Dual-output voltage reduction circuit, power supply unit and air conditioner

Abstract

This application provides a dual-output step-down circuit, a power supply unit, and an air conditioner, relating to the field of step-down circuit technology. The circuit includes a rectifier and filter module, a step-down chip, a feedback module, a first step-down module, and a second step-down module. The rectifier and filter module is electrically connected to the respective step-down chip, the first step-down module, and the second step-down module. The step-down chip is electrically connected to the first step-down module and the second step-down module through the feedback module. The first step-down module and the second step-down module are electrically connected. The first step-down module includes a first inductor, and the second step-down module includes a second inductor. The first and second inductors share the same magnetic core, but their turns ratios are different, allowing the first and second step-down modules to output different voltages. This application offers advantages such as good stability and low cost.

Description

Technical Field

[0001] This invention relates to the field of step-down circuit technology, and more specifically, to a dual-output step-down circuit, a power supply unit, and an air conditioner. Background Technology

[0002] Air conditioners are necessities in people's daily lives and are therefore widely used. During the operation of the DC indoor unit of an air conditioner, it typically requires two power supplies: 15V and 12V.

[0003] In existing technologies, BUCK circuits are commonly used to achieve power output. However, BUCK power supplies can only output in a single channel, so a 7812 chip is required for voltage conversion, resulting in low power conversion efficiency and a high failure rate. At the same time, the cost is also high due to the addition of the 7812 chip.

[0004] In summary, existing technologies suffer from low circuit conversion efficiency, high failure rate, and high cost. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-output step-down circuit, a power supply unit, and an air conditioner to solve the problems of low circuit conversion efficiency, high failure rate, and high cost in the prior art.

[0006] To address the aforementioned problems, this application provides a dual-output buck circuit. The circuit includes a rectifier-filter module, a buck chip, a feedback module, a first buck module, and a second buck module. The rectifier-filter module is electrically connected to the buck chip, the first buck module, and the second buck module, respectively. The buck chip is electrically connected to the first buck module and the second buck module via the feedback module. The first buck module is electrically connected to the second buck module.

[0007] The first step-down module includes a first inductor, and the second step-down module includes a second inductor. The first inductor and the second inductor share the same magnetic core, and the first inductor and the second inductor have different turns ratios, so that the first step-down module and the second step-down module output different voltages.

[0008] Because the 7812 chip is eliminated in the dual-output buck circuit provided in this application, and the same buck chip is used with two buck modules to output different voltages as power supplies, the circuit voltage does not actually need to undergo two conversions, resulting in higher conversion efficiency and a lower failure rate. Furthermore, since the first and second inductors share the same magnetic core, it essentially uses only one inductor, leading to lower costs.

[0009] Optionally, the first step-down module further includes a capacitor bank and a first diode. The output terminal of the step-down chip is electrically connected to one end of the first inductor and the cathode of the first diode, respectively. The other end of the first inductor is electrically connected to the feedback module, the second step-down module, and one end of the capacitor bank, respectively. The other end of the capacitor bank is electrically connected to the anode of the first diode and the rectifier-filter module, respectively.

[0010] When the buck chip is closed, the buck chip, the first inductor, and the capacitor bank form a charging circuit;

[0011] When the step-down chip is disconnected, the first inductor, the capacitor bank, and the first diode form a discharge circuit.

[0012] Optionally, the capacitor bank includes a first electrolytic capacitor and a first capacitor, wherein the first electrolytic capacitor and the first capacitor are connected in parallel.

[0013] Optionally, the second step-down module further includes a second diode and a second electrolytic capacitor. One end of the second inductor is electrically connected to the first inductor, and the other end of the second inductor is electrically connected to the anode of the second diode. The cathode of the second diode is connected to one end of the second electrolytic capacitor, and the other end of the second electrolytic capacitor is electrically connected to the anode of the first diode and the rectifier-filter module, respectively.

[0014] When the buck chip is closed, the buck chip, the first inductor, the second inductor, and the second electrolytic capacitor form a charging circuit;

[0015] When the step-down chip is disconnected, the first inductor, the second inductor, the second diode, the second electrolytic capacitor, and the first diode form a discharge circuit.

[0016] Optionally, the feedback module includes three diodes, the anode of the third diode is electrically connected to the first inductor and the second inductor respectively, and the cathode of the third diode is electrically connected to the feedback terminal of the step-down chip; wherein,

[0017] The third diode is used to feed back the current voltage of the first buck module to the buck chip;

[0018] The step-down chip is also used to update to a closed state when the current voltage is less than a preset voltage value.

[0019] Optionally, the feedback module further includes a second capacitor, one end of which is electrically connected to the cathode of the third diode, and the other end of which is grounded.

[0020] Optionally, the rectifier-filter circuit includes a rectifier bridge and a π-type filter module. The input terminal of the rectifier bridge is electrically connected to an AC power supply, and the output terminal of the rectifier bridge is electrically connected to the π-type filter module. The π-type filter module is electrically connected to the respective step-down chip, the first step-down module, and the second step-down module.

[0021] Optionally, the π-type filter module includes a third capacitor, a fourth capacitor, a third inductor, and a resistor. One end of the third capacitor is electrically connected to the output terminal of the rectifier bridge, one end of the third inductor, and one end of the resistor. The other end of the third capacitor is grounded. One end of the fourth capacitor is electrically connected to the other ends of the third inductor and the resistor, and the step-down chip, respectively. The other end of the fourth capacitor is electrically connected to the first step-down module and the second step-down module, respectively.

[0022] Secondly, embodiments of this application also provide a power supply unit, which includes the aforementioned dual-output step-down circuit.

[0023] Thirdly, embodiments of this application also provide an air conditioner, which includes the power supply unit described above. Attached Figure Description

[0024] Figure 1 This is a circuit diagram of a dual-output buck converter in the prior art.

[0025] Figure 2 This is a schematic diagram of the dual-output buck circuit described in an embodiment of this application.

[0026] Figure 3 A circuit diagram of the dual-output buck circuit described in this application embodiment.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100 - Dual-output step-down circuit; 110 - Rectifier and filter module; 120 - Step-down chip; 130 - Feedback module; 140 - First step-down module; 150 - Second step-down module; D1 - First diode; D2 - Second diode; D3 - Third diode; E1 - First electrolytic capacitor; E2 - Second electrolytic capacitor; E3 - Third electrolytic capacitor; C1 - First capacitor; C2 - Second capacitor; BD1 - Rectifier bridge; C3 - Third capacitor; C4 - Fourth capacitor; L1 - First inductor; L2 - Second inductor; L3 - Third inductor; R1 - Resistor. Detailed Implementation

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] As described in the background section, DC indoor air conditioners typically require two power supplies, 15V and 12V. Currently, BUCK circuits are commonly used to achieve power output. However, BUCK power supplies can only output power on a single circuit.

[0031] For example, such as Figure 1 As shown, Figure 1 This is a circuit diagram of a DC indoor unit air conditioner in the prior art. The AC power supply, after rectification and filtering, outputs 15V DC through a BUCK circuit. To simultaneously output 12V DC, a 7812 chip is added to the output of the BUCK circuit. The 7812 chip performs voltage conversion, outputting a rated 12V DC voltage. The 7812 chip generally refers to the LM7812, a three-terminal voltage regulator integrated circuit (IC) suitable for various power supply voltage regulation circuits. It offers good output stability, ease of use, and automatic overcurrent and overheat protection. Common three-terminal voltage regulator ICs include the LM78×× series for positive voltage output and the LM79×× series for negative voltage output, which will not be elaborated upon here.

[0032] Because providing dual DC output requires the simultaneous use of the BUCK circuit and the 7812 chip, the existing technology suffers from low conversion efficiency and high failure rate. In addition, the addition of the 7812 chip inevitably increases the cost.

[0033] In view of this, this application provides a dual-output buck circuit, which uses one buck chip and two buck modules to form two buck circuits to achieve dual output, thereby improving conversion efficiency and failure rate, while reducing cost.

[0034] The dual-output buck circuit provided in this application is described below as an example:

[0035] As an optional implementation, please refer to Figure 2 The dual-output step-down circuit 100 includes a rectifier and filter module 110, a step-down chip 120, a feedback module 130, a first step-down module 140, and a second step-down module 150. The rectifier and filter module 110 is electrically connected to the step-down chip 120, the first step-down module 140, and the second step-down module 150, respectively. The step-down chip 120 is electrically connected to the first step-down module 140 and the second step-down module 150, respectively, through the feedback module 130. The first step-down module 140 is electrically connected to the second step-down module 150.

[0036] The first step-down module 140 includes a first inductor L1, and the second step-down module 150 includes a second inductor L2. The first inductor L1 and the second inductor L2 share the same magnetic core, and the turns ratios of the first inductor L1 and the second inductor L2 are different, so that the first step-down module 140 and the second step-down module 150 output different voltages.

[0037] By setting up a step-down chip 120 and two step-down modules, two BUCK circuits are formed between the step-down chip 120 and the two step-down modules, thereby enabling the output of two different voltages, such as 15V DC voltage and 12V DC voltage. Compared with the prior art, the technical solution provided in this application eliminates the 7812 chip, thus eliminating the need for the 7812 chip for power conversion, greatly improving power conversion efficiency and reducing the failure rate caused by 7812 failure, while also reducing costs.

[0038] It should be noted that the BUCK step-down circuit is a common circuit in existing technology. Its main working principle consists of two processes: charging and discharging. During the charging process, a circuit is formed between the switching device and the inductor, the switching device conducts, and the inductor is energized. Figure 1 The BUCK circuit shown is illustrated as an example. During the charging process, the current from pins 1 and 2 of the chip flows through inductor L3 and capacitors E1 and C1, forming a loop, and inductor L3 stores energy. During the discharge process, the inductor and freewheeling diode form a loop, at which point the inductor releases energy to power the subsequent load; continuing with... Figure 1 The BUCK circuit shown is illustrated as an example. When in the discharge process, the chip is turned off, and the inductor L3, capacitors E1 and C1 and freewheeling diode D2 form a circuit. At this time, the inductor discharges, thereby supplying power to the subsequent load.

[0039] Understandably, inductors are crucial in buck circuits. In this application, the first buck module 140 and the second buck module 150 use the same magnetic core for their inductors. In other words, the two buck circuits formed by the first buck module 140 and the second buck module 150 use the same inductor, only differing in their turns ratios. For example, an inductor may have 50 turns in total, with one end serving as the input and the other end and the middle section serving as the output. The inductor leading to the output from the other end has 50 turns, while the inductor leading to the output from the middle section has fewer than 50 turns, for example, only 30 turns. Therefore, the inductor can output different voltages when discharging. The inductor with fewer turns corresponds to a smaller DC voltage output, such as 12V, while the inductor with more turns corresponds to a larger DC voltage output, such as 15V. Furthermore, since the two inductors share the same magnetic core, the cost of the circuit is further reduced.

[0040] As an optional implementation, the first step-down module 140 further includes a capacitor bank and a first diode D1. The output terminal of the step-down chip 120 is electrically connected to one end of the first inductor L1 and the cathode of the first diode D1, respectively. The other end of the first inductor L1 is electrically connected to the feedback module 130, the second step-down module 150, and one end of the capacitor bank, respectively. The other end of the capacitor bank is electrically connected to the anode of the first diode D1 and the rectifier filter module 110, respectively. When the step-down chip 120 is closed, the step-down chip 120, the first inductor L1, and the capacitor bank form a charging circuit. When the step-down chip 120 is open, the first inductor L1, the capacitor bank, and the first diode D1 form a discharging circuit.

[0041] It should be noted that the chip provided in this application has a built-in switching transistor, and pins 5, 6, 7 and 8 of the chip are all used as input terminals, while pins 1 and 2 of the chip are used as output terminals. When the chip is closed, current flows through the inside of the chip and flows to the first inductor L1, the capacitor bank and then back to the negative terminal of the rectifier filter module 110 to form a circuit. During this process, the first inductor L1 stores energy.

[0042] When the chip is off, since the first inductor L1 stores energy, it forms a circuit with the capacitor bank and the first diode D1 to release the energy stored in the first inductor L1 and simultaneously supply power to the downstream load. Understandably, the first diode D1 acts as a freewheeling diode. Furthermore, because the energy storage inductor in the BUCK circuit formed by the first step-down module 140 only includes the first inductor L1, its output DC voltage is relatively small, at 12V.

[0043] Optionally, the capacitor bank includes a first electrolytic capacitor E1 and a first capacitor C1, which are connected in parallel. The first electrolytic capacitor E1 serves as an energy storage capacitor, and the first capacitor C1 serves as a filter.

[0044] In one implementation, the second step-down module 150 further includes a second diode D2 and a second electrolytic capacitor E2. One end of the second inductor L2 is electrically connected to the first inductor L1, and the other end of the second inductor L2 is electrically connected to the anode of the second diode D2. The cathode of the second diode D2 is connected to one end of the second electrolytic capacitor E2, and the other end of the second electrolytic capacitor E2 is electrically connected to the anode of the first diode D1 and the rectifier filter module 110, respectively. When the step-down chip 120 is closed, the step-down chip 120, the first inductor L1, the second inductor L2, and the second electrolytic capacitor E2 form a charging circuit. When the step-down chip 120 is open, the first inductor L1, the second inductor L2, the second diode D2, the second electrolytic capacitor E2, and the first diode D1 form a discharging circuit.

[0045] Similar to the step-down circuit formed by the first step-down module 140 described above, the working principle of the second step-down module 150 is as follows:

[0046] When the chip is turned on, the output current from pins 1 and 2 of the chip passes through the first inductor L1, the second inductor L2 and the second electrolytic capacitor E2 and returns to the negative terminal of the rectifier and filter module 110, forming a charging circuit to charge the first inductor L1 and the second inductor L2.

[0047] When the chip is closed, the electrical energy stored in the first inductor L1 and the second inductor L2 needs to be released through a discharge circuit. The electrical energy of the first inductor L1 and the second inductor L2 is released through the circuit of the second diode D2, the second electrolytic capacitor E2 and the first diode D1, and supplies power to the subsequent load.

[0048] Understandably, since the discharge circuit discharges simultaneously through the first inductor L1 and the second inductor L2, the number of turns of the inductor is significantly greater than the number of turns of the first inductor L1, resulting in a larger discharge voltage and the ability to output a 15V DC voltage.

[0049] Furthermore, it should be noted that since the two discharge modules essentially store and discharge energy through an inductor, the discharge is synchronous, meaning that 12V and 15V DC voltages can be output simultaneously.

[0050] Based on this, in order to realize the switching on and off of the automatic control chip, this application uses a feedback module 130 to collect the output voltage to realize the continuous switching on and off of the chip. As one implementation method, the feedback module 130 includes three diodes. The anode of the third diode D3 is electrically connected to the first inductor L1 and the second inductor L2 respectively, and the cathode of the third diode D3 is electrically connected to the feedback terminal of the buck converter chip 120. The third diode D3 is used to feed back the current voltage of the first buck converter module 140 to the buck converter chip 120. The buck converter chip 120 is also used to update to the closed state when the current voltage is less than a preset voltage value.

[0051] Understandably, the third diode D3 is actually used to collect the voltage output from the first inductor L1 and feed the voltage back to pin 4 of the chip. The chip also includes a comparator, which controls the on and off states of the internal switching transistor by comparing the voltage at pin 4 with a preset voltage.

[0052] In this circuit, the first inductor L1 outputs a 12V DC voltage during discharge. The third diode D3 collects this voltage and feeds it back to the chip. Since the voltage drop of the diode is typically 0.7V, the chip internally compares the collected voltage with 11.3V (12V - 0.7V). When the collected voltage is lower than 11.3V, the chip turns on, meaning the internal switch is activated, and the first inductor L1 and the second inductor L2 are in the process of storing electricity. The voltage of the first inductor L1 gradually increases until it exceeds 11.3V. At this point, the comparator outputs the opposite value. For example, when the voltage is less than 11.3V, the comparator outputs 1, and when it is greater than 11.3V, the comparator outputs 0; or, when the voltage is less than 11.3V, the comparator outputs 0, and when it is greater than 11.3V, the comparator outputs 1. No specific limitation is imposed here. Based on this, when the comparator outputs the opposite value, the chip is turned off. At this time, the switching transistor is cut off, and the first inductor L1 and the second inductor L2 are in the discharge state again. At this time, the voltage of the first inductor L1 gradually decreases until the voltage is lower than 11.3V. Then the comparator outputs the opposite value again, the switching transistor is turned on, and the first inductor L1 and the second inductor L2 are charged. This cycle continues.

[0053] It should be noted that since the states of the first inductor L1 and the second inductor L2 are synchronized, when the feedback module 130 feeds back the voltage of the first inductor L1, it can simultaneously control the second inductor L2, making it less prone to failure.

[0054] In one alternative implementation, to make the feedback voltage more stable, the feedback module 130 further includes a second capacitor C2. One end of the second capacitor C2 is electrically connected to the cathode of the third diode D3, and the other end of the second capacitor C2 is grounded. By setting the second capacitor C2, the feedback voltage can be filtered. Of course, to further improve the filtering effect, the feedback module 130 also includes a third electrolytic capacitor E3 to further enhance the filtering effect.

[0055] By implementing the above method, the traditional 7812 chip is reduced, the conversion efficiency is improved and the failure rate is reduced. At the same time, since only a second inductor L2 and a second diode D2 are added, and the second inductor L2 and the first inductor L1 share the same magnetic core, essentially only one inductor is used, thus reducing the cost.

[0056] Optionally, the rectifier filter circuit includes a rectifier bridge BD1 and a π-type filter module. The input terminal of the rectifier bridge BD1 is electrically connected to the AC power supply, and the output terminal of the rectifier bridge BD1 is electrically connected to the π-type filter module. The π-type filter module is electrically connected to the step-down chip 120, the first step-down module 140, and the second step-down module 150, respectively.

[0057] To ensure power supply safety, the dual-output step-down circuit 100 also includes a fuse. One end of the fuse is connected to the live wire of the power supply, and the other end is connected to the rectifier bridge BD1. The neutral wire of the power supply is also connected to the rectifier bridge BD1.

[0058] Meanwhile, the π-type filter module includes a third capacitor C3, a fourth capacitor C4, a third inductor L3, and a resistor R1. One end of the third capacitor C3 is electrically connected to the output terminal of the rectifier bridge BD1, one end of the third inductor L3, and one end of the resistor R1. The other end of the third capacitor C3 is grounded. One end of the fourth capacitor C4 is electrically connected to the other end of the third inductor L3 and the resistor R1, and to the step-down chip 120. The other end of the fourth capacitor C4 is electrically connected to the first step-down module 140 and the second step-down module 150.

[0059] Based on the above implementation, this application embodiment also provides a power supply unit, which includes the aforementioned dual-output step-down circuit 100. The power supply unit can output two different DC power supplies to the downstream load, and it offers high stability and low cost.

[0060] Based on the above implementation, this application embodiment also provides an air conditioner, which includes the above-mentioned power supply unit. The power supply unit can be applied to the DC indoor unit of the air conditioner and simultaneously provides two different DC power supplies, 12V and 15V, to the DC indoor unit.

[0061] In summary, this application provides a dual-output buck circuit, a power supply unit, and an air conditioner. The dual-output buck circuit includes a rectifier and filter module, a buck chip, a feedback module, a first buck module, and a second buck module. The rectifier and filter module is electrically connected to the buck chip, the first buck module, and the second buck module, respectively. The buck chip is electrically connected to the first buck module and the second buck module via the feedback module. The first buck module and the second buck module are electrically connected. The first buck module includes a first inductor, and the second buck module includes a second inductor. The first and second inductors share the same magnetic core, but their turns ratios are different, allowing the first and second buck modules to output different voltages. Because the 7812 chip is eliminated in the dual-output buck circuit provided by this application, and the same buck chip is used with different voltages from the two buck modules as power supplies, the circuit voltage does not actually need to undergo two conversions, resulting in higher conversion efficiency and a lower failure rate. At the same time, since the first inductor and the second inductor share the same magnetic core, it essentially uses only one inductor, resulting in lower cost.

[0062] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A dual output step-down circuit (100), characterized by, The circuit comprises a rectification filter module (110), a step-down chip (120), a feedback module (130), a first step-down module (140) and a second step-down module (150), the rectification filter module (110) is electrically connected with the step-down chip (120), the first step-down module (140) and the second step-down module (150) respectively, the step-down chip (120) is electrically connected with the first step-down module (140) and the second step-down module (150) through the feedback module (130), and the first step-down module (140) is electrically connected with the second step-down module (150); wherein The first step-down module (140) comprises a first inductor (L1), the second step-down module (150) comprises a second inductor (L2), the first inductor (L1) and the second inductor (L2) share the same magnetic core, and in a certain inductance, one end is used as an input end, the other end and the middle part are used as output ends respectively, forming the first inductor (L1) and the second inductor (L2), so that the turns ratio of the first inductor (L1) and the second inductor (L2) is different; The first step-down module (140) and the second step-down module (150) form two BUCK circuits, the first inductor (L1) and the second inductor (L2) are used as energy storage inductors of the two BUCK circuits, so that the first step-down module (140) and the second step-down module (150) output different voltages; The first step-down module (140) further comprises a capacitor group and a first diode (D1), an output end of the step-down chip (120) is electrically connected with one end of the first inductor (L1) and a cathode of the first diode (D1) respectively, the other end of the first inductor (L1) is electrically connected with the feedback module (130), the second step-down module (150) and one end of the capacitor group respectively, and the other end of the capacitor group is electrically connected with an anode of the first diode (D1) and the rectification filter module (110) respectively; wherein When the step-down chip (120) is closed, the step-down chip (120), the first inductor (L1) and the capacitor group constitute a charging circuit; When the step-down chip (120) is disconnected, the first inductor (L1), the capacitor group and the first diode (D1) constitute a discharging circuit; The second step-down module (150) further comprises a second diode (D2) and a second electrolytic capacitor (E2), one end of the second inductor (L2) is electrically connected with the first inductor (L1), the other end of the second inductor (L2) is electrically connected with an anode of the second diode (D2), a cathode of the second diode (D2) is connected with one end of the second electrolytic capacitor (E2), and the other end of the second electrolytic capacitor (E2) is electrically connected with an anode of the first diode (D1) and the rectification filter module (110) respectively; wherein When the voltage reduction chip (120) is closed, the voltage reduction chip (120), the first inductor (L1), the second inductor (L2), the second diode (D2) and the second electrolytic capacitor (E2) constitute a charging circuit; When the voltage reduction chip (120) is opened, the first inductor (L1), the second inductor (L2), the second diode (D2), the second electrolytic capacitor (E2) and the first diode (D1) constitute a discharging circuit.

2. The dual output voltage reducing circuit (100) according to claim 1, characterized in that The capacitor group comprises a first electrolytic capacitor (E1) and a first capacitor (C1), and the first electrolytic capacitor (E1) and the first capacitor (C1) are connected in parallel.

3. The dual output voltage reducing circuit (100) according to claim 1, characterized in that The feedback module (130) comprises a third diode, the anode of the third diode (D3) is electrically connected with the first inductor (L1) and the second inductor (L2) respectively, and the cathode of the third diode (D3) is electrically connected with the feedback end of the voltage reduction chip (120); wherein, The third diode (D3) is configured to feed back the current voltage of the first voltage reduction module (140) to the voltage reduction chip (120). The voltage reduction chip (120) is further configured to update to a closed state when the current voltage is less than a preset voltage value.

4. The dual output voltage reducing circuit (100) according to claim 3, characterized in that The feedback module (130) further comprises a second capacitor (C2), one end of the second capacitor (C2) is electrically connected with the cathode of the third diode (D3), and the other end of the second capacitor (C2) is grounded.

5. The dual output voltage reducing circuit (100) according to claim 1, characterized in that, The rectification and filtering module comprises a rectification bridge (BD1) and a π-type filtering module, the input end of the rectification bridge (BD1) is electrically connected with an alternating current power supply, the output end of the rectification bridge (BD1) is electrically connected with the π-type filtering module, and the π-type filtering module is electrically connected with the voltage reduction chip (120), the first voltage reduction module (140) and the second voltage reduction module (150) respectively.

6. The dual output voltage reducing circuit (100) according to claim 5, characterized in that The π-type filtering module comprises a third capacitor (C3), a fourth capacitor (C4), a third inductor (L3) and a resistor (R0), one end of the third capacitor (C3) is electrically connected with the output end of the rectification bridge (BD1), the third inductor (L3) and one end of the resistor (R0), the other end of the third capacitor (C3) is grounded, one end of the fourth capacitor (C4) is electrically connected with the other end of the third inductor (L3) and the resistor (R0), the voltage reduction chip (120) and the other end of the fourth capacitor (C4) is electrically connected with the first voltage reduction module (140) and the second voltage reduction module (150) respectively.

7. A power supply unit, characterized by The power supply unit comprises the dual-path output voltage reduction circuit (100) according to any one of claims 1 to 6.

8. An air conditioner characterized by comprising: The air conditioner comprises the power supply unit according to claim 7.

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