizing tube ZD1; the positive electrode of the voltage-stabilizing tube ZD1 and the other end of the resistor R102 are both grounded; the other end of the resistor R104 is connected to the positive input end of the operational amplifier U1C; the negative input end of the operational amplifier U1C is respectively connected to the positive input end of the resistor R105 One end of the dual-path diode D1 is connected to one end of the resistor R106; the other end of the resistor R105 is grounded; the other end of the resistor R106 is respectively connected to one end of the resistor R107 and the output end of the operational amplifier U1C; the other end of the resistor R107 is respectively connected to the common end of the dual-path diode D1 and one end of the resistor R109; the other end of the resistor R109 is grounded; the cathode end of the dual-path diode D1 is connected to the voltage VCC; the anode end of the dual-path diode D1 is grounded; the common end of the dual-path diode D1, the resistor R107 and the resistor R109 is the output end of the dual-lamp tube voltage detection circuit.

5. The electronic ballast for monitoring power balance of two lamps according to claim 1, characterized in that: The single lamp tube voltage detection circuit specifically includes: a resistor R101A, a resistor R102A, a resistor R103A, a resistor R104A, a resistor R105A, a resistor R106A, a resistor R107A, a resistor R109A, a dual-path diode D1A, an operational amplifier U2C, and a voltage regulator diode ZD1A; One end of the resistor R101A serves as the input end of the single-lamp tube voltage detection circuit and is connected to the single-lamp tube voltage output end of the single-lamp and double-lamp state machine; the other end of the resistor R101A is respectively connected to one end of the resistor R103A and one end of the resistor R102A; the other end of the resistor R103A is respectively connected to one end of the resistor R104A and the negative electrode of the voltage-stabilizing tube ZD1A; the positive electrode of the voltage-stabilizing tube ZD1A and the other end of the resistor R102A are both grounded; the other end of the resistor R104A is connected to the positive input end of the operational amplifier U2C; the negative input end of the operational amplifier U2C is respectively connected to one end of the resistor R105A The cathode of the dual-path diode D1A is connected to the voltage VCC; the anode of the dual-path diode D1A is grounded; the common end of the dual-path diode D1A, the resistor R107A and the resistor R109A is the output end of the single-lamp voltage detection circuit.

6. The electronic ballast for monitoring power balance of two lamps according to claim 1, characterized in that: The lamp current sampling circuit specifically includes: a resistor R8 and a capacitor C1; One end of the resistor R8 serves as the input end of the lamp current sampling circuit and is connected to the lamp current output end of the power conversion circuit; the other end of the resistor R8 is connected to one end of the capacitor C1; the other end of the capacitor C1 is grounded; and the common end of the resistor R8 and the capacitor C1 serves as the output end of the lamp current sampling circuit.

7. The electronic ballast for monitoring power balance of two lamps according to claim 1, characterized in that: The lamp current detection circuit specifically includes: a resistor R201, a resistor R202, a resistor R203, a resistor R204, a resistor R205, a dual-path diode D2, an operational amplifier U1A and a voltage regulator diode ZD2; One end of the resistor R201 is connected to the negative electrode of the voltage regulator ZD2, and is connected to the output end of the lamp current sampling circuit as the input end of the lamp current detection circuit; the positive electrode of the voltage regulator ZD2 is grounded; the other end of the resistor R201 is connected to the positive input end of the operational amplifier U1A; the negative input end of the operational amplifier U1A is respectively connected to one end of the resistor R203 and one end of the resistor R202; the other end of the resistor R202 is grounded; the other end of the resistor R203 is respectively connected to one end of the resistor R204 and the output end of the operational amplifier U1A; the other end of the resistor R204 is respectively connected to one end of the resistor R205 and the common end of the dual-path diode D2; the other end of the resistor R205 is grounded; the negative end of the dual-path diode D2 is connected to the voltage VCC; the positive end of the dual-path diode D2 is grounded; the common end of the dual-path diode D2, the resistor R204 and the resistor R205 is the output end of the lamp current detection circuit.

8. The electronic ballast for monitoring power balance of two lamps according to claim 1, characterized in that: If the judgment result is that both the first ultraviolet lamp and the second ultraviolet lamp are connected to the electronic ballast or only the first ultraviolet lamp is connected to the electronic ballast, the MCU calculates the actual power using a difference operation method based on the dual-lamp voltage signal collected by the dual-lamp voltage detection circuit and the lamp current signal collected by the lamp current detection circuit; If the judgment result is that only the second ultraviolet lamp is connected to the electronic ballast, the MCU calculates the actual power using a difference operation method based on the single lamp voltage signal collected by the single lamp voltage detection circuit and the lamp current signal collected by the lamp current detection circuit.

9. The electronic ballast for monitoring power balance of two lamps according to claim 8, characterized in that: The actual power is compared with the power threshold preset by the MCU; if the actual power is greater than or equal to the power threshold, the MCU increases the frequency of the output PWM pulse signal; if the actual power is less than the power threshold, the MCU reduces the frequency of the output PWM pulse signal.

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