Constant output power control circuit and electronic device

Abstract

The application provides a constant output power control circuit, comprising a reference circuit, a power detection circuit and a pulse width modulation circuit, wherein the power detection circuit comprises a conversion unit and a first integrator module; the reference circuit is used for outputting a reference voltage signal; the reference voltage signal and a load voltage signal of a load are input into the conversion unit, and the conversion unit converts the load voltage signal into a time quantity according to the reference voltage signal; an input end of the first integrator module is electrically connected to a mirror current source through a first resistor, and a control end is electrically connected to the conversion unit; the mirror current source is also grounded through a second resistor, and a current output by the mirror current source is a current flowing through the load; the first integrator module integrates a voltage of the second resistor and outputs a first voltage signal corresponding to an actual output power of the load under the control of the time quantity; and the pulse width modulation circuit is electrically connected to the first integrator module and is used for adjusting an output pulse width modulation signal according to the first voltage signal, so as to realize constant output of the load power.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a constant output power control circuit and electronic device. Background Technology

[0002] Many electronic devices on the market require heating control. This is achieved by applying voltage across a heat-generating load and controlling the duty cycle of that voltage. A typical application of electronic heaters is the mosquito repellent liquid heater. The heater uses battery voltage applied to the heating wire, generating heat that is applied to a carbon rod. The heated carbon rod vaporizes the mosquito repellent liquid, thus repelling mosquitoes. To ensure this effect, the heating wire's output power must be constant. The output power is the product of the voltage across the heating wire and the corresponding current flowing through it. However, in practical applications, the resistance of the heating wire changes with temperature during heating, causing the output power to fluctuate and making it impossible to guarantee a constant power output. Summary of the Invention

[0003] The purpose of this invention is to provide a constant output power control circuit and electronic device that can solve the above-mentioned problems.

[0004] One aspect of this invention provides a constant output power control circuit, including a reference circuit, a power detection circuit, and a pulse width modulation circuit. The power detection circuit includes a conversion unit and a first integrator module. The reference circuit outputs a reference voltage signal. The conversion unit is electrically connected to the reference circuit and a load. The reference voltage signal and the load voltage signal of the load are input to the conversion unit, which converts the load voltage signal into a time quantity based on the reference voltage signal. The first integrator module has its input terminal electrically connected to a mirror current source via a first resistor, and its control terminal electrically connected to the conversion unit. The mirror current source is also grounded via a second resistor. The current output by the mirror current source is the current flowing through the load. The first integrator module integrates the voltage across the second resistor and outputs a first voltage signal corresponding to the actual output power of the load under the control of the time quantity. The pulse width modulation circuit is electrically connected to the first integrator module and adjusts the output pulse width modulation signal according to the first voltage signal.

[0005] Preferably, the conversion unit includes: a second integrator module, including a first input terminal, a second input terminal, and an output terminal; the first input terminal of the second integrator module receives the reference voltage signal through a third resistor; the second input terminal of the second integrator module is grounded; and the output terminal of the second integrator module is electrically connected to the first input terminal of the second integrator module through a first capacitor; a first comparator module, including a first input terminal, a second input terminal, and an output terminal; the first input terminal of the first comparator module is electrically connected to the output terminal of the second integrator module; the second input terminal of the first comparator module receives the load voltage signal; and the output terminal of the first comparator module is electrically connected to the input terminal of the first integrator module; the output terminal of the first comparator module outputs the time quantity.

[0006]

[0007] Wherein, T represents the time quantity, VRH represents the load voltage signal, R3 represents the resistance value of the third resistor, C1 represents the capacitance value of the first capacitor, and VBG represents the reference voltage signal.

[0008] Preferably, the first integrator module includes a first input terminal, a second input terminal, a control terminal, and an output terminal. The first input terminal of the first integrator module is electrically connected to the common terminal of the mirror current source and the second resistor via the first resistor. The second input terminal of the first integrator module is grounded. The control terminal of the first integrator module is electrically connected to the output terminal of the first comparator module. The output terminal of the first integrator module is electrically connected to the first input terminal of the first integrator module via a second capacitor, and is also electrically connected to the pulse width modulation circuit. The first voltage signal output by the output terminal of the first integrator module is:

[0009]

[0010] Wherein, Vout represents the voltage value of the first voltage signal, VRH represents the voltage value of the load voltage signal, IRH represents the current value of the current flowing through the load, R2 represents the resistance value of the second resistor, VBG represents the voltage value of the reference voltage signal, the resistance value of the third resistor is equal to the resistance value of the first resistor, and the capacitance value of the first capacitor is the same as the capacitance value of the first capacitor.

[0011] Preferably, the pulse width modulation circuit includes a second conversion unit, a third conversion unit, and a logic unit. The second conversion unit includes: a third integrator module, including a first input terminal, a second input terminal, and an output terminal; the first input terminal of the third integrator module receives a reference voltage signal through a fourth resistor; the second input terminal of the third integrator module is grounded; and the output terminal of the third integrator module is electrically connected to the first input terminal through a third capacitor; a second comparator module, including a first input terminal, a second input terminal, and an output terminal; the input terminal of the second comparator module is electrically connected to the output terminal of the third integrator module; the second input terminal of the second comparator module receives the first voltage signal; and the output terminal of the second comparator module is electrically connected to the logic unit to output a first output signal to the logic unit; the third conversion unit includes: a fourth integrator module. The fourth integrator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fourth integrator module receives the reference voltage through a fifth resistor. The second input terminal of the fourth integrator module is grounded. The output terminal of the fourth integrator module is electrically connected to the first input terminal of the fourth integrator module through a fourth capacitor. The third comparator module includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the third comparator module is electrically connected to the output terminal of the fourth integrator module. The second input terminal of the third comparator module receives a voltage signal corresponding to the target power. The output terminal of the third comparator module is electrically connected to the logic unit to output a second output signal to the logic unit. The logic unit is electrically connected to the output terminals of the second and third comparator modules and is used to output the pulse width modulation signal according to the first and second output signals.

[0012] Preferably, the third integrator module integrates the reference voltage signal until the power corresponding to the reference voltage signal reaches the power corresponding to the first voltage signal, and the integration time of the third integrator module is:

[0013]

[0014] Wherein, Tout represents the integration time of the third integrator module OP3, Vout represents the voltage value of the first voltage signal, R4 represents the resistance value of the fourth resistor, VREF represents the voltage value of the reference voltage; C3 represents the capacitance value of the third capacitor, the resistance value of the fourth resistor is the same as the resistance value of the fifth resistor, and the capacitance value of the third capacitor is the same as the capacitance value of the fourth capacitor; the second comparator module compares the output signal of the third integrator module with the first voltage signal, and outputs a first reset signal and a first logic inverted signal.

[0015] Preferably, the fourth integrator module integrates the reference voltage signal until the power corresponding to the reference voltage signal reaches the target power, and the integration time of the fourth integrator module is:

[0016]

[0017] Wherein, TVBG represents the integration time of the fourth integrator module, n*VBG represents the voltage value corresponding to the target power, R5 is the resistance value of the fifth resistor, and VREF represents the reference voltage signal; the third comparator module compares the output signal of the fourth integrator module with the voltage signal corresponding to the target power, and outputs a second reset signal and a second logic inverse signal; the logic unit performs a logical AND operation on the first logic inverse signal and the second logic inverse signal, and outputs the pulse width modulation signal.

[0018] Preferably, the pulse width modulation circuit includes a fourth conversion unit, a fifth conversion unit, and a second logic unit. The fourth conversion unit includes: a fifth integrator module, including a first input terminal, a second input terminal, and an output terminal; the first input terminal of the fifth integrator module receives the first voltage signal through a sixth resistor; the second input terminal of the fifth integrator module is grounded; and the output terminal of the fifth integrator module is electrically connected to the first input terminal through a fifth capacitor; a fourth comparator module, including a first input terminal, a second input terminal, and an output terminal; the input terminal of the fourth comparator module is electrically connected to the output terminal of the fifth integrator module; the second input terminal of the fourth comparator receives the voltage signal corresponding to the target power; and the output terminal of the fourth comparator module is electrically connected to the logic unit to output a third output signal to the logic unit. The fifth conversion unit includes: a sixth integrator module. The sixth integrator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the sixth integrator module receives the voltage signal corresponding to the target power through a seventh resistor. The second input terminal of the sixth integrator module is grounded. The output terminal of the sixth integrator module is electrically connected to the first input terminal of the sixth integrator module through a sixth capacitor. The fifth comparator module includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the fifth comparator module is electrically connected to the output terminal of the fifth integrator module. The second input terminal of the fifth comparator module receives the voltage signal of the target power. The output terminal of the fifth comparator module is electrically connected to the logic unit to output a fourth output signal. The logic unit is electrically connected to the output terminals of the fourth and fifth comparator modules and is used to output the pulse width modulation signal according to the third and fourth output signals.

[0019] Preferably, the fifth integrator module integrates the first voltage signal until the actual output power corresponding to the first voltage signal reaches the integral value of the target power within a preset time. The integration time of the fifth integrator module is:

[0020]

[0021] Wherein, Tout1 represents the integration time of the fifth integrator, Vout represents the voltage value of the first voltage signal, R6 is the resistance value of the sixth resistor, n*VBG represents the voltage value corresponding to the target power, and Period represents the period of the pulse width modulation signal; the fourth comparator module compares the output signal of the fifth integrator module with the voltage value corresponding to the integral value of the target power within a preset time, and outputs a third reset signal and a third logic inverse signal.

[0022] Preferably, the sixth integrator module integrates the voltage signal corresponding to the target power until the power corresponding to the voltage signal of the target power reaches the integral value of the target power within a preset time. The integration time of the sixth integrator module is:

[0023]

[0024] Wherein, TVBG1 represents the integration time of the sixth integrator module, n*VBG represents the voltage value corresponding to the target power, R7 represents the resistance value of the seventh resistor, VBG represents the voltage value of the reference voltage signal, C6 represents the capacitance value of the sixth capacitor, the resistance value of the sixth resistor is the same as the resistance value of the seventh resistor, and the capacitance value of the fifth capacitor is the same as the capacitance value of the sixth capacitor; the fifth comparator module compares the output signal of the sixth integrator module with the voltage value corresponding to the integral value of the target power within a preset time, and outputs a fourth reset signal and a fourth logic inverse signal; the logic unit performs a logical AND operation on the fourth logic inverse signal and outputs the pulse width modulation signal.

[0025] Another aspect of the present invention provides an electronic device, including a load; a power supply unit electrically connected to the load for supplying power to the load; and a constant output power control circuit as described in any of the preceding claims, electrically connected to the load and the power supply unit, for adjusting the output pulse width modulation signal according to the actual output power of the load to control the load to output a constant power.

[0026] Compared to existing technologies, the constant output power control circuit and electronic device proposed in this invention converts the load voltage signal applied to the load into a time quantity by a conversion unit, and then integrates the voltage of the second resistor by a first integrator module. The current flowing through the second resistor is the load current. Under the control of the time quantity, a first voltage signal corresponding to the actual output power of the load is output. Then, the pulse width modulation circuit adjusts the output pulse width modulation signal according to the first voltage signal to achieve constant power output.

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 The schematic diagram illustrates the structure of an electronic device according to Embodiment 1 of the present invention.

[0030] Figure 2 A schematic diagram of a constant output power control circuit according to Embodiment 1 of the present invention is shown.

[0031] Figure 3 The schematic diagram illustrates the circuit structure of a conversion unit according to an embodiment of the present invention.

[0032] Figure 4 The schematic diagram illustrates the circuit structure of a pulse width modulation circuit according to an embodiment of the present invention.

[0033] Figure 5 The diagram illustrates a first reset signal and a first logic inverse signal according to an embodiment of the present invention.

[0034] Figure 6 The diagram illustrates a second reset signal and a second logic inverse signal according to an embodiment of the present invention.

[0035] Figure 7 The schematic diagram illustrates the circuit structure of a pulse width modulation circuit according to another embodiment of the present invention.

[0036] Figure 8 The diagram illustrates a third reset signal and a third logic inverse signal according to an embodiment of the present invention.

[0037] Figure 9 The diagram illustrates a fourth reset signal and a fourth logic inverse signal according to an embodiment of the present invention.

[0038] Explanation of key component symbols:

[0039] Electronic device 1

[0040] Load 10

[0041] Power supply 20

[0042] Constant output power control circuit 30

[0043] Reference circuit 31

[0044] Power detection circuit 32

[0045] Pulse width modulation circuit 33

[0046] Conversion Unit 320

[0047] First Integrator Module - Sixth Integrator Module OP1-OP6

[0048] First comparator module - Fifth comparator module CP1-CP5

[0049] First resistor - Seventh resistor R1-R7

[0050] First capacitor - Sixth capacitor C1-C6 Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various different configurations. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0053] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "electrically connected" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal connection of two elements. It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element present.

[0054] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0055] The terminology involved in this invention is explained as follows:

[0056] VRH: Load voltage signal applied across the load terminals.

[0057] IRH: Current flowing through the load.

[0058] Vout: The first voltage signal that represents the actual output power of the load.

[0059] The inventors have discovered that many electronic devices on the market require heating control. This is achieved by applying voltage across a heating load and controlling the duty cycle of that voltage. Taking a mosquito repellent liquid heater as an example, the heater applies a power supply voltage to the heating wire, generating heating power that is applied to a carbon rod. The heated carbon rod vaporizes the mosquito repellent liquid, thus repelling mosquitoes. To ensure this effect, the heating wire's output power must be kept constant. The output power is the product of the voltage across the heating wire and the corresponding current flowing through it. However, in practical applications, the resistance of the heating wire changes with temperature during heating, causing the output power to fluctuate and making it impossible to guarantee a constant power output.

[0060] The inventors have discovered that constant power output can be achieved using the root mean square voltage method, as shown in the following two expressions of the power formula:

[0061]

[0062] Power = Duty * I 2 *R

[0063] However, constant power output achieved based on RMS voltage essentially relies on voltage detection and feedback control of the output duty cycle (Duty) to achieve constant power output. However, during the entire loop control process, the load resistance is not detected or controlled. Therefore, when the load resistance changes, the output power duty cycle remains unchanged, and the achieved constant power output is no longer constant. Thus, the key to maintaining constant power output lies in how to feedback control the output duty cycle (Duty) when the resistance changes.

[0064] In view of this, embodiments of the present invention provide a constant output power control circuit and an electronic device, thereby solving the problem that the electronic device cannot maintain a constant power output when the load resistance changes.

[0065] Specifically:

[0066] A new constant output power control circuit is provided.

[0067] This new constant output power control circuit detects the load voltage signal applied to the load and outputs a first voltage signal corresponding to the actual output power of the load. Then, it uses a pulse width modulation circuit to adjust the output pulse width modulation signal according to the first voltage signal to achieve constant power output.

[0068] Figure 1 A schematic diagram of the structure of an electronic device 1 according to Embodiment 1 of the present invention is shown. Figure 1 As shown, the electronic device 1 includes a load 10, a power supply 20, and a constant output power control circuit 30. The power supply 20 is electrically connected to the load 10 to supply power to it. The constant output power control circuit 30 is electrically connected to both the load 10 and the power supply 20, and is used to adjust the output pulse width modulation signal according to the voltage corresponding to the actual output power of the load 10 to control the load to output a constant power 10. Therefore, when the resistance of the load 10 changes, the actual output power changes accordingly. The actual output power is represented by voltage, thereby adjusting the output pulse width modulation signal to dynamically adjust the time for applying voltage to the load 10, controlling the load to output a constant power.

[0069] Example

[0070] Figure 2 A schematic diagram of a constant output power control circuit 30 according to Embodiment 1 of the present invention is shown. Figure 2 As shown, the constant output power control circuit 30 includes a reference circuit 31, a power detection circuit 32, and a pulse width modulation circuit 33. The power detection circuit 32 includes a conversion unit 320 and a first integrator module OP1.

[0071] In this embodiment, the reference circuit 31 is used to output a reference voltage signal VBG. The conversion unit 320 is electrically connected to the reference circuit 31 and the load 10. The reference voltage signal and the load voltage signal VRH of the load 10 are input to the conversion unit 320. The conversion unit 320 converts the load voltage VRH into a time quantity based on the reference voltage signal VNG. The first integrator module OP1 has its input terminal electrically connected to the mirror current source Ir through a first resistor R1, and its control terminal electrically connected to the conversion unit. The mirror current source Ir is also grounded through a second resistor R2. The current output by the mirror current source Ir is the current IRH flowing through the load 10. The current output by the mirror current source Ir converts the current IRH into a voltage signal IRH*R2 through the second resistor R2, i.e., the voltage across the second resistor R2 is IRH*R2. The first integrator module OP1 integrates the voltage signal IRH*R2 and, under the control of the time quantity, outputs a first voltage signal Vout corresponding to the actual output power of the load 10.

[0072] The pulse width modulation circuit 33 is electrically connected to the first integrator module OP1 and is used to adjust the output pulse width modulation signal according to the first voltage signal Vout. The actual output power of the load 10 is represented by the first voltage signal Vout. The pulse width modulation circuit outputs the pulse width modulation signal by adjusting the first voltage signal Vout. In this embodiment, the actual output power of the load 10 is used as feedback to dynamically adjust the pulse width modulation signal, thereby achieving a constant power output of the load 10.

[0073] In one embodiment of the present invention, combined with Figure 3 , Figure 3 A schematic diagram of the circuit structure of a conversion unit according to an embodiment of the present invention is shown. The conversion unit 320 includes a second integrator module OP2 and a first comparator module CP1. The second integrator module OP2 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the second integrator module OP2 receives the reference voltage signal VBG through a third resistor R3. The second input terminal of the second integrator module OP2 is grounded. The output terminal of the second integrator module OP2 is electrically connected to the first input terminal of the second integrator module OP2 through a first capacitor C1. The first comparator module CP1 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the first comparator module CP1 is electrically connected to the output terminal of the second integrator module OP2. The second input terminal of the first comparator module CP1 receives the load voltage signal of load 10. The output terminal of the first comparator module CP1 is electrically connected to the input terminal of the first integrator module OP1. The second integrator module OP2, in conjunction with the first comparator module CP1, together converts the load voltage signal VRH into a time quantity T based on the reference voltage signal VBG. The output terminal of the first comparator module CP1 outputs the time quantity T.

[0074]

[0075] Wherein, T represents the time quantity, VRH represents the load voltage signal, R3 represents the resistance value of the third resistor, C1 represents the capacitance value of the first capacitor, and VBG represents the reference voltage signal.

[0076] The first integrator module OP1 includes a first input terminal, a second input terminal, a control terminal, and an output terminal. The first input terminal of the first integrator module OP1 is electrically connected to the common terminal of the current mirror source Ir and the second resistor R2 via a first resistor R1 to receive the voltage signal IRH*R2. The second input terminal of the first integrator module OP1 is grounded. The control terminal of the first integrator module OP1 is electrically connected to the output terminal of the first comparator module CP1. The output terminal of the first integrator module OP1 is electrically connected to the first input terminal of the first integrator module OP1 via a second capacitor C2, and is also electrically connected to the pulse width modulation circuit 33. The first voltage signal output by the output terminal of the first integrator module OP1 is:

[0077]

[0078] Wherein, Vout represents the voltage value of the first voltage signal corresponding to the actual output power of load 10, VRH represents the voltage value of the voltage signal applied to load 10, IRH represents the current value of the current flowing through load 10, R2 represents the resistance value of the second resistor R2, VBG represents the voltage value of the reference voltage signal, the resistance value of the third resistor is equal to the resistance value of the first resistor, and the capacitance value of the first capacitor is the same as the capacitance value of the first capacitor.

[0079] In one specific embodiment of the present invention, combined with Figure 4 , Figure 4A schematic diagram of the circuit structure of a pulse width modulation circuit according to an embodiment of the present invention is shown. The pulse width modulation circuit 33 includes a second conversion unit 330, a third conversion unit 331, and a logic unit 332. The second conversion unit 330 includes a third integrator module OP3 and a second comparator module CP2. The third integrator module OP3 includes a first input terminal, a second input terminal, and an output terminal. The fourth resistor R4 at the first input terminal of the third integrator module OP3 inputs a reference voltage signal VREF. The second input terminal of the third integrator module OP3 is grounded. The third capacitor C3 at the output terminal of the third integrator module OP3 is electrically connected to the first input terminal of the third integrator module OP3. The second comparator module CP2 includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the second comparator module CP2 is electrically connected to the output terminal of the third integrator module OP3. The second input terminal of the second comparator module CP2 inputs the first voltage signal Vout. The output terminal of the second comparator module CP2 is electrically connected to the logic unit 332 to output a first output signal to the logic unit 332.

[0080] The third conversion unit 331 includes a fourth integrator module OP4 and a third comparator module CP3. The fourth integrator module OP4 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fourth integrator module OP4 receives the reference voltage VREF through a fifth resistor R5. The second input terminal of the fourth integrator module OP4 is grounded. The output terminal of the fourth integrator module OP4 is electrically connected to the first input terminal through a fourth capacitor C4. The third comparator module CP3 includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the third comparator module CP3 is electrically connected to the output terminal of the fourth integrator module OP4. The second input terminal of the third comparator module CP3 receives the voltage signal n*VBG corresponding to the target power. The output terminal of the third comparator module CP3 is electrically connected to logic unit 332 to output a second output signal to logic unit 332.

[0081] The logic unit 332 is electrically connected to the output of the second comparator module CP2 and the output of the third comparator module CP3 to output the pulse width modulation signal according to the first output signal and the second output signal.

[0082] Specifically, the third integrator module OP3 integrates the reference voltage signal VREF until the power corresponding to the reference voltage signal VREF reaches the power corresponding to the first voltage signal Vout. The integration time of the third integrator module OP3 is:

[0083]

[0084] Where Tvout represents the integration time of the third integrator module OP3, Vout represents the voltage value of the first voltage signal, R4 is the resistance value of the fourth resistor R4, VREF represents the voltage value of the reference voltage, and C3 represents the capacitance value of the third capacitor C3.

[0085] The second comparator module CP2 compares the output signal of the third integrator module OP3 with the first voltage signal Vout, and outputs the first reset signal Reset1 and the first logic inverse signal PWM1. Combined with... Figure 5 , Figure 5 The diagram illustrates the first reset signal Reset1 and the first logic inverse signal PWM1.

[0086] The fourth integrator module OP4 integrates the reference voltage signal VREF until the power corresponding to the reference voltage signal VREF reaches the target power. The integration time of the fourth integrator module OP4 is:

[0087]

[0088] Wherein, TVBG represents the integration time of the fourth integrator module, n*VBG represents the voltage value corresponding to the target power, R5 is the resistance value of the fifth resistor R5, VREF represents the voltage value of the reference voltage signal, the resistance value of the fourth resistor R4 is the same as the resistance value of the fifth resistor R5, and the capacitance value of the third capacitor C3 is the same as the capacitance value of the fourth capacitor C4.

[0089] The third comparator module CP3 compares the output signal of the fourth integrator module OP4 with the voltage signal n*VBG corresponding to the target power, and outputs the second reset signal Reset2 and the second logic inverse signal PWM2. Combined with... Figure 6 , Figure 6 This is a schematic diagram of the second reset signal Reset2 and the second logic inverse signal PWM2.

[0090] The ratio of the integration time Tvout of the third integrator module OP3 to the integration time TVBG of the fourth integrator module OP4 is:

[0091]

[0092] Therefore, the ratio of time is actually the ratio of target power to actual power.

[0093] The logic unit 332 performs a logical AND operation on the first inverse logic signal and the second inverse logic signal to output the pulse width modulation signal.

[0094] In this embodiment, the pulse width modulation signal is adjusted by the first voltage signal that characterizes the actual output power, so that the load 10 maintains a constant power output.

[0095] In another embodiment of the invention, combined with Figure 7 , Figure 7 The schematic diagram illustrates the circuit structure of a pulse width modulation circuit according to another embodiment of the present invention. In this embodiment, the pulse width modulation circuit 33 includes a fourth conversion unit 333, a fifth conversion unit 334, and a second logic unit 335.

[0096] The fourth conversion unit 333 includes a fifth integrator module OP5 and a fourth comparator module CP4. The fifth integrator module OP5 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fifth integrator module OP5 receives the first voltage signal Vout through a sixth resistor R6. The second input terminal of the fifth integrator module OP5 is grounded. The output terminal of the fifth integrator module OP5 is electrically connected to the first input terminal through a fifth capacitor C5. The fourth comparator module CP4 includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the fourth comparator module CP4 is electrically connected to the output terminal of the fifth integrator module OP5. The second input terminal of the fourth comparator module CP4 receives the voltage signal n*VBG corresponding to the target power. The output terminal of the fourth comparator module CP4 is electrically connected to logic unit 335 to output a third output signal to logic unit 335.

[0097] The fifth conversion unit 334 includes a sixth integrator module OP6 and a fifth comparator module CP5. The sixth integrator module OP6 includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the sixth integrator module OP6 receives the voltage signal n*VBG corresponding to the target power through a seventh resistor R7. The second input terminal of the sixth integrator module OP6 is grounded, and the output terminal of the sixth integrator module OP6 is electrically connected to the first input terminal through a sixth capacitor C6. The fifth comparator module CP5 includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the fifth comparator module CP5 is electrically connected to the output terminal of the fifth integrator module CP5. The second input terminal of the fifth comparator module CP5 receives the voltage signal of the target power, and the output terminal of the fifth comparator module CP5 is electrically connected to logic unit 335 to output a fourth output signal.

[0098] The logic unit 335 is electrically connected to the output of the fourth comparator module CP4 and the output of the fifth comparator module CP5, and is used to output the pulse width modulation signal according to the third output signal and the fourth output signal.

[0099] In this embodiment, the fifth integrator module OP5 integrates the first voltage signal Vout until the actual output power corresponding to the first voltage signal Vout reaches the integral value of the target power within a preset time. The integration time of the fifth integrator module OP5 is:

[0100]

[0101] Wherein, Tout1 represents the integration time of the fifth integrator module OP5, Vout represents the voltage value of the first voltage signal Vout, R6 is the resistance value of the sixth resistor R6, n*VBG represents the voltage value corresponding to the target power, and Period represents the period of the pulse width modulation signal.

[0102] The fourth comparator module OP4 compares the output signal of the fifth integrator module CP5 with the voltage value corresponding to the integral value of the target power within a preset time, and outputs the third reset signal Reset3 and the third logic inverse signal PWM3, in conjunction with the appendix. Figure 8 , attached Figure 8 The waveform diagrams are for the third reset signal Reset3 and the third logic inverse signal PWM3.

[0103] The sixth integrator module OP6 integrates the voltage signal corresponding to the target power until the power corresponding to the voltage signal reaches the integral value of the target power within a preset time. The integration time of the sixth integrator module OP6 is:

[0104]

[0105] Wherein, TVBG1 represents the integration time of the sixth integrator module OP6, n*VBG represents the voltage value corresponding to the target power, R7 is the resistance value of the seventh resistor, VBG represents the voltage value of the reference voltage signal, C6 represents the capacitance value of the sixth capacitor, the resistance value of the sixth resistor R6 is the same as the resistance value of the seventh resistor R7, and the capacitance value of the fifth capacitor C5 is the same as the capacitance value of the sixth capacitor C6.

[0106] The ratio of the integration time Tvout1 of the fifth integrator module OP5 to the integration time TVBG1 of the sixth integrator module OP6 is:

[0107]

[0108] Therefore, the ratio of time is actually the ratio of target power to actual power.

[0109] The fifth comparator module CP5 compares the output signal of the sixth integrator module OP6 with the voltage value corresponding to the integral value of the target power within a preset time, and outputs a fourth reset signal and a fourth logic inverse signal, combined with... Figure 9 , Figure 9 This is a waveform diagram of the fourth reset signal and the fourth logic inverted signal.

[0110] The logic unit 335 performs a logical AND operation on the third and fourth logical inverse signals to output the pulse width modulation signal.

[0111] In this embodiment, the pulse width modulation signal is adjusted by the first voltage signal that characterizes the actual output power, so that the load 10 maintains a constant power output.

[0112] Compared to existing technologies, the constant output power control circuit and electronic device proposed in this invention converts the load voltage signal applied to the load into a time quantity by a conversion unit, and then integrates the voltage of the second resistor by a first integrator module. The current flowing through the second resistor is the load current. Under the control of the time quantity, a first voltage signal corresponding to the actual output power of the load is output. Then, the pulse width modulation circuit adjusts the output pulse width modulation signal according to the first voltage signal to achieve constant power output.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A constant output power control circuit, characterized in that, It includes a reference circuit, a power detection circuit, and a pulse width modulation circuit. The power detection circuit includes a conversion unit and a first integrator module. The reference circuit is used to output a reference voltage signal; The conversion unit is electrically connected to the reference circuit and the load. The reference voltage signal and the load voltage signal of the load are input to the conversion unit. The conversion unit is used to convert the load voltage signal into a time quantity according to the reference voltage signal. The first integrator module has its input terminal electrically connected to the mirror current source via a first resistor, and its control terminal electrically connected to the conversion unit. The mirror current source is also grounded via a second resistor. The current output by the mirror current source is the current flowing through the load. The first integrator module integrates the voltage of the second resistor and outputs a first voltage signal corresponding to the actual output power of the load under the control of the time quantity. The pulse width modulation circuit is electrically connected to the first integrator module and is used to adjust the output pulse width modulation signal according to the first voltage signal.

2. The constant output power control circuit according to claim 1, characterized in that, The conversion unit includes: The second integrator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the second integrator module receives the reference voltage signal through a third resistor. The second input terminal of the second integrator module is grounded. The output terminal of the second integrator module is electrically connected to the first input terminal of the second integrator module through a first capacitor. A first comparator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the first comparator module is electrically connected to the output terminal of the second integrator module. The second input terminal of the first comparator module receives the load voltage signal. The output terminal of the first comparator module is electrically connected to the input terminal of the first integrator module. The output terminal of the first comparator module outputs the time quantity. Wherein, T represents the time quantity, VRH represents the load voltage signal, R3 represents the resistance value of the third resistor, C1 represents the capacitance value of the first capacitor, and VBG represents the reference voltage signal.

3. The constant output power control circuit according to claim 2, characterized in that: The first integrator module includes a first input terminal, a second input terminal, a control terminal, and an output terminal, wherein, The first input terminal of the first integrator module is electrically connected to the common terminal of the mirror current source and the second resistor through the first resistor; the second input terminal of the first integrator module is grounded; the control terminal of the first integrator module is electrically connected to the output terminal of the first comparator module; the output terminal of the first integrator module is electrically connected to the first input terminal of the first integrator module through the second capacitor, and is also electrically connected to the pulse width modulation circuit; the first voltage signal output by the output terminal of the first integrator module is: Wherein, Vout represents the voltage value of the first voltage signal, VRH represents the voltage value of the load voltage signal, IRH represents the current value of the current flowing through the load, R2 represents the resistance value of the second resistor, VBG represents the voltage value of the reference voltage signal, the resistance value of the third resistor is equal to the resistance value of the first resistor, and the capacitance value of the first capacitor is the same as the capacitance value of the first capacitor.

4. The constant output power control circuit according to claim 3, characterized in that, The pulse width modulation circuit includes a second conversion unit, a third conversion unit, and a logic unit, wherein... The second conversion unit includes: The third integrator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the third integrator module receives a reference voltage signal through a fourth resistor. The second input terminal of the third integrator module is grounded. The output terminal of the third integrator module is electrically connected to the first input terminal of the third integrator module through a third capacitor. The second comparator module includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the second comparator module is electrically connected to the output terminal of the third integrator module. The second input terminal of the second comparator module receives the first voltage signal, and the output terminal of the second comparator module is electrically connected to the logic unit to output a first output signal to the logic unit. The third conversion unit includes: The fourth integrator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fourth integrator module receives the reference voltage through a fifth resistor. The second input terminal of the fourth integrator module is grounded. The output terminal of the fourth integrator module is electrically connected to the first input terminal of the fourth integrator module through a fourth capacitor. The third comparator module includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the third comparator module is electrically connected to the output terminal of the fourth integrator module. The second input terminal of the third comparator module receives a voltage signal corresponding to the target power. The output terminal of the third comparator module is electrically connected to the logic unit to output a second output signal to the logic unit. The logic unit is electrically connected to the output terminal of the second comparator module and the output terminal of the third comparator module, and is used to output the pulse width modulation signal according to the first output signal and the second output signal.

5. The constant output power control circuit according to claim 4, characterized in that: The third integrator module integrates the reference voltage signal until the power corresponding to the reference voltage signal reaches the power corresponding to the first voltage signal. The integration time of the third integrator module is: Wherein, Tout represents the integration time of the third integrator module OP3, Vout represents the voltage value of the first voltage signal, R4 represents the resistance value of the fourth resistor, VREF represents the voltage value of the reference voltage; C3 represents the capacitance value of the third capacitor, the resistance value of the fourth resistor is the same as the resistance value of the fifth resistor, and the capacitance value of the third capacitor is the same as the capacitance value of the fourth capacitor. The second comparator module compares the output signal of the third integrator module with the first voltage signal, and outputs a first reset signal and a first logic inverted signal.

6. The constant output power control circuit according to claim 5, characterized in that: The fourth integrator module integrates the reference voltage signal until the power corresponding to the reference voltage signal reaches the target power. The integration time of the fourth integrator module is: Where TVBG represents the integration time of the fourth integrator module. R5 represents the voltage value corresponding to the target power, R5 is the resistance value of the fifth resistor, and VREF represents the reference voltage signal. The third comparator module compares the output signal of the fourth integrator module with the voltage signal corresponding to the target power, and outputs a second reset signal and a second logic inverse signal; The logic unit performs a logical AND operation on the first inverse logic signal and the second inverse logic signal, and outputs the pulse width modulation signal.

7. The constant output power control circuit according to claim 3, characterized in that, The pulse width modulation circuit includes a fourth conversion unit, a fifth conversion unit, and a second logic unit, wherein... The fourth conversion unit includes: The fifth integrator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the fifth integrator module receives the first voltage signal through a sixth resistor. The second input terminal of the fifth integrator module is grounded. The output terminal of the fifth integrator module is electrically connected to the first input terminal of the fifth integrator module through a fifth capacitor. The fourth comparator module includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the fourth comparator module is electrically connected to the output terminal of the fifth integrator module. The second input terminal of the fourth comparator module receives a voltage signal corresponding to the target power. The output terminal of the fourth comparator module is electrically connected to the logic unit to output a third output signal to the logic unit. The fifth conversion unit includes: The sixth integrator module includes a first input terminal, a second input terminal, and an output terminal. The first input terminal of the sixth integrator module receives the voltage signal corresponding to the target power through a seventh resistor. The second input terminal of the sixth integrator module is grounded. The output terminal of the sixth integrator module is electrically connected to the first input terminal of the sixth integrator module through a sixth capacitor. The fifth comparator module includes a first input terminal, a second input terminal, and an output terminal. The input terminal of the fifth comparator module is electrically connected to the output terminal of the fifth integrator module. The second input terminal of the fifth comparator module receives the voltage signal corresponding to the target power. The output terminal of the fifth comparator module is electrically connected to the logic unit to output a fourth output signal. The logic unit is electrically connected to the output terminals of the fourth comparator module and the fifth comparator module, and is used to output the pulse width modulation signal according to the third output signal and the fourth output signal.

8. The constant output power control circuit according to claim 7, characterized in that, The fifth integrator module integrates the first voltage signal until the actual output power corresponding to the first voltage signal reaches the integral value of the target power within a preset time. The integration time of the fifth integrator module is: Where Tout1 represents the integration time of the fifth integrator, Vout represents the voltage value of the first voltage signal, and R6 is the resistance value of the sixth resistor. The voltage value corresponding to the target power is represented by , and Period represents the period of the pulse width modulation signal. The fourth comparator module compares the output signal of the fifth integrator module with the voltage value corresponding to the integral value of the target power within a preset time, and outputs a third reset signal and a third logic inverse signal.

9. The constant output power control circuit according to claim 8, characterized in that, The sixth integrator module integrates the voltage signal corresponding to the target power until the power corresponding to the voltage signal reaches the integral value of the target power within a preset time. The integration time of the sixth integrator module is: Wherein, TVBG1 represents the integration time of the sixth integrator module. R7 represents the voltage value corresponding to the target power, VBG represents the voltage value of the reference voltage signal, C6 represents the capacitance value of the sixth capacitor, the resistance value of the sixth resistor is the same as the resistance value of the seventh resistor, and the capacitance value of the fifth capacitor is the same as the capacitance value of the sixth capacitor. The fifth comparator module compares the output signal of the sixth integrator module with the voltage value corresponding to the integral value of the target power within a preset time, and outputs a fourth reset signal and a fourth logic inversion signal; The logic unit performs a logical AND operation on the fourth logic inverse signal and the fourth logic inverse signal, and outputs the pulse width modulation signal.

10. An electronic device, characterized in that, include: load; A power supply unit, electrically connected to the load, is used to supply power to the load; The constant output power control circuit as described in any one of claims 1 to 9 is electrically connected to the load and the power supply unit, and is used to adjust the output pulse width modulation signal according to the actual output power of the load to control the load to output constant power.

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