Patent Description:
Electronic cigarettes are a kind of relatively common simulative electronic-cigarette electronic products. The electronic cigarettes are mainly used for quitting cigarettes and substituting cigarettes. Main structures of an electronic cigarette include a battery rod and an atomizer. When a smoke inhaling action from smokers is detected, the battery rod supplies power to the atomizer to turn on the atomizer. When the atomizer is turned on, heating wires of the atomizer heat up, and tobacco liquid is heated and atomized to form an aerosol that simulates cigarette smoke. As a result, smokers have a similar experience for smoking electronic cigarettes to experience for smoking cigarettes.

In the process of realizing the present application, the named inventor found that the related technology as described above has the following problem. Currently, the existing electronic cigarette controls power output of the atomizer through a single switch circuit. When smoking, a controller controls to turn on the single switch circuit, and further turn on the atomizer. When smoking is finished, the controller controls to turn off the single switch circuit, and the atomizer is therefore turned off. Such output control circuit of the above mentioned electronic cigarette has a simple structure and a better cost advantage. However, when the controller fails or is in an abnormal state, or when the single switch circuit fails, the atomizer of the electronic cigarette is hence led to turn on and continue to output power. As a result, safety risks such as fire, etc., may be caused.

Of note is patent document <CIT> which discloses an aerosol delivery device that includes a control body having a first switching circuit, and a cartridge having a heating element, an authentication device and a second switching circuit. The first and second switching circuits are coupled to manage the exchange of authentication signals and the supply of power to the heating element.

In order to solve the aforementioned technical problem, an output control circuit is provided in accordance with a preferred embodiment of the present invention, and reliability and safety of products related to the output control circuit are therefore enhanced.

In order to solve the aforementioned technical problem, an output control circuit applied in an electronic cigarette is provided in accordance with a preferred embodiment of the present invention. The electronic cigarette includes a battery assembly and an atomizer. The output control circuit includes a controller, a first switching circuit, a driving circuit and a second switching circuit. The controller is used to control switching-on or switching-off of the first switching circuit, and to provide pulse-width modulation (PWM) signals to the driving circuit.

The first switching circuit is respectively electrically connected with the battery assembly, the controller and the atomizer.

The driving circuit is electrically connected with the controller. The driving circuit is used for driving to switch on or switch off the second switching circuit according to the PWM signals.

The second switching circuit is respectively electrically connected with the battery assembly, the driving circuit and the atomizer.

The controller is electrically connected with the battery assembly.

The first switching circuit, the atomizer and the second switching circuit are electrically connected in series. The atomizer is switched on when the first switching circuit and the second switching circuit are switched on simultaneously.

The driving circuit includes a trigger circuit, a monostable circuit and a pulse width modulation (PWM) circuit.

The trigger circuit is respectively electrically connected with the battery assembly, the controller, the monostable circuit and the PWM circuit. The trigger circuit is used for triggering the controller to decide whether or not the monostable circuit is provided with PWM signals.

The monostable circuit is respectively electrically connected with the battery assembly, the controller, the second switching circuit and the PWM circuit. The monostable circuit includes an input and an output. The input of the monostable circuit is used to receive PWM signals, and the output of the monostable circuit is used to output high voltage level signals or low voltage level signals in order to control switching on or switching off of the second switching circuit based on the received PWM signals.

The PWM circuit is further electrically connected with the battery assembly. The PWM circuit is used to regulate pulse widths of the high voltage level signals or low voltage level signals.

Alternatively, the trigger circuit includes a first resistor and a switch.

A first end of the first resistor is electrically connected with the controller, and a second end of the first resistor is electrically connected with the monostable circuit.

A first end of the switch is electrically connected with the first end of the first resistor, and a second end of the switch is electrically connected with ground.

Alternatively, the PWM circuit includes a second resistor and a first capacitor.

A first end of the second resistor is respectively electrically connected with the battery assembly and the second end of the first resistor. A second end of the second resistor is respectively electrically connected with a first end of the first capacitor and the monostable circuit.

A second end of the first capacitor is electrically connected with ground.

Alternatively, the first switching circuit includes a second capacitor, a third resistor, a fourth resistor and a first metal oxide semiconductor field effect transistor (MOS) tube.

A first end of the second capacitor is electrically connected with the battery assembly, and a second end of the second capacitor is electrically connected with ground.

A first end of the third resistor is respectively electrically connected with the first end of the second capacitor and a source electrode of the first MOS tube. A second end of the third resistor is respectively electrically connected with the controller and a first end of the fourth resistor.

A second end of the fourth resistor is electrically connected with a gate electrode of the first MOS tube.

A drain electrode of the first MOS tube is electrically connected with a positive electrode of the atomizer.

Alternatively, the second switching circuit includes a second MOS tube. A gate electrode of the second MOS tube is electrically connected with an output of a monostable circuit of the driving circuit. A source electrode of the second MOS tube is electrically connected with ground. A drain electrode of the second MOS tube is electrically connected with a negative electrode of the atomizer.

Alternatively, the output control circuit further includes a current-limiting circuit. The current-limiting circuit is parallel electrically connected between the positive electrode of the atomizer and the negative electrode of the atomizer.

The current-limiting circuit includes a fifth resistor. The fifth resistor is used for restricting a quantity of electrical currents flowing into the atomizer.

Alternatively, the battery assembly includes the following.

A protective circuit is included. The protective circuit is electrically connected with the charging circuit.

A lithium battery is included. The lithium battery is electrically connected with the protective circuit.

A voltage stabilizing buck circuit is included. The voltage stabilizing buck circuit is respectively electrically connected with the lithium battery, the controller and the driving circuit.

Alternatively, the output control circuit further includes a prompt circuit. The prompt circuit is respectively electrically connected with the charging circuit and the controller.

The prompt circuit includes a sixth resistor and a light-emitting diode (LED) tube. A first end of the sixth resistor is electrically connected with the charging circuit, and a second end of the sixth resistor is electrically connected with a positive electrode of the LED tube. A negative electrode of the LED tube is electrically connected with the controller.

Alternatively, the atomizer includes a heating assembly and a temperature detecting circuit connected with the heating assembly. The temperature detecting circuit is electrically connected with the controller, and is used to detect temperature values of the heating assembly and to transmit the temperature values to the controller.

Beneficial advantages of the present invention include the following. In comparison with existing technology, the output control circuit is provided in accordance with a preferred embodiment of the present invention. Switching on of the atomizer is simultaneously controlled by the first switching circuit and the second switching circuit. Safety risk such as fire incidents is accordingly avoided when the atomizer of the electronic cigarette continuously outputs power due to the controller being out of order, either one of the first and second switching circuits being out of order, or the controller being in the malfunctioned status. Reliability and safety of products related to the electronic cigarette are therefore enhanced.

One or more embodiments in accordance with the present invention are illustratively exemplified for explanation through figures shown in the corresponding attached drawings. These exemplified descriptions do not constitute any limitation on the embodiments. The elements with the same reference numerals in the attached drawings are denoted as similar elements. Unless otherwise stated, the figures in the attached drawings do not constitute any scale limitation.

In order to facilitate best understanding of the present invention, the present invention will be illustrated in more detail below in conjunction with the attached drawings and preferred embodiments. It should be noted that when an element is expressed as "being fixed to" another element, this element may be directly on the another element, or there may be one or more intervening elements between this element and the another element. When an element is expressed as "being connected to" another element, this element can be directly connected to the another element, or there may be one or more intervening elements between this element and the another element. In addition, terminology such as "first", "second", etc., is only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

Unless otherwise defined, any technical and scientific terminology used in this specification has the same meaning as commonly understood by those skilled in the technical field of the present invention. Terminology used in this specification of the present invention is only for a purpose of describing specific embodiments, and is not used to limit the present invention. Terminology such as "and/or" used in this specification includes any and all combinations of one or more related listed items.

In addition, technical features involved in different embodiments of the present invention described below can be mutually combined as long as they do not conflict with one another.

Please refer to <FIG> is schematic structural view of an electronic cigarette in accordance with a preferred embodiment of the present invention. As shown in <FIG>, an electronic cigarette <NUM> includes an output control circuit <NUM>, a battery assembly <NUM> and an atomizer <NUM>. Understandably, the output control circuit <NUM>, the battery assembly <NUM> and the atomizer <NUM> are all disposed in an outer shell of the electronic cigarette <NUM>. In particular, the output control circuit <NUM> is disposed between the battery assembly <NUM> and the atomizer <NUM> in order to control power supply connection of the battery assembly <NUM> with the atomizer <NUM>.

The output control circuit <NUM> includes a controller <NUM>, a first switching circuit <NUM>, a driving circuit <NUM> and a second switching circuit <NUM>.

The controller <NUM> is respectively electrically connected with the battery assembly <NUM>, the first switching circuit <NUM> and the driving circuit <NUM>. In particular, the controller <NUM> includes a single-chip microcomputer, a microprocessor or a digital signal processor (DSP). The battery assembly <NUM> supplies a direct current power to the controller <NUM>, and a voltage value of the direct current power is usually <NUM>. 8V (Volt), <NUM>. 3V or 5V When the controller <NUM> is an integrated circuit, a required voltage for its normal working is available by looking up a data manual of the controller <NUM>.

According to the claimed invention, the controller <NUM> is used to control switching-on or switching-off of the first switching circuit <NUM>, and to provide pulse-width modulation (PWM) signals to the driving circuit <NUM>.

The first switching circuit <NUM> is respectively electrically connected with the battery assembly <NUM>, the controller <NUM> and the atomizer <NUM>. The first switching circuit <NUM> works as a switch serially electrically connected between the battery assembly <NUM> and the atomizer <NUM>. When a smoker starts smoking, the controller <NUM> controls the first switching circuit <NUM> to switch on, i.e., switch closed for electrical connection, the battery assembly <NUM> supplies power to the atomizer <NUM>. The atomizer <NUM> is then switched on to normally output power. Liquid tobacco in the atomizer <NUM> is accordingly heated to be atomized. When the smoker quits smoking, the controller <NUM> controls the first switching circuit <NUM> to switch off, i.e., switch opened for disconnection, a power supply feeding circuit of the atomizer <NUM> is cut off. The atomizer <NUM> stops working, and heating of the liquid tobacco in the atomizer <NUM> is stopped to terminate atomization of the liquid tobacco.

In particular, the first switching circuit <NUM>, the atomizer <NUM> and the second switching circuit <NUM> are electrically connected in series. Understandably, the first switching circuit <NUM> can be firstly electrically connected with the atomizer <NUM> in series, and then be electrically connected with the second switching circuit <NUM> in series. Of course, the first switching circuit <NUM> can alternatively be firstly electrically connected with the second switching circuit <NUM> in series, and then be electrically connected with the atomizer <NUM> in series.

It is required to be explained that, in a preferred embodiment in accordance with the present invention, the first switching circuit <NUM> is firstly electrically connected with the atomizer <NUM> in series, and then is electrically connected with the second switching circuit <NUM> in series. At the moment, the power supply feeding circuit of the atomizer <NUM> is a circuit formed by starting from a positive electrode of the battery assembly <NUM>, passing the first switching circuit <NUM>, the atomizer <NUM> and the second switching circuit <NUM> in sequence, and then returning to a negative electrode of the battery assembly <NUM>. A flowing direction of an electrical current i of the power supply feeding circuit of the atomizer <NUM> is shown in <FIG>. If the first switching circuit <NUM> is firstly electrically connected with the second switching circuit <NUM> in series and then is electrically connected with the atomizer <NUM> in series, the power supply feeding circuit of the atomizer <NUM> is a circuit formed by starting from a positive electrode of the battery assembly <NUM>, passing the first switching circuit <NUM>, the second switching circuit <NUM> and the atomizer <NUM> in sequence, and then returning to a negative electrode of the battery assembly <NUM>.

Please refer to <FIG> cooperatively. In a preferred embodiment, the first switching circuit <NUM> includes a second capacitor C2, a third resistor R3, a fourth resistor R4 and a first metal oxide semiconductor field effect transistor (MOSFET, short for "MOS") tube Q1.

In particular, a first end of the second capacitor C2 is electrically connected with the battery assembly <NUM>. A second end of the second capacitor C2 is electrically connected with ground. A first end of the third resistor R3 is respectively electrically connected with the first end of the second capacitor C2 and a source electrode of the first MOS tube Q1. A second end of the third resistor R3 is respectively electrically connected with the controller <NUM> and a first end of the fourth resistor R4. A second end of the fourth resistor R4 is electrically connected with a gate electrode of the first MOS tube Q1. A drain electrode of the first MOS tube Q1 is electrically connected with a positive electrode of the atomizer <NUM>.

Switching-on or switching-off of the first switching circuit <NUM> is controlled based on control signals from the controller <NUM>. The first switching circuit <NUM> can be a switching MOS tube circuit provided as a preferred embodiment of the present invention. Of course, the first switching circuit <NUM> is not limited to a form of physical circuits provided in the preferred embodiment. For example, the first switching circuit <NUM> is provided to include only the first MOS tube Q1, or to include a transistor and its peripheral circuits. The first switching circuit <NUM> can further be other forms of switching circuits, such as relays, contact switches, etc. Switching-on or switching-off of the first switching circuit <NUM> is controlled based on the control signals from the controller <NUM>. Correspondingly, the control signals include electrical current signals or voltage signals.

Please refer to <FIG>. The driving circuit <NUM> includes a trigger circuit <NUM>, a monostable circuit <NUM> and a pulse width modulation (PWM) circuit <NUM>.

In particular, the trigger circuit <NUM> is respectively electrically connected with the battery assembly <NUM>, the controller <NUM>, the monostable circuit <NUM> and the PWM circuit <NUM>. The trigger circuit <NUM> is used for triggering the controller <NUM> to decide whether or not the monostable circuit <NUM> is provided with PWM signals.

As shown in <FIG>, the trigger circuit <NUM> includes a first resistor R1 and a switch S <NUM>. A first end of the first resistor R1 is electrically connected with the controller <NUM>, and a second end of the first resistor R1 is electrically connected with the monostable circuit <NUM>. A first end of the switch S1 is electrically connected with the first end of the first resistor R1, and a second end of the switch S1 is electrically connected with ground.

In particular, the switch S1 is switched on or switched off based on smoke inhaling operation of users. A physical form of the switch S1 can be a mechanical push-button switch or a pneumatic sensor. When the switch S1 is switched on, a sub-circuit of the first resistor R1 is short circuited, voltage at a PB4 port of the controller <NUM> is <NUM>, and the controller <NUM> is triggered to provide PWM signals to the monostable circuit <NUM>. When the switch S1 is switched off, voltage at the PB4 port of the controller <NUM> is a dividing voltage of the first resistor R1 when VCC voltage passes through the first resistor R1, i.e., the voltage at the PB4 port of the controller <NUM> is at a high voltage level, and the controller <NUM> is triggered to terminate provision of PWM signals to the monostable circuit <NUM>.

The monostable circuit <NUM> is further respectively electrically connected with the battery assembly <NUM>, the controller <NUM>, the second switching circuit <NUM> and the PWM circuit <NUM>. The monostable circuit <NUM> includes an input and an output. The input is used to receive PWM signals, and the output is used to output high voltage level signals or low voltage level signals in order to control switching on or switching off of the second switching circuit <NUM> based on the PWM signals.

The monostable circuit <NUM> is a basic pulse elementary circuit having two working states including a steady state and a transient state. Without externally applied signals (i.e., the PWM signals), the monostable circuit <NUM> is in the steady state. With triggering of the externally applied signals, the monostable circuit <NUM> is turned from the steady state to the transient state. After a period of time, the monostable circuit <NUM> is automatically turned to the steady state. The period of time for being in the transient state is decided based on parameters of the monostable circuit <NUM> itself, and is irrelevant to a working time of the PWM signals. The monostable circuit <NUM> can be further used to generate positive/negative pulse signals with a preset time interval, i.e., to output high voltage level signals or low voltage level signals with a preset time interval.

In a preferred embodiment, the monostable circuit <NUM> includes a 74LVC1G123 integrated circuit chip. In other embodiments, the monostable circuit <NUM> can be constituted by discrete components and logical gating circuits. Alternatively, the monostable circuit <NUM> can be realized by using a <NUM> timer integrated circuit chip (<NUM> timer IC).

The PWM circuit <NUM> is further electrically connected with the battery assembly <NUM>. The PWM circuit <NUM> is used to regulate pulse widths of high voltage level signals or low voltage level signals. As shown in <FIG>, the PWM circuit <NUM> includes a second resistor R2 and a first capacitor C1. A first end of the second resistor R2 is respectively electrically connected with the battery assembly <NUM> and the second end of the first resistor R1. A second end of the second resistor R2 is respectively electrically connected with a first end of the first capacitor C1 and the monostable circuit <NUM>. A second end of the first capacitor C1 is electrically connected with ground.

In particular, a ratio between the second resistor R2 and the first capacitor C1 is used to set up pulse widths of output pulses of the monostable circuit <NUM>, i.e., pulse widths of high voltage level signals or low voltage level signals. The PWM circuit <NUM> adopts a simulative control method, and is able to regulate a base electrode of a transistor or a gate electrode of a MOS tube based on variation of corresponding loads (i.e., pulse widths of high voltage level signals or low voltage level signals) in order to realize change of a turn-on time of the transistor or the MOS tube. As shown in <FIG>, the monostable circuit <NUM> is electrically connected with a gate electrode of a second MOS tube Q2. In other embodiments, the PWM circuit <NUM> adopts, but does not limit to, the performing method published according to the preferred embodiment.

The second switching circuit <NUM> is respectively electrically connected with the battery assembly <NUM>, the driving circuit <NUM> and the atomizer <NUM>.

In a preferred embodiment, the second switching circuit <NUM> includes a second MOS tube Q2. Agate electrode of the second MOS tube Q2 is electrically connected with the output of the monostable circuit <NUM>. A source electrode of the second MOS tube Q2 is electrically connected with ground. A drain electrode of the second MOS tube Q2 is electrically connected with a negative electrode of the atomizer <NUM>. Understandably, in other embodiments, the second switching circuit <NUM> adopts, but does not limit to, the performing method illustrated according to the preferred embodiment.

Please refer to <FIG>. The battery assembly <NUM> includes a charging circuit <NUM>, a protective circuit <NUM>, a lithium battery <NUM> and a voltage stabilizing buck circuit <NUM>. In particular, the protective circuit <NUM> is electrically connected with the charging circuit <NUM>. The lithium battery <NUM> and the controller <NUM> are electrically connected with the driving circuit <NUM>.

In a preferred embodiment, the charging circuit <NUM> includes a universal serial bus (USB) port circuit, a filter circuit, a power management chip and their peripheral circuits. The protective circuit <NUM> includes lithium ion/lithium polymer battery protective chip and its peripheral circuits. The protective circuit <NUM> has functions of voltage and electric current protection against overcharge, voltage and electric current protection against overdischarge, protection against overheating, protection against short circuits, protection against reverse connection of battery cells and protection against reverse connection of chargers, etc..

Since the lithium battery <NUM> has advantages of high average voltage for a single cell, high energy density, light weight for battery bodies, long lives, strong adaption to high and low temperatures and green environmental protection, etc., in a preferred embodiment, the lithium battery <NUM> is a priority choice as energy storage equipment for the electronic cigarette <NUM>. The lithium battery <NUM> is constituted by three parts of battery cells, a protective plate and a plastic shell. The lithium battery <NUM> is mainly classified as two types, lithium metal batteries and lithium ion batteries. A lithium ion battery does not contain lithium metal, and is chargeable. The lithium ion battery works mainly by movement of lithium ions between a positive electrode and a negative electrode. In a charging/discharging process thereof, lithium ions (Li+) move back and forth between the positive electrode and the negative electrode for intercalation and/or deintercalation. When the lithium ion battery is charged, the lithium ions (Li+) are deintercalated from the positive electrode, and are intercalated into the negative electrode through electrolytes. The negative electrode is in a high lithium concentration state. Discharging of the lithium ion battery is just the other way around.

Understandably, the lithium battery <NUM> has two processes of a charging process and a discharging process. When the lithium battery <NUM> is charged, the lithium battery <NUM> is in an energy storage process. When the lithium battery <NUM> is discharged, the lithium battery <NUM> supplies power to the controller <NUM>, the first switching circuit <NUM> and the driving circuit <NUM>.

In a preferred embodiment, the voltage stabilizing buck circuit <NUM> is a resistance capacitance step-down circuit. The voltage stabilizing buck circuit <NUM> is used to lower direct current voltages at two ends of the lithium battery <NUM> down to a normal working voltage for the controller <NUM> and the monostable circuit <NUM>.

Please refer to <FIG>. The atomizer <NUM> includes a heating assembly <NUM> and a temperature detecting circuit <NUM> connected with the heating assembly <NUM>. The temperature detecting circuit <NUM> is electrically connected with the controller <NUM>, and is used to detect temperature values of the heating assembly <NUM> and to transmit the temperature values to the controller <NUM>.

In other embodiments, the heating assembly <NUM> includes a wire coil, a coil-winding part and a liquid absorbing part. The liquid absorbing part is contacted with the wire coil in order to conduct absorbed tobacco liquid or tobacco oil toward the wire coil. When the atomizer <NUM> works normally, the tobacco liquid or tobacco oil is vaporized by the wire coil to generate smoke. If the wire coil has a higher heating quantity, a using life of the wire coil may be caused to be shortened, and the wire coil is therefore required to be replaced. Besides, excess heating may also lead to overheating of an outer shell of the electronic cigarette <NUM>, and may cause shortening a using life of the electronic cigarette <NUM>, etc., and further affect use of the electronic cigarette <NUM> for its users. Hence, the temperature detecting circuit <NUM> is added in the electronic cigarette <NUM> for use of detecting temperature values of the heating assembly <NUM>. When temperature of the heating assembly <NUM> exceeds a preset temperature threshold, the controller <NUM> controls to shut down the first switching circuit <NUM> and/or the second switching circuit <NUM> in order to further cut off the power supply feeding circuit of the atomizer <NUM>. The heating assembly <NUM> is then stopped to heat and to avoid extremely high temperature of the heating assembly <NUM>.

As previously mentioned, a physical working process for the electronic cigarette <NUM> is depicted as follows.

When there is an inhaling action from users, the first switching circuit <NUM> is controlled to be switched on (i.e., the first MOS tube Q1 is turned on) according to control signals of the controller <NUM>. In the meantime, the trigger circuit <NUM> triggers the controller <NUM> to decide whether or not the monostable circuit <NUM> is provided with PWM signals. The monostable circuit <NUM> outputs high voltage level signals or low voltage level signals to switch on the second switching circuit <NUM> (i.e., the second MOS tube Q2 is turned on) based on the PWM signals after the monostable circuit <NUM> detects the PWM signals. At this moment, the battery assembly <NUM>, the first switching circuit <NUM>, the atomizer <NUM> and the second switching circuit <NUM> together form an electric current circuit, i.e., the power supply feeding circuit of the atomizer <NUM> is electrically connected and the atomizer <NUM> is switched on.

When the first switching circuit <NUM> is out of order (i.e., the first MOS tube Q1 stops being turned on), in other words, the above mentioned electric current circuit is disconnected, the atomizer <NUM> stops working due to no power supply. When the controller <NUM> is out of order or in a malfunctioned status, the controller <NUM> stops providing the PWM signals to the monostable circuit <NUM>. The monostable circuit <NUM> reverses its output high voltage level signals or low voltage level signals when no PWM signals are detected (For example, the gate electrode of the second MOS tube Q2 is set to receive high voltage level signals for turning on the second MOS tube Q2, then the high voltage level signals are reversed to low voltage level signals when the controller <NUM> is out of order or in the malfunctioned status). The second switching circuit <NUM>, i.e., the above mentioned electric current circuit, is disconnected (i.e., the second MOS tube Q2 stops being turned on). The atomizer <NUM> stops working due to no power supply.

In conclusion, the first switching circuit <NUM> and the second switching circuit <NUM> cannot be switched on simultaneously either when the first switching circuit <NUM> is out of order or when the controller <NUM> is out of order or in the malfunctioned status. As a result, a complete electric current circuit between the atomizer <NUM> and the battery assembly <NUM> cannot be formed (i.e., the power supply feeding circuit of the atomizer <NUM> is caused to be disconnected). Safety risk such as fire incidents is avoided when the atomizer <NUM> of the electronic cigarette <NUM> continuously outputs power due to the controller <NUM> being out of order, either one of switching circuits (the first switching circuit <NUM> or the second switching circuit <NUM>) being out of order, or the controller <NUM> being in the malfunctioned status. Reliability and safety of products related to the electronic cigarette <NUM> are therefore enhanced.

Please refer to <FIG>. The output control circuit <NUM> further includes a current-limiting circuit <NUM> and a prompt circuit <NUM>.

The current-limiting circuit <NUM> is parallel electrically connected between the positive electrode of the atomizer <NUM> and the negative electrode of the atomizer <NUM>. The atomizer <NUM> is electrically connected between a port UOT+ and a port UOT- of the current-limiting circuit <NUM>. The current-limiting circuit <NUM> includes a fifth resistor R5. The fifth resistor R5 is used for restricting a quantity of electrical currents flowing into the atomizer <NUM>.

The prompt circuit <NUM> is respectively electrically connected with the charging circuit <NUM> and the controller <NUM>. The prompt circuit <NUM> is used to indicate a power output status of the atomizer <NUM>. The power output status includes switching on or switching off of the atomizer <NUM>, and power output ranks of the atomizer <NUM>. In some embodiment, the prompt circuit <NUM> includes a display for displaying the power output status of the atomizer <NUM>.

In practice, the prompt circuit <NUM> includes a sixth resistor R6 and a light-emitting diode (LED) tube D1. A first end of the sixth resistor R6 is electrically connected with the charging circuit <NUM>, and a second end of the sixth resistor R6 is electrically connected with a positive electrode of the LED tube D1. A negative electrode of the LED tube D1 is electrically connected with the controller <NUM>.

In some embodiment, a number of the LED tube D1 can be plural. The LED tube D1 can displays at least two kinds of colors. Alternatively, brightness of displayed color of the LED tube D1 can be gradually varied from being bright to dark. For example, the number of the LED tube D1 is <NUM>. When all of the four LED tubes D1 light up, an output power of the atomizer <NUM> is set to be 20W, i.e., the atomizer <NUM> works in a higher power rank. When only one of the four LED tubes D1 counting from a side of the four LED tubes D1 lights up, the output power of the atomizer <NUM> is set to be 5W, i.e., the atomizer <NUM> works in a lower power rank.

The output control circuit <NUM> is provided in accordance with a preferred embodiment of the present invention. Switching on of the atomizer <NUM> is simultaneously controlled by the first switching circuit <NUM> and the second switching circuit <NUM>. Safety risk such as fire incidents is accordingly avoided when the atomizer <NUM> of the electronic cigarette <NUM> continuously outputs power due to the controller <NUM> being out of order, either one of the first and second switching circuits <NUM>, <NUM> being out of order, or the controller <NUM> being in the malfunctioned status. Reliability and safety of products related to the electronic cigarette <NUM> are therefore enhanced.

Claim 1:
An output control circuit (<NUM>) for an electronic cigarette (<NUM>) comprising a battery assembly (<NUM>) and an
atomizer (<NUM>), wherein the output control circuit further comprises a controller (<NUM>), a first switching circuit (<NUM>), a driving circuit (<NUM>) and a second switching circuit (<NUM>),
wherein the first switching circuit is electrically connected with the battery assembly, the controller and the atomizer; wherein the controller is electrically connected with the battery assembly; wherein the second switching circuit is electrically connected with the battery assembly, the driving circuit and the atomizer;
wherein the first switching circuit, the atomizer and the second switching circuit are electrically connected in series and are configured such that the atomizer is switched on when the first switching circuit and the second switching circuit are switched on simultaneously; wherein the controller is adapted to control switching-on or switching-off the first switching circuit and to provide pulse-width modulation, PWM, signals to the driving circuit;
and wherein the driving circuit is electrically connected with the controller and is configured for driving to switch on or switch off the second switching circuit based on the PWM signals;
characterised in that the driving circuit comprises a trigger circuit (<NUM>), a monostable circuit (<NUM>) and a PWM circuit (<NUM>); the trigger circuit is electrically connected with the battery assembly, the controller, the monostable circuit and the PWM circuit; and the trigger circuit is configured for triggering the controller to decide whether or not the monostable circuit is provided with PWM signals.