A low power consumption control circuit for smart home appliances

Abstract

A low-power control circuit for smart home appliances includes a rectifier module, a constant voltage control chip, a buck conversion module and a load compensation module. The rectifier module receives an alternating current and outputs a first direct current. A drain terminal of the constant voltage control chip is coupled to the rectifier module. The buck conversion module is coupled to the rectifier module and the power supply terminal of the constant voltage control chip. The buck conversion module receives the first direct current and outputs a second direct current after buck conversion and supplies power to the constant voltage control chip through the power supply terminal, and allows the constant voltage control chip to sample the power supply terminal as a feedback signal to adjust the second direct current. The load compensation module is electrically connected to the power supply terminal, and provides a compensation voltage to improve a load adjustment rate generated based on an external load.

Description

Technical Field

[0001] The present invention relates to a control circuit, and in particular to a low-power consumption control circuit for smart home appliances. Background Art

[0002] Smart home appliances refer to all kinds of home appliances with intelligent features. From the perspective of hardware architecture, in addition to the existing modules related to home appliance functions, modules that provide intelligent functions must be set up, such as wireless communication modules and sensor modules. However, when setting up these additional modules, from the perspective of power control, two major issues must usually be considered: one is the stable power output; the other is the standby power consumption.

[0003] The conventional power supply control circuit basically includes a rectifier unit, a control unit and a buck unit, wherein the control unit includes a feedback terminal, which obtains the DC power outputted by the buck unit to the load, thereby adjusting the power supply to achieve the purpose of constant voltage output; on the other hand, the power supply of the control unit comes from a junction gate field-effect transistor (JFET) disposed inside the control unit, but the power supply of the control unit provided by the JFET must pass through the bus and the auxiliary winding. In addition to the high complexity of the circuit, the high voltage difference between the two ends of the JFET will lead to high standby power consumption of the control unit. Therefore, there is a need for improvement in the conventional technology. Summary of the invention

[0004] The main purpose of the present invention is to solve the problem of high power consumption of existing control circuits for smart home appliances.

[0005] To achieve the above object, the present invention provides a low power consumption control circuit for smart home appliances, which is characterized by comprising:

[0006] A rectifier module receives an alternating current and outputs a first direct current;

[0007] A constant voltage control chip, comprising a drain terminal, a ground terminal and a power terminal, wherein the drain terminal is coupled to the rectifier module;

[0008] a step-down conversion module coupled to the rectifier module, the power supply terminal of the constant voltage control chip and the ground terminal, the step-down conversion module receives the first DC power and outputs a second DC power after step-down conversion and supplies power to the constant voltage control chip through the power supply terminal, and allows the constant voltage control chip to sample the power supply terminal as a feedback signal to adjust the second DC power; and

[0009] A load compensation module is electrically connected to the power supply end, and the load compensation module provides a compensation voltage to improve a load regulation rate generated based on an external load.

[0010] In one embodiment, the buck conversion module includes a freewheeling diode, an output capacitor coupled in parallel with the freewheeling diode, and an inductor coupled between the freewheeling diode and the output capacitor.

[0011] In one embodiment, a cathode of the freewheeling diode is coupled to one end of the inductor to form a first node, an anode of the freewheeling diode is coupled to the output capacitor, the other end of the inductor is coupled to the output capacitor to form a second node, the first node is coupled to the ground end, and the second node is coupled to the power supply end of the constant voltage control chip.

[0012] In one embodiment, the buck conversion module further includes a bootstrap diode and a power supply capacitor coupled to the bootstrap diode, and the bootstrap diode includes an anode coupled to the second node and a cathode forming a third node with the power supply capacitor.

[0013] In one embodiment, the constant voltage control chip further includes a current detection terminal coupled to the first node.

[0014] In one embodiment, a detection resistor is coupled between the current detection terminal and the first node.

[0015] In one embodiment, the constant voltage control chip further includes a feedback terminal, and at least one feedback resistor is coupled between the feedback terminal and the buck conversion module to adjust the second DC power.

[0016] In one embodiment, the constant voltage control chip further includes a control terminal, and the control terminal is selectively coupled to the power terminal or the ground terminal to adjust the second DC power.

[0017] In one embodiment, the load compensation module includes a power end sampling module and a regulation module. The power end sampling module is coupled to the power end of the constant voltage control chip and outputs a power end sampling signal to the regulation module. The regulation module receives a reference signal and the power end sampling signal and outputs a load compensation signal coupled to the power end.

[0018] In one embodiment, the control module includes an error amplifier and a control unit, a first input terminal of the error amplifier is coupled to the power supply sampling module, an output terminal of the error amplifier is coupled to the control unit, and the control unit receives the reference signal and feeds back the load compensation signal to the second input terminal of the error amplifier.

[0019] In one embodiment, the control module includes:

[0020] a first resistor, a first end of which is coupled to the second input end of the error amplifier and forms a fourth node;

[0021] a second resistor, a first end of the second resistor being coupled to a second end of the first resistor and forming a fifth node for inputting a reference voltage;

[0022] a first voltage-controlled current source, comprising an input terminal coupled to the output terminal of the error amplifier, a control terminal coupled to the fifth node, and an output terminal coupled to a second terminal of the second resistor; and

[0023] A second voltage-controlled current source is coupled between the power supply terminal and the second input terminal of the error amplifier.

[0024] In one embodiment, the power supply end sampling signal includes:

[0025] a third resistor coupled between the first input terminal of the error amplifier and the power terminal; and

[0026] A fourth resistor is coupled to one end of the third resistor to form a sixth node, and the other end of the fourth resistor is grounded.

[0027] In one embodiment, the constant voltage control chip further includes a selection terminal, and the selection terminal selects different second DC power outputs.

[0028] In one embodiment, the selection terminal is coupled to the load compensation module.

[0029] In one embodiment, the constant voltage control chip further comprises:

[0030] a logic controller;

[0031] a driver coupled to the logic controller;

[0032] a power switch coupled to the driver; and

[0033] A comparator has a first input terminal coupled to the load compensation module, a second input terminal inputting a first reference voltage, and an output terminal coupled to the logic controller.

[0034] In one embodiment, the voltage value of the second DC power is between 2.5V and 3.3V.

[0035] The present invention also provides a smart home appliance system, comprising:

[0036] A main drive circuit module, which converts an alternating current into a main drive direct current power;

[0037] An electrical module coupled to the main drive module and inputting the main drive DC power;

[0038] A control circuit as described above, wherein the control circuit outputs the second DC power according to the AC power; and

[0039] A smart module is provided, wherein the smart module operates by utilizing the second DC power.

[0040] In one embodiment, the smart module is a wireless signal receiver or a sensor.

[0041] In one embodiment, the voltage value of the second DC power is between 2.5V and 5V.

[0042] The present invention utilizes the second DC power output by the step-down conversion module directly as the power supply source of the constant voltage control chip instead of through the JFET, thereby solving the problem of high standby power consumption; at the same time, the present invention sets up the load compensation module, which samples the voltage of the power supply end, that is, uses the voltage of the power supply end as a feedback signal to achieve constant voltage regulation. Since the sampled feedback voltage of the power supply end is a reference signal relative to the ground end of the constant voltage control chip, there is no need to set a sampling and holding circuit, thereby reducing the complexity of the circuit structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] 『 Figure 1 ' is a circuit diagram of a low power consumption control circuit according to an embodiment of the present invention.

[0044] 『 Figure 2 ' is a circuit diagram of the load compensation module in one embodiment of the present invention.

[0045] 『 Figure 3 ' is a circuit diagram of the constant voltage control chip in another embodiment of the present invention.

[0046] 『 Figure 4 ', is a load regulation rate variation diagram of an embodiment of the present invention and a comparative example

[0047] 『 Figure 5 ' is a comparison diagram of standby power consumption of an embodiment of the present invention and a comparative example.

[0048] 『 Figure 6 ",for" Figure 5 』A circuit diagram of a comparative example.

[0049] 『 Figure 7 ' is a circuit diagram of a low power consumption control circuit according to another embodiment of the present invention.

[0050] 『 Fig. 8A "and" Figure 8B ' is a circuit diagram of a low power consumption control circuit according to yet another embodiment of the present invention.

[0051] 『 Fig. 9' is a schematic diagram of a smart home appliance system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The detailed description and technical contents of the present invention are now described as follows with reference to the accompanying drawings:

[0053] The present invention discloses a low power consumption control circuit for smart home appliances. In the following embodiments, the smart home appliances are illustrated by smart lighting, such as smart light emitting diode lamps. Figure 1 ' is a circuit diagram of a low-power control circuit of an embodiment of the present invention, including a rectifier module 10, a constant voltage control chip 20, a step-down conversion module 30 and a load compensation module 40. The rectifier module 10 receives an alternating current Vac. In one embodiment, the alternating current Vac is an external mains. The constant voltage control chip 20 includes a drain terminal D, a ground terminal G and a power supply terminal VCC. The rectifier module 10 outputs a first direct current power DC1 after rectifying the alternating current Vac. In this embodiment, the rectifier module 10 includes a rectifier unit 11 and an input capacitor 12 coupled to the rectifier unit 11. The rectifier module 10 can be a bridge rectifier as shown in the figure. The coupling of two or more components described herein can be a direct electrical connection between components, or an electrical connection formed by other components between components.

[0054] The drain terminal D of the constant voltage control chip 20 is coupled to the rectifier module 10 to receive the first DC power DC1. The buck conversion module 30 is also coupled to the rectifier module 10. The buck conversion module 30 receives the first DC power DC1 and then performs a buck conversion and outputs a second DC power DC2 to an external load. In addition, the second DC power DC2 is fed back to the power terminal VCC of the constant voltage control chip 20 to supply power to the constant voltage control chip 20. In one embodiment of the present invention, the voltage value of the second DC power DC2 is less than 5V. In one embodiment, the voltage value of the second DC power is between 2.5V and 5V, for example, 3.3V or 2.5V.

[0055] The buck conversion module 30 includes a freewheeling diode 31, an output capacitor 32, an inductor 33, a bootstrap diode 34 and a power supply capacitor 35. A cathode 31a of the freewheeling diode 31 is coupled to an end 33a of the inductor 33 to form a first node N1. An anode 31b of the freewheeling diode 31 is coupled to the drain terminal D of the constant voltage control chip 20. The other end 33b of the inductor 33 is coupled to the output capacitor 32 to form a second node N2. The first node N1 is coupled to the ground terminal G, and the second node N2 is coupled to the power supply terminal VCC of the constant voltage control chip 20. The power supply capacitor 35 is coupled to the bootstrap diode 34. The bootstrap diode 34 includes an anode 34b coupled to the second node N2 and a cathode 34a between the bootstrap diode 34 and the power supply capacitor 35 to form a third node N3. The inductor 33 is coupled between the freewheeling diode 31 and the output capacitor 32.

[0056] Please refer to Figure 2 ' is a circuit diagram of the load compensation module in an embodiment of the present invention. The load compensation module 40 includes a power supply end sampling module 40a and a regulation module 40b. The power supply end sampling module 40a is coupled to the power supply end VCC of the constant voltage control chip 20 to output a power supply end sampling signal S to the regulation module 40b. The regulation module 40b receives a reference signal and the power supply end sampling signal S and outputs a load compensation signal to the power supply end VCC. The reference signal here is Vref. In the present embodiment, the control module 40b includes an error amplifier 41 and a control unit, the control unit includes a first resistor 42, a second resistor 43, a first voltage-controlled current source 44 and a second voltage-controlled current source 45, the power end sampling module 40a includes a third resistor 46 and a fourth resistor 47, the error amplifier 41 includes a first input terminal 41a, a second input terminal 41b and an output terminal 41c, the first resistor 42 includes a first terminal 42a and a second terminal 42b, the second resistor 43 includes a first terminal 43a and a second terminal 43b, the first voltage-controlled current source 44 includes an input terminal 44a, a control terminal 44b and an output terminal 44c. In the present embodiment, the load compensation module 40 is disposed in the constant voltage control chip 20, and in other embodiments, the load compensation module 40 can be disposed outside the constant voltage control chip 20.

[0057] The first input terminal 41a and the second input terminal 41b of the error amplifier 41 are coupled to the power end sampling module 40a, and the output terminal 41c of the error amplifier 41 is coupled to the control unit. The control unit receives the reference signal and feeds back the load compensation signal to the second input terminal 41b of the error amplifier 41.

[0058] The first end 42a of the first resistor 42 is coupled to the second input end 41b to form a fourth node N4, the second end 42b of the first resistor 42 is coupled to the first end 43a of the second resistor 43 to form a fifth node N5, the second end 43b of the second resistor 43 is grounded, and the fifth node N5 is input with the reference voltage Vref. The third resistor 46 and the fourth resistor 47 are connected in series with each other and coupled to the first input end 41a of the error amplifier 41 from a sixth node N6 therebetween. In this embodiment, the voltage of the first input end 41a is VA, and the voltage of the second input end 41b is VB, wherein the fourth node N4 (i.e., VB) serves as an output end of the load compensation module 40, i.e., for outputting the load compensation signal.

[0059] Please continue to refer to Figure 3 ' is a circuit diagram of the constant voltage control chip in another embodiment of the present invention, ' Figure 3 』 further shows a detailed configuration of the constant voltage control chip 20. In this embodiment, the constant voltage control chip 20 further has a current detection terminal CS and a control terminal SEL, and the constant voltage control chip 20 also includes a logic controller 21, a driver 22, a power switch 23, a hysteresis comparator 24, a current detection unit 25, a leading-edge blanking (LEB) unit 26, a high voltage unit 27, an oscillator 28 and at least one protection unit. The protection unit may include an over-temperature protection unit 29 and an over-voltage and over-load protection unit 210. In addition, the constant voltage control chip 20 is further provided with The load compensation module 40 includes a power supply sampling module 40a and a control module. The control module includes an error amplifier 41 and a control unit 40c. The power supply sampling module 40a includes a first switch 401a, a second switch 402a and a plurality of resistors 403a. A first input terminal 41a and a second input terminal 41b of the error amplifier 41 are coupled to the power supply sampling module 40a. An output terminal 41c of the error amplifier 41 is coupled to the control unit 40c. The control unit 40c receives a reference signal Vref and feeds back the load compensation signal to the second input terminal 41b of the error amplifier 41. For the load compensation module 40 of this embodiment, please refer to 『 Figure 2 ' configuration, other configurations may also be used.

[0060] The logic controller 21 outputs a control signal to the driver 22 to control the power switch 23. In the present embodiment, the power switch 23 is a metal oxide semiconductor field effect transistor (MOSFET), but it is not limited thereto. The power switch 23 may also be one or more triodes. A first input terminal 24a of the hysteresis comparator 24 is coupled between the power supply terminal VCC and the high voltage unit 27. A second input terminal 24b of the hysteresis comparator 24 inputs a reference voltage Vref between 2.6V and 3V. An output terminal 24c of the hysteresis comparator 24 outputs to the logic controller 21. The current detection unit 25 is coupled between the current detection terminal CS and the logic controller 21, and is coupled to the leading edge blanking unit 26. The oscillator 28, the over-temperature protection unit 29 and the over-voltage and over-load protection unit 210 are coupled to the logic controller 21.

[0061] In the present embodiment, the high voltage unit 27 is a junction gate field-effect transistor (JFET). When it is started, the JFET in the constant voltage control chip 20 will first supply power to the constant voltage control chip 20. After power-on, the second DC power DC2 gradually increases. Once it increases to a threshold value, the junction gate field-effect transistor will be turned off, and the second DC power DC2 will supply power to the constant voltage control chip 20. In the present embodiment, the threshold value is 2.9V. In addition, when overload or short circuit protection is in effect, the second DC power DC2 decreases, and the junction gate field effect transistor will be switched to supply power to the constant voltage control chip 20. At this time, the supply voltage of the junction gate field effect transistor is lower than the second DC power DC2 in the normal state; when the overload or short circuit protection is released, the second DC power DC2 increases, and the second DC power DC2 will be switched to supply power to the constant voltage control chip 20, and the junction gate field effect transistor will be turned off to reduce standby power consumption.

[0062] As mentioned above, after the second DC power DC2 gradually rises and exceeds the threshold value, the junction gate field effect transistor is turned off, at which time the freewheeling diode 31 is turned on, and the second DC power DC2 charges the power supply capacitor 35, and the power required for the operation of the constant voltage control chip 20 is provided by the second DC power DC2; when the junction gate field effect transistor is turned on, the power required for the operation of the constant voltage control chip 20 is provided by the power supply capacitor 35. In the present invention, the constant voltage control chip 20 samples the divided voltage of the power supply terminal VCC, and cooperates with the current loop formed by the bootstrap diode 34 to adjust the output voltage to be constant, that is, the constant of the second DC power DC2. Further, since the present invention samples the power supply terminal VCC, the sampled feedback signal is relative to the ground terminal G of the constant voltage control chip 20, so the sampled feedback signal is the reference signal, and there is no need to set a sample and hold circuit. The constant voltage control chip 20 can directly and continuously receive the feedback signal sampled from the power supply terminal VCC.

[0063] In addition to adjusting the second DC power DC2 to be constant, since the present invention is applied to a low-power control circuit of a smart home appliance, especially a low-voltage load below 5V, a poor load regulation rate will cause a greater negative impact than a load above 5V. For example, the required voltage of a typical microcontroller (MCU) is 3.3V. If the input voltage exceeds 3.6V, the microcontroller will be broken down. If the input voltage is lower than 3.0V, the microcontroller will be shut down. Therefore, within the full load range, it must be maintained between 3.0V and 3.6V. To solve this problem, the present invention sets the load compensation module 40 to reduce the load regulation rate.

[0064] by" Figure 1 "Cooperate" Figure 2 ' is used as an example to illustrate, Figure 2The current of the circuit has the following relationship: I2 = I1 + I0 (Formula 1), I0 is a fixed current, and the voltage of the second DC power DC2 is Vout, and Vout has the following relationship: Vout = K*VA-Vf1+Vf2 (Formula 2), where K is the gain of the error amplifier, which is a fixed value, VA is the input voltage of the first input terminal 41a, Vf1 is the voltage drop of the freewheeling diode 31, and Vf2 is the voltage drop of the bootstrap diode 34. Vf1 changes with the load current. When the load current increases, Vf1 also increases, and Vf2 is a fixed value; when the load current increases, the second DC power DC2 decreases, and the voltage of the power supply terminal VCC also decreases accordingly, so that the input voltage VA of the first input terminal 41a of the error amplifier 41 decreases, and the voltage Veao output by the output terminal 41c of the error amplifier 41 also decreases, and further, the current I1 output by the first voltage-controlled current source 44 increases. According to Formula 1, I0 is a fixed current, so when I1 increases, I2 also increases. According to Formula 2, Vref is fixed, so when I2 increases, VB also increases, and VB=VA, so VA also increases, thus providing compensation for Vout, offsetting the voltage drop of the freewheeling diode 31, and making the voltage Vout of the second DC power DC2 approach a constant.

[0065] Please refer to Figure 4 ' is a load regulation rate variation diagram of an embodiment of the present invention and a comparative example, line 4A is the variation of the output voltage Vout under different output currents Iout when the load compensation module 40 is set; and line 4B is the variation of the output voltage Vout under different output currents Iout when the load compensation module 40 is not set. Figure 4 It is obvious that under the condition of the same output current Iout, the change of line 4A is smaller than that of line 4B; in other words, the change of the output voltage Vout of line 4A with the load compensation module 40 is smaller than that of line 4B without the load compensation module 40, and line 4A shows a better load adjustment rate. If the load compensation module 40 is not set, when the output current Iout continues to rise, the output voltage Vout will be lower than 3V, causing the microcontroller to shut down; and after adding the load compensation module 40, in addition to the small change of the output voltage Vout, even under full load, the output voltage Vout can be maintained within the operating voltage range of the microcontroller, allowing the microcontroller to operate normally. In this embodiment, the operating voltage range of the microcontroller is 3V to 3.6V. Please refer to 『 Figure 5' is a comparison diagram of standby power consumption of an embodiment of the present invention and a comparative example. Line 5A is the standby power consumption of the low-power control circuit of the present invention; and line 5B is the standby power consumption of the traditional control circuit. It is obvious that the standby power consumption of the low-power control circuit of the present invention within the full voltage range is less than 20mW, which is 5 times lower than the maximum standby power consumption of the traditional structure of 104mW. ' Figure 5 For the circuit diagram of the comparative example in ' Figure 6 The control circuit 90 includes a rectifier module 91, a chip 92, a first feedback resistor Rb1, a second feedback resistor Rb2, a capacitor 93, an inductor 94 and a diode 95. After an alternating current (AC IN) is input into the circuit 90, a direct current (DC OUT) is output. Figure 6 』 is the architecture of a traditional control circuit, which is normally powered by the JFET in the chip 92. The two ends of the JFET are electrically connected to the Drain and VJ respectively. Among them, VJ is generally the pinch-off voltage, so there is a high voltage difference between the two ends of the JFET, resulting in low efficiency and high power consumption, and it is difficult to meet the ultra-low standby power consumption requirements.

[0066] Please refer to Figure 7 ' is a circuit diagram of a low power consumption control circuit according to another embodiment of the present invention. This embodiment is based on ' Figure 1 The circuit further includes at least one feedback resistor, such as a first feedback resistor Rfb1 and a second feedback resistor Rfb2, which are coupled between a feedback terminal FB of the constant voltage control chip 20 and the buck conversion module 30. The voltage value of the second DC power DC2 is adjusted by setting the feedback resistor and changing its resistance value. In this embodiment, the voltage value of the second DC power DC2 ranges from 2.5V to 5V. Please refer to " Fig. 8A "and" Figure 8B ' is a circuit diagram of a low power consumption control circuit according to another embodiment of the present invention. This embodiment is based on ' Figure 1 The circuit further comprises a detection resistor Rs, and the detection resistor Rs is coupled between the first node N1 and the current detection terminal CS; and, by Figure 3 』 In the power supply end sampling module 40a of the constant voltage control chip 20, the configuration of the first switch 401a, the second switch 402a and the resistor can allow the control end SEL of the constant voltage control chip 20 to be selectively coupled to the power supply end VCC or the ground end G to adjust the second DC power DC2. When the control end SEL is coupled to the power supply end VCC, the second DC power DC2 is 3.3V; when the control end SEL is coupled to the ground end G, the second DC power DC2 is 5V. In the present invention, in order to adjust the voltage value of the second DC power DC2, in addition to the method of 『 Figure 7In addition to the configuration shown in FIG. 1 , the feedback resistor can also be directly set in the constant voltage control chip 20. In this way, there is no need to set the first feedback resistor Rfb1, the second feedback resistor Rfb2 and the feedback terminal FB separately, which is beneficial to reduce the component cost of the chip peripheral circuit.

[0067] Please refer to " Fig. 9 ', discloses a smart home appliance system 100, including a main driving circuit module 200, an electrical module 300, a smart module 400 and a control circuit, the main driving module 300 converts an alternating current Vac into a main driving DC power, the main driving DC power is input into the electrical module 300 to supply the power required for operation, the control circuit adopts the above-mentioned, for outputting the second DC power DC2 according to the alternating current Vac, the second DC power DC2 is input into the smart module 400 to supply the power required for operation, wherein the smart module 400 can be a wireless signal receiver or a sensor.

[0068] In summary, the present invention uses the second DC power output by the step-down conversion module directly as the power supply source of the constant voltage control chip, rather than through JFET, thereby solving the problem of high standby power consumption; at the same time, the present invention sets the load compensation module in the constant voltage control chip, and the load compensation module samples the voltage of the power supply end, that is, the constant voltage is adjusted by using the voltage of the power supply end as a feedback signal. Since the voltage of the power supply end is a reference signal relative to the ground end of the constant voltage control chip, there is no need to set a sampling and holding circuit, which reduces the complexity of the circuit structure. In general, the present invention is suitable for ultra-low standby power consumption applications with an output voltage lower than 5V.

Claims

1. A low power consumption control circuit for smart home appliances, characterized in that include: A rectifier module receives an alternating current and outputs a first direct current; A constant voltage control chip, comprising a drain terminal, a ground terminal and a power terminal, wherein the drain terminal is coupled to the rectifier module; a step-down conversion module coupled to the rectifier module, the power supply terminal of the constant voltage control chip and the ground terminal, the step-down conversion module receives the first DC power and outputs a second DC power to an external load after step-down conversion and supplies power to the constant voltage control chip through the power supply terminal, and allows the constant voltage control chip to sample the power supply terminal as a feedback signal to adjust the second DC power; and A load compensation module is electrically connected to the power supply end, and the load compensation module provides a compensation voltage to the power supply end to improve a load regulation rate generated based on an external load.

2. The control circuit according to claim 1, characterized in that: The buck conversion module includes a freewheeling diode, an output capacitor coupled in parallel with the freewheeling diode, and an inductor coupled between the freewheeling diode and the output capacitor.

3. The control circuit according to claim 2, characterized in that: A cathode of the freewheeling diode is coupled to one end of the inductor to form a first node, an anode of the freewheeling diode is coupled to the output capacitor, the other end of the inductor is coupled to the output capacitor to form a second node, the first node is coupled to the ground end, and the second node is coupled to the power supply end of the constant voltage control chip.

4. The control circuit according to claim 3, characterized in that: The buck conversion module further includes a bootstrap diode and a power supply capacitor coupled to the bootstrap diode. The bootstrap diode includes an anode coupled to the second node and a cathode forming a third node with the power supply capacitor.

5. The control circuit according to claim 3, characterized in that: The constant voltage control chip also includes a current detection terminal coupled to the first node.

6. The control circuit according to claim 5, characterized in that: A detection resistor is coupled between the current detection terminal and the first node.

7. The control circuit according to claim 1, characterized in that: The constant voltage control chip further includes a feedback terminal. At least one feedback resistor is coupled between the feedback terminal and the buck conversion module to adjust the second DC power.

8. The control circuit according to claim 1, characterized in that: The constant voltage control chip further includes a control terminal, which is selectively coupled to the power terminal or the ground terminal to adjust the second DC power.

9. The control circuit according to claim 1, characterized in that: The load compensation module includes a power supply end sampling module and a regulation module. The power supply end sampling module is coupled to the power supply end of the constant voltage control chip and outputs a power supply end sampling signal to the regulation module. The regulation module receives a reference signal and the power supply end sampling signal and outputs a load compensation signal coupled to the power supply end.

10. The control circuit according to claim 9, characterized in that: The control module includes an error amplifier and a control unit. A first input terminal of the error amplifier is coupled to the power supply sampling module, an output terminal of the error amplifier is coupled to the control unit, and the control unit receives the reference signal and feeds back the load compensation signal to the second input terminal of the error amplifier.

11. The control circuit according to claim 10, characterized in that: The control unit includes: a first resistor, a first end of which is coupled to the second input end of the error amplifier and forms a fourth node; a second resistor, a first end of the second resistor being coupled to a second end of the first resistor and forming a fifth node for inputting a reference voltage; a first voltage-controlled current source, comprising an input terminal coupled to the output terminal of the error amplifier, a control terminal coupled to the fifth node, and an output terminal coupled to a second terminal of the second resistor; and A second voltage-controlled current source is coupled between the power supply terminal and the second input terminal of the error amplifier.

12. The control circuit according to claim 10, characterized in that: The power supply end sampling signal includes: a third resistor coupled between the first input terminal of the error amplifier and the power terminal; and A fourth resistor is coupled to one end of the third resistor to form a sixth node, and the other end of the fourth resistor is grounded.

13. The control circuit according to claim 1, characterized in that: The constant voltage control chip also includes a selection end, and the selection end selects different second DC power outputs.

14. The control circuit according to claim 13, characterized in that: The selection terminal is coupled to the load compensation module.

15. The control circuit according to claim 1, characterized in that: The constant voltage control chip further comprises: a logic controller; a driver coupled to the logic controller; a power switch coupled to the driver; and A comparator has a first input terminal coupled to the load compensation module, a second input terminal inputting a first reference voltage, and an output terminal coupled to the logic controller.

16. The control circuit according to claim 1, characterized in that: The voltage value of the second DC power is between 2.5V and 5V.

17. A smart home appliance system, comprising: A main drive circuit module, which converts an alternating current into a main drive direct current power; An electrical module coupled to the main drive circuit module and inputting the main drive DC power; A control circuit as claimed in any one of claims 1 to 16, wherein the control circuit outputs the second DC power according to the AC power; and A smart module is provided, wherein the smart module operates by utilizing the second DC power.

18. The smart home appliance system according to claim 17, characterized in that: The intelligent module is a wireless signal receiver or a sensor.

19. The smart home appliance system according to claim 18, characterized in that: The voltage value of the second DC power is between 2.5V and 5V.

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