CN107517536B

CN107517536B - Breathing lamp control circuit and electronic equipment

Info

Publication number: CN107517536B
Application number: CN201710763650.5A
Authority: CN
Inventors: 王奔; 尹奇红
Original assignee: Shenzhen Xinguodu Payment Technology Co Ltd
Current assignee: Shenzhen Xinguodu Payment Technology Co Ltd
Priority date: 2017-08-30
Filing date: 2017-08-30
Publication date: 2020-01-17
Anticipated expiration: 2037-08-30
Also published as: CN107517536A

Abstract

The invention discloses a breathing lamp control circuit and electronic equipment, which comprise a square wave generating circuit, a control circuit and a control circuit, wherein the square wave generating circuit is connected with an IO port of a controller and outputs a variable square wave signal under the control of a level signal of the IO port; the waveform adjusting circuit is connected with the output side of the square wave generating circuit and is used for adjusting the square wave signal from the square wave generating circuit and outputting a triangular wave signal; and the switching circuit is connected with the output side of the waveform adjusting circuit, and the on-off of the switching circuit is controlled by a triangular wave signal so as to control the operation of the breathing lamp D34 connected with the switching circuit. Compared with the prior art, the breathing lamp control circuit is connected with an IO port of the controller through a control line, the level signal through the IO port controls the breathing lamp control circuit to achieve the effect of the breathing lamp, the IO port resource of the controller is effectively saved, and the breathing lamp control program adopting the control line is relatively simple compared with the breathing lamp control programs of multiple control lines, the development is easy, and the development cost is low.

Description

Breathing lamp control circuit and electronic equipment

Technical Field

The invention relates to the technical field of electronic equipment, in particular to a breathing lamp control circuit and electronic equipment.

Background

The breathing lamp is a decorative lamp, is widely used in various fields such as digital products, computers, sound equipment, automobiles and the like, has good visual decoration effect, for example, the breathing lamp is designed on a mobile phone, and when unprocessed notifications, such as missed calls, short messages which are not checked and received, and the like exist in the mobile phone, the breathing lamp changes from dark to bright, and is rhythmic like breathing, so that the function of notification reminding is realized; the breathing lamp is designed on the POS machine, and the electric quantity condition of the POS machine, including low electric quantity, charging, full power and other states, can be indicated by the breathing lamp, so that a user can charge and use the POS machine in time.

The design of breathing lamp can not leave breathing lamp control circuit, at present, general breathing lamp scheme adopts dedicated breathing lamp IC chip to control the mode realization of breathing lamp control circuit usually, need IIC bus in the hardware design, but often need two IO mouths to simulate the IIC bus because the bus is not enough, all need go the communication through the IIC interface when the control breathing lamp of every time of will operating, cause design software to need a large amount of time, the cost of labor, and this kind of scheme is difficult to realize under the limited condition of system IO mouth resource. For example, in the chinese patent application "201611033925.1", the processing module controls the light emission of the light emitting diode LED1, the light emitting diode LED2, and the light emitting diode LED3 through four output terminals, so that a processing chip in the processing module needs to provide four IO ports, and thus needs to occupy more IO ports of the processing chip.

In order to avoid wasting the IO port resources of the controllers such as the CPU and the like, the number of connecting lines between the breathing lamp control circuit and the controllers such as the CPU and the like is reduced as much as possible, so that the IO port resources are saved, and meanwhile, the program design is simpler.

Disclosure of Invention

The invention aims to provide a breathing lamp control circuit and electronic equipment for realizing the breathing lamp effect by using single IO port control.

In order to solve the technical problems, the invention discloses the following technical scheme: a breathing lamp control circuit, breathing lamp control circuit includes:

the square wave generating circuit is connected with an IO port of the controller and is controlled by a level signal of the IO port to output a changed square wave signal;

the waveform adjusting circuit is connected with the output side of the square wave generating circuit and is used for adjusting the square wave signal from the square wave generating circuit and outputting a triangular wave signal;

and the switching circuit is connected with the output side of the waveform adjusting circuit, and the on-off of the switching circuit is controlled by the triangular wave signal so as to control the work of the breathing lamp connected with the switching circuit.

The further technical scheme is as follows: the square wave generating circuit comprises a comparator U37A, a resistor R408 and a capacitor C17, wherein the non-inverting input end of the comparator U37A is connected with a reference voltage VCC1, the output end of the comparator U37A is serially connected with the capacitor C17 through the resistor R408 to be grounded, one end of the capacitor C17 connected with the resistor R408 is also connected with the inverting input end of the comparator U37A, the output end of the comparator U37A is connected with the waveform adjusting circuit, and the IO port of the controller is connected between the capacitor C17 and the resistor R408.

The further technical scheme is as follows: and two ends of the capacitor C17 are also connected with a resistor R410 for voltage division in parallel.

The further technical scheme is as follows: still insert between the noninverting input of comparator U37A and reference voltage VCC1 and have a divider circuit and resistance R371, reference voltage VCC1 pass through divider circuit, resistance R371 and comparator U37A's noninverting input is connected, just comparator U37A's output passes through resistance R355 and connects in comparator U371A's noninverting input.

The further technical scheme is as follows: the waveform adjusting circuit is an integrating circuit.

The further technical scheme is as follows: the integrating circuit comprises a resistor R370 and a capacitor C39, wherein one end of the resistor R370 is connected with the square wave generating circuit, the other end is grounded through a capacitor C39, and the end is connected with the switch circuit.

The further technical scheme is as follows: the switching circuit comprises a switching tube, the switching tube is connected with the waveform adjusting circuit and is controlled by a triangular wave signal output by the waveform adjusting circuit to be switched on and off.

The further technical scheme is as follows: the switch tube is field effect transistor Q40, switch circuit is still including breathing lamp power VCC3, resistance R114 and resistance R373, the positive pole of breathing lamp is passed through resistance R114 and is connected with power VCC3, the negative pole of breathing lamp with field effect transistor Q40's drain electrode is connected, field effect transistor Q40's grid with the waveform adjustment circuit is connected, field effect transistor Q40's grid is still through resistance R373 ground connection, field effect transistor Q40's source ground connection.

The further technical scheme is as follows: the switch tube is triode Q15, switch circuit is still including breathing lamp power VCC3, resistance R114 and resistance R373, the positive pole of breathing lamp pass through resistance R114 with breathing lamp power VCC3 connects, the negative pole of breathing lamp with triode Q15's projecting pole is connected, triode Q15's base with the waveform adjustment circuit connects, triode Q15's base still passes through resistance R373 ground connection, triode Q15's collecting electrode ground connection.

An electronic device comprises the breathing lamp control circuit.

The beneficial technical effects of the invention are as follows: the breathing lamp control circuit comprises a square wave generating circuit, a waveform adjusting circuit and a switch circuit, wherein the square wave generating circuit is connected with an IO port of a controller, a level signal through the IO port controls the square wave generating circuit to output a changed square wave signal, the square wave signal is adjusted into a triangular wave signal through the waveform adjusting circuit to control the on-off of the switch circuit, and therefore the work of the breathing lamp is controlled.

Drawings

FIG. 1 is a block diagram schematic of the structure of one embodiment of the present invention;

FIG. 2 is a circuit diagram of an embodiment of the present invention;

FIG. 3 is a waveform diagram of a triangular wave signal outputted from the waveform adjustment circuit according to an embodiment of the present invention;

fig. 4 is a circuit diagram of another embodiment of the present invention.

Detailed Description

In order to more fully understand the technical content of the present invention, the technical solution of the present invention is further described and illustrated below with reference to the schematic drawings, but not limited thereto.

As shown in fig. 1, fig. 2 and fig. 4, in the present invention, a breath lamp control circuit 1 is connected to a controller 2, the breath lamp control circuit 1 includes a square wave generating circuit 11, a waveform adjusting circuit 12 and a switch circuit 13, wherein the square wave generating circuit 11 is connected to an IO port of the controller 2, and the square wave generating circuit 11 is controlled by a level signal of the IO port to output a varying square wave signal; the waveform adjusting circuit 12 is connected to the output side of the square wave generating circuit 11, and is configured to adjust the square wave signal from the square wave generating circuit 11 to output a triangular wave signal; the switching circuit 13 is connected to the output side of the waveform adjusting circuit 12, and the on/off of the switching circuit is controlled by a triangular wave signal to control the operation of the breathing lamp connected thereto. When the breathing lamp works, the breathing lamp is indirectly controlled by the level signal of the IO port to present different working states, including three different working states of normally on, normally off, breathing lamp and the like. According to the circuit connection mode and the control effect of the invention, when the breathing lamp control circuit 1 is connected with the controller 2, only one IO port of the controller 2 is occupied, and the controller 2 sends a level signal to the breathing lamp control circuit 1 through the IO port, so that the work of the breathing lamp in the control circuit can be realized. Meanwhile, compared with the control programs of a plurality of IO ports, the control program of a single IO port is simpler, the development speed is higher, and the development cost is lower.

As shown in fig. 2, the square wave generating circuit 11 includes a comparator U37A, a resistor R408, and a capacitor C17, wherein a non-inverting input terminal of the comparator U37A is connected to a reference voltage VCC1, an output terminal of the comparator U37A is serially connected to the capacitor C17 through the resistor R408, and is grounded, one end of the capacitor C17 connected to the resistor R408 is further connected to an inverting input terminal of the comparator U37A, an output waveform adjusting circuit 12 of the comparator U37A is connected, and an IO port of the controller is connected between the capacitor C17 and the resistor R408. The CTR-LAMP connection in fig. 2 is a control line connecting the square wave generating circuit 11 and the IO port of the controller 2, a level signal of the IO port is transmitted to the square wave generating circuit 11 through the CTR-LAMP connection, the level of the level signal affects the voltage difference between the two ends of the capacitor C17, thereby affecting the working state of the capacitor C17, the capacitor C17 mainly includes three different working states of charging, discharging or non-charging and discharging, and when the capacitor C17 is continuously switched among the three different working states, the output end of the comparator U37A outputs a changed square wave signal. In addition, the voltage frequency of the output end of the comparator U37A is closely related to the capacity of the capacitor C17 and the resistance of the resistor R408, and the voltage frequency of the output end of the square wave generating circuit 11 can be adjusted by adjusting the sizes of the capacitor C17 and the resistor R408, so as to control the operating frequency of the breathing lamp.

In this embodiment, as shown in fig. 2, a resistor R410 is further connected in parallel to each end of the capacitor C17, and the resistor R410 is used for dividing voltage to raise the level of the inverting input terminal of the comparator U37A, so as to better control the output terminal of the comparator U37A to output a varying square wave signal.

In this embodiment, a voltage dividing circuit and a resistor R371 are further connected between the non-inverting input terminal of the comparator U37A and the reference voltage VCC1, the reference voltage VCC1 is connected to the non-inverting input terminal of the comparator U37A through the voltage dividing circuit and the resistor R371, and the output terminal of the comparator U37A is connected to the non-inverting input terminal of the comparator U371A through the resistor R355. In the present embodiment, as shown in fig. 2, the voltage divider circuit is implemented by a resistor R353 and a resistor R354 connected in series, wherein the resistor R353 is connected to the reference voltage VCC1, the resistor R354 is grounded, and the resistor R371 is connected between the resistor R353 and the resistor R354. Meanwhile, the precision of the resistor R353 and the resistor R354 in the embodiment is 1%, and the high-precision resistor R353 and the high-precision resistor R354 enable the voltage division of the voltage division circuit to be more accurate, so that the circuit effect can be realized.

In the square wave generating circuit 11 provided in this embodiment, the comparator U37A has a model number TP1542A-SR, the capacitor C17 is 4.7UF, the resistor R408 and the resistor R410 are both 680K Ω, the reference power source VCC1 is 1.8V, the power voltage VCC2 is 4.2V, the resistor R353 and the resistor R354 are both 10K Ω, the resistor R371 is 100K Ω, and the resistor R355 is 470K Ω.

In the present embodiment, the waveform adjusting circuit 12 is an integrating circuit, and the integrating circuit can adjust the square wave signal output by the square wave generating circuit 11 into a triangular wave signal, so as to moderate the voltage signal change input to the switching circuit 13, and avoid sudden change of the current flowing through the breathing lamp to cause the breathing lamp to suddenly turn on or turn off, which makes the breathing lamp easily damaged. As shown in fig. 2, the integrating circuit includes a resistor R370 and a capacitor C39, wherein one end of the resistor R370 is connected to the square wave generator 11, the other end is grounded via a capacitor C39, and the other end is connected to the switch circuit 13. The resistor R370 is 2M Ω, and the capacitor C39 is 1 UF.

In addition, the breath lamp in the invention is connected to the switch circuit 13, the working state of the breath lamp is influenced by the on-off of the switch circuit 13, in order to realize the breath lamp effect, the switch circuit 13 comprises an on-off tube, the on-off tube is connected with the waveform adjusting circuit 12, the on-off tube is closed or opened under the control of the output triangular wave signal of the waveform adjusting circuit 12, thereby the switch circuit 3 is switched on or off.

In the present embodiment, as shown in fig. 2, the switching tube is implemented by a field effect tube Q40, and the breathing lamp is implemented by a light emitting diode D34. Specifically, the switch circuit 13 further includes a breathing lamp power supply VCC3, a resistor R114, and a resistor R373, the anode of the light emitting diode D34 is connected to the power supply VCC3 through the resistor R114, the cathode of the light emitting diode D34 is connected to the drain of the field effect transistor Q40, the gate of the field effect transistor Q40 is connected to the output side of the waveform adjusting circuit 12, the gate of the field effect transistor Q40 is further grounded through the resistor R373, and the source of the field effect transistor Q40 is grounded. In the circuit, the resistor R114 plays a role of current limiting and is used for preventing the light emitting diode D34 from being burnt out due to excessive current. In addition, the resistor R373 and the resistor R370 in the waveform adjusting circuit 12 divide the voltage to adjust the voltage between the gate and the source of the fet Q40. In this embodiment, the fet Q40 is an N-channel fet, the fet Q40 is model DSS138, the breathing lamp power supply VCC3 is 3.3V, the resistor R114 is 1K Ω, and the resistor R373 is 3M Ω. Of course, in some other preferred embodiments, the fet Q40 may be implemented by a P-channel fet, and the specific connection circuit thereof is designed correspondingly according to the switching characteristics of the P-channel fet.

In other embodiments, the source of the fet Q4 may be connected to a 0 Ω resistor R422, and then grounded, and the resistor R422 may fine-tune the voltage between the gate and the source of the fet Q40, so as to better realize the breathing lamp effect of the led D34 controlled by the switching circuit 13. In addition, a 0 omega resistor R421 can be connected to the CTR-LAMP connection of the controller 2 and the square wave generating circuit 11 for the convenience of debugging the circuit.

In the breathing LAMP control circuit, a controller 2 inputs different level signals to a square wave generating circuit 11 through a CTR-LAMP connection wire, the level signals control voltage difference at two ends of a capacitor C17 to change, so that three different working states of charging, discharging or non-charging and discharging occur in the capacitor C17, therefore, the voltage at the inverting input end of a comparator U37A changes, the voltage at the output end of the comparator U37A changes along with the voltage change at the inverting input end, namely the comparator U37A outputs the changed square wave signals, then the square wave signals are adjusted into triangular wave signals through a waveform adjusting circuit 12, and the triangular wave signals control a switch circuit 13 to be switched on and switched off, so that a light emitting diode D34 is controlled to present a breathing LAMP effect. During actual work, level signal includes high level, low level and unsettled three kinds of types, and this breathing lamp control circuit realizes different operating condition according to the level signal of difference, specifically includes following three kinds of behavior:

(1) when the controller 2 outputs a high level to the square wave generating circuit 11 through the control line, the level of the inverting input terminal of the comparator U37A is greater than the level of the non-inverting input terminal of the comparator U37A, the output terminal of the comparator U37A outputs a low level, at this time, since the voltages at the two ends of the capacitor C17 are fixed, the capacitor C17 does not perform charging and discharging operations, the output terminal of the comparator U37A outputs a low level, the output terminal of the comparator U37A is connected with the gate of the field-effect transistor Q40 through the resistor R370, the voltage between the gate and the source of the field-effect transistor Q40 is low, the field-effect transistor Q40 is turned off, no current flows through the switching circuit 13, and the light-emitting diode D34 is;

(2) when the controller 2 outputs a low level to the square wave generating circuit 11 through the control line, the level of the inverting input terminal of the comparator U37A is lower than the level of the non-inverting input terminal of the comparator U37A, the output terminal of the comparator U37A outputs a high level, at this time, since the voltages at the two ends of the capacitor C17 are fixed, the capacitor C17 does not perform charging and discharging operations, the output terminal of the comparator U37A outputs a high level, the output terminal of the comparator U37A is connected with the gate of the field-effect transistor Q40 through the resistor R370, the voltage between the gate and the source of the field-effect transistor Q40 is higher, the field-effect transistor Q40 is turned on, a current flows through the switch circuit 13, and the light-emitting diode D34;

(3) when the controller 2 controls the control line to be empty, at the moment that the switch circuit 13 is powered on, the non-inverting input terminal of the comparator U37A is at a high level, the inverting input terminal of the comparator U37A is at a low level, and the output terminal of the comparator U37A is at a high level, at this moment, the square wave generating circuit 11 operates to charge the capacitor C17, the voltage at the inverting input terminal of the comparator U37A increases with the charging voltage of the capacitor C17, until the voltage at the inverting input terminal of the comparator U37A is greater than the voltage at the non-inverting input terminal of the comparator U37A, the output terminal of the comparator U37A outputs a low level, the capacitor C17 starts to discharge, the capacitor C17 starts to charge again after the voltage at the inverting input terminal of the comparator U37A is less than the voltage at the non-inverting input terminal of the comparator U37A, so that the capacitor C17 repeatedly charges and discharges, the output terminal of the comparator U37A forms an oscillator circuit through the repeated charge-discharge conversion, the output voltage is in a rectangular wave state, and the rectangular wave is input to the waveform adjusting circuit 12 to be adjusted, and the resistor R370 and the capacitor C39 in the waveform adjusting circuit 12 constitute an integrating circuit, so that the rising and falling of the rectangular wave are slowed down, and the rectangular wave is adjusted into a triangular wave, and the triangular wave controls the operation of the light emitting diode D34 through the switch circuit 13. As can be seen from the waveform of the triangular wave signal outputted from the waveform adjusting circuit shown in fig. 3, the waveform of the voltage outputted from the waveform adjusting circuit 12 is in a triangular wave state, so that the voltage signal inputted to the switching circuit 13 is constantly changed, that is, the voltage between the gate and the source of the fet Q40 is constantly changed, the fet Q40 constantly switches the switching state, specifically, when the voltage inputted to the switching circuit 13 is at the top end of the triangular wave, the fet Q40 is turned on, the led D34 lights, when the voltage inputted to the switching circuit 13 slowly drops from the top end of the triangular wave to the bottom end of the triangular wave, the fet Q40 gradually changes from the on state to the off state, and the led D34 gradually changes from on to off, and so on, the led D34 continuously flickers, thereby generating the breathing lamp effect.

In addition, in some other preferred embodiments, as shown in fig. 4, the light-on tube can be implemented by a transistor Q15, and the breathing light can be implemented by a light-emitting diode D34. Specifically, the switch circuit 13 further includes a breathing lamp power supply VCC3, a resistor R114, and a resistor R373, the anode of the light emitting diode D34 is connected to the breathing lamp power supply VCC3 through the resistor R114, the cathode of the light emitting diode D34 is connected to the emitter of the transistor Q15, the base of the transistor Q15 is connected to the output side of the waveform adjusting circuit 12, the base of the transistor Q15 is further grounded through the resistor R373, and the collector of the transistor Q15 is grounded. The resistor R114 plays a role of current limiting, and is used to prevent the led D34 from being burned out due to excessive current. In this embodiment, the transistor Q15 is implemented by a PNP transistor, the type of the transistor is SS8550, the power supply VCC3 is 3.3V, the resistor R114 is 1k Ω, and the resistor R373 is 3M Ω. Of course, in some other preferred embodiments, the transistor Q15 may also be implemented as an NPN transistor, and the specific connection circuit thereof is designed correspondingly according to the switching characteristics of the NPN transistor.

The circuit of the embodiment shown in fig. 4 operates in a manner substantially similar to the circuit of the embodiment provided in fig. 2, except that the transistor Q15 is used instead of the fet Q40 to implement the switching transistor. In actual operation, when the controller 2 outputs a high level to the square wave generating circuit 11 through the control line, the voltage at two ends of the capacitor C17 is fixed, the capacitor C17 cannot be charged and discharged, the low level output by the output end of the comparator U37A is fixed, the output end of the comparator U37A is connected with the base electrode of the triode Q15 through the resistor R370, the base electrode of the triode Q15 is at a low level, the triode Q15 is turned on, current flows through the switch circuit 13, and the light emitting diode D34 is in a normally bright state; when the controller 2 outputs a low level to the square wave generating circuit 11 through the control line, the voltage at two ends of the capacitor C17 is fixed, the capacitor C17 cannot realize a charging and discharging effect, the high level output by the output end of the comparator U37A is fixed, the output end of the comparator U37A is connected with the base electrode of the triode Q15 through the resistor R370, the base electrode of the triode Q15 is high level, the triode Q15 is cut off, no current flows through the switch circuit 13, and the light emitting diode D34 is in a normally off state; when the controller 2 controls the control line to be suspended, the capacitor C17 is repeatedly charged and discharged to form a voltage rectangular wave, the rectangular wave is adjusted to be a triangular wave by the waveform adjusting circuit 12, the base voltage of the triode Q15 is continuously changed, when the voltage input into the switching circuit 13 is at the top end of the triangular wave, the triode Q15 is cut off, the light emitting diode D34 is extinguished, when the voltage input into the switching circuit 13 is slowly lowered from the top end of the triangular wave to the bottom end of the triangular wave, the field effect transistor Q40 is slowly changed into a switched-on state from the cut-off state, the light emitting diode D34 is slowly lightened from the off state, and the operation is repeated, namely, the light emitting diode D34 continuously flickers, so that the breathing.

In the switching circuit 13 provided by the invention, the controller 2 is connected with the square wave generating circuit 11 through only one control line, the controller 2 inputs different level signals to the square wave generating circuit 11, the square wave generating circuit 11 outputs a changed square wave signal according to the level signal correspondingly, the square wave signal is adjusted into a triangular wave signal through the waveform adjusting circuit 12 and then is input into the switching circuit 13, and the breathing lamp is controlled to show three different effect changes of normally on, normally off or breathing lamp by controlling the on-off of the light-on tube in the switching circuit 13.

The present invention further provides an electronic device, which includes the above-mentioned breathing lamp control circuit, and the specific structure of the breathing lamp control circuit refers to the above-mentioned embodiments. The electronic device may be a POS machine, a mobile phone, or an electronic device such as a computer.

The above preferred embodiments should be considered as examples of the embodiments of the present application, and technical deductions, substitutions, improvements and the like similar to, similar to or based on the embodiments of the present application should be considered as the protection scope of the present patent.

Claims

1. A breath lamp control circuit is characterized in that the breath lamp control circuit comprises a square wave generating circuit, a waveform adjusting circuit and a switch circuit,

the square wave generating circuit is connected with an IO port of the controller and is controlled by a level signal of the IO port to output a variable square wave signal, the square wave generating circuit comprises a comparator U37A, a resistor R408, a resistor R410 and a capacitor C17, a non-inverting input end of the comparator U37A is connected with a reference voltage VCC1, an output end of the comparator U37A is serially connected with a capacitor C17 through the resistor R408 and is grounded, one end of the capacitor C17 connected with the resistor R408 is also connected with an inverting input end of the comparator U37A, the resistor R410 is connected with two ends of the capacitor C17 in parallel, an output end of the comparator U37A is connected with the waveform adjusting circuit, and the IO port of the controller is connected between the capacitor C17 and the resistor R408;

the switching circuit is connected with the output side of the waveform adjusting circuit, and the on-off of the switching circuit is controlled by a triangular wave signal so as to control the work of a breathing lamp connected with the switching circuit.

2. The breath lamp control circuit as claimed in claim 1, wherein a voltage divider circuit and a resistor R371 are further connected between the non-inverting input terminal of the comparator U37A and a reference voltage VCC1, the reference voltage VCC1 is connected to the non-inverting input terminal of the comparator U37A through the voltage divider circuit and the resistor R371, and the output terminal of the comparator U37A is connected to the non-inverting input terminal of the comparator U371A through the resistor R355.

3. The breath lamp control circuit of claim 1, wherein said waveform adjustment circuit is an integrating circuit.

4. The breath lamp control circuit as claimed in claim 3, wherein the integration circuit comprises a resistor R370 and a capacitor C39, wherein one end of the resistor R370 is connected to the square wave generating circuit, the other end is connected to ground via a capacitor C39, and the other end is connected to the switch circuit.

5. The breath lamp control circuit as claimed in claim 1, wherein the switch circuit comprises a switch tube, the switch tube is connected to the waveform adjusting circuit and is controlled by the triangular wave signal outputted from the waveform adjusting circuit to be turned on or off.

6. The breath lamp control circuit according to claim 5, wherein the switch transistor is a fet Q40, the switch circuit further comprises a breath lamp power VCC3, a resistor R114 and a resistor R373, the anode of the breath lamp is connected to the power VCC3 through the resistor R114, the cathode of the breath lamp is connected to the drain of the fet Q40, the gate of the fet Q40 is connected to the waveform adjustment circuit, the gate of the fet Q40 is further grounded through the resistor R373, and the source of the fet Q40 is grounded.

7. The breath lamp control circuit according to claim 5, wherein the switch tube is a transistor Q15, the switch circuit further comprises a breath lamp power supply VCC3, a resistor R114 and a resistor R373, the positive electrode of the breath lamp is connected to the breath lamp power supply VCC3 through the resistor R114, the negative electrode of the breath lamp is connected to the emitter of the transistor Q15, the base of the transistor Q15 is connected to the waveform adjusting circuit, the base of the transistor Q15 is further grounded through the resistor R373, and the collector of the transistor Q15 is grounded.

8. An electronic device, characterized in that the electronic device comprises a breathing lamp control circuit according to any of claims 1-7.