Constant power control circuit and method, cigarette rod, electronic cigarette

Abstract

This invention discloses a constant power control circuit and method, a cigarette holder, and an electronic cigarette. The constant power control circuit includes: a load voltage and current detection module, a reference power setting module, and a duty cycle adjustment module. The load voltage and current detection module inputs the detected load voltage signal and a second detected voltage signal representing the load current signal to the duty cycle adjustment module. The reference power setting module inputs a reference power signal to the duty cycle adjustment module. The duty cycle adjustment module generates the on-time and switching period of the load circuit switch based on the load voltage signal, the second detected voltage signal, and the reference power signal, controlling the load circuit switch to turn on and off so that the output power is proportional to the reference power. Using this invention, by real-time detection of the load voltage and current, combined with a pre-set reference power, a periodic duty cycle signal is generated to control the on and off of the external load circuit switch, achieving constant load power.

Description

Technical Field

[0001] This invention relates to the field of electronic circuits, and more particularly to a circuit for an electronic cigarette. Background Technology

[0002] An electronic cigarette is an electronic product that mimics a traditional cigarette, consisting of a device and a cartridge, which are usually separate. Consumers purchase the device and cartridge and assemble them together for use. The control circuitry and battery are typically located in the device, while the atomizer is usually located in the cartridge. The atomizer includes an e-liquid cartridge that stores e-liquid and a heating coil that heats the cartridge to produce vapor. The amount of vapor is adjusted by controlling the power of the heating coil.

[0003] The amount of vapor and flavor of e-cigarettes are strongly related to the output voltage, current and power of the control circuit. Generally, the amount of vapor will change with the output voltage, current and power. In particular, the voltage of the e-cigarette battery will change with the user's use, resulting in changes in the amount of vapor and flavor, and causing a deterioration in the user experience. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a constant power control circuit and method, which controls the power output from the battery to the heating wire to be a constant power, thereby keeping the amount of smoke stable, improving the taste and avoiding waste. The technical solution is as follows:

[0005] On one hand, the present invention provides a constant power control circuit, including: a load voltage and current detection module, a reference power setting module, and a duty cycle adjustment module;

[0006] The load voltage and current detection module inputs the detected load voltage signal and the second detection voltage signal corresponding to the load current signal into the duty cycle adjustment module. The reference power setting module inputs the reference power signal into the duty cycle adjustment module. The duty cycle adjustment module generates the on-time and switching cycle of the load circuit switch based on the load voltage signal, the second detection voltage signal, and the reference power signal, and controls the load circuit switch to turn on and off so that the output power is proportional to the reference power.

[0007] Preferably, the load voltage and current detection module includes a sampling MOSFET, an intermediate MOSFET, a detection current operational amplifier, a first voltage divider resistor, a second voltage divider resistor, and a third conversion resistor; the load circuit switch includes a Power MOSFET.

[0008] The source of the Power MOSFET is electrically connected to the power supply, the gate of the Power MOSFET is electrically connected to the output terminal of the duty cycle adjustment module, the drain of the Power MOSFET is electrically connected to the load, and the drain of the Power MOSFET is also electrically connected to the first voltage divider resistor. One end of the second voltage divider resistor is connected in series with the first voltage divider resistor, and the other end is grounded. The end of the second voltage divider resistor connected to the first voltage divider resistor is also electrically connected to the duty cycle adjustment module for outputting the load voltage signal. The Power MOSFET is also used to implement the function of switching the load circuit.

[0009] The source of the sampling MOSFET is electrically connected to the power supply, the gate of the sampling MOSFET is electrically connected to the gate of the Power MOSFET, the drain of the sampling MOSFET is electrically connected to the inverting input of the current detection operational amplifier, the inverting input is also electrically connected to the source of the intermediate MOSFET, the gate of the intermediate MOSFET is electrically connected to the output of the current detection operational amplifier, the drain of the intermediate MOSFET is electrically connected to the third conversion resistor, the other end of the third conversion resistor is grounded, the non-inverting input of the current detection operational amplifier is electrically connected to the drain of the Power MOSFET; the end of the third conversion resistor connected to the intermediate MOSFET is also electrically connected to the duty cycle adjustment module for outputting the second detection voltage signal.

[0010] Preferably, the reference power setting module includes a power setting operational amplifier, a reference voltage operational amplifier, a third MOSFET, a fourth MOSFET, and a fourth conversion resistor;

[0011] The non-inverting input of the power setting operational amplifier is connected to the second reference voltage generated inside the constant power control circuit. The source of the third MOSFET is electrically connected to the power supply, the gate of the third MOSFET is electrically connected to the output of the power setting operational amplifier, and the drain of the third MOSFET is electrically connected to the inverting input of the power setting operational amplifier. The drain of the third MOSFET is also used to connect to an external power setting resistor. The external power setting resistor is used to set the reference power.

[0012] The source of the fourth MOSFET is electrically connected to the power supply, the gate of the fourth MOSFET is electrically connected to the gate of the third MOSFET, the drain of the fourth MOSFET is electrically connected to the fourth conversion resistor, and the other end of the fourth conversion resistor is grounded; the end of the fourth conversion resistor connected to the fourth MOSFET is also electrically connected to the duty cycle adjustment module to output a second reference voltage signal corresponding to the current signal of the fourth conversion resistor.

[0013] The non-inverting input of the reference voltage operational amplifier is the first reference voltage generated inside the constant power control circuit. The output of the reference voltage operational amplifier is electrically connected to the inverting input, and the output is also electrically connected to the duty cycle adjustment module to output the first reference voltage signal.

[0014] Preferably, the duty cycle adjustment module includes a detection power multiplier and a reference power multiplier;

[0015] The two input terminals of the detection power multiplier are electrically connected to the two output terminals of the load voltage and current detection module, respectively. The detection power multiplier is used to obtain the detection power corresponding to the load.

[0016] The two input terminals of the reference power multiplier are electrically connected to the two output terminals of the reference power setting module. The reference power multiplier is used to obtain the reference power.

[0017] Preferably, the duty cycle adjustment module further includes an on-time adjustment module, a switching cycle adjustment module, and a drive module;

[0018] The input terminal of the turn-on time adjustment module is electrically connected to the output terminal of the detection power multiplier, and its output terminal is electrically connected to the input terminal of the drive module. It is used to obtain the turn-on time of the load circuit switch according to the detection power, and output the turn-on time signal to the drive module, which controls the load circuit switch to turn off.

[0019] The input terminal of the switching cycle adjustment module is electrically connected to the output terminal of the reference power setting module, and the output terminal of the switching cycle adjustment module is electrically connected to the input terminal of the drive module. It is used to calculate the switching cycle of the load circuit switch according to the reference power and output the switching cycle signal to the drive module, which controls the load circuit switch to be turned on.

[0020] The switching cycle adjustment module is also electrically connected to the on-time adjustment module. The switching cycle adjustment module outputs a control signal according to the switching cycle signal to control the switching cycle adjustment module and the on-time adjustment module to reset their states at the end of each cycle.

[0021] The output terminal of the drive module is electrically connected to the control terminal of the load circuit switch to control the opening and closing of the load circuit switch.

[0022] Preferably, the turn-on time adjustment module includes a detection power operational amplifier, a fifth MOSFET, a sixth MOSFET, a fifth switching resistor, a first switching capacitor, a first switch, a second switch, a first comparator, and a shared RS flip-flop;

[0023] The non-inverting input of the power detection operational amplifier is electrically connected to the output of the power detection multiplier. The source of the fifth MOSFET is electrically connected to the power supply. The gate of the fifth MOSFET is electrically connected to the output of the power detection operational amplifier. The drain of the fifth MOSFET is electrically connected to the inverting input of the power detection operational amplifier. The drain of the fifth MOSFET is also electrically connected to the fifth switching resistor. The other end of the fifth switching resistor is grounded.

[0024] The source of the sixth MOSFET is electrically connected to the power supply, the gate of the sixth MOSFET is electrically connected to the gate of the fifth MOSFET, and the drain of the sixth MOSFET is electrically connected to the first switching capacitor through the first switch. The other end of the first switching capacitor is grounded, and the second switch is connected in parallel with the first switching capacitor.

[0025] The non-inverting input of the first comparator is electrically connected to the first switching capacitor, the inverting input of the first comparator is connected to the third reference voltage generated inside the constant power control circuit, and the output of the first comparator is electrically connected to one input of a shared RS flip-flop.

[0026] The turn-on time adjustment module converts the output of the power detection multiplier into current to charge the first conversion capacitor. The first comparator generates high-low level toggles based on the voltage on the first conversion capacitor. The first comparator inputs a high or low level to the common RS flip-flop, thereby generating the turn-on time of the load circuit switch.

[0027] Preferably, the switching cycle adjustment module includes a reference power operational amplifier, a seventh MOSFET, an eighth MOSFET, a sixth switching resistor, a second switching capacitor, a third switch, a fourth switch, and a second comparator;

[0028] The non-inverting input of the reference power operational amplifier is electrically connected to the output of the reference power setting module. The source of the seventh MOSFET is electrically connected to the power supply. The gate of the seventh MOSFET is electrically connected to the output of the reference power operational amplifier. The drain of the seventh MOSFET is electrically connected to the inverting input of the reference power operational amplifier and is also electrically connected to the sixth conversion resistor. The other end of the sixth conversion resistor is grounded.

[0029] The source of the eighth MOSFET is electrically connected to the power supply, the gate of the eighth MOSFET is electrically connected to the gate of the seventh MOSFET, and the drain of the eighth MOSFET is electrically connected to the second switching capacitor through the third switch. The other end of the second switching capacitor is grounded, and the fourth switch is connected in parallel with the second switching capacitor.

[0030] The non-inverting input of the second comparator is electrically connected to the second switching capacitor, the inverting input of the second comparator is connected to the third reference voltage, and the output of the second comparator is electrically connected to the other input of the shared RS flip-flop.

[0031] The reference power operational amplifier and the detection power operational amplifier have the same specifications, the second comparator has the same specifications as the first comparator, the sixth conversion resistor has the same resistance value as the fifth conversion resistor, and the second conversion capacitor has the same specifications as the first conversion capacitor.

[0032] The turn-on time adjustment module converts the output of the reference power multiplier into current to charge the second conversion capacitor. The second comparator generates high-low level toggles based on the voltage on the second conversion capacitor, inputting a high or low level to the common RS flip-flop, thereby generating the turn-on cycle of the load circuit switch.

[0033] The output of the second comparator is also electrically connected to the control terminals of the first, second, third, and fourth switches to control the opening and closing of the four switches according to the generated high and low level switching signals, thereby controlling the charging and discharging of the second and first conversion capacitors. The first and third switches are simultaneously turned on and off, and the second and fourth switches are simultaneously turned on and off.

[0034] Preferably, the relationship between the turn-on time and the switching cycle is as follows:

[0035] The on / off time is less than the switching cycle;

[0036] The activation time is calculated from the start time of the switching cycle;

[0037] During the on-time period, the load circuit switch is in the ON state;

[0038] During the switching cycle time excluding the on-time, the load circuit switch is in the off state.

[0039] On the other hand, the present invention provides a constant power control method, comprising:

[0040] S1: Detect load voltage V load and load current I load Converted into load voltage signal V vsen Second detection voltage signal V isen The detected power signal, which characterizes the real-time load power, is then obtained through a detected power multiplier.

[0041] S2: Detect the reference power and convert it into a voltage signal to obtain the second reference voltage signal V, which characterizes the reference power. psen ;

[0042] S3: Convert the detected power signal into current to charge the first capacitor, thereby generating the on-time of the load circuit switch;

[0043] S4: Convert the reference power signal into current to charge the second capacitor and generate the switching cycle of the load circuit.

[0044] S5: The duty cycle of the load circuit switch is obtained based on the turn-on time and the switching cycle, thereby realizing the disconnection and conduction of the load circuit.

[0045] Furthermore, step S2 also includes:

[0046] S21: Set the reference voltage and convert it into a voltage signal V. ref1 Then, together with the second reference voltage signal, it passes through a reference power multiplier to obtain a reference power signal that characterizes the reference power;

[0047] S22: Set resistor R according to external power. set Obtain the external power flowing through it and set the resistor R. set These represent different reference power levels.

[0048] Furthermore, the load voltage signal V vsen With load voltage V load The relationship is:

[0049] Among them, R1 and R2 are voltage divider resistors;

[0050] Second detection voltage signal V isen With load current I load The relationship is:

[0051] Where R3 is the conversion resistor used to convert the load current into a voltage signal, and KI is the current mirror ratio;

[0052] Second reference voltage signal V psen With external power setting resistor R set The relationship is:

[0053] Where V2 is the internal reference voltage of the circuit, R4 is the switching resistor, and K p It is the current mirror ratio;

[0054] Opening time is:

[0055] Where R5 is the switching resistor, C1 is the capacitor, V3 is the internal reference voltage, and A is the amplification factor;

[0056] The switching cycle is:

[0057] Where R6 is the switching resistor, C2 is the capacitor, V3 is the internal reference voltage, and A is the amplification factor.

[0058] Duty cycle is:

[0059]

[0060] Based on four voltage signals V vsen V isen V psen V ref1 The duty can be obtained as:

[0061]

[0062] By setting R3 = R4, the power can be obtained as follows:

[0063]

[0064] The circuit can be configured as follows during the initial design:

[0065] V1 and V2 are internal reference voltages, which are fixed values;

[0066] R1 and R2 are matching resistors, and are designed with a fixed ratio, therefore... It is also a constant; K p It is the current mirror ratio, and it is also a constant.

[0067] R set It is an external resistor with a fixed value;

[0068] This ensures that the output power P is a constant value, achieving constant power output.

[0069] In another aspect, the present invention provides a smoking rod, including a constant power control circuit and an external power setting resistor as described above, wherein the external power setting resistor is electrically connected to a reference power setting module.

[0070] In another aspect, the present invention provides an electronic cigarette, including the above-mentioned cigarette holder.

[0071] The beneficial effects of this invention are as follows: When the electronic cigarette is in the ignition and heating state, the voltage and current of the load are detected in real time, and a value that can characterize the real-time output power is calculated. Combined with a pre-set reference power, a periodic duty cycle signal is generated to control the on and off of the load circuit switch, so that the power output to the load remains constant. The vapor volume of the constant power electronic cigarette is more uniform, which has a better user taste. At the same time, the constant power output is more stable and energy-saving, and will not cause the electronic cigarette to overheat and affect its use. Therefore, the constant power output type of electronic cigarette will have more advantages. Attached Figure Description

[0072] Figure 1 This is a circuit diagram of the first embodiment of the simulated constant power control of the present invention;

[0073] Figure 2 This is a schematic diagram of a load voltage and current detection module circuit according to the present invention;

[0074] Figure 3 This is a schematic diagram of a reference power setting module circuit according to the present invention;

[0075] Figure 4This is a schematic diagram of a switch duty adjustment circuit according to the present invention;

[0076] Figure 5 This is a circuit diagram of the second embodiment of the digital constant power control of the present invention;

[0077] Figure 6 This is a schematic diagram of an analog-to-digital converter (ADC) module circuit according to the present invention;

[0078] Figure 7 This is a schematic diagram illustrating the waveform principle of a duty cycle digital processing module for calculating the switching period T according to the present invention.

[0079] Figure 8 This is a circuit diagram of a third embodiment of the analog constant power control of the present invention;

[0080] Figure 9A This is a circuit diagram of a fourth embodiment of analog constant power control according to the present invention;

[0081] Figure 9B This is a schematic diagram of a load battery and a current detection circuit according to the present invention;

[0082] Figure 9C This is a schematic diagram of a divider circuit according to the present invention;

[0083] Figure 9D This is a schematic diagram of an integrator circuit according to the present invention;

[0084] Figure 9E This is a schematic diagram of a sawtooth wave generator circuit according to the present invention;

[0085] Figure 9F This is a schematic diagram of a PWM comparator circuit according to the present invention;

[0086] Figure 9G This is a schematic diagram of an RS flip-flop circuit according to the present invention;

[0087] Figure 10 This is a circuit diagram of the fifth embodiment of the analog constant power control of the present invention. Detailed Implementation

[0088] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0089] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0090] To address the problem this invention aims to solve, five constant power control circuits and methods are provided below. Among them, Embodiment 1, Embodiment 3, Embodiment 4 and Embodiment 5 are analog constant power schemes, while Embodiment 2 is a digital constant power scheme. Different schemes can be referenced and combined for different scenarios to achieve better results.

[0091] Example 1

[0092] like Figure 1-4 As shown, this embodiment discloses a simulated constant power control circuit, including: a load voltage and current detection module 11, a reference power setting module 12, and a duty cycle adjustment module 13. The load voltage and current detection module 11 inputs the detected load voltage signal and the second detection voltage signal corresponding to the load current signal to the duty cycle adjustment module 13. The reference power setting module 12 inputs the reference power signal to the duty cycle adjustment module 13. The duty cycle adjustment module 13 generates the on-time and switching period of the load circuit switch according to the load voltage signal, the second detection voltage signal, and the reference power signal, and controls the load circuit switch to turn on and off so that the output power is proportional to the reference power. Here, the ratio is, for example, 1:1, 1:2, 1:3, 1:4, 2:1, 3:1, 4:1, etc., preferably 1:1, at which time the output power is equal to the reference power.

[0093] Preferably, for the load voltage and current detection module 11, please refer to... Figure 2 The diagram below shows a preferred load voltage and current detection module 11 of the present invention.

[0094] The load voltage and current detection module 11 includes a sampling MOSFET M2, an intermediate MOSFET M0, a current detection operational amplifier A1, a first voltage divider resistor R1, a second voltage divider resistor R2, and a third conversion resistor R3; the load circuit switch includes a Power MOSFET M1.

[0095] Specifically, the source of Power MOSFET M1 is electrically connected to a power supply, which can be the battery voltage or a converted battery voltage. The gate of Power MOSFET M1 is electrically connected to the output terminal of the duty cycle adjustment module 13. The drain of Power MOSFET M1 is electrically connected to the load and also to the first voltage divider resistor R1. One end of the second voltage divider resistor R2 is connected in series with the first voltage divider resistor R1, and the other end is grounded. The end of the second voltage divider resistor R2 connected to the first voltage divider resistor R1 is also electrically connected to the duty cycle adjustment module for outputting the load voltage signal. The drain of Power MOSFET M1 is also used to connect an external load, and the other end of the load is grounded. The load includes the atomizer of an electronic cigarette, etc. The load can be powered on and off by turning Power MOSFET M1 on and off.

[0096] Specifically, the source of the sampling MOSFET is electrically connected to the power supply, the gate of the sampling MOSFET is electrically connected to the gate of the Power MOSFET M1, the drain of the sampling MOSFET is electrically connected to the inverting input of the current detection operational amplifier A1, the inverting input is also electrically connected to the source of the intermediate MOSFET M0, the gate of the intermediate MOSFET M0 is electrically connected to the output of the current detection operational amplifier, the drain of the intermediate MOSFET M0 is electrically connected to the third conversion resistor R3, the other end of the third conversion resistor R3 is grounded, the non-inverting input of the current detection operational amplifier A1 is electrically connected to the drain of the Power MOSFET M1; the end of the third conversion resistor R3 connected to the intermediate MOSFET M0 is also electrically connected to the duty cycle adjustment module 13 for outputting the second detection voltage signal.

[0097] Specifically, the first voltage divider resistor R1 and the second voltage divider resistor R2 are used to sample the load voltage and output the load voltage signal V. vsen The third conversion resistor R3 is used to convert the sampling current into voltage, outputting the second detection voltage signal V. isen .

[0098] Let the load voltage be denoted as V. load The load current is denoted as I. load The load voltage signal V is described in further detail below. vsen Second detection voltage signal V isen With load voltage V load Load current I load The relationship.

[0099] Where KI:1 is the ratio of the width-to-length ratio of the channel of Power MOSFET M1 to the width-to-length ratio of the channel of sampling MOSFET M2. Therefore, the real-time sampled load voltage signal V can be obtained through this load voltage and current detection module 11 circuit. vsenThe second detection voltage signal V is converted from the real-time sampled load current. isen As shown below:

[0100]

[0101]

[0102] This yields the load voltage signal V. vsen Second detection voltage signal V isen This allows us to calculate the load power.

[0103] Furthermore, the sampling of the load voltage is described in detail below:

[0104] like Figure 2 As shown, AT is the terminal for the external load.

[0105] The circuit within the dashed box on the right side of AT is used to detect load voltage and current.

[0106] The source of Power MOSFET M1 is connected to the power supply VDD, the gate of Power MOSFET M1 is connected to the circuit that outputs the PWM signal for control, and the drain of Power MOSFET M1 is connected to both the load and the voltage divider circuit, forming a parallel connection between the load circuit and the voltage divider circuit. Therefore, we can obtain:

[0107]

[0108] The sampling of the load voltage has now been completed.

[0109] Next, the sampling of current will be explained as follows:

[0110] Circuit design principle: Since the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 are extremely large, the current of PowerMOS transistor M1 can be considered equal to the load current; and since PowerMOS transistor M1 and sampling MOS transistor M2 operate in the linear region, and the source, gate, and drain voltages of PowerMOS transistor M1 and sampling MOS transistor M2 are equal, the currents of PowerMOS transistor M1 and sampling MOS transistor M2 are directly proportional.

[0111] Specifically, the resistances of R1 and R2 are much greater than the resistance of the load. This causes the current of the Power MOSFET M1 to primarily flow through the load in the parallel circuit, while the current flowing through the other circuit, namely R1 and R2, is relatively smaller than the load current I. load This can be ignored. Therefore, we can obtain the following relationship:

[0112] Let the current flowing through M1 be denoted as I.M1 The current flowing through M2 is denoted as I. M2 ,

[0113] There is I M1 =I load

[0114] For KI:1, this is the width-to-length ratio of the channels of the two MOSFETs M1 and M2.

[0115] By connecting two MOSFETs in parallel, both operating in the linear region, and ensuring that their three terminals have the same voltage, a constant proportional relationship is maintained between the current flowing through M1 and the current flowing through M2: I M1 =KI* I M2 ,

[0116] Specifically, M1 is a high-power switching transistor, and M2 is a general-purpose MOSFET. This is because M1 also serves to provide current to the load and control the switch to achieve constant power, which requires the current flowing through M1 to be much greater than the current flowing through M2. In other words, KI in the above relationship is also a very large value.

[0117] In addition, since high-power switching transistors operate in the saturation region, the losses will be very large. Therefore, M1 must be set to operate in the linear region to reduce the losses of the MOSFET.

[0118] Therefore, to ensure current matching between M2 and M1, M2 must operate in the linear region, and the voltages at all three terminals of M1 and M2 must be identical. The source of M2, like M1, is connected to VDD, and the gate of M2 is connected to M1. Therefore, the source voltages and gate voltages of M1 and M2 are equal; only their drains are connected to different resistors. This necessitates the introduction of a current-sensing operational amplifier A1, whose function is to ensure that the drain voltage of M2 equals the drain voltage of M1.

[0119] Combine I M1 =I load , and I M1 =KI*I M2 ,

[0120] Also:

[0121]

[0122] Thus, V can be obtained. isen with I load The direct proportional relationship:

[0123]

[0124] The above completes the sampling of the load current.

[0125] Preferably, please refer to Figure 3 This is a circuit diagram of a preferred reference power setting module 12 of the present invention.

[0126] The reference power setting module 12 includes a power setting operational amplifier A3, a third MOSFET M3, a fourth MOSFET M4, and a fourth conversion resistor R4.

[0127] The non-inverting input of the power setting operational amplifier A3 is the second reference voltage V2 generated inside the constant power control circuit. The source of the third MOSFET M3 is electrically connected to the power supply. The gate of the third MOSFET M3 is electrically connected to the output of the power setting operational amplifier A3. The drain of the third MOSFET M3 is electrically connected to the inverting input of the power setting operational amplifier A3, and is also electrically connected to the external power setting resistor Rset. The other end of the external power setting resistor Rset is grounded.

[0128] The source of the fourth MOSFET M4 is electrically connected to the power supply, the gate of the fourth MOSFET M4 is electrically connected to the gate of the third MOSFET M3, the drain of the fourth MOSFET M4 is electrically connected to the fourth switching resistor R4, and the other end of the fourth switching resistor R4 is grounded.

[0129] The third MOSFET M3 and the fourth MOSFET M4 are operating in the saturation region, and their source and gate voltages are equal, which makes the current of the third MOSFET M3 and the fourth MOSFET M4 directly proportional.

[0130] The external power setting resistor Rset is used to set the reference power. Different resistance values ​​of the external power setting resistor Rset correspond to different reference powers. The fourth conversion resistor R4 is used to convert the current flowing through the external power setting resistor Rset into voltage, outputting the second reference voltage signal V. psen .

[0131] Where V1 and V2 are the first reference voltage and the second reference voltage generated internally by the constant power control circuit, R set The external power setting resistor Rset is used to set the reference power. The resistance value of the fourth conversion resistor R4 is equal to that of the third conversion resistor R3. When laying out the components, you need to consider matching and select components with the same model and specifications.

[0132] Set V ref1 =V1, then the second reference voltage signal V can be obtained through the reference power setting module 12 circuit. psen With external power setting resistor R set The relationship is as follows:

[0133]

[0134] Furthermore, a detailed description of the circuit of the reference power setting module 12 is provided below:

[0135] V1 and V2 are fixed values ​​derived from the power supply VDD through an internal voltage conversion module.

[0136] A2 and A3 are two identical operational amplifiers, and their output voltage is equal to their input voltage.

[0137] Since the detection current does not need to be supplied to an external load, it can be set to a very small value. Therefore, both MOSFETs in this circuit can be ordinary MOSFETs, denoted as M3 and M4, and both operate in the saturation region. This is because as long as Vgs, that is, the voltage difference between the gate and source of the MOSFET, is equal, the current flowing through the two MOSFETs can be guaranteed to be in a certain proportional relationship.

[0138] I M3 =K P *I M4

[0139] P set The terminals of the external power setting resistor Rset have the following relationship:

[0140]

[0141]

[0142] Therefore, based on the above three equations, we can obtain:

[0143]

[0144] The above sampling can be achieved by using a common MOSFET, setting it to the saturation region, and ensuring that the gate and source voltage differences are equal. This saves the need for an operational amplifier compared to a voltage and current sensing module, because it eliminates the need to adjust the drain voltage to make them equal.

[0145] Preferably, refer to Figure 1 The duty cycle adjustment module 13 includes a detection power multiplier 1301, an on-time adjustment module 1303, a switching cycle adjustment module 1304, and a drive module 1305.

[0146] The input terminal of the power detection multiplier 1301 is electrically connected to the output terminal of the load voltage and current detection module 11, and the output terminal of the power detection multiplier 1301 is electrically connected to the input terminal of the turn-on time adjustment module 1303. The power detection multiplier 1301 is used to convert the load voltage signal V... vsen Second detection voltage signal V isen Converted into detection power;

[0147] The output terminal of the turn-on time adjustment module 1303 is electrically connected to the input terminal of the drive module 1305. It is used to calculate the turn-on time of the load circuit switch based on the detected power and output the turn-on time signal to the drive module 1305, which then controls the load circuit switch to turn off.

[0148] The input terminal of the switching cycle adjustment module 1304 is electrically connected to the output terminal of the reference power setting module 12, and the output terminal of the switching cycle adjustment module 1304 is electrically connected to the input terminal of the drive module 1305. It is used to calculate the switching cycle of the load circuit switch according to the reference power and output the switching cycle signal to the drive module 1305, which controls the load circuit switch to be turned on.

[0149] The switching cycle adjustment module 1304 is also electrically connected to the on-time adjustment module 1303. The switching cycle adjustment module 1304 outputs a control signal according to the switching cycle signal to control the switching cycle adjustment module 1304 and the on-time adjustment module 1303 to reset their states at the end of each cycle.

[0150] The output terminal of the drive module 1305 is electrically connected to the gate of the Power MOS transistor M1 of the load voltage and current detection module 11 (i.e., the control terminal of the load circuit switch) to control the opening and closing of the load circuit switch.

[0151] Preferably, refer to Figure 3 The reference power setting module 12 also includes a reference voltage operational amplifier A2. The non-inverting input of the reference voltage operational amplifier A2 is the first reference voltage generated internally by the constant power control circuit. The output of the reference voltage operational amplifier A2 is electrically connected to the inverting input, used to convert the first reference voltage into a reference voltage and output the first reference voltage signal V. ref1 ;

[0152] refer to Figure 1 , Figure 4 The duty cycle adjustment module 13 also includes a reference power multiplier 1302; the input terminal of the reference power multiplier 1302 is electrically connected to the output terminal of the reference power setting module 12, and the output terminal of the reference power multiplier 1302 is electrically connected to the input terminal of the switching cycle adjustment module 1304.

[0153] Specifically, the reference power multiplier 1302 has the same specifications as the detection power multiplier 1301, and is used to convert the first reference voltage signal and the second reference voltage signal into an adjusted reference power to offset the delay in multiplier amplification factor caused by the detection power multiplier 1301 due to temperature and process angle deviation.

[0154] As can be seen from the above, the duty cycle adjustment module 13 mainly performs the following functions:

[0155] The output Multi1 of the power detection multiplier 1301 is converted into current, which charges the capacitor C and generates Ton, which is the turn-on time of the power transistor.

[0156] The output Multi2 of the reference power multiplier 1302 is converted into current to charge capacitor C, generating T, which is the switching cycle of the power transistor.

[0157] Duty cycle is the ratio of on-time to switching cycle.

[0158] The drive module 1305 controls the Power MOS to have a switching cycle of T and an on-time of Ton based on the on-time and switching cycle obtained above.

[0159] Preferably, please refer to Figure 4 This is a schematic diagram of a preferred duty cycle adjustment circuit of the present invention.

[0160] The turn-on time adjustment module 1303 includes a detection power operational amplifier A4, a fifth MOSFET M5, a sixth MOSFET M6, a fifth conversion resistor R5, a first conversion capacitor C1, a first switch K1, a second switch K2, a first comparator Comp1, and a shared RS flip-flop.

[0161] The non-inverting input of the power detection operational amplifier A4 is electrically connected to the output of the power detection multiplier 1301. The source of the fifth MOSFET M5 is electrically connected to the power supply. The gate of the fifth MOSFET M5 is electrically connected to the output of the power detection operational amplifier A4. The drain of the fifth MOSFET M5 is electrically connected to the inverting input of the power detection operational amplifier A4, and is also electrically connected to the fifth conversion resistor R5. The other end of the fifth conversion resistor R5 is grounded.

[0162] The source of the sixth MOSFET M6 is electrically connected to the power supply, the gate of the sixth MOSFET M6 is electrically connected to the gate of the fifth MOSFET M5, and the drain of the sixth MOSFET M6 is electrically connected to the first switching capacitor C1 through the first switch K1. The other end of the first switching capacitor C1 is grounded, and the second switch K2 is connected in parallel with the first switching capacitor C1.

[0163] The non-inverting input of the first comparator Comp1 is electrically connected to the first switching capacitor C1, the inverting input of the first comparator Comp1 is the internal third reference voltage, and the output of the first comparator Comp1 is electrically connected to the common RS flip-flop.

[0164] The turn-on time adjustment module 1303 converts the output of the power detection multiplier 1301 into current to charge the first conversion capacitor C1. Combined with the first comparator Comp1, it generates a high-low level flip and inputs a high or low level to the common RS flip-flop, thereby generating the turn-on time of the load circuit switch.

[0165] Preferably, the switching cycle adjustment module 1304 includes a reference power operational amplifier A5, a seventh MOSFET M7, an eighth MOSFET M8, a sixth conversion resistor R6, a second conversion capacitor C2, a third switch K3, a fourth switch K4, and a second comparator Comp2;

[0166] The non-inverting input of the reference power operational amplifier A5 is electrically connected to the output of the reference power setting module 12. The source of the seventh MOSFET M7 is electrically connected to the power supply. The gate of the seventh MOSFET M7 is electrically connected to the output of the reference power operational amplifier A5. The drain of the seventh MOSFET M7 is electrically connected to the inverting input of the reference power operational amplifier A5 and is also electrically connected to the sixth conversion resistor R6. The other end of the sixth conversion resistor R6 is grounded.

[0167] The source of the eighth MOSFET M8 is electrically connected to the power supply, the gate of the eighth MOSFET M8 is electrically connected to the gate of the seventh MOSFET M7, the drain of the eighth MOSFET M8 is electrically connected to the second conversion capacitor C2 through the third switch K3, the other end of the second conversion capacitor C2 is grounded, and the fourth switch K4 is connected in parallel with the second conversion capacitor C2.

[0168] The non-inverting input of the second comparator Comp2 is electrically connected to the second switching capacitor C2, the inverting input of the second comparator Comp2 is the internal third reference voltage, and the output of the second comparator Comp2 is electrically connected to the common RS flip-flop.

[0169] The reference power operational amplifier A5 and the detection power operational amplifier A4 have the same specifications; the second comparator Comp2 and the first comparator Comp1 have the same specifications; the sixth conversion resistor R6 and the seventh conversion resistor have the same specifications; and the second conversion capacitor C2 and the first conversion capacitor C1 have the same specifications.

[0170] The start-up time adjustment module 1303 converts the output of the reference power multiplier 1302 into current to charge the second conversion capacitor C2. Combined with the second comparator Comp2, it generates a high-low level flip and inputs a high or low level to the common RS flip-flop, thereby generating the switching cycle of the load circuit switch.

[0171] The output of the second comparator Comp2 is also electrically connected to the first switch K1, the second switch K2, the third switch K3, and the fourth switch K4. This connection controls the opening and closing of the four switches based on the generated high and low level switching signals, thereby controlling the charging and discharging of the second conversion capacitor C2 and the first conversion capacitor C1. Specifically, the first switch K1 and the third switch K3 are simultaneously turned on and off, and the second switch K2 and the fourth switch K4 are simultaneously turned on and off. The first switch K1 and the third switch K3 are not simultaneously turned on, unlike the second switch K2 and the fourth switch K4.

[0172] Preferably, the relationship between the turn-on time and the switching cycle is as follows:

[0173] The on / off time is less than the switching cycle;

[0174] The activation time is calculated from the start time of the switching cycle;

[0175] During the on-time period, the load circuit switch is in the ON state;

[0176] During the switching cycle time excluding the on-time, the load circuit switch is in the off state.

[0177] The following describes in detail how to obtain the duty cycle related parameters:

[0178] like Figure 4 As shown, multiplier 1 and multiplier 2 are two identical multipliers with a gain of A. Using two identical multipliers can compensate for the variation in gain of a single multiplier due to temperature and process angle, thereby improving the accuracy of the entire circuit system.

[0179] A4 and A5 are two identical operational amplifiers, and comp1 and comp2 are two identical comparators. R5 and R6 are equal and have the same layout, and C1 and C2 are equal and have the same layout.

[0180] The low-level time Ton and period T of the Driver signal can be obtained through the duty cycle adjustment module 13 circuit as follows:

[0181]

[0182]

[0183] By setting R5 = R6 and C1 = C2, the duty can be obtained as follows:

[0184]

[0185] Based on the four voltage signals V in the aforementioned load voltage and current detection module 11 circuit and reference power setting module 12 circuit... vsen Visen V psen V ref1 The duty cycle can be obtained as:

[0186]

[0187] By setting R3 = R4, the power can be obtained as follows:

[0188]

[0189] During the initial circuit design, the above parameters can be set as constant values, as follows:

[0190] V1 and V2 are internal reference voltages, which are fixed values;

[0191] R1 and R2 are matching resistors, and are designed with a fixed ratio, therefore... It is also a constant; K p It is the current mirror ratio, and it is also a constant.

[0192] R set It is an external resistor, and once set, it is a fixed value;

[0193] Therefore, it can be seen from the above formula that the output power P is a constant.

[0194] Furthermore, the resistance R can be set by electrically connecting an external power supply with different resistance values. set By doing so, different reference powers can be obtained, and thus different output powers P can be obtained.

[0195] Furthermore, the following provides a detailed explanation of how the duty cycle adjustment circuit's switching control section obtains Ton and the period T:

[0196] Regarding MOSFETs M5, M6, M7, and M8:

[0197] Since the duty cycle adjustment circuit is an internal circuit, its current does not need to supply an external load, so it can be set to a very small value. Therefore, the four MOSFETs in this duty cycle adjustment circuit can all be ordinary MOSFETs, denoted as M5, M6, M7, and M8, and all operate in the saturation region. This is because as long as Vgs, that is, the voltage difference between the gate and source of the MOSFET, is equal, the current flowing through the two MOSFETs can be guaranteed to have a certain proportional relationship.

[0198] I M5 =K P *I M6

[0199] I M7 =K P *IM8

[0200] In this duty cycle adjustment circuit, K P =1, therefore we have:

[0201] I M5 =I M6

[0202] I M7 =I M8

[0203] Regarding switches K1, K2, K3, and K4:

[0204] The output of comparator comp2 controls the opening and closing of four switches;

[0205] K1 and K3 are simultaneously turned on, charging C1 and C2;

[0206] K2 and K4 are simultaneously turned on, discharging C1 and C2. The discharge is instantaneous and the time is negligible compared to the charging time.

[0207] Therefore, Q = C * U = I * t

[0208] Where C remains constant, I is a constant value, and U increases accordingly as time t increases.

[0209] The charging time of C1 is shorter than that of C2, so the comparator comp1 connected to C1 always inverts first.

[0210] When C2 is fully charged, comp2 will also invert. Simultaneously, since the input level of comp2 also controls the switching—that is, when it inverts to a high level, it controls K1 and K3 to simultaneously turn off, and K2 and K4 to simultaneously turn on—the fully charged C1 and C2 will discharge simultaneously. Since the discharge is instantaneous, its time is negligible compared to the charging time. Therefore, when the discharge ends, comp2 will immediately invert again, releasing a low level that controls K1 and K3 to simultaneously turn on, and K2 and K4 to simultaneously turn off, thus causing C1 and C2 to begin charging simultaneously, and the next cycle begins.

[0211] By repeating the above cycle, the charging time of C1 can be set to Ton, and the charging time of C2 can be set to T.

[0212] These two times are input to the driver from a shared RS flip-flop. In this embodiment, the shared RS flip-flop is composed of NOR gates and is inverted by an inverter in the driver, thus inputting to... Figure 2 M1 in the middle controls whether M1 is turned on or off.

[0213] The relationship between Ton, T, the sampled voltage and current, and the set reference power is as follows:

[0214] Since Q = C * U = I * t and:

[0215] I M5 =I M6 and I M7 =I M8 ,

[0216] Then we have:

[0217]

[0218] Therefore:

[0219]

[0220] Similarly, we can obtain:

[0221]

[0222] Therefore:

[0223]

[0224] On the other hand, the present invention provides a method for constant power control, comprising:

[0225] S1: Detects load voltage and load current, and converts them into a load voltage signal V. vsen Second detection voltage signal V isen The detected power signal, representing the real-time load power, is then obtained through the detected power multiplier 1301.

[0226] S2: Set the reference power and convert it into a voltage signal to obtain the second reference voltage signal V, which characterizes the reference power. psen ;

[0227] S3: Convert the detected power signal into current, charge the capacitor, and generate the on-time of the load circuit switch;

[0228] S4: Convert the second reference voltage signal, which represents the reference power, into current to charge the capacitor and generate the switching cycle of the load circuit.

[0229] S5: Control the duty cycle of the load circuit switch according to the turn-on time and the switching cycle to realize the disconnection and conduction of the load circuit.

[0230] Furthermore, step S2 also includes:

[0231] S21: Set the reference voltage and convert it into a voltage signal V. ref1Then, together with the second reference voltage signal, it passes through the reference power multiplier 1302 to obtain the reference power signal characterizing the reference power.

[0232] Furthermore, step S2 also includes:

[0233] S22: The steps for setting the reference power include replacing the external power setting resistor RsetR. set Different external power setting resistors RsetR set These represent different reference power levels.

[0234] Preferably, the load voltage signal V vsen With real-time load voltage V load The relationship is:

[0235] Among them, R1 and R2 are voltage divider resistors.

[0236] Preferably, the second detection voltage signal V isen With real-time load current I load The relationship is:

[0237] R3 is the conversion resistor used to convert the load current into a voltage signal, and KI is the current mirror ratio.

[0238] Preferably, the second reference voltage signal V psen With external power setting resistor RsetR set The relationship is:

[0239] Where V2 is the internal reference voltage of the circuit, R4 is the switching resistor, and K p It is the current mirror ratio.

[0240] Preferably, the start time is:

[0241] Where R5 is the switching resistor, C1 is the capacitor, V3 is the internal reference voltage, and A is the amplification factor.

[0242] Preferably, the switching cycle is:

[0243] Where R6 is the switching resistor, C2 is the capacitor, V3 is the internal reference voltage, and A is the amplification factor.

[0244] Furthermore, the duty cycle is:

[0245]

[0246] Based on four voltage signals V vsen V isen Vpsen V ref1 The duty can be obtained as:

[0247]

[0248] By setting R3 = R4, the power can be obtained as follows:

[0249]

[0250] The circuit can be configured as follows during the initial design:

[0251] V1 and V2 are internal reference voltages, which are fixed values;

[0252] R1 and R2 are matching resistors, and are designed with a fixed ratio, therefore... It is also a constant; K p It is the current mirror ratio, and it is also a constant.

[0253] R set It is an external resistor, and once set, it is a fixed value;

[0254] Therefore, by ensuring that the output power P is a constant value, constant power output is achieved.

[0255] The acquisition of parameters in the above methods has been described in detail in the previous circuit introduction, and will not be repeated here.

[0256] In another aspect, the present invention provides a smoking rod, including a constant power control circuit and an external power setting resistor as described above, wherein the external power setting resistor is electrically connected to a reference power setting module.

[0257] In another aspect, the present invention provides an electronic cigarette, including the aforementioned cigarette holder.

[0258] Therefore, the solution of this embodiment can achieve the following functions: after the circuit is connected and powered on, based on the four voltage signals V in the aforementioned load voltage and current detection module 11 circuit and reference power setting module 12 circuit... vsen V isen V psen V ref1 The input is sent to the duty cycle adjustment module 13, which then generates the connection time Ton and period T of the driver. Finally, the driver module controls the Power MOS switch to ensure that the output power P is a constant value.

[0259] Furthermore, the external power setting resistor R can be adjusted. set By setting different reference power and simply replacing an external resistor, the power requirements of different models of equipment can be met, saving production and assembly costs.

[0260] All of the above circuits are implemented using analog circuits, eliminating the need for multiple digital-to-analog or analog-to-digital conversions, saving components and making them economical.

[0261] Example 2

[0262] like Figure 5 As shown, this embodiment discloses a digital constant power control circuit, including: a load voltage and current detection module 21, a reference power setting module 22, an analog-to-digital conversion module 23, and a duty cycle digital processing module 24;

[0263] The load voltage and current detection module 21 inputs the detected load voltage signal Vvsen and the second detection voltage signal Visen, representing the load current signal, into the analog-to-digital conversion module 23. The reference power setting module 22 inputs the second reference voltage signal and the first reference voltage signal, representing the reference power, into the analog-to-digital conversion module 23. The analog-to-digital conversion module 23 converts the load voltage signal, the second detection voltage signal, the second reference voltage signal, and the first reference voltage signal into digital signals and inputs them into the duty cycle digital processing module 24. The duty cycle digital processing module 24 generates the on-time and switching cycle of the load circuit switch and controls the load circuit switch to be on and off so that the output power is proportional to the reference power. Here, the ratio is, for example, 1:1, 1:2, 1:3, 1:4, 2:1, 3:1, 4:1, etc., preferably 1:1, at which time the output power is equal to the reference power.

[0264] Among them, reference Figure 2-3 The load voltage and current detection module 21 and the reference power setting module 22 have the same control principle as the analog circuit in Embodiment 1, and will not be described again here.

[0265] Preferably, refer to Figure 5-6 The analog-to-digital conversion module 23 includes a selector 2301 and an analog-to-digital converter 2302;

[0266] The input terminals of selector 2301 are electrically connected to load voltage and current detection module 21 and reference power setting module 22, respectively. The control terminal of selector is electrically connected to the output terminal of duty cycle digital processing module 24. Duty cycle digital processing module 24 controls selector 2301 to output load voltage signal, second detection voltage signal, second reference voltage signal and first reference voltage signal in a time-division manner. The output terminal of selector 2301 is electrically connected to the input terminal of analog-to-digital converter 2302, so as to sample and output the load voltage signal, second detection voltage signal and second reference voltage signal and first reference voltage signal to analog-to-digital converter 2302 in a time-division manner.

[0267] The input terminal of the analog-to-digital converter 2302 is electrically connected to the output terminal of the duty cycle digital processing module 24, and the output terminal of the analog-to-digital converter 2302 is electrically connected to the input terminal of the duty cycle digital processing module 24. This is used to convert the load voltage signal, the second detection voltage signal, the second reference voltage signal, and the first reference voltage signal into digital signals and output them to the duty cycle digital processing module 24. The sampling quantization index of the digital signal is adjusted according to the sampling quantization index control command of the duty cycle digital processing module 24.

[0268] Specifically, for the analog-to-digital converter 2302, please refer to... Figure 6 This is a schematic diagram of a preferred analog-to-digital converter (ADC) circuit according to the present invention.

[0269] Analog-to-digital converters (ADCs) employ a successive approximation method, converting the sampled values ​​V of the input signal into a digital signal. sh The logic output is sequentially compared with the reference voltage value generated by the DAC conversion network, producing the logic output from the most significant bit to the least significant bit.

[0270] Among them, V in It is the output of the MUX, which is the load voltage signal V. vsen The second detected voltage signal V isen The second reference voltage signal V psen The first reference voltage signal V ref1 One of them; V ref It is the reference voltage of the ADC, V vsen V isen V psen V ref1 The specific method of obtaining it is the same as in Example 1, and will not be repeated here.

[0271] Taking a 10-bit analog-to-digital converter (ADC) as an example, 10 bits represents 2 to the power of 10, meaning the sampling quantization index is 1024, V psen (D) represents V psen The quantized value after ADC conversion, that is, V ref Divided into 1024 parts, the value of Vref is fixed, and the voltage value of each part is Vref / 1024. psen The number of parts represents the quantization value of Vpsen, which is denoted by Vpsen(D), as shown below:

[0272]

[0273] Similarly, we can obtain V vsen V isen V ref1 The quantization values ​​are shown below:

[0274]

[0275]

[0276]

[0277] Preferably, the input terminal of the duty cycle digital processing module 24 is electrically connected to the output terminal of the analog-to-digital converter module 23, and the output terminal of the duty cycle digital processing module 24 is also electrically connected to the selector 2301 and the analog-to-digital converter 2302.

[0278] The duty cycle digital processing module 24 uses a fixed on-time T. on The switching cycle adjustment module 2401 generates a switching cycle T based on the sampled load voltage signal, the second detection voltage signal, the second reference voltage signal, and the quantized values ​​of the first reference voltage signal, and outputs an on-time signal and a switching cycle signal to control the load circuit to turn on and off.

[0279] The duty cycle digital processing module 24 also adjusts the start time T. on The switching cycle T outputs a selection control command, and the selector 2301 outputs one of the load voltage signal, the second detection voltage signal, the second reference voltage signal, and the first reference voltage signal to the analog-to-digital converter 2302.

[0280] Preferably, the relationship between the turn-on time and the switching cycle is as follows:

[0281] The on / off time is less than the switching cycle;

[0282] The activation time is calculated from the start time of the switching cycle;

[0283] During the on-time period, the load circuit switch is in the ON state;

[0284] During the switching cycle time excluding the on-time, the load circuit switch is in the off state.

[0285] Specifically, for the switching cycle adjustment module 2401, please refer to... Figure 7 The diagram below illustrates the waveform principle of a preferred switching cycle adjustment module 2401 of the present invention for acquiring the switching cycle T.

[0286] This control scheme uses a fixed Ton time, for example, 512 clock cycles, based on the sampled V. psen (D) / V vsen (D) / V isen (D) / V ref1 The (D) value is used to adjust the T time.

[0287] To reuse the analog-to-digital converter (ADC), a time-division sampling method is used.

[0288] like Figure 7 As shown, when Adc_ch = 0, the sampling V psen (D), and only one sample is taken each time it is enabled, because the power is only related to R. set Related, once R set The power is set to be constant, and only one sampling is needed.

[0289] When Adc_ch = 1 / 2 / 3, sample V respectively. vsen (D) / V isen (D) / V ref1 (D)

[0290] Specifically, the following is a method for determining the required switching cycle T based on the circuit settings when the Ton time is fixed at 512 clk:

[0291] Assuming the required switching cycle T is N clk cycles, then:

[0292]

[0293] At the same time, the voltage and current values ​​of the load can be derived by reverse calculation, as shown below:

[0294]

[0295]

[0296] Furthermore, since the power is constant, the following relationship can be established:

[0297]

[0298] Where K4 is a constant, and the power P and external resistor R are... set They are inversely proportional. Therefore, according to V... psen quantization value The following relationship can be obtained:

[0299]

[0300] Furthermore, according to the definition of power, the following relationship exists:

[0301]

[0302] Therefore, we get:

[0303]

[0304] This includes the following relationships:

[0305]

[0306] From the above equations, we can obtain the equation containing V. psen (D) / V vsen (D) / V isn (D) / V ref1 The N value of (D):

[0307]

[0308] In the above formula, V2, KI, V ref1 K p K4, R1, and R2 are all constants, so the calculated values ​​can be used to determine the relationship between them. The ratio is adjusted proportionally to obtain a fixed P value, thus achieving constant power.

[0309] On the other hand, the present invention provides a constant power control method, comprising:

[0310] S1: Detect load voltage V load and load current I load Converted into load voltage signal V vsen Second detection voltage signal V isen ;

[0311] S2: Set the reference power and reference voltage, and convert them into a voltage signal to obtain the second reference voltage signal V, which characterizes the reference load power. psen and the first reference voltage signal V that characterizes the reference voltage ref1 ;

[0312] S3: Transfer the load voltage signal V vsen Second detection voltage signal V isen Second reference voltage signal V psen and the first reference voltage signal V ref1 Time-division sampling converts the signal into a digital signal;

[0313] S4: Set a fixed on-time based on the load voltage signal V. vsen Second detection voltage signal V isen Second reference voltage signal V psen and the first reference voltage signal V ref1 The converted digital signal adjusts the switching cycle;

[0314] S5: Control the duty cycle of the load circuit switch according to the turn-on time and the switching cycle to realize the disconnection and conduction of the load circuit.

[0315] Furthermore, the load voltage signal V vsen With load voltage V load The relationship is:

[0316] Wherein, R1 and R2 are the first voltage divider resistor and the second voltage divider resistor;

[0317] When the quantization exponent for sampling is 1024, V vsen The quantization value is:

[0318] Where V ref This is the reference voltage during analog-to-digital conversion.

[0319] Furthermore, the second detection voltage signal V isen with I load The load current relationship is as follows:

[0320] The third conversion resistor R3 is used to convert the load current into a voltage signal, and KI is the current mirror ratio.

[0321] When the quantization exponent for sampling is 1024, V isen The quantization value is:

[0322] Where V ref This is the reference voltage during analog-to-digital conversion.

[0323] Furthermore, the relationship between the second reference voltage signal and the external power setting resistor is as follows:

[0324] Where V2 is the second reference voltage inside the circuit, R4 is the fourth switching resistor, and K... p It is the current mirror ratio;

[0325] When the sampling quantization index is 1024, V psen The quantization value is:

[0326]

[0327] Output the first reference voltage signal V ref1 The quantization value is: Where V ref This is the reference voltage during analog-to-digital conversion.

[0328] Furthermore, the on / off time is set to 512 clock cycles, the on / off cycle is N clock cycles, and the duty cycle is:

[0329]

[0330] Furthermore, set the load power to Where K4 is a constant, R set By setting a resistor for the external power supply, the switching cycle can be obtained as follows:

[0331]

[0332] Where V2 is the internal second reference voltage, R1 and R2 are the first and second voltage divider resistors, respectively, and K... p R is the current mirror ratio. set A resistor is set for the external power; therefore, V2, KI, V ref1 K p K4, R1, and R2 are all constants, so they can be calculated based on the results. The ratio is adjusted proportionally to obtain a fixed P value, thus achieving constant power.

[0333] The acquisition of parameters in the above methods has been described in detail in the previous circuit introduction, and will not be repeated here.

[0334] In another aspect, the present invention provides a smoking rod, including a constant power control circuit and an external power setting resistor as described above, wherein the external power setting resistor is electrically connected to a reference power setting module.

[0335] In another aspect, the present invention provides an electronic cigarette, including the aforementioned cigarette holder.

[0336] Therefore, the solution in this embodiment can achieve the following functions:

[0337] After the circuit is connected and powered on, the four voltage signals V from the aforementioned load voltage and current detection module 21 circuit and reference power setting module 22 circuit are used. vsen V isen V psen V ref1 The input is sent to the duty cycle digital processing module 24, which then generates the on-time Ton and the switching period T to control the opening and closing of the load circuit in real time, ensuring that the output load power P is a constant value.

[0338] Furthermore, the external power setting resistor R can be adjusted. set Different reference power levels can be set without modifying other circuit parameters and configurations. This allows for meeting the power requirements of different device models simply by replacing an external resistor, saving production and assembly costs.

[0339] The analog-to-digital conversion module 23 and the duty cycle digital processing module 24 differ from the analog control circuit in Embodiment 1; they are implemented using digital control circuits. These include a selector 2301MUX, an analog-to-digital converter 2302ADC, and a digital input.

[0340] This solution uses a selector to output the collected voltage, current, and power-related parameter values ​​one by one in a time-division manner, and uses a single analog-to-digital converter 2302 to perform analog-to-digital conversion on these parameter values. This can save on the number of components such as the analog-to-digital converter 2302, thus reducing costs.

[0341] This scheme uses a fixed Ton time, for example, 512 clock cycles, based on the sampled V. psen (D) / V vsen (D) / V isen (D) / V ref1 The (D) value is used to adjust the T time. This method can obtain a more accurate adjustment time. In addition, the quantization bits of the analog-to-digital converter and the fixed Ton time can be modified to obtain a variety of methods to adjust the T time.

[0342] This embodiment only requires one selector and one analog-to-digital converter, eliminating the need for multiple analog-to-digital converters and reducing the cost of achieving constant power in electronic cigarettes.

[0343] Example 3

[0344] like Figure 8 As shown, this embodiment discloses an analog constant power control circuit. It includes: a load voltage and current detection module 31, a power detection multiplier 32, and a duty cycle adjustment module 33.

[0345] The load voltage and current detection module 31 inputs the detected load voltage signal and the second detection voltage signal corresponding to the load current signal to the detection power multiplier 32. After multiplying the load voltage signal and the second detection voltage signal, a detection power signal is generated and output to the duty cycle adjustment module 33. The duty cycle adjustment module 33 generates the on-time and switching period of the load circuit switch according to the detection power signal, and controls the load circuit switch to conduct and close, so as to output constant power.

[0346] Preferably, the load voltage and current detection module 31 includes a voltage sampling module 3101 and a current sampling module 3102;

[0347] The implementation of the load voltage and current detection module 31 and the detection power multiplier 32 is similar to that in Embodiment 1, and will not be repeated here.

[0348] The main difference between this embodiment and Embodiment 1 lies in the duty cycle adjustment module 33, see reference... Figure 8 Preferably, the duty cycle adjustment module 33 includes an on-time adjustment module, a switching cycle adjustment module, and a drive module 3305;

[0349] The input terminal of the turn-on time adjustment module is electrically connected to the output terminal of the detection power multiplier 32, the output terminal of the turn-on time adjustment module is electrically connected to the input terminal of the drive module 3305, and the turn-on time adjustment module is also electrically connected to the switch cycle adjustment module. It is used to calculate the turn-on time of the load circuit switch according to the detection power signal and the control signal of the switch cycle adjustment module, and output the turn-on time signal to the drive module 3305, which controls the load circuit switch to open.

[0350] The output of the switching cycle adjustment module is electrically connected to the input of the drive module 3305. It is used to calculate the switching cycle of the load circuit switch and output the switching cycle signal to the drive module 3305. The drive module 3305 controls the load circuit switch to be turned on. The switching cycle adjustment module also outputs a control signal according to the switching cycle signal to control the switching cycle adjustment module and the turn-on time adjustment module to reset their states at the end of each cycle.

[0351] The output terminal of the drive module 3305 is electrically connected to the gate of the Power MOS transistor of the load voltage and current detection module 31 (the Power MOS transistor is also used as a load circuit switch here) to control the opening and closing of the load circuit switch.

[0352] Preferably, the turn-on time adjustment module includes a first voltage-controlled current source i1, a first conversion capacitor C1, a first switch K1, a first comparator 3301, and a first RS flip-flop 3303;

[0353] The control terminal of the first voltage-controlled current source i1 is electrically connected to the output terminal of the detection power multiplier 32. The output current of the first voltage-controlled current source i1 is proportional to the output voltage of the detection power multiplier 32. The output terminal of the first voltage-controlled current source i1 is electrically connected to the first conversion capacitor C1. The other end of the first conversion capacitor C1 is grounded. The first voltage-controlled current source i1 is used to charge the first conversion capacitor C1. The first switch K1 is connected in parallel with the first conversion capacitor C1 and is used to control the charging and discharging of the first conversion capacitor C1.

[0354] The non-inverting input of the first comparator 3301 is electrically connected to the first switching capacitor C1. The inverting input of the first comparator 3301 is connected to the first internal reference voltage REF. The output of the first comparator 3301 is electrically connected to the R input of the first RS flip-flop 3303. The Q output of the first RS flip-flop 3303 is electrically connected to the drive module 3305. The Q / output of the first RS flip-flop 3303 is electrically connected to the control terminal of the first switch K1. The S input of the first RS flip-flop 3303 is electrically connected to the switch cycle adjustment module.

[0355] The turn-on time adjustment module converts the output of the detection power multiplier 32 into current through the first voltage-controlled current source i1 to charge the first conversion capacitor C1. Combined with the first comparator 3301 to generate high-low level switching, it inputs a high level or low level to the first RS flip-flop 3303, thereby generating the turn-on time of the load circuit switch.

[0356] When the start time is reached, the Q output of the first RS flip-flop 3303 sends an electrical signal to the drive module 3305, thereby controlling the disconnection of the load circuit switch.

[0357] When the turn-on time is reached, the Q / output of the first RS flip-flop 3303 outputs a signal to control the first switch K1 to turn on, discharging the first switching capacitor C1. After the instantaneous discharge ends, the first comparator 3301 generates a high-low level flip again, and the Q / output of the first RS flip-flop 3303 outputs a signal to control the first switch K1 to turn off; or after the instantaneous discharge ends, the first switch K1 continues to turn on until the S input of the first RS flip-flop 3303 receives a signal, and then the Q / output of the first RS flip-flop 3303 outputs a signal to control the first switch K1 to turn off.

[0358] Preferably, the switching cycle adjustment module includes a reference power setting module (see the reference of Embodiment 1). Figure 3 ), second voltage-controlled current source i2, second conversion capacitor C2, second switch K2, second comparator 3302, second RS flip-flop 3304;

[0359] The control terminal of the second voltage-controlled current source i2 is electrically connected to the output terminal of the reference power setting module. The output current of the second voltage-controlled current source i2 is proportional to the output voltage of the reference power setting module. The output terminal of the second voltage-controlled current source i2 is electrically connected to the second conversion capacitor C2. The other end of the second conversion capacitor C2 is grounded to charge the second conversion capacitor C2. The second switch K2 is connected in parallel with the second conversion capacitor C2 to control the charging and discharging of the second conversion capacitor C2.

[0360] The non-inverting input of the second comparator 3302 is electrically connected to the second switching capacitor C2, the inverting input of the second comparator 3302 is connected to the first internal reference voltage REF, the output of the second comparator 3302 is electrically connected to the S input of the second RS flip-flop 3304, and the Q output of the second RS flip-flop 3304 is electrically connected to the control terminal of the second switch K2.

[0361] The output terminal Q of the second RS flip-flop 3304 is also electrically connected to the S input terminal of the first RS flip-flop 3303 of the start-up time adjustment module, and is also electrically connected to the R input terminal of the second RS flip-flop 3304 through a rising edge trigger pulse generator.

[0362] The switching cycle adjustment module charges the second conversion capacitor C2 through the second voltage-controlled current source i2, and in conjunction with the second comparator 3302, generates a high-low level flip, inputting a high level or a low level to the second RS flip-flop 3304, thereby generating the switching cycle of the load circuit switch;

[0363] When the switching cycle is reached, the Q output of the second RS flip-flop 3304 sends an electrical signal to the S input of the first RS flip-flop 3303, which controls the Q output of the first RS flip-flop 3303 to send an electrical signal to the drive module 3305, thereby controlling the conduction of the load circuit switch to start the next cycle.

[0364] When the switching cycle is reached, the Q output of the second RS flip-flop 3304 outputs a signal to control the second switch K2 to turn on, discharging the second switching capacitor C2. After the instantaneous discharge ends, the second comparator 3302 generates a high-low level flip again, controlling the second switch K2 to turn off through the Q output signal of the second RS flip-flop 3304, or waiting for the rising edge trigger pulse generator to output a signal to the R input of the second RS flip-flop 3304, triggering the Q output of the second RS flip-flop 3304 to control the second switch K2 to turn off again.

[0365] When the switching cycle is reached, the Q output of the second RS flip-flop 3304 outputs a signal to trigger a rising edge trigger pulse generator to generate a trigger pulse, which is input to the R input of the second RS flip-flop 3304 to reset the state of the second RS flip-flop 3304. The reset method of the second RS flip-flop 3304 is not limited to this one.

[0366] Preferably, the second voltage-controlled current source i2 has the same specifications as the first voltage-controlled current source i1, the second comparator 3302 has the same specifications as the second comparator 3302, and the second conversion capacitor C2 has the same specifications as the first conversion capacitor C1.

[0367] Preferably, the load voltage and current detection module includes a voltage sampling module and a current sampling module;

[0368] The input terminal of the voltage sampling module is electrically connected to the load circuit to detect the load voltage. The input terminal of the current sampling module is electrically connected to the load circuit to detect the second detection voltage signal. The output terminal of the voltage sampling module is electrically connected to the input terminal of the detection power multiplier. The output terminal of the current sampling module is electrically connected to the input terminal of the detection power multiplier to input the detected load voltage signal and the second detection voltage signal to the detection power multiplier. For details, please refer to the load voltage and current detection module in Embodiment 1.

[0369] Preferably, the relationship between the turn-on time and the switching cycle is as follows:

[0370] The on / off time is less than the switching cycle;

[0371] The activation time is calculated from the start time of the switching cycle;

[0372] During the on-time period, the load circuit switch is in the ON state;

[0373] During the switching cycle time excluding the on-time, the load circuit switch is in the off state.

[0374] The following is a detailed explanation of the principles and parameters:

[0375] In this embodiment, during the conduction phase, the load voltage signal is preferably the BAT voltage. The BAT voltage and BAT current are sampled, multiplied, and then i1 is generated through a voltage-controlled current source to charge C1, thereby generating a sawtooth wave Ramp. This wave is compared with the first internal reference voltage REF through a PWM comparator, and then a duty cycle is generated to control the PowerMOS transistor connected to the load circuit.

[0376] Furthermore, based on the circuit setup, and since Q = C * U = I * t, the following relationship can be obtained:

[0377]

[0378]

[0379]

[0380]

[0381] Furthermore, the parameters are explained as follows:

[0382] Among them, T on It is the on-time, T is the switching cycle, Duty is the duty cycle, and P is the load power;

[0383] C1 / C2 are proportional quantities, R2 / R1 are proportional quantities, REF is the internal fixed reference voltage, REF1 is the input voltage of the voltage-controlled current source that generates i2, BAT is the load voltage, I is the load current, K1 is the voltage division coefficient for detecting the load voltage, K2 is the current conversion coefficient after detecting the load current and converting it into voltage, and the sampling accuracy depends on K1 and K2.

[0384] Therefore, different constant power levels can be set by modifying the values ​​of K1 and K2.

[0385] Furthermore, the following provides a detailed explanation of the circuit's operating logic:

[0386] The output Q of the RS flip-flop below: When the Ton time is up, the drive DR above is turned off; the load current becomes 0, and at this time, the output Q makes the output current of the first voltage-controlled current source i1 0 regardless of whether C1 is on or off.

[0387] After period T is reached, the following flip-flop Q has the following three output lines:

[0388] 1. This causes capacitor C2 to discharge;

[0389] 2. The rising edge trigger pulse generator delays for one pulse time to generate a reset pulse signal, which is output to the R input terminal of the flip-flop, causing the Q output terminal of the flip-flop to reverse again, the C2 switch below to reverse, and the discharge ends, discharging for only one pulse time.

[0390] 3. A signal is sent to the S input terminal of the first RS flip-flop, causing the drive module DR to turn on the switch of the load circuit and start providing load current; at the same time, the first switch K1 is also turned off.

[0391] When the first switch K1 is opened, this is the starting moment of Ton, which is also the starting moment of T.

[0392] On the other hand, the present invention provides a constant power control method, characterized in that it includes:

[0393] S1: The load voltage BAT and load current I are detected, converted into a load voltage signal and a second detection voltage signal representing the load current signal, and then passed through the detection power multiplier 32 to obtain the detection power signal representing the real-time load power.

[0394] S2: The detected power signal is converted into current i1 by a voltage-controlled current source, which charges capacitor C1. The current i1 is then compared with the internal fixed reference voltage REF by a comparator, thereby generating the on-time of the load circuit switch.

[0395] S3: Current i2 is generated by the voltage-controlled current source to charge capacitor C2. The current i2 is then compared with the internal fixed reference voltage REF by the comparator, thereby generating the switching cycle of the load circuit switch.

[0396] S4: Control the duty cycle of the load circuit switch according to the turn-on time and the switching cycle to realize the disconnection and conduction of the load circuit.

[0397] Furthermore, step S1 also includes:

[0398] S11: Modify the voltage division coefficient K1 of the detected load voltage and the current conversion coefficient K2 after the detected load current is converted into voltage, thereby setting different reference power.

[0399] Furthermore, the start time T onThe calculation method is as follows:

[0400] Where C1 is a capacitor, R1 is the resistor of the voltage-controlled current source, REF is the internal fixed reference voltage, REF1 is the input voltage of the voltage-controlled current source that generates i2, BAT is the load voltage, I is the load current, K1 is the voltage division coefficient for detecting the load voltage, and K2 is the current conversion coefficient after the load current is converted into voltage.

[0401] Furthermore, the switching period T is calculated as follows:

[0402] Where C2 is a capacitor, R2 is the resistor of the voltage-controlled current source, REF is the internal fixed reference voltage, and REF1 is the input voltage of the voltage-controlled current source that generates i2.

[0403] Furthermore, the duty cycle (Duty) is calculated as follows:

[0404]

[0405] The load power P is:

[0406]

[0407] Where C1 / C2 is a proportional quantity, R2 / R1 is a proportional quantity, REF is an internal fixed reference voltage, REF1 is the input voltage of the voltage-controlled current source that generates i2, BAT is the load voltage, I is the load current, K1 is the voltage division coefficient for detecting the load voltage, K2 is the current conversion coefficient after the load current is converted into voltage, and the sampling accuracy depends on K1 and K2.

[0408] The acquisition of parameters in the above methods has been described in detail in the previous circuit introduction, and will not be repeated here.

[0409] In another aspect, the present invention also provides a smoking rod, including a constant power control circuit and an external power setting resistor, wherein the external power setting resistor is electrically connected to a reference power setting module.

[0410] In another aspect, the present invention provides an electronic cigarette, including the aforementioned cigarette holder.

[0411] Therefore, the solution of this embodiment can achieve the following functions: after the circuit is connected and powered on, the load power is sampled according to the load voltage detection module, current sampling module 3102 and multiplier, and the sampled value is input to the duty cycle adjustment module 33. Then, the duty cycle adjustment module 33 generates the connection time Ton and period T of the driver, and finally the driver module controls the Power MOS switch to ensure that the output power P is a constant value.

[0412] Furthermore, different reference powers can be set by adjusting the sampling coefficients K1 and K2.

[0413] All of the above circuits are implemented using analog circuits, eliminating the need for multiple digital-to-analog or analog-to-digital conversions, saving components and making them economical.

[0414] Example 4

[0415] like Figure 9A-9G As shown, on one hand, the present invention provides a constant power control circuit, including: a load power detection module 41 and a duty cycle adjustment module 42, wherein the duty cycle adjustment module 42 includes a divider 4103 and an integrator 4104;

[0416] The load voltage detection module 4101 samples the load voltage BAT throughout the entire process. The load voltage BAT can be the battery voltage or other voltages. The load current detection module 4102 samples the load current CS throughout the entire process.

[0417] Preferably, the load power detection module 41 inputs the detected load voltage signal to the divider 4103. The output terminal REF of the divider 4103 is electrically connected to one input terminal of the integrator 4104. The load power detection module 41 outputs the detected second detection voltage signal, which represents the load current signal, to the other input terminal of the integrator 4104. The output terminal of the integrator 4104 is electrically connected to the duty cycle adjustment module 42. The duty cycle adjustment module 42 generates the on-time and switching period of the load circuit switch and controls the load circuit switch to conduct and close, so as to achieve constant power output.

[0418] Preferably, the load power detection module 41 includes a load voltage detection module 4101 and a load current detection module 4102.

[0419] The input terminal of the load voltage detection module 4101 is electrically connected to the load circuit to detect the load voltage. The input terminal of the load current detection module 4102 is electrically connected to the load circuit to obtain a second detection voltage signal characterizing the load current. The output terminal of the load voltage detection module 4101 is electrically connected to the input terminal of the divider 4103. The output terminal of the divider 4103 is electrically connected to the non-inverting input terminal of the integrator 4104. The output terminal of the load current detection module 4102 is electrically connected to the inverting input terminal of the integrator 4104. The output terminal of the integrator 4104 is electrically connected to the input terminal of the duty cycle adjustment module 42 to perform division and integration operations on the detected load voltage signal and the second detection voltage signal corresponding to the load current signal, and output the result to the duty cycle adjustment module 42.

[0420] Preferably, refer to Figure 9CThe divider 4103 includes a first operational amplifier 41031, a second capacitor C2, a third resistor R3, and an internal multiplier 41032.

[0421] The non-inverting input of the first operational amplifier 41031 is electrically connected to the second internal reference voltage V2, and its inverting input is electrically connected to the output of the internal multiplier 41032 through the third resistor R3. The inverting input is also electrically connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is electrically connected to the output of the first operational amplifier 41031. The output of the first operational amplifier 41031 is also electrically connected to one of the inputs of the internal multiplier 41032, and serves as the output of the divider. The other input of the internal multiplier 41032 is connected to the load voltage signal.

[0422] Preferably, refer to Figure 9D The integrator 4104 includes a second operational amplifier 41041, a fourth capacitor C4, a sixth resistor R6, and a clamping circuit 41042.

[0423] The non-inverting input of the second operational amplifier 41041 is electrically connected to the output of the divider. The inverting input of the second operational amplifier 41041 is connected to the second detection voltage signal through the sixth resistor R6. The inverting input of the second operational amplifier 41041 is also electrically connected to one end of the fourth capacitor C4, and the other end of the fourth capacitor C4 is electrically connected to the output of the second operational amplifier 41041. The output of the second operational amplifier 41041 is electrically connected to the clamping circuit 41042, and the output of the clamping circuit 41042 serves as the output of the integrator. The clamping circuit 41042 is used to keep the output voltage of the second operational amplifier 41041 within a certain range.

[0424] Preferably, the duty cycle adjustment module 42 further includes a sawtooth wave generator 4201, a PWM comparator 4202, and an RS flip-flop 4203;

[0425] The input terminal of PWM comparator 4202 is electrically connected to the first output terminal of sawtooth wave generator 4201. The other input terminal of PWM comparator 4202 is also electrically connected to the output terminal of integrator 4104. The output terminal of PWM comparator 4202 is electrically connected to the R input terminal of RS flip-flop 4203 to generate the on-time of load circuit switch and output the on-time signal to the R input terminal of RS flip-flop 4203.

[0426] The S input terminal of the RS flip-flop 4203 is electrically connected to the second output terminal of the sawtooth wave generator 4201 to generate the switching cycle of the load circuit switch and output the switching cycle signal to the S input terminal of the RS flip-flop 4203.

[0427] The Q output of the RS flip-flop 4203 is electrically connected to the input of the drive module 4204, and the output of the drive module 4204 is electrically connected to the gate of the Power MOS transistor in the load voltage and current detection module. When the turn-on time and the switching cycle are reached, the RS flip-flop 4203 outputs a high or low level to the drive module 4204 according to the turn-on time signal and the switching cycle signal. The drive module 4204 controls the opening and closing of the load circuit switch.

[0428] The input terminal of the sawtooth wave generator 4201 is electrically connected to the output terminal of the drive module 4204, which is used to reset the state of the sawtooth wave generator 4201 at the end of the cycle.

[0429] Preferably, refer to Figure 9E The sawtooth wave generator 4201 includes a first pulse generator 42011, a fourth comparator S4, a third capacitor C3, a third comparator S3, and a fifth resistor R5.

[0430] The input terminal of the first pulse generator 42011 is the input terminal of the sawtooth wave generator. The output terminal of the first pulse generator 42011 is electrically connected to the non-inverting input terminal of the fourth comparator S4, and the inverting input terminal of the fourth comparator S4 is grounded. The output terminal of the fourth comparator S4 is electrically connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is grounded. The output terminal of the fourth comparator S4 is the first output terminal of the sawtooth wave generator.

[0431] The output of the fourth comparator S4 is also electrically connected to the non-inverting input of the third comparator S3. The inverting input of the third comparator S3 is connected to the sixth internal reference voltage. The output of the third comparator S3 is electrically connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is grounded. The output of the third comparator S3 is the second output of the sawtooth wave generator 4201.

[0432] Preferably, refer to Figure 9F The PWM comparator 4202 includes a second comparator S2, a fourth resistor R4, and a second pulse generator 42021;

[0433] The non-inverting input of the second comparator S2 is electrically connected to the first output of the sawtooth wave generator 4201, and its inverting input is electrically connected to the output of the integrator 4104.

[0434] The output of the second comparator S2 is grounded through the fourth resistor R4;

[0435] The output of the second comparator S2 is electrically connected to the second pulse generator 42021, whose output is also the output of the PWM comparator 4202. When the second pulse generator 42021 receives a high-level signal, the inverter U5 will delay its output by one pulse, thus the AND gate will output a high level. After one pulse time, the inverter U5 outputs a low-level signal to the AND gate U4, and the AND gate U4 outputs a low level. The principle of the first pulse generator 42011 is similar and will not be described further.

[0436] Preferably, the relationship between the start time and the start cycle is as follows:

[0437] The activation time is shorter than the activation cycle;

[0438] The start time is calculated from the beginning time of the start period;

[0439] During the on-time period, the load circuit switch is in the ON state;

[0440] During the switching cycle time other than the on-time, the load circuit switch is in the off state.

[0441] Preferably, the S input terminal of the RS flip-flop 4203 is electrically connected to a periodic pulse signal generator to generate the switching cycle of the load circuit switch and output the switching cycle signal to the S input terminal of the RS flip-flop 4203.

[0442] Depend on Figure 9C It can be seen that the detected battery voltage BAT is used to obtain REF = k / bat through a divider 4103, where the output value of the multiplier is divided by the multiplier's amplification factor to obtain a fixed value k. Then, the voltage signal REF and the second detected voltage signal CS are converted into current signals and integrated with the fourth capacitor C4 through an integrator 4104 to obtain the EAO voltage signal.

[0443] The EAO voltage signal is compared with the sawtooth wave Ramp generated by the sawtooth wave generator 4201 to generate the on-time Ton in the duty cycle, which is used to control the on and off of the power MOSFET of the load circuit 4205. Another output terminal of the sawtooth wave generator 4201 outputs a CLK signal to represent the period of T.

[0444] Different constant power values ​​can be set by modifying k and the current sampling ratio.

[0445] Specifically, Figure 9B A load battery and current detection circuit suitable for this embodiment is shown. Here, the output BATT is the sampled load voltage signal, CS is a voltage signal characterizing the sampled load current, and GATE is the signal driving the control switch of the load circuit 4205.

[0446] Specifically, Figure 9D An integrator circuit 4104 suitable for this embodiment is shown. The non-inverting input is the calculated voltage signal REF, and the inverting input is the second detected voltage signal CS. The EAO voltage signal can be obtained through this integrator 4104. Furthermore, this integrator circuit is also connected to a clamping circuit 41042 to control the output voltage within a range, which is 0.4V-1.9V in the figure. This ensures higher efficiency when comparing the output voltage with the output of the subsequent sawtooth wave generator 4201.

[0447] When the power MOSFET is turned on, the current can be calculated from the CS voltage, the voltage signal REF, and the resistor R6. This current charges the capacitor C4, satisfying the following equation:

[0448] Ton*(CS-REF) / R6=C4*(REF-EAO);

[0449] When the power MOSFET is turned off, the voltage at CS is 0, and capacitor C4 discharges. To achieve steady state, the following equation must be satisfied:

[0450] Toff*REF / R6=C4*(REF-EAO);

[0451] Substituting the period T = Ton + Toff, REF = K / BAT, and CS = K1 * Iload into the two equations above, we get:

[0452] P = Iload * BAT * Ton / T = K / K1, where P is the constant power output.

[0453] Specifically, Figure 9EA specific circuit diagram of a sawtooth wave generator 4201 applicable to this embodiment is shown. The sawtooth wave generator 4201 has two output terminals: a Ramp output terminal (first output terminal) and a CLK output terminal (second output terminal). The Ramp output is input to the PWM comparator 4202, which compares it with the output of the integrator to generate the Ton time and corresponding signal. The CLK output is input to the S input terminal of the RS flip-flop 4203 to generate the T time and corresponding signal. In this embodiment, the period T is determined by the sawtooth wave generator 4201. Furthermore, the sawtooth wave generator 4201 also has an input terminal, the GATE input electrical signal, which, as before, is the signal driving the control load circuit switch 4205. Here, after the GATE input is high, the NOT gate U2 will lag by one timing pulse. That is, both inputs of the AND gate will be high during this timing pulse, causing the AND gate U3 to output a high level. This controls the switch S4 to conduct, allowing for a momentary discharge of C3. After this timing pulse, the NOT gate U2 will output a low level, causing the AND gate U3 to output a low level, controlling the switch S4 to turn off. This allows capacitor C3 to charge, and the sawtooth wave begins to rise from 0. Here, the NOT gate U2 and the AND gate U3 together constitute the first pulse generator 42011.

[0454] Here, I1*T = C3*V6, thus obtaining the value of period T, where I1 is the output current of the current source. Afterwards, control switch S3 is turned on, and CLK outputs a high level to the RS flip-flop 4203.

[0455] Specifically, Figure 9F A PWM comparator 4202 circuit suitable for this embodiment is shown. The inputs are the Ramp signal output from the sawtooth wave generator 4201 and the EAO signal representing the real-time power value output from the integrator circuit. These two signals are compared by the PWM comparator 4202. When they are equal, a timing high-level pulse is generated, indicating that the Ton time in the current cycle has been reached. This pulse is input to one input of the RS flip-flop 4203 and ultimately output to GATE, controlling the load circuit 4205 to turn off. Here, the NOT gate U5 and the AND gate U4 together constitute the second pulse generator.

[0456] Specifically, Figure 9G An RS flip-flop 4203 circuit suitable for this embodiment is shown. The R input receives a signal representing Ton, and the S input receives a signal representing T. The output is given to GATE to control the switching on and off of the load circuit 4205.

[0457] On the other hand, the present invention provides a constant power control method, comprising:

[0458] S1: Detect the load voltage, convert it into a load voltage signal, and then pass it through divider 4103 to obtain a reference voltage signal that is inversely proportional to the load voltage signal;

[0459] S2: Detect the load current and convert it into a second detection voltage signal that characterizes the load current signal;

[0460] S3 passes the reference voltage signal and the second detected voltage signal through the integrator 4104 to obtain the integrated signal;

[0461] S4: Compare the integrated power signal with the sawtooth wave to generate the on-time of the load circuit switch;

[0462] S5: Generates the switching cycle of the load circuit switch, and the switching cycle is a fixed value;

[0463] S6: Control the duty cycle of the load circuit switch according to the turn-on time and the switching cycle to realize the disconnection and conduction of the load circuit.

[0464] Furthermore, step S1 also includes:

[0465] S11: Modify the coefficients of the divider 4103 to set different constant power.

[0466] Furthermore, step S2 also includes:

[0467] S21: Modify the current sampling ratio of the detected load current to set different constant power.

[0468] In another aspect, the present invention provides a smoking rod including the aforementioned constant power control circuit.

[0469] In another aspect, the present invention provides an electronic cigarette, including the aforementioned cigarette holder.

[0470] Therefore, the solution of this embodiment can achieve the following functions: After the circuit is connected and powered on, the load power is sampled by the load voltage detection module 4101, the load current detection module 4102, the divider 4103, and the integrator 4104, and the sampled values ​​are input to the duty cycle adjustment module 42. The duty cycle adjustment module 4233 then generates the connection time Ton and period T of the control drive module 4204Driver. Finally, the drive module 4204Driver controls the conduction and disconnection of the Power MOS switch of the load circuit 4205 to ensure that the output power P is a constant value.

[0471] Furthermore, different reference power can be set by adjusting the current sampling coefficient and the coefficient k of the divider 4103.

[0472] All of the above circuits are implemented using analog circuits, eliminating the need for multiple digital-to-analog or analog-to-digital conversions, saving components and making them economical.

[0473] Example 5

[0474] like Figure 10 As shown, this embodiment discloses an analog constant power control circuit.

[0475] On one hand, the present invention provides a constant power control circuit, including: a power detection module 51 and a duty cycle adjustment module 5252.

[0476] The power detection module 51 includes: a current sampling module 5101, a voltage sampling module 5102, and a multiplier 5105.

[0477] The duty cycle adjustment module 5252 includes an error amplifier 5201, a PWM comparator 5202, and a drive module 5204.

[0478] The power detection module 51 multiplies the detected load voltage signal, which represents the voltage on the load circuit, and the second detection voltage signal, which represents the current flowing through the load, to generate a detection power signal that can represent the load power. This signal is then output to the duty cycle adjustment module 52. Based on the detection power signal, the duty cycle adjustment module 52 generates the on-time and switching cycle of the load circuit 5205 switch and controls the load circuit 5205 switch to be turned on and off to ensure constant power output.

[0479] Preferably, the power detection module 51 includes a current sampling module 5101, a voltage sampling module 5102, a low-pass filter, and a multiplier 5105;

[0480] The input terminal of the voltage sampling module 5102 is electrically connected to the load circuit 5205 to detect the load voltage and obtain a load voltage signal. The input terminal of the current sampling module 5101 is electrically connected to the load circuit 5205 to detect the load current and obtain a second detection voltage signal. The output terminal of the voltage sampling module 5102 is electrically connected to the input terminal of the first low-pass filter 5103. The output terminal of the first low-pass filter 5103 is electrically connected to the input terminal of the multiplier 5105. The output terminal of the current sampling module 5101 is electrically connected to the input terminal of the second low-pass filter 5104. The output terminal of the second low-pass filter 5104 is electrically connected to the input terminal of the multiplier 5105. The output terminal of the multiplier 5105 is electrically connected to the input terminal of the duty cycle adjustment module 52. This module performs low-pass filtering to remove noise from the detected load voltage signal and the second detection voltage signal, and then performs multiplication to generate a detection power signal that can characterize the load power, which is then output to the duty cycle adjustment module 52.

[0481] Preferably, the duty cycle adjustment module 52 includes an error amplifier 5201, a PWM comparator 5202, and a drive module 5204;

[0482] The negative input terminal of the error amplifier 5201 is electrically connected to the output terminal of the power detection module 51, and the positive input terminal of the error amplifier 5201 receives a preset reference power voltage signal, which is used to compare the detected power signal with the reference power signal to obtain the power difference.

[0483] The input terminal of PWM comparator 5202 is electrically connected to the output terminal of error amplifier 5201. The other input terminal of PWM comparator 5202 receives a sawtooth wave signal. The output terminal of PWM comparator 5202 is electrically connected to the input terminal of drive module 5204. The output terminal of drive module 5204 is electrically connected to the control terminal of load circuit switch. When the turn-on time and switching cycle time points are reached, PWM comparator 5202 outputs high and low levels to drive module 5204 according to the turn-on time signal and the switching cycle signal. Drive module 5204 controls the opening and closing of load circuit switch.

[0484] Preferably, the duty cycle adjustment module further includes an RS trigger 5203;

[0485] The output of PWM comparator 5202 is electrically connected to the R input of RS flip-flop 5203. The S input of RS flip-flop 5203 receives clock pulse signals and is used to generate the switching cycle of the load circuit.

[0486] The Q output of RS flip-flop 5203 is electrically connected to the input of driver 5204 module, and the output of driver 5204 module is electrically connected to the gate of Power MOS transistor in load circuit 5205. When the turn-on time and switching cycle time are reached, RS flip-flop 5203 outputs high and low levels to driver 5204 module according to the turn-on time signal and switching cycle signal. Driver 5204 module controls the opening and closing of load circuit 5205 switch.

[0487] Preferably, the relationship between the turn-on time and the switching cycle is as follows:

[0488] The on / off time is less than the switching cycle;

[0489] The activation time is calculated from the start time of the switching cycle;

[0490] During the on-time, the load circuit 5205 switch is in the ON state;

[0491] During the switching cycle time excluding the on-time, the load circuit 5205 switch is in the off state.

[0492] Preferably, the positive terminal of the input of the error amplifier 5201 is set to the reference power VREF to be achieved, and the negative terminal of the input is set to the output of the multiplier 5105.

[0493] The output of error amplifier 5201 is: V 输出 =K*(V + -V - )

[0494] Error V 输出 Compared to the sawtooth wave RAMP, the PWM comparator 5202 generates a duty cycle, which ultimately controls the on / off state of the switching MOSFET in the load circuit 5205. Here, CLK is a period T, which is longer than the Ton time controlled by the output of the PWM comparator 5202.

[0495] Therefore, in this embodiment, different constant power can be set by setting the value of VREF at the positive input terminal of the error amplifier 5201.

[0496] On the other hand, the present invention provides a constant power control method, comprising:

[0497] S1: Detect the load voltage, convert it into an electrical signal, and then pass it through a low-pass filter to obtain a noise-removed load voltage signal;

[0498] S2: Detects the load current, converts it into an electrical signal, and then passes it through a low-pass filter to obtain a second detection voltage signal with noise removed;

[0499] S3: The load voltage signal and the second detection voltage signal are multiplied by the multiplier 5105 to obtain a detection power signal that can characterize the load power;

[0500] S4: Compare the detected power signal with a preset reference power voltage to obtain the power difference;

[0501] S5: Compare the power difference with the sawtooth wave to generate the turn-on time of the 5205 switch in the load circuit;

[0502] S6: Generates the switching cycle of the 5205 switch in the load circuit. The switching cycle is a fixed value.

[0503] S7: Control the duty cycle of the load circuit 5205 switch according to the turn-on time and the switching cycle, so as to control the opening and closing of the load circuit 5205.

[0504] Furthermore, step S1 also includes:

[0505] S11: Obtain the voltage sampling coefficient when detecting the load voltage to obtain different constant power.

[0506] Furthermore, step S2 also includes:

[0507] S21: Obtain the current sampling ratio of the detected load current to obtain different constant power.

[0508] Furthermore, step S4 also includes:

[0509] S41: The power difference is amplified by an error amplifier to obtain the coefficient of the error amplifier and adjust the accuracy of the power difference.

[0510] Furthermore, step S4 also includes:

[0511] S42: Different constant power can be obtained by adjusting the preset reference power voltage.

[0512] The acquisition of parameters in the above methods has been described in detail in the previous circuit introduction, and will not be repeated here.

[0513] In another aspect, the present invention provides a smoking rod that includes the aforementioned constant power control circuit.

[0514] In another aspect, the present invention provides an electronic cigarette, including the aforementioned cigarette holder.

[0515] Therefore, the solution of this embodiment can achieve the following functions: After the circuit is connected and powered on, the load power is sampled by the current sampling module 5101, voltage sampling module 5102, low-pass filter, and multiplier 5105, and the sampled value is input to the duty cycle adjustment module 5252. The duty cycle adjustment module 5252 then generates the connection time Ton and period T of the driver, and finally the driver module 5204 controls the load circuit switch to ensure that the output power P is a constant value.

[0516] Furthermore, different constant power can be obtained by using different voltage and current sampling coefficients.

[0517] All of the above circuits are implemented using analog circuits, eliminating the need for multiple digital-to-analog or analog-to-digital conversions, saving components and making them economical.

Claims

1. A constant power control circuit, characterized in that, The constant power control circuit includes: a load voltage and current detection module, a reference power setting module, and a duty cycle adjustment module; The load voltage and current detection module inputs the detected load voltage signal and the second detection voltage signal characterizing the load current signal to the duty cycle adjustment module. The reference power setting module inputs the reference power signal to the duty cycle adjustment module. The duty cycle adjustment module generates the on-time and switching cycle of the load circuit switch according to the load voltage signal, the second detection voltage signal and the reference power signal, and controls the load circuit switch to turn on and off so that the output power is proportional to the reference power. The reference power signal includes a first reference voltage signal and a second reference voltage signal; The duty cycle adjustment module includes a detection power multiplier and a reference power multiplier with the same specifications as the detection power multiplier. The two input terminals of the detection power multiplier are electrically connected to the two output terminals of the load voltage and current detection module, respectively. The detection power multiplier is used to convert the load voltage signal and the second detection voltage signal into the detection power corresponding to the load. The two input terminals of the reference power multiplier are electrically connected to the two output terminals of the reference power setting module. The reference power multiplier is used to convert the first reference voltage signal and the second reference voltage signal into reference power.

2. The constant power control circuit according to claim 1, characterized in that, The load voltage and current detection module includes a sampling MOSFET, an intermediate MOSFET, a detection current operational amplifier, a first voltage divider resistor, a second voltage divider resistor, and a third conversion resistor; the load circuit switch includes a Power MOSFET. The source of the Power MOS transistor is electrically connected to the power supply, the gate of the Power MOS transistor is electrically connected to the output terminal of the duty cycle adjustment module, the drain of the Power MOS transistor is used to be electrically connected to the load, the drain of the Power MOS transistor is also electrically connected to the first voltage divider resistor, one end of the second voltage divider resistor is connected in series with the first voltage divider resistor, and the other end is grounded. The end of the second voltage divider resistor connected to the first voltage divider resistor is also electrically connected to the duty cycle adjustment module to output the load voltage signal. The source of the sampling MOS transistor is electrically connected to the power supply, the gate of the sampling MOS transistor is electrically connected to the gate of the Power MOS transistor, the drain of the sampling MOS transistor is electrically connected to the inverting input terminal of the detection current operational amplifier, the inverting input terminal is also electrically connected to the source of the intermediate MOS transistor, the gate of the intermediate MOS transistor is electrically connected to the output terminal of the detection current operational amplifier, the drain of the intermediate MOS transistor is electrically connected to the third conversion resistor, the other end of the third conversion resistor is grounded, the non-inverting input terminal of the detection current operational amplifier is electrically connected to the drain of the Power MOS transistor; the end of the third conversion resistor connected to the intermediate MOS transistor is also electrically connected to the duty cycle adjustment module for outputting a second detection voltage signal.

3. The constant power control circuit according to claim 1, characterized in that, The reference power setting module includes a power setting operational amplifier, a reference voltage operational amplifier, a third MOSFET, a fourth MOSFET, and a fourth conversion resistor; The non-inverting input of the power setting operational amplifier is connected to a second reference voltage generated inside the constant power control circuit. The source of the third MOS transistor is electrically connected to the power supply, the gate of the third MOS transistor is electrically connected to the output of the power setting operational amplifier, and the drain of the third MOS transistor is electrically connected to the inverting input of the power setting operational amplifier. The drain of the third MOS transistor is also used to connect to an external power setting resistor. The external power setting resistor is used to set the reference power. The source of the fourth MOS transistor is electrically connected to the power supply, the gate of the fourth MOS transistor is electrically connected to the gate of the third MOS transistor, the drain of the fourth MOS transistor is electrically connected to the fourth conversion resistor, and the other end of the fourth conversion resistor is grounded; the end of the fourth conversion resistor connected to the fourth MOS transistor is also electrically connected to the duty cycle adjustment module to output a second reference voltage signal corresponding to the current signal of the fourth conversion resistor. The non-inverting input of the reference voltage operational amplifier is the first reference voltage generated inside the constant power control circuit. The output of the reference voltage operational amplifier is electrically connected to the inverting input. The output is also electrically connected to the duty cycle adjustment module to output the first reference voltage signal.

4. The constant power control circuit according to claim 3, characterized in that, The duty cycle adjustment module also includes an on-time adjustment module, a switching cycle adjustment module, and a drive module; The input terminal of the turn-on time adjustment module is electrically connected to the output terminal of the detection power multiplier, and its output terminal is electrically connected to the input terminal of the drive module. It is used to obtain the turn-on time of the load circuit switch according to the detection power, and output the turn-on time signal to the drive module, so that the drive module controls the load circuit switch to turn off. The input terminal of the switching cycle adjustment module is electrically connected to the output terminal of the reference power setting module, and the output terminal of the switching cycle adjustment module is electrically connected to the input terminal of the drive module. It is used to calculate the switching cycle of the load circuit switch according to the reference power and output the switching cycle signal to the drive module, so that the drive module controls the load circuit switch to be turned on. The switching cycle adjustment module is also electrically connected to the on-time adjustment module. The switching cycle adjustment module outputs a control signal according to the switching cycle signal to control the switching cycle adjustment module and the on-time adjustment module to reset their states at the end of each cycle. The output terminal of the drive module is electrically connected to the control terminal of the load circuit switch to control the opening and closing of the load circuit switch.

5. The constant power control circuit according to claim 4, characterized in that, The turn-on time adjustment module includes a detection power operational amplifier, a fifth MOSFET, a sixth MOSFET, a fifth switching resistor, a first switching capacitor, a first switch, a second switch, a first comparator, and a shared RS flip-flop; The non-inverting input terminal of the detection power operational amplifier is electrically connected to the output terminal of the detection power multiplier. The source of the fifth MOS transistor is electrically connected to the power supply. The gate of the fifth MOS transistor is electrically connected to the output terminal of the detection power operational amplifier. The drain of the fifth MOS transistor is electrically connected to the inverting input terminal of the detection power operational amplifier. The drain of the fifth MOS transistor is also electrically connected to the fifth conversion resistor. The other end of the fifth conversion resistor is grounded. The source of the sixth MOS transistor is electrically connected to the power supply, the gate of the sixth MOS transistor is electrically connected to the gate of the fifth MOS transistor, and the drain of the sixth MOS transistor is electrically connected to the first switching capacitor through the first switch. The other end of the first switching capacitor is grounded, and the second switch is connected in parallel with the first switching capacitor. The non-inverting input of the first comparator is electrically connected to the first switching capacitor, the inverting input of the first comparator is connected to the third reference voltage generated inside the constant power control circuit, and the output of the first comparator is electrically connected to one input of a shared RS flip-flop. The turn-on time adjustment module converts the output of the detection power multiplier into current to charge the first conversion capacitor. The first comparator generates high-low level toggles based on the voltage on the first conversion capacitor. The first comparator inputs a high or low level to the common RS flip-flop, thereby generating the turn-on time of the load circuit switch.

6. The constant power control circuit according to claim 5, characterized in that, The switching cycle adjustment module includes a reference power operational amplifier, a seventh MOSFET, an eighth MOSFET, a sixth switching resistor, a second switching capacitor, a third switch, a fourth switch, and a second comparator; The non-inverting input terminal of the reference power operational amplifier is electrically connected to the output terminal of the reference power setting module. The source of the seventh MOS transistor is electrically connected to the power supply. The gate of the seventh MOS transistor is electrically connected to the output terminal of the reference power operational amplifier. The drain of the seventh MOS transistor is electrically connected to the inverting input terminal of the reference power operational amplifier and is also electrically connected to the sixth conversion resistor. The other end of the sixth conversion resistor is grounded. The source of the eighth MOS transistor is electrically connected to the power supply, the gate of the eighth MOS transistor is electrically connected to the gate of the seventh MOS transistor, the drain of the eighth MOS transistor is electrically connected to the second conversion capacitor through the third switch, the other end of the second conversion capacitor is grounded, and the fourth switch is connected in parallel with the second conversion capacitor. The non-inverting input of the second comparator is electrically connected to the second switching capacitor, the inverting input of the second comparator is connected to the third reference voltage, and the output of the second comparator is electrically connected to the other input of the shared RS flip-flop. The reference power operational amplifier has the same specifications as the detection power operational amplifier, the second comparator has the same specifications as the first comparator, the sixth conversion resistor has the same resistance value as the fifth conversion resistor, and the second conversion capacitor has the same specifications as the first conversion capacitor. The turn-on time adjustment module converts the output of the reference power multiplier into current to charge the second conversion capacitor. The second comparator generates high-low level toggles based on the voltage on the second conversion capacitor, inputting a high or low level to the common RS flip-flop, thereby generating the turn-on cycle of the load circuit switch. The output of the second comparator is also electrically connected to the control terminals of the first, second, third, and fourth switches to control the opening and closing of the four switches according to the generated high and low level switching signals, thereby controlling the charging and discharging of the second conversion capacitor and the first conversion capacitor. The first and third switches are simultaneously turned on and off, and the second and fourth switches are simultaneously turned on and off.

7. The constant power control circuit according to any one of claims 1-3, characterized in that, The relationship between the activation time and the switching period is as follows: The opening time is less than the switching cycle; The activation time is calculated from the start time of the switching cycle; During the specified activation time, the load circuit switch is in the ON state; During the switching cycle time other than the on-time, the load circuit switch is in the off state.

8. A constant power control method, characterized in that, include: S1: Detect load voltage and load current Converted into load voltage signal Second detection voltage signal The detected power signal, which characterizes the real-time load power, is then obtained through a detected power multiplier. S2: Set the reference voltage and reference power, and convert them into voltage signals to obtain the first reference voltage signal. Second reference voltage signal First reference voltage signal Together with the second reference voltage signal, the reference power signal is obtained by passing it through a reference power multiplier to form a reference power signal characterizing the reference power, wherein the reference power multiplier has the same specifications as the detection power multiplier; S3: Convert the detected power signal into current to charge the first capacitor, thereby generating the on-time of the load circuit switch; S4: Convert the reference power signal into current to charge the second capacitor and generate the switching cycle of the load circuit switch; S5: Obtain the duty cycle of the load circuit switch based on the turn-on time and the switching cycle, and realize the disconnection and conduction of the load circuit.

9. The constant power control method according to claim 8, characterized in that, Step S2 also includes: S22: Set the resistor according to the external power. Obtain the external power flowing through and set the resistor. These represent different reference power levels.

10. The constant power control method according to claim 9, characterized in that, The load voltage signal With the load voltage The relationship is: Where R1 and R2 are voltage divider resistors; The second detection voltage signal With the load current The relationship is: R3 is the conversion resistor used to convert the load current into a voltage signal, and KI is the current mirror ratio; The second reference voltage signal With external power setting resistor The relationship is: V2 is the internal reference voltage of the circuit. It is a switching resistor. It is the current mirror ratio; The opening time is: ,in For conversion resistor, For capacitors, The internal reference voltage is A, and the amplification factor is A. The switching cycle is: ,in For conversion resistor, For capacitors, The internal reference voltage is A, and the amplification factor is A. The duty cycle is: According to the four voltage signals , , , You can get for: Among them, by setting Then the power can be obtained as: in, , This is the internal reference voltage, which is a fixed value. , It is a matching resistor, and it is designed with a fixed ratio, therefore, It is also a constant value; It is the current mirror ratio, and it is also a constant. It is an external resistor with a fixed value; This ensures that the output power P is a constant value, achieving constant power output.

11. A cigarette holder, characterized in that, The system includes the constant power control circuit and external power setting resistor as described in any one of claims 1-7, wherein the external power setting resistor is electrically connected to the reference power setting module.

12. An electronic cigarette, characterized in that, Includes the smoking rod as described in claim 11.

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