CN103338545B - A kind of fluorescent lamp light adjusting circuit and method of work thereof - Google Patents

Abstract

The invention discloses a fluorescent lamp dimming circuit and its working method. The dimming circuit includes a main circuit, an auxiliary power supply module, a single-chip microcomputer control module and a drive module; the input power supply Vac is connected to the input of the auxiliary power supply module, and the output of the auxiliary power supply module Connect to the power input terminals of the single-chip control module and the drive module respectively, the single-chip control module samples the input voltage of the main circuit, the voltage at both ends of the fluorescent lamp and the voltage at both ends of the first capacitor, the input of the drive module is connected to the drive signal terminal of the single-chip control module, and drives The output of the module is connected to four switch tubes in the main circuit. The working method is that the single-chip microcomputer controls the on-off of the four switch tubes to change the capacitance value at both ends of the first capacitor according to the brightness adjustment requirements of the fluorescent lamp, thereby changing the voltage at both ends of the fluorescent lamp. The present invention is mainly used for adjusting the fluorescent lamp when the power is very low so that the fluorescent lamp will not be completely cut off.

Description

A fluorescent lamp dimming circuit and its working method

technical field

The invention relates to fluorescent lamp dimming technology, in particular to a dimming circuit and working method of fluorescent lamps, mercury lamps, sodium lamps and other fluorescent lamps.

Background technique

Lighting plays a vital role in reducing energy consumption and greenhouse gas emissions. New lighting equipment such as LED lights can be used to improve lighting efficiency. However, by effectively reducing power consumption (such as in some occasions through absence The fluorescent lamps are dimmed when people come, and the fluorescent lamps are turned on to reduce energy consumption when people come). Traditional fluorescent lamps are still very meaningful in terms of energy saving.

Controlling fluorescent lamps like fluorescent, mercury and sodium lamps, which are much more efficient than light bulbs, presents some serious challenges. Lights such as fluorescent lamps, each time they are turned on, reduce their life by about one hour, so they cannot be turned on and off frequently. However, many electronic ballasts currently used, such as Buck converters, adjust the brightness of fluorescent lamps by quickly and frequently turning on and off fluorescent lamps, which greatly reduces the life of fluorescent lamps. This is why electronic ballasts are not popular in the field of adjusting fluorescent lamps. reason for getting up.

Contents of the invention

In view of the above background, in order to overcome the existing deficiencies, the present invention provides a fluorescent lamp dimming circuit and its working method, which not only solves the problem that the electronic rectifier frequently cuts off the fluorescent lamp and reduces the life of the fluorescent lamp, but also consumes a lot of energy itself. low, so as to achieve the purpose of energy saving.

In order to achieve the above object, the technical scheme that the present invention takes is:

Fluorescent lamp dimming circuit, which includes the main circuit, auxiliary power module, single-chip control module and drive module; AC+ of the input power supply Vac is connected to the input of the auxiliary power module, and AC- is grounded; the output Vcc of the auxiliary power module is connected to the single-chip control module and the driver respectively. The power supply input terminal Vcc of the module is connected, the first voltage sensor 1 samples the voltage across the power supply, the second voltage sensor 2 samples the voltage across C1, the third voltage sensor 3 samples the voltage across the fluorescent lamp, the first voltage sensor 1 and the second voltage The output terminals of sensor 2 and the third voltage sensor 3 are connected to the voltage sampling terminal of the single-chip microcomputer control module; the input of the drive module is connected to the drive signal end of the single-chip control module, and the first drive signal, the second drive signal, and the third drive signal output by the drive module and the fourth driving signal are respectively connected to the gates of the first, second, third and fourth switching tubes in the main circuit.

Further optimized, the main circuit includes a first switch tube, a second switch tube, a third switch tube, a first switch tube, a first diode, a second diode, a third diode, and a fourth diode , the first capacitor, the fluorescent lamp, the first voltage sensor, the second voltage sensor and the third voltage sensor; The switch tube is connected in antiparallel with the third diode, the fourth switch tube is connected in antiparallel with the fourth diode, the drain of the first switch tube is connected in series with the drain of the second switch tube to form a bridge arm, the source of the third switch tube is connected with the The source of the fourth switching tube is connected in series to form a bridge arm, the positive pole of the first capacitor is connected to the drain of the first switching tube, the negative pole of the first capacitor is connected to the drain of the third switching tube; the input terminal of the first voltage sensor and the power input terminal In parallel, the input of the second voltage sensor is connected in parallel with the first capacitor, the input of the third voltage sensor is connected in parallel with the first fluorescent lamp, and the outputs of the first voltage sensor, the second voltage sensor and the third voltage sensor are connected to the voltage sampling terminal of the single-chip microcomputer control module; Fluorescent lamps are connected in series in the main circuit.

Further optimized, the auxiliary power supply module includes a rectifier bridge Bridge, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, and a fifth diode; a first regulator chip for outputting 15V DC voltage TL783 and the second regulator chip 7805 for outputting 5V DC voltage; the upper and lower ends of the rectifier bridge Bridge are respectively connected to the AC+ and AC- ends of the input power supply Vac, and the two ends are respectively connected to the two ends of the second capacitor; the second capacitor The positive terminal of the first voltage regulator chip is connected to the input terminal Vin of the first voltage regulator chip, the output terminal Vout of the first voltage regulator chip is connected to the input terminal Vin of the second voltage regulator chip, and the output terminal Vout of the second voltage regulator chip is connected to the single chip microcomputer module and the driver module. The input terminal Vcc is connected; the ground terminal of the first voltage stabilizing chip is connected to one end of the second resistor, and the other end of the second resistor is grounded; one end of the first resistor is connected to one end of the second resistor, and the other end is connected to the first voltage stabilizing chip. The output terminal Vout; the third capacitor is connected to the input terminal of the second voltage stabilizing chip, and the other end is grounded; the positive terminal of the fourth capacitor is connected to the output terminal of the second voltage stabilizing chip, and the other end is grounded; the positive terminal of the fifth diode is connected to the first The output terminal Vout of the second regulator tube is connected to the input terminal Vin of the second voltage regulator chip.

Further optimized, the drive module includes a NOT gate, a third resistor, a fourth resistor, a fifth capacitor, a sixth capacitor, a first AND gate, a second AND gate, four identical drive isolation circuits 1, 2, and 2. Drive isolation circuit three, drive isolation circuit four; the driving signal output by the single-chip microcomputer control module is respectively connected to the input of the NOT gate, one end of the fourth resistor and an input end of the first AND gate and the second AND gate; the output of the NOT gate is connected to the first AND gate One end of the three resistors, the other end of the third resistor is connected to one end of the first AND gate and one end of the fifth capacitor, and the other end of the fifth capacitor is grounded; the other end of the fourth resistor is connected to one end of the sixth capacitor and the second AND gate The other input end of the sixth capacitor is also grounded; the outputs of the first and second AND gates are respectively connected to the drive isolation circuit 1 and the drive isolation circuit 2.

Further optimized, each drive isolation circuit includes a fifth resistor, a sixth resistor, a fifth switch tube, an optocoupler isolator, a seventh resistor, and an eighth resistor; the drive isolation circuit and the sixth resistor of the drive isolation circuit are connected at one end The output of the first AND gate drives the isolation circuit, one end of the sixth resistor driving the isolation circuit is connected to the output of the second AND gate, the other end of the sixth resistor is connected to the base of the fifth switching tube, and the source of the fifth switching tube is grounded , the collector of the fifth open light tube is connected to the cathode of the input terminal of the optocoupler isolator, the anode of the optocoupler driver is connected to the fifth resistor, and the fifth resistor is connected to the output of the second voltage regulator chip in the auxiliary power module; the output of the optocoupler isolator The end is connected to the source of the main circuit drive switch tube, the other output end of the optocoupler isolator is connected to the eighth resistor and the seventh resistor, and the other end of the seventh resistor is connected to the output of the first voltage regulator chip in the auxiliary power module. The other end of the eight resistors is connected to the gate of the main circuit driving switch tube.

The working method of the above-mentioned fluorescent lamp dimming circuit: change the capacitance value at both ends of the first capacitor by the principle of voltage division, thereby changing the voltage division value at both ends of the first capacitor, thereby changing the voltage at both ends of the fluorescent lamp; the single-chip microcomputer control circuit in the single-chip microcomputer control module Receive the input power supply voltage sampled by the main circuit, the voltage across the first capacitor and the voltage across the fluorescent lamp, and then control the on-off of the four switch tubes to change the capacitance value at both ends of the first capacitor according to the brightness adjustment requirements of the fluorescent lamp.

Compared with the prior art, the present invention has the following advantages and technical effects: the present invention not only solves the problem that the electronic ballast frequently cuts off the fluorescent lamp to reduce the service life of the fluorescent lamp, but also consumes very low energy itself, thereby achieving energy saving the goal of. The single-chip microcomputer control module receives signals from the first voltage sensor, the second voltage sensor, and the third voltage sensor, and selects the moment when the first, second, third, and fourth switch tubes are turned on and off, thereby changing the capacitance value of the first capacitor, Change the voltage of the fluorescent lamp, thereby changing the brightness of the fluorescent lamp. The adjustment range of the fluorescent lamp adjusting circuit is wide, and the fluorescent lamp can be adjusted to a very dark level without turning off the fluorescent lamp.

Description of drawings

Fig. 1 is the general structural diagram of the present invention;

Fig. 2 is the circuit diagram of auxiliary power supply module of the present invention;

Fig. 3 is the circuit diagram of the drive module of the present invention;

Fig. 4 is a drive isolation circuit diagram in the drive module of the present invention;

detailed description

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings, but the implementation and protection scope of the present invention are not limited thereto.

Fig. 1 shows the overall structure diagram of the fluorescent lamp dimming circuit of the example of the present invention, which includes a main circuit, an auxiliary power supply module, a single-chip microcomputer control module, and a driving module. The main circuit includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first diode D1, a second diode D2, a third diode D1, a fourth switch tube Diode D2, first capacitor C1, fluorescent lamp, first voltage sensor 1, second voltage sensor 2, third voltage sensor 3. The first switching tube is connected in antiparallel to the first diode, the second switching tube is connected in antiparallel to the second diode, the third switching tube is connected in antiparallel to the third diode, and the fourth switching tube is connected in antiparallel to the fourth diode. In parallel, the drain of the first switching tube is connected in series with the drain of the second switching tube to form a bridge arm, the source of the third switching tube is connected in series with the source of the fourth switching tube to form a bridge arm, and the positive pole of the first capacitor is connected to the first switching tube The drain of the first capacitor is connected to the drain of the third switching tube. The input of the first voltage sensor 1 is connected in parallel with the input terminal of the power supply, the input of the second voltage sensor 2 is connected in parallel with the first capacitor, the input of the third voltage sensor 3 is connected in parallel with the first fluorescent lamp, the first voltage sensor 1, the second voltage sensor 2 and The output of the third voltage sensor 3 is connected to the voltage sampling terminal of the single-chip microcomputer control module. Fluorescent lamps are connected in series in the main circuit. The auxiliary power supply module converts the 220V AC voltage into 15V and 5V DC voltage outputs, and serves as the auxiliary power supply for the single-chip microcomputer control module and the drive module. Three voltage sensors sample voltage signals and input them to the single-chip microcomputer control module, and the single-chip microcomputer control module outputs driving signals to the driving module. The drive module divides the drive signal into two sets of isolated drive signals to drive the four switch tubes in the main circuit. By adjusting the conduction time of the first, second, third, and fourth switch tubes, the first, second, third, and fourth switch tubes are adjusted. The capacitance of a capacitor can adjust the brightness of the fluorescent lamp.

Figure 2 shows the circuit diagram of the auxiliary power module of the fluorescent lamp dimming circuit. The auxiliary power module includes a rectifier bridge Bridge, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1, a second resistor R2, a fifth capacitor diode. The first voltage regulator chip TL783 for outputting 15V DC voltage and the second voltage regulator chip 7805 for outputting 5V DC voltage. The upper and lower ends of the rectifier bridge Bridge are respectively connected to the AC+ and AC- ends of the input power Vac, and the two ends are respectively connected to the two ends of the second capacitor. The positive end of the second capacitor is connected to the Vin terminal of the first voltage regulator chip, the output terminal Vout of the first voltage regulator chip is connected to the input terminal Vin of the second voltage regulator chip, and the output terminal Vout of the second voltage regulator chip is connected to the microcontroller module and the driver. The input terminal Vcc of the module is connected. The ground end of the first voltage stabilizing chip is connected to one end of the second resistor, and the other end of the second resistor is grounded. One end of the first resistor is connected to one end of the second resistor, and the other end is connected to the output end of the first voltage stabilizing chip. The third capacitor C3 is connected to the input end of the second voltage stabilizing chip, and the other end is grounded. The positive terminal of the fourth capacitor is connected to the output terminal of the second voltage stabilizing chip, and the other terminal is grounded. The positive terminal of the fifth diode is connected to the output terminal Vout of the second voltage regulator transistor, and the other terminal is connected to the input terminal Vin of the second voltage regulator chip. The rectifier bridge rectifies the 220V AC voltage into a DC voltage, the fourth capacitor C2 is a filter capacitor, the resistance values of the first resistor and the second resistor adjust the output voltage of TL783, and the third capacitor C3 is the output of the first voltage regulator chip TL783 The filter capacitor and the input filter capacitor of the second voltage regulator chip 7805. The fourth capacitor C4 is an output filter capacitor of the second voltage stabilizing chip. The fifth diode protects the voltage regulator chip 7805 and provides a discharge circuit. TL783 and 7805 output DC voltage of 15V and 5V respectively, as the power supply of each control circuit inside the system.

Figure 3 is a circuit diagram of the drive module, the drive module includes a NOT gate U, a third resistor R3, a fourth resistor R4, a fifth capacitor C5, a sixth capacitor C6, a first AND gate U1, and a second AND gate U2, four of which are the same Drive isolation circuit 1, drive isolation circuit 2, drive isolation circuit 3, and drive isolation circuit 4. The drive signal output by the single-chip microcomputer control module is respectively connected to the input of the NOT gate, one end of the fourth resistor and one input end of the first AND gate and the second AND gate. The output of the NOT gate is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the first AND gate and one end of the fifth capacitor, the other end of the fifth capacitor is grounded; the other end of the fourth resistor is connected to the sixth capacitor One terminal and the other input terminal of the second AND gate, and the other terminal of the sixth capacitor are also grounded. Outputs of the first and second AND gates are respectively connected to the driving isolation circuit 1 and the driving isolation circuit 2. The NOT gate U reverses the driving signal of the single-chip microcomputer control module. When the high level of the NOT gate U arrives, since the voltage at both ends of the fifth capacitor C5 cannot change abruptly, the time for the rising edge of the output signal of the first AND gate U1 to arrive There is a certain delay in the arrival time of the rising edge of the output signal of the non-inverting gate U, resulting in a dead time. The two driving isolation circuits have the same structure, and their function is to isolate the driving signal, thereby solving the problem of isolated driving of the first and second switching tubes. Also for U2, the dead time is generated by the constant voltage across the sixth capacitor C6.

Fig. 4 is a circuit diagram of drive isolation in the drive module, each drive isolation circuit includes a fifth resistor, a sixth resistor, a fifth switch tube, an optocoupler isolator T1, a seventh resistor, and an eighth resistor; the drive isolation circuit 1, One end of the sixth resistor driving the isolation circuit 3 is connected to the output of the first AND gate, one end of the sixth resistor driving the isolation circuit 2 and the driving isolation circuit 4 is connected to the output of the second AND gate, and the other end of the sixth resistor is connected to the fifth switch tube The base of the fifth light switch, the source of the fifth light switch is grounded, the collector of the fifth light switch is connected to the cathode of the input terminal of the optocoupler isolator T1, the anode of the optocoupler driver T1 is connected to the fifth resistor, and the fifth resistor is connected to the auxiliary power supply module The output of the second voltage regulator chip; the output terminal of the optocoupler isolator T1 is connected to the source of the main circuit drive switch tube, the other output terminal of the optocoupler isolator T1 is connected with the eighth resistor and the seventh resistor, and the seventh resistor The other end is connected to the output of the first voltage stabilizing chip in the auxiliary power module, and the other end of the eighth resistor is connected to the gate of the main circuit drive switch tube. When the high level of the driving signal arrives, the fifth triode is turned on, and the optocoupler isolator T1 acts to drive the first and third switching transistors to turn on when the driving signal is at a low level. When the low level of the driving signal arrives, the fifth transistor is turned off, and the optocoupler isolator T1 acts to drive the second and fourth switching transistors to conduct when the driving signal is at a high level.

In the working method of the fluorescent lamp dimming circuit, the working method of the above fluorescent lamp dimming circuit: by the principle of voltage division, the capacitance value at both ends of the first capacitor C1 is changed, thereby changing the voltage division value at both ends of the first capacitor C1, thus changing the two ends of the fluorescent lamp. terminal voltage; the single-chip microcomputer control circuit in the single-chip microcomputer control module receives the input power supply voltage sampled by the main circuit, the voltage at both ends of the first capacitor C1, and the voltage at both ends of the fluorescent lamp, and then according to the brightness adjustment needs of the fluorescent lamp, the measured voltage and the above four The conduction relationship of the switch tubes determines the high and low pulse signals output by the single-chip microcomputer control module, so as to control the on-off of the four switch tubes to change the capacitance value at both ends of the first capacitor C1.

Working process: The single-chip microcomputer control module receives the signals of the first voltage sensor 1, the second voltage sensor 2, and the third voltage sensor 3, and selects the moment when the first, second, third, and fourth switch tubes are turned on and off, thereby changing the first voltage sensor The capacitance value of a capacitor changes the voltage of the fluorescent lamp, thereby changing the brightness of the fluorescent lamp. The adjustment range of the fluorescent lamp adjusting circuit is wide, and the fluorescent lamp can be adjusted to a very dark level without turning off the fluorescent lamp.

Claims (1)

1. a fluorescent lamp light adjusting circuit, is characterized in that comprising main circuit, auxiliary power module, single chip control module and driver module; The AC-of input power Vac connects auxiliary power module, the first voltage sensor, tertiary voltage transducer, and AC+ connects one end of the rectifier bridge in auxiliary power module; The output Vcc of auxiliary power module is connected with the power input Vcc of single chip control module and driver module respectively, first voltage sensor sampling both ends of power voltage, first electric capacity (C1) both end voltage in second voltage sensor sampling main circuit, tertiary voltage sensor sample fluorescent lamp both end voltage; The input of driver module connects the drive singal end of single chip control module, and the first drive singal that driver module exports, the second drive singal, the 3rd drive singal and four-wheel drive signal correspondingly connect the grid of the first, second, third and fourth switching tube in main circuit respectively; Main circuit comprises the first switching tube (Q1), second switch pipe (Q2), the 3rd switching tube (Q3), the 4th switching tube (Q4), the first diode (D1), the second diode (D2), the 3rd diode (D3), the 4th diode (D4), the first electric capacity (C1), fluorescent lamp, the first voltage sensor, the second voltage sensor and tertiary voltage transducer; First switching tube and the first diode inverse parallel, second switch pipe and the second diode inverse parallel, 3rd switching tube and the 3rd diode inverse parallel, 4th switching tube and the 4th diode inverse parallel, first switching tube drain electrode forms brachium pontis with the drain series of second switch pipe, the source series of the 3rd switching tube source electrode and the 4th switching tube forms brachium pontis, and the positive pole of the first electric capacity connects the drain electrode of the first switching tube, and the negative pole of the first electric capacity connects the source electrode of the 3rd switching tube; First voltage sensor and power sources in parallel, second voltage sensor and the first Capacitance parallel connection, tertiary voltage transducer and fluorescent lamp parallel connection, the output of the first voltage sensor, the second voltage sensor and tertiary voltage transducer connects the voltage sample end of single chip control module; Daylight lamp string is associated in main circuit; Auxiliary power module comprises rectifier bridge Bridge, the second electric capacity (C2), the 3rd electric capacity (C3), the 4th electric capacity (C4), the first resistance (R1), the second resistance (R2), the 5th diode; For exporting the first voltage stabilizing chip TL783 of 15V direct voltage and the second voltage stabilizing chip 7805 for exporting 5V direct voltage; The upper and lower two ends of rectifier bridge Bridge connect AC+ and the AC-two ends of input power Vac respectively, and output connects with the second electric capacity two ends respectively; The input Vin of the positive pole termination first voltage stabilizing chip of the second electric capacity, the output end vo ut of the first voltage stabilizing chip meets the input Vin of the second voltage stabilizing chip, and the output end vo ut of the second voltage stabilizing chip is connected with the input Vcc of single chip control module and driver module; The earth terminal of the first voltage stabilizing chip is connected with second resistance one end, the other end ground connection of the second resistance; One end of first resistance is connected to the tie point of the second resistance and the first voltage stabilizing chip TL783 earth terminal, the output end vo ut of another termination first voltage stabilizing chip; 3rd electric capacity (C3) connects the input of the second voltage stabilizing chip, other end ground connection; The output of the 4th capacitance cathode termination second voltage stabilizing chip, other end ground connection; The output end vo ut of the positive termination second voltage stabilizing chip of the 5th diode, the input Vin of another termination second voltage stabilizing chip; Driver module comprises not gate (S1), the 3rd resistance (R3), the 4th resistance (R4), the 5th electric capacity (C5), the 6th electric capacity (C6), first and door (U1), second and door (U2), four identical driving isolation circuit one, driving isolation circuit two, driving isolation circuit three, driving isolation circuit four; The drive singal that single chip control module exports connects the input of not gate, one end of the 4th resistance and first and door and second and an input of door respectively; The output of not gate connects one end of the 3rd resistance, another termination first of the 3rd resistance and another input of door and one end of the 5th electric capacity, the other end ground connection of the 5th electric capacity; One end of another termination the 6th electric capacity of the 4th resistance and second and another input of door, the other end also ground connection of the 6th electric capacity; First and second connect driving isolation circuit one, driving isolation circuit two respectively with the output of door; Each driving isolation circuit comprises the 5th resistance, the 6th resistance, the 5th switching tube, optical coupling isolator (T1), the 7th resistance, the 8th resistance; The 6th resistance one end of driving isolation circuit one, driving isolation circuit three connects the output of first and door, the 6th resistance one end of driving isolation circuit two, driving isolation circuit four connects the output of second and door, the other end of the 6th resistance connects the base stage of the 5th switching tube, the grounded emitter of the 5th switching tube, the collector electrode of the 5th switching tube connects the negative electrode of optical coupling isolator (T1) input, the anode of optical coupling isolator (T1) is connected with the 5th resistance, and the 5th resistance connects the output of the second voltage stabilizing chip in auxiliary power module; The source electrode of the output termination main circuit driving switch pipe of optical coupling isolator (T1), another output of optical coupling isolator (T1) is connected with the 7th resistance with the 8th resistance, the output of the first voltage stabilizing chip in another termination auxiliary power module of 7th resistance, the grid of another termination main circuit driving switch pipe of the 8th resistance; By changing the capacitance at the first electric capacity (C1) two ends, thus change the partial pressure value at the first electric capacity (C1) two ends, thus change the voltage at fluorescent lamp two ends; Single chip machine controlling circuit in single chip control module receives main circuit and to sample the input supply voltage, the first electric capacity (C1) both end voltage and the fluorescent lamp both end voltage that obtain, then according to fluorescent lamp brightness regulation needs, the break-make controlling four switching tubes changes the size of the capacitance at the first electric capacity (C1) two ends.