CN218185268U - Electron cigarette electromagnetic heating circuit and electron cigarette - Google Patents

Abstract

The utility model discloses an electronic cigarette electromagnetic heating circuit and an electronic cigarette, wherein the electromagnetic heating circuit comprises a switch circuit and a self-oscillation circuit, the self-oscillation circuit is used for receiving a self-oscillation working power supply to realize resonance and outputting a generated oscillation signal to an induction coil; the switching circuit is used for controlling the power supply connected according to the PWM signal to be converted into a grid power supply VGG and outputting the grid power supply VGG to a power tube of the self-oscillation circuit so as to control whether the self-oscillation circuit works and adjust the average power of the self-oscillation circuit during working based on the duty ratio of the PWM signal; and the utility model discloses a separate the VGG power, the power tube has better condition of starting to vibrate, generates heat still less, but also can reach the purpose that changes average power through PWM control VGG mains operated to change the temperature of heating member.

Description

Electron cigarette electromagnetic heating circuit and electron cigarette

Technical Field

The utility model relates to an electron cigarette field especially relates to an electron cigarette electromagnetic heating circuit and electron cigarette.

Background

In the existing electronic cigarette, a software-controlled oscillation circuit is adopted, an MOS tube in the software-controlled oscillation circuit completes oscillation, the software control difficulty is high, the time sequence control needs to be connected to a micro-level, the output waveform output to an induction coil is not ideal, and the harmonic distortion is large.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in, to prior art's above-mentioned defect, provide an electron cigarette electromagnetic heating circuit and electron cigarette.

The utility model provides a technical scheme that its technical problem adopted is: constructing an electronic cigarette electromagnetic heating circuit, wherein the electromagnetic heating circuit comprises:

the self-oscillation circuit is used for receiving a self-oscillation working power supply to realize resonance, outputting a generated oscillation signal to the induction coil and finally converting electric energy into heat energy of a heating body through an electromagnetic induction phenomenon, and comprises a working power supply receiving end and a power tube power supply receiving end, wherein the working power supply receiving end is used for receiving the self-oscillation working power supply, and the power tube power supply receiving end is used for receiving a grid power supply VGG (voltage gradient G) to supply a grid of a power tube in the self-oscillation circuit so as to drive the power tube to work;

the switching circuit comprises an output end connected with a power tube power supply receiving end of the self-oscillation circuit, a control end for receiving PWM signals, and an input end connected with a power supply of a single battery or a power supply after boosting processing, and is used for controlling the connected power supply to be converted into the grid power supply VGG according to the PWM signals and outputting the grid power supply VGG to the power tube power supply receiving end of the self-oscillation circuit so as to control whether the self-oscillation circuit works and adjust the average power of the self-oscillation circuit during working based on the duty ratio of the PWM signals.

Preferably, the electromagnetic heating circuit further comprises a first voltage boost circuit, which is used for boosting the power supply of the single battery, and the boosted power supply is input to the input end of the switch circuit to provide sufficient power supply for the power tube in the self-oscillation circuit.

Preferably, the electromagnetic heating circuit further comprises:

and the second booster circuit is used for boosting the power supply of the single battery, and inputting the boosted power supply to the working power supply receiving end of the self-oscillation circuit so as to provide enough self-oscillation working power supply for the self-oscillation circuit.

Preferably, the electromagnetic heating circuit further includes a third voltage boost circuit, configured to boost a power supply of a single battery, and input the boosted power supply to the input terminal of the switch circuit and the working power supply receiving terminal of the self-oscillation circuit, so as to provide a sufficient power supply for a power tube in the self-oscillation circuit and a sufficient self-oscillation working power supply for the self-oscillation circuit.

Preferably, the switch circuit includes a first switch tube and a second switch tube, an input end of the first switch tube is connected to an output end of the first voltage boost circuit, an output end of the first switch tube outputs the gate power VGG, a control end of the first switch tube is connected to an input end of the second switch tube, an output end of the second switch tube is connected to a power ground, and a control end of the second switch tube receives the PWM signal.

Preferably, the first switch tube is an MOS tube or a triode, and the second switch tube is an MOS tube or a triode.

Preferably, the first switching tube is an MOS tube, a source of the MOS tube is connected to the output end of the first boost circuit, a drain of the MOS tube outputs the gate power VGG, and a resistor is connected between the source and the gate, the second switching tube is a triode, a collector of the triode is connected to a gate of the MOS tube, a base of the triode receives the PWM signal through the resistor, and an emitter of the triode is connected to a power ground.

Preferably, the induction coil is a two-pin coil, the self-oscillation circuit includes two inductors, two MOS transistors, two diodes, and a capacitor, a first pin of the two-pin coil is connected to a first end of the first inductor, a cathode of the first diode, and a drain of the first MOS transistor, a cathode of the first diode is further connected to a second pin of the two-pin coil via the capacitor, a second pin of the two-pin coil is further connected to a first end of the second inductor, a cathode of the second diode, and a drain of the second MOS transistor, a second end of the first inductor and a second end of the second inductor respectively receive the self-oscillation working power supply, an anode of the first diode and an anode of the second diode respectively receive the gate power supply VGG via the resistor, an anode of the first diode is further connected to a gate of the second MOS transistor, an anode of the second diode is further connected to a gate of the first MOS transistor, a gate of the first MOS transistor and a gate of the second MOS transistor are further connected to a power supply ground via the resistor, and a source of the first MOS transistor and a source of the second MOS transistor are connected to a ground.

Preferably, the induction coil is a three-pin coil with a tap in the middle, the self-oscillation circuit includes an inductor, two MOS transistors, two diodes, and a capacitor, the tap in the middle of the three-pin coil is connected to a first end of the inductor, a second end of the inductor receives the self-oscillation working power supply, a first pin of the three-pin coil is connected to a cathode of the first diode and a drain of the first MOS transistor, a cathode of the first diode is further connected to a second pin of the three-pin coil via the capacitor, a second pin of the three-pin coil is further connected to a cathode of the second diode and a drain of the second MOS transistor, an anode of the first diode and an anode of the second diode respectively receive the gate power supply VGG via a resistor, an anode of the first diode is further connected to a gate of the second MOS transistor, an anode of the second diode is further connected to a gate of the first MOS transistor, a gate of the first MOS transistor and a gate of the second MOS transistor are further connected to a power ground via a resistor, and a source of the first MOS transistor and a source of the second MOS transistor are connected to a power ground.

The utility model discloses still construct an electron cigarette, include as aforesaid any one the electromagnetic heating circuit.

Further, the electronic cigarette is a heating non-combustion electronic cigarette.

The utility model discloses an electron cigarette electromagnetic heating circuit and electron cigarette has following beneficial effect: the self-oscillation circuit which consists of power tubes and works alternatively is adopted to generate harmonic waves, so that the waveform is good, the distortion is small, the electromagnetic interference is small, the electromagnetic compatibility characteristic is good, software does not need to intervene each oscillating time sequence deeply, and the method is very simple; and the utility model discloses well grid power supply VGG of power tube among the self-oscillating circuit and self-oscillating circuit's self-oscillation working power supply are detached, grid power supply VGG is by the switch circuit input, be the power supply alone, the grid operating voltage value of self-oscillating circuit's power tube has probably been drawn higher possibility like this, can let the power tube have better condition of starting to shake, the generating heat of power tube can still less, and through PWM control VGG mains operated, reach the purpose that changes average power, thereby change the temperature of heating member.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts:

fig. 1 is a schematic circuit structure diagram of an electromagnetic heating circuit of an electronic cigarette according to a first embodiment of the present invention;

fig. 2 is a circuit schematic of a self-oscillating circuit of the first embodiment;

fig. 3 is a schematic circuit diagram of the booster circuit according to the first embodiment;

FIG. 4 is two circuit schematic diagrams of the switching circuit of the first embodiment;

fig. 5 is a circuit schematic diagram of a self-oscillation circuit of the second embodiment;

fig. 6 is a schematic circuit structure diagram of an electromagnetic heating circuit of an electronic cigarette according to a third embodiment of the present invention;

fig. 7 is a schematic circuit structure diagram of an electromagnetic heating circuit of an electronic cigarette according to a fourth embodiment of the present invention;

fig. 8 is a schematic circuit structure diagram of an electromagnetic heating circuit of an electronic cigarette according to a fifth embodiment of the present invention.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. Exemplary embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The terms including ordinal numbers such as "first", "second", and the like used in the present specification may be used to describe various components, but the components are not limited by the terms. These terms are used only for the purpose of distinguishing one constituent element from other constituent elements. For example, a first component may be named as a second component, and similarly, a second component may also be named as a first component, without departing from the scope of the present invention. The word "connected" or "connecting" is intended to encompass not only the direct connection of two entities, but also the indirect connection via other entities with beneficial and improved effects.

Referring to fig. 1, the general idea of the present invention is: an electronic cigarette and an electromagnetic heating circuit thereof are constructed, and the electronic cigarette can be a heating non-combustion electronic cigarette, namely an HNB electronic cigarette. This electromagnetic heating circuit includes:

the self-oscillation circuit 103 is used for receiving a self-oscillation working power supply to realize resonance, outputting a generated oscillation signal to the induction coil and finally converting electric energy into heat energy of a heating body through an electromagnetic induction phenomenon, and comprises a working power supply receiving end and a power tube power supply receiving end, wherein the working power supply receiving end is used for receiving the self-oscillation working power supply, and the power tube power supply receiving end is used for receiving a grid power supply VGG (voltage grid generator) to supply a grid of a power tube in the self-oscillation circuit so as to drive the power tube to work.

The switch circuit 102 includes an output terminal connected to a power tube power receiving terminal of the self-oscillation circuit 103, a control terminal for receiving a PWM signal, and an input terminal connected to a power source of a single battery or a power source after boosting, and the switch circuit 102 is configured to control the power source connected according to the PWM signal to be converted into the gate power VGG and output the gate power VGG to the power tube power receiving terminal of the self-oscillation circuit 103, so as to control whether the self-oscillation circuit 103 operates and adjust an average power of the self-oscillation circuit 103 during operation based on a duty ratio of the PWM signal. The PWM signal includes a first level and a second level, where the first level is a low level and the second level is a high level, or the first level is a high level and the second level is a low level. When the PWM signal is at the first level, the switch circuit 102 is turned on, and the gate power VGG output by the switch circuit 102 can be output to the gate of the power transistor of the self-oscillation circuit 103, so that the self-oscillation circuit 103 can operate; on the contrary, when the PWM signal is at the second level, the switch circuit 102 is turned off, and the switch circuit 102 does not output any power to the gate of the power transistor of the self-oscillation circuit 103, so that the self-oscillation circuit 103 cannot operate.

The self-oscillation circuit which consists of power tubes and works alternatively is adopted to generate harmonic waves, so that the waveform is good, the distortion is small, the electromagnetic interference is small, the electromagnetic compatibility characteristic is good, software does not need to intervene each oscillating time sequence so deeply, and the method is very simple. And because grid power VGG of the power tube and the self-oscillation working power supply of the self-oscillation circuit 103 are separated, and the grid power VGG is supplied with power by the switching circuit alone, the grid working voltage value of the power tube can be pulled higher, the power tube can have better oscillation starting conditions, the power tube can generate less heat, and the working time of the self-oscillation circuit 103 can be controlled by adjusting the ratio of the first level and the second level, so that the power of the self-oscillation circuit 103 can be adjusted, and the temperature of the heating body can be changed.

In order to better understand the technical solutions, the technical solutions will be described in detail below with reference to the drawings and the specific embodiments of the specification, and it should be understood that the specific features in the embodiments and examples of the present invention are detailed descriptions of the technical solutions of the present application, but not limitations of the technical solutions of the present application, and the technical features in the embodiments and examples of the present invention can be combined with each other without conflict.

Example one

The electromagnetic heating circuit of the electronic cigarette in the embodiment is suitable for electronic cigarettes with single batteries, and VDD in fig. 2 represents a power supply of the single battery. The electromagnetic heating circuit includes a first booster circuit 101, a switching circuit 102, and a self-oscillating circuit 103, which are connected in this order.

The specific composition and function of each circuit is explained in detail below.

Referring to fig. 2, the induction coil of this embodiment is a two-pin coil, the self-oscillation circuit 103 includes two inductors, two MOS transistors, two diodes, and a resonant capacitor, a first pin L + of the two-pin coil is connected to a first end of a first inductor L2, a negative electrode of the first diode D1, and a drain of the first MOS transistor Q1, a negative electrode of the first diode D1 is further connected to a second pin L-of the two-pin coil through the resonant capacitor C1, a second pin L-of the two-pin coil is further connected to a first end of a second inductor L3, a negative electrode of the second diode D2, and a drain of the second MOS transistor Q2, and a second end of the first inductor L2 and a second end of the second inductor L3 respectively receive the self-oscillation working power supply, that is, a connection between the second end of the first inductor L2 and the second end of the second inductor L3 is used as a working power supply receiving end of the self-oscillation circuit 103. In the embodiment, the self-oscillation operating power supply is specifically provided by a single battery, and is therefore specifically VDD. The anode of the first diode D1 and the anode of the second diode D2 receive the gate power VGG through the resistors R1 and R2, respectively, that is, the connection node of the resistors R1 and R2 is the power transistor power receiving end of the self-oscillation circuit 103. The positive electrode of the first diode D1 is further connected with the grid electrode of the second MOS tube Q2, the positive electrode of the second diode D2 is further connected with the grid electrode of the first MOS tube Q1, the grid electrode of the first MOS tube Q1 and the grid electrode of the second MOS tube Q2 are further connected with a power ground through resistors R3 and R4 respectively, and the source electrode of the first MOS tube Q1 and the source electrode of the second MOS tube Q2 are connected with the power ground.

Wherein, the resistance values of the resistors R1 and R2 are less than about 500R, R3 and R4 and are about 10K. The capacitor C1 is a resonance capacitor, the C1 and the induction coil jointly determine the oscillation frequency, and the induction coil, the resonance capacitor and the power tube which alternately works form an oscillator with certain output power. C1 is a capacitor having a high withstand voltage ratio and good high-frequency characteristics, and has a capacitance value of more than 0.1uF. The resonance frequency is above 100KHZ, and belongs to the ISMB wave band. The inductances L2 and L3 are selected to have inductance values less than 1uH for packaging and current-passing reasons. The package should be as large as possible in view of PCB board space size, but in practice there may not be enough space on the board to fit, with a minimum package of 0630 integrated inductor. The MOS transistor is selected to be more than 30V, the junction capacitance is relatively small, and the on-resistance is also as small as possible.

In this embodiment, the whole self-oscillation circuit 103 is externally connected with two power supplies: VDD and VGG. VDD is the self-oscillation power supply of the self-oscillation circuit 103, and this embodiment separately introduces VGG to supply power to the gate of the MOS transistor on the basis again, mainly for better oscillation starting, specifically: VGG once adds, the grid voltage of two MOS pipes Q1, Q2 has a rise process, be equivalent to the process that grid capacitance is charged, receive the dispersibility influence that the grid source electric capacity of resistance R1, R2 and Q1, Q2 exists, grid voltage rising speed can be different, thereby it switches on to rise fast reach the voltage that switches on the needs earlier this MOS, pull down the grid of another MOS simultaneously, let this MOS turn-off, thereby begin to oscillate (also start to vibrate). Because the grid power VGG of the MOS tube Q1 and the grid power VGG of the MOS tube Q2 are separated and independently supply power, the grid working voltage values of the two MOS tubes can be pulled higher, the higher VGG can enable the MOS tubes to have better oscillation starting conditions, and the heat generation of the MOS tubes is less.

The PWM signal is sent by the MCU of the electronic cigarette, and the PWM signal is a signal for controlling the average output power of the self-oscillation circuit 103, when the PWM signal is high, the self-oscillation circuit 103 works, and the MOS tubes Q1 and Q2 are alternately switched on and off; when this signal is low, the self-oscillation circuit 103 does not operate. The frequency of the signal should be much lower than the frequency of the self-oscillation circuit 103, and is selected to be about 200Hz, and the minimum duty ratio should ensure that the self-oscillation circuit 103 can oscillate for more than 100 (about) oscillation cycles, so as to ensure the working safety of the oscillator.

The purpose of the first voltage boost circuit 101 is to boost the voltage of the battery-supplied power source VDD to the switch circuit 102, thereby ensuring that sufficient gate power source VGG is supplied to the power transistor gate of the self-oscillation circuit 103. The first boosting circuit 101 in this embodiment includes a boosting control chip and its peripheral circuits, such as a voltage dividing circuit. The input end of the boost control chip is connected with the battery to obtain a power supply VDD, and the power supply VDD is boosted according to the proportion of the voltage division circuit and then output, and specifically, a power supply VG is output to the switch circuit 102.

Specifically, referring to fig. 3, U1 represents a boost control chip, a VIN pin and an EN pin of the boost control chip are connected to a battery, a power supply VDD is connected, an inductor L1 is connected in series between the VIN pin and a SW pin, the SW pin is also connected to an anode of a diode D3, a cathode of the diode D3 outputs a boosted power supply, which is temporarily recorded as a power supply VG, the power supply VG is 4.2-12V, and an output current of 500mA is sufficient. The resistors R7 and R8 constitute a voltage dividing circuit, and U2 can be boosted according to the voltage dividing ratio of R7 and R8. And the capacitors C2 and C3 are connected in parallel and are connected between the cathode of the diode D3 and the power ground for filtering.

It should be noted that the first voltage boost circuit 101 of the present embodiment is only an example, and the first voltage boost circuit 101 may take various forms as long as the required voltage and output current can be achieved, which is not limited.

Referring to fig. 4, the switch circuit 102 includes a first switch tube Q3 and a second switch tube Q4, wherein an input terminal of the first switch tube Q3 is connected to an output terminal of the first boost circuit 101, that is, an input terminal of the first switch tube Q3 is used for receiving the power supply VG at the input terminal of the switch circuit 102. The output end of the first switch tube Q3 is used as the output end of the switch circuit 102 to output the gate power VGG, the control end of the first switch tube Q3 is connected to the input end of the second switch tube Q4, the output end of the second switch tube Q4 is connected to a power ground, the control end of the second switch tube Q4 is used as the control end of the switch circuit 102 to receive the PWM signal, and the temperature is adjusted and controlled by PWM control of the gate power VGG.

It is understood that the first switching tube Q3 may be a MOS tube or a transistor, and the second switching tube Q4 may be a MOS tube or a transistor. For example, in the left diagram (a) of fig. 4, the first switching tube Q3 is a PMOS tube, a source of the PMOS tube is connected to the output end of the first boosting circuit 101, a drain of the PMOS tube outputs the gate power VGG, and a resistor is connected between the source and the gate, the second switching tube Q4 is an NPN type triode, a collector of the NPN type triode is connected to a gate of the PMOS tube, a base of the NPN type triode receives the PWM signal via the resistor, and an emitter of the NPN type triode is connected to the power VGG, more specifically, Q3 is a low-power PMOS, and the current 2A is packaged with an SOT 23; q4 is an NPN triode packaged by the SOT23 or the SOT523 and used for level conversion. For another example, the right diagram (b) in fig. 4 shows another mode, in which Q3 and Q4 are both NPN transistors.

In fig. 4, the VG voltage is always present (except for the electronic cigarette sleep), but the VGG voltage should control whether the VGG voltage is added or not according to actual needs, when Q4 is turned on, the voltage of VG is added to VGG for the subsequent self-oscillation circuit 103 to use, otherwise, when Q4 is turned off, the self-oscillation circuit 103 cannot work.

In conclusion, the beneficial effects of the embodiment are as follows: in this embodiment, since software does not intervene in the operating behavior of the MOS transistor in the oscillation circuit in the oscillation period, it is not necessary to control the timing sequence in the oscillation period, a self-oscillation hardware circuit is used, the software controls the output power by controlling PWM, the oscillation output (signals at both ends of the induction coil) is a harmonic wave, and since the resonant frequency changes automatically after the heating metal tube and the smoke cartridge are added to the induction coil, the oscillation circuit is always resonant as long as the oscillation circuit operates, and therefore, the voltage waveform on the induction coil is a sine wave, so that the signals are cleaner, the distortion is small, and the electromagnetic compatibility characteristic is better. In addition, the common oscillation circuit is difficult to apply to the electronic cigarette, especially to the HNB electronic cigarette, because the working voltage VDD of the electronic cigarette is too low, the oscillation starting difficulty is large, and once the MOS cannot be burned, the oscillation starting circuit is extremely unsafe. In addition, the size of an inductor of a common oscillating circuit is overlarge, the heat generated by the inductor is overlarge, and the temperature of the PCBA is overhigh, so that the temperature of a shell is overhigh, the overall efficiency is overlow, and the use value is not high. Therefore, the HNB electronic cigarette is not applied to the HNB electronic cigarette at present. In the embodiment, the power supply VDD is divided into two paths of power supplies, namely VDD and VGG, and one path of boosted VGG is provided for the grid electrode of the MOS tube independently, so that better bias voltage can be provided for the power amplifier tube, the power tube has better oscillation starting conditions, and the power tube generates less heat; and the output average power can be controlled by controlling the existence or nonexistence of the output of the grid power supply VGG (PWM control to the grid power supply) so as to control the temperature of the heated body, because the switching circuit controls the working or nonexistence of the self-oscillation circuit through a PWM signal and controls the working duty ratio of the oscillation circuit, thereby changing the average power of the self-oscillation circuit and changing the temperature of the heating body.

Example two

Referring to fig. 5, the difference between this embodiment and the first embodiment is that the induction coil is a three-pin coil with a tap in the middle, the self-oscillation circuit 103 includes an inductor, two MOS transistors, two diodes, and a capacitor, the tap L0 in the middle of the three-pin coil is connected to a first end of the inductor L2, a second end of the inductor L2 receives a power supply VDD, a first pin L + of the three-pin coil is connected to a negative electrode of a first diode D1 and a drain of a first MOS transistor Q1, a negative electrode of the first diode D1 is further connected to a second pin L-of the three-pin coil through the capacitor C1, the second pin L-of the three-pin coil is further connected with the cathode of the second diode D2 and the drain of the second MOS tube Q2, the anode of the first diode D1 and the anode of the second diode D2 receive the grid power VGG through the resistors R1 and R2 respectively, the anode of the first diode D1 is further connected with the grid of the second MOS tube Q2, the anode of the second diode D2 is further connected with the grid of the first MOS tube Q1, the grid of the first MOS tube Q1 and the grid of the second MOS tube Q2 are further connected with the power ground through the resistors R3 and R4 respectively, and the source of the first MOS tube Q1 and the source of the second MOS tube Q2 are connected with the power ground.

EXAMPLE III

Referring to fig. 6, the present embodiment is different from the first embodiment in that the batteries are specifically multiple batteries connected in series. Therefore, the power supply VDD provided by the battery is large enough, and boosting is not necessary, so that the first boosting circuit 101 in the first embodiment can be omitted, and the input terminal of the switching circuit 102 is directly connected to the power supply VDD of a single battery.

Example four

Referring to fig. 7, the present embodiment is different from the first embodiment in that a second voltage boosting circuit 104 is additionally added for performing voltage boosting processing on the power supply VDD of a single battery, and the boosted power supply VD is input to the working power supply receiving terminal of the self-oscillation circuit 103, so as to provide sufficient self-oscillation working power supply for the self-oscillation circuit.

The first booster circuit 101 can be boosted to a higher voltage of, for example, 5-12V, and the second booster circuit 104 can be powered by the first booster circuit 101 with a lower voltage but with a strong driving capability to power the self-oscillating circuit with a voltage of 4-12V.

EXAMPLE five

Referring to fig. 8, the present embodiment is different from the first embodiment in that the first booster circuit 101 of the first embodiment is replaced with a third booster circuit 105. The third voltage boost circuit 105 boosts the power of a single battery, and inputs the boosted power VD to the input terminal of the switch circuit 102 and the working power receiving terminal of the self-oscillation circuit 103, that is, to provide sufficient power for the power tube in the self-oscillation circuit and sufficient self-oscillation working power for the self-oscillation circuit at the same time. For example, the third boost circuit 105 may be a high power boost circuit, the output voltage is 4-12V, which is higher than a battery voltage, and the driving capability is strong.

To sum up, the utility model discloses in, an oscillator that has certain output constitutes from alternate work's among the oscillating circuit power tube and resonant capacitor and induction coil, when this oscillator during operation the direct current voltage of battery becomes the alternating voltage on the induction coil, rethread electromagnetic induction phenomenon finally converts the electric energy into the heat energy of heat-generating body. The utility model separates the grid power supply VGG from the self-oscillation circuit through processing, the VGG is used as a control signal, the switch circuit is responsible for carrying out necessary control on the VGG signal according to the PWM signal characteristic, the oscillator can work intermittently according to the requirement, the average power output by the oscillator can be controlled according to the requirement, thus the temperature of the heating element is also controlled; moreover, the VGG power supply is independently supplied with power, so that the power tube has better oscillation starting conditions and generates less heat; moreover, the oscillator is always resonant when in operation, the output waveform is a sine wave, the distortion is small, the electromagnetic compatibility characteristic is good, and software does not need to intervene each oscillating time sequence deeply. The heating temperature is controlled more simply by software; because the current of the circuit is continuously changed, the whole heating process has no current sound. It is very quiet.

While the embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many modifications may be made by one skilled in the art without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims (10)

1. An electronic cigarette electromagnetic heating circuit, characterized in that, the electromagnetic heating circuit includes:

the self-oscillation circuit is used for receiving a self-oscillation working power supply to realize resonance, outputting a generated oscillation signal to the induction coil and finally converting electric energy into heat energy of a heating body through an electromagnetic induction phenomenon, and comprises a working power supply receiving end and a power tube power supply receiving end, wherein the working power supply receiving end is used for receiving the self-oscillation working power supply, and the power tube power supply receiving end is used for receiving a grid power supply VGG (voltage gradient G) to supply a grid of a power tube in the self-oscillation circuit so as to drive the power tube to work;

the switching circuit comprises an output end connected with a power tube power supply receiving end of the self-oscillation circuit, a control end for receiving PWM signals, and an input end connected with a power supply of a single battery or a power supply after boosting processing, and is used for controlling the connected power supply to be converted into the grid power supply VGG according to the PWM signals and outputting the grid power supply VGG to the power tube power supply receiving end of the self-oscillation circuit so as to control whether the self-oscillation circuit works and adjust the average power of the self-oscillation circuit during working based on the duty ratio of the PWM signals.

2. The electromagnetic heating circuit of the electronic cigarette according to claim 1, further comprising a first voltage boosting circuit for boosting the power of the single battery, wherein the boosted power is input to the input terminal of the switching circuit to provide sufficient power for the power tube in the self-oscillating circuit.

3. The electronic cigarette electromagnetic heating circuit of claim 2, wherein the electromagnetic heating circuit further comprises:

and the second booster circuit is used for boosting the power supply of the single battery, and inputting the boosted power supply to the working power supply receiving end of the self-oscillation circuit so as to provide enough self-oscillation working power supply for the self-oscillation circuit.

4. The electromagnetic heating circuit of claim 1, further comprising a third voltage boosting circuit for boosting the power of the single battery, and inputting the boosted power to the input terminal of the switching circuit and the working power receiving terminal of the self-oscillating circuit, so as to provide sufficient power for the power tube in the self-oscillating circuit and sufficient self-oscillating working power for the self-oscillating circuit.

5. The electronic cigarette electromagnetic heating circuit of claim 2, wherein the switch circuit comprises a first switch tube and a second switch tube, an input end of the first switch tube is connected to an output end of the first boost circuit, an output end of the first switch tube outputs the gate power VGG, a control end of the first switch tube is connected to an input end of the second switch tube, an output end of the second switch tube is connected to a power ground, and a control end of the second switch tube receives the PWM signal.

6. The electronic cigarette electromagnetic heating circuit of claim 5, wherein the first switch tube is an MOS tube or a triode, and the second switch tube is an MOS tube or a triode.

7. The electromagnetic heating circuit of claim 6, wherein the first switch tube is an MOS tube, a source of the MOS tube is connected to the output terminal of the first boost circuit, a drain of the MOS tube outputs the gate power VGG, and a resistor is connected between the source and the gate, the second switch tube is a triode, a collector of the triode is connected to the gate of the MOS tube, a base of the triode receives the PWM signal through the resistor, and an emitter of the triode is connected to a power ground.

8. The electromagnetic heating circuit of claim 1, wherein the induction coil is a two-pin coil, the self-oscillating circuit comprises two inductors, two MOS transistors, two diodes, and a capacitor, a first pin of the two-pin coil is connected to a first end of the first inductor, a cathode of the first diode, and a drain of the first MOS transistor, a cathode of the first diode is further connected to a second pin of the two-pin coil via the capacitor, a second pin of the two-pin coil is further connected to a first end of the second inductor, a cathode of the second diode, and a drain of the second MOS transistor, a second end of the first inductor and a second end of the second inductor receive the self-oscillating working power supply, an anode of the first diode and an anode of the second diode receive the gate power VGG via the resistor, an anode of the first diode is further connected to a gate of the second MOS transistor, an anode of the second diode is further connected to a gate of the first MOS transistor, a gate of the first MOS transistor and a gate of the second MOS transistor are further connected to a power supply ground via the resistor, and a source of the second MOS transistor is further connected to a ground.

9. The electromagnetic heating circuit of claim 1, wherein the induction coil is a three-pin coil with a tap in the middle, the self-oscillating circuit comprises an inductor, two MOS transistors, two diodes, and a capacitor, the tap in the middle of the three-pin coil is connected to a first end of the inductor, a second end of the inductor receives the self-oscillating operating power supply, a first pin of the three-pin coil is connected to a cathode of the first diode and a drain of the first MOS transistor, a cathode of the first diode is further connected to a second pin of the three-pin coil via the capacitor, a second pin of the three-pin coil is further connected to a cathode of the second diode and a drain of the second MOS transistor, an anode of the first diode and an anode of the second diode receive the gate power VGG via the resistor, an anode of the first diode is further connected to a gate of the second MOS transistor, an anode of the second diode is further connected to a gate of the first MOS transistor, and a gate of the first MOS transistor are further connected to a power ground via the resistor, and a source of the first MOS transistor and a source of the second MOS transistor are further connected to a ground via the resistor.

10. An electronic cigarette, comprising an electromagnetic heating circuit according to any one of claims 1 to 8.

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