Passive PFC valley fill circuit

Abstract

The utility model discloses a passive PFC valley fill circuit, which comprises an alternating current circuit and a direct current circuit, a bridge rectifier is arranged between the alternating current circuit and the direct current circuit, the output end of the alternating current circuit is connected with the input end of the bridge rectifier, and the input end of the direct current circuit is connected with the output end of the bridge rectifier; wherein the direct-current circuit comprises a first electrolytic capacitor, a second electrolytic capacitor and a third electrolytic capacitor, the positive electrode of the first electrolytic capacitor is connected with the positive electrode of the bridge rectifier, and the negative electrode of the first electrolytic capacitor is connected with the positive electrode of the second electrolytic capacitor through a first diode; the negative electrode of the second electrolytic capacitor is connected with the positive electrode of the third electrolytic capacitor through a second diode, and the negative electrode of the third electrolytic capacitor is connected with a direct current negative electrode. The positive electrode of the bridge rectifier, the first electrolytic capacitor, the first diode, the second electrolytic capacitor, the second diode, the third electrolytic capacitor and the negative electrode of the bridge rectifier form a charging loop. The power factor of the power supply is higher, and the power supply can be adapted to the commercial power of more than 120V.

Description

Technical Field

[0001] This utility model relates to the field of valley filling circuit technology, and in particular to a passive PFC valley filling circuit. Background Technology

[0002] Valley filler circuits are low-cost, passive power factor correction circuits. They utilize the circuitry following the rectifier bridge to significantly increase the conduction angle of the rectifier diodes, thereby altering the waveform of the input current. Specifically, valley filler circuits fill in the valley areas of the current waveform, transforming the input current from a spike pulse to a near-sine wave, thus improving the power factor.

[0003] The lowest stable DC output voltage of existing passive PFC valley-filling circuits is 1 / 2 of VCC, with a conduction angle of about 180 degrees. However, when these existing passive PFC valley-filling circuits are applied to 220V small household appliances or the LED industry, the low stable DC voltage of the valley-filling circuits will fail to meet the normal use requirements of small household appliances or LEDs.

[0004] Therefore, it is urgent to research and develop a passive PFC valley-fill circuit that can achieve a conduction angle of about 2 / 3 and has a higher power factor to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a passive PFC valley filling circuit, which has a higher power factor and can be used with mains power of 120V or higher.

[0006] To achieve the above objectives, this utility model provides a passive PFC valley-fill circuit, the specific implementation of which is as follows:

[0007] A passive PFC valley-filling circuit includes an AC circuit and a DC circuit, with a rectifier bridge between the AC circuit and the DC circuit. The output terminal of the AC circuit is connected to the input terminal of the rectifier bridge, and the input terminal of the DC circuit is connected to the output terminal of the rectifier bridge.

[0008] The DC circuit includes a first electrolytic capacitor, a second electrolytic capacitor, and a third electrolytic capacitor. The positive terminal of the first electrolytic capacitor is connected to the positive terminal of the rectifier bridge. The negative terminal of the first electrolytic capacitor is connected to the positive terminal of the second electrolytic capacitor through a first diode. The negative terminal of the second electrolytic capacitor is connected to the positive terminal of the third electrolytic capacitor through a second diode. The negative terminal of the third electrolytic capacitor is connected to a DC negative terminal. The positive terminal of the rectifier bridge, the first electrolytic capacitor, the first diode, the second electrolytic capacitor, the second diode, the third electrolytic capacitor, and the negative terminal of the rectifier bridge form a charging circuit.

[0009] In some embodiments, the positive terminals of the first electrolytic capacitor, the second electrolytic capacitor, and the third electrolytic capacitor are all directly or indirectly connected to a DC positive terminal.

[0010] In some embodiments, the DC circuit further includes a third diode, the anode of which is connected to the negative terminal of the DC power supply, and the cathode of which is connected to the negative terminal of the first electrolytic capacitor. A first discharge circuit with a DC circuit is formed by passing from the positive terminal of the first electrolytic capacitor through the positive terminal of the DC power supply, the negative terminal of the DC power supply, and the anode of the third diode back to the negative terminal of the first electrolytic capacitor.

[0011] In some embodiments, the DC circuit further includes a fourth diode and a fifth diode. The anode of the fourth diode is connected to the positive terminal of the second electrolytic capacitor, and the cathode of the fourth diode is connected to the positive DC terminal. The anode of the fifth diode is connected to the negative terminal of the second electrolytic capacitor, and the cathode of the fifth diode is connected to the negative DC terminal. A second discharge circuit with a DC circuit is formed by passing from the positive terminal of the second electrolytic capacitor through the fourth diode, the positive DC terminal, the negative DC terminal, and the fifth diode back to the negative terminal of the second electrolytic capacitor.

[0012] In some embodiments, the DC circuit further includes a sixth diode, the anode of which is connected to the positive terminal of the third electrolytic capacitor, and the cathode of which is connected to the positive DC terminal. A third discharge circuit with a DC circuit is formed by passing from the positive terminal of the third electrolytic capacitor through the sixth diode, the positive DC terminal, and the negative DC terminal back to the negative terminal of the third electrolytic capacitor.

[0013] In some embodiments, the anode of the first diode is connected to the cathode of the first electrolytic capacitor, the cathode of the first diode is connected to the anode of the second electrolytic capacitor, the anode of the second diode is connected to the cathode of the second electrolytic capacitor, and the cathode of the second diode is connected to the anode of the third electrolytic capacitor.

[0014] In some embodiments, the output terminal of the AC circuit includes a first AC output circuit and a second AC output circuit, both of which are connected to the input terminal of the rectifier bridge.

[0015] Based on the above technical solution, this utility model has the following beneficial effects compared with the prior art:

[0016] By employing a structure consisting of a first electrolytic capacitor, a second electrolytic capacitor, and a third electrolytic capacitor, along with a first diode and a second diode, as the DC circuit portion of the valley-filling circuit, AC mains power is input to the rectifier bridge during operation. The rectifier bridge converts the AC power into DC power, which then passes sequentially through the first electrolytic capacitor, the first diode, the second electrolytic capacitor, the second diode, and the third electrolytic capacitor before returning to the negative terminal of the rectifier bridge to form a charging circuit. Furthermore, the inclusion of three electrolytic capacitors ensures a stable DC voltage output at 1 / 3 of the rated DC voltage and a 2 / 3 conduction angle, resulting in 2 / 3 of the charging time. This allows for greater access to the grid's conduction angle, improving the power factor of the valley-filling circuit. It is suitable for use in 220V small household appliances or the LED industry. Attached Figure Description

[0017] Figure 1 This is a circuit diagram of the present invention.

[0018] Explanation of reference numerals in the attached figures:

[0019] 100, AC circuit; 200, DC circuit; DP, rectifier bridge; E1, first electrolytic capacitor; E2, second electrolytic capacitor; E3, third electrolytic capacitor; D1, third diode; D2, first diode; D3, fourth diode; D4, fifth diode; D5, second diode; D6, sixth diode; O+, positive DC terminal; O-, negative DC terminal; AC1, first AC output circuit; AC2, second AC output circuit. Detailed Implementation

[0020] To facilitate understanding of this utility model, the specific embodiments of this utility model will be described in more detail below with reference to the accompanying drawings.

[0021] Unless otherwise specified or defined, the terms "first," "second," etc., used in this document are for distinguishing names only and do not represent a specific number or order.

[0022] Unless otherwise stated or defined, the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0023] It should be noted that in this article, "fixed to" or "connected to" can mean directly fixed to or connected to a component, or indirectly fixed to or connected to a component.

[0024] like Figure 1As shown, the passive PFC valley-filling circuit provided in this embodiment includes an AC circuit 100 and a DC circuit 200. A rectifier bridge DP is provided between the AC circuit 100 and the DC circuit 200. The output terminal of the AC circuit 100 is connected to the input terminal of the rectifier bridge DP, and the input terminal of the DC circuit 200 is connected to the output terminal of the rectifier bridge DP.

[0025] The DC circuit 200 includes a first electrolytic capacitor E1, a second electrolytic capacitor E2, and a third electrolytic capacitor E3. The positive terminal of the first electrolytic capacitor E1 is connected to the positive terminal of the rectifier bridge DP. The negative terminal of the first electrolytic capacitor E1 is connected to the positive terminal of the second electrolytic capacitor E2 through a first diode D2. The negative terminal of the second electrolytic capacitor E2 is connected to the positive terminal of the third electrolytic capacitor E3 through a second diode D5. The negative terminal of the third electrolytic capacitor E3 is connected to the DC negative terminal O-. The positive terminal of the rectifier bridge DP, the first electrolytic capacitor E1, the first diode D2, the second electrolytic capacitor E2, the second diode D5, the third electrolytic capacitor E3, and the negative terminal of the rectifier bridge DP form a charging circuit.

[0026] In some embodiments, the positive terminals of the first electrolytic capacitor E1, the second electrolytic capacitor E2, and the third electrolytic capacitor E3 are all directly or indirectly connected to the positive DC terminal O+.

[0027] In some embodiments, the DC circuit 200 further includes a third diode D1, the anode of the third diode D1 being connected to the DC negative terminal O-, and the cathode of the third diode D1 being connected to the negative terminal of the first electrolytic capacitor E1. A first discharge circuit of the DC circuit 200 is formed by passing from the positive terminal of the first electrolytic capacitor E1 through the DC positive terminal O+, the DC negative terminal O-, and the anode of the third diode D1 back to the negative terminal of the first electrolytic capacitor E1.

[0028] In some embodiments, the DC circuit 200 further includes a fourth diode D3 and a fifth diode D4. The anode of the fourth diode D3 is connected to the positive terminal of the second electrolytic capacitor E2, and the cathode of the fourth diode D3 is connected to the positive DC terminal O+. The anode of the fifth diode D4 is connected to the negative terminal of the second electrolytic capacitor E2, and the cathode of the fifth diode D4 is connected to the negative DC terminal O-. A second discharge circuit of the DC circuit 200 is formed by passing from the positive terminal of the second electrolytic capacitor E2 through the fourth diode D3, the positive DC terminal O+, the negative DC terminal O-, and the fifth diode D4 back to the negative terminal of the second electrolytic capacitor E2.

[0029] In some embodiments, the DC circuit 200 further includes a sixth diode D6, the anode of which is connected to the positive terminal of the third electrolytic capacitor E3, and the cathode of which is connected to the positive DC terminal O+. A third discharge circuit of the DC circuit 200 is formed by passing sequentially from the positive terminal of the third electrolytic capacitor E3 through the sixth diode D6, the positive DC terminal O+, and the negative DC terminal O- back to the negative terminal of the third electrolytic capacitor E3.

[0030] In some embodiments, the anode of the first diode D2 is connected to the cathode of the first electrolytic capacitor E1, the cathode of the first diode D2 is connected to the anode of the second electrolytic capacitor E2, the anode of the second diode D5 is connected to the cathode of the second electrolytic capacitor E2, and the cathode of the second diode D5 is connected to the anode of the third electrolytic capacitor E3.

[0031] In some embodiments, the output terminal of the AC circuit includes a first AC output circuit AC1 and a second AC output circuit AC2, both of which are connected to the input terminal of the rectifier bridge DP.

[0032] This embodiment provides a passive PFC valley-filling circuit. Compared to existing technologies, it uses a structure with a first electrolytic capacitor E1, a second electrolytic capacitor E2, and a third electrolytic capacitor E3, along with a first diode D2 and a second diode D5, as the DC circuit part of the valley-filling circuit. In use, AC mains power is input to the rectifier bridge DP. The rectifier bridge DP converts the AC power into DC power, which passes through the first electrolytic capacitor E1, the first diode D2, the second electrolytic capacitor E2, the second diode D5, and the third electrolytic capacitor E3 before returning to the negative terminal of the rectifier bridge DP to form a charging loop. Furthermore, due to the inclusion of three electrolytic capacitors, the valley-filling circuit achieves a stable DC voltage output for 1 / 3 of the time and a charging time for 2 / 3 of the time. It can obtain more conduction angle from the grid, improving the power factor of the valley-filling circuit. It is suitable for applications in 220V small household appliances or the LED industry.

[0033] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. A passive PFC valley-fill circuit, characterized in that, It includes an AC circuit and a DC circuit, with a rectifier bridge between the AC circuit and the DC circuit. The output terminal of the AC circuit is connected to the input terminal of the rectifier bridge, and the input terminal of the DC circuit is connected to the output terminal of the rectifier bridge. The DC circuit includes a first electrolytic capacitor, a second electrolytic capacitor, and a third electrolytic capacitor. The positive terminal of the first electrolytic capacitor is connected to the positive terminal of the rectifier bridge. The negative terminal of the first electrolytic capacitor is connected to the positive terminal of the second electrolytic capacitor through a first diode. The negative terminal of the second electrolytic capacitor is connected to the positive terminal of the third electrolytic capacitor through a second diode. The negative terminal of the third electrolytic capacitor is connected to a DC negative terminal. The positive terminal of the rectifier bridge, the first electrolytic capacitor, the first diode, the second electrolytic capacitor, the second diode, the third electrolytic capacitor, and the negative terminal of the rectifier bridge form a charging circuit.

2. The passive PFC valley-fill circuit as described in claim 1, characterized in that, The positive terminals of the first electrolytic capacitor, the second electrolytic capacitor, and the third electrolytic capacitor are all directly or indirectly connected to the positive terminal of a direct current.

3. The passive PFC valley-fill circuit as described in claim 2, characterized in that, The DC circuit also includes a third diode, the anode of which is connected to the negative terminal of the DC power supply, and the cathode of which is connected to the negative terminal of the first electrolytic capacitor. The first discharge circuit is formed by passing from the positive terminal of the first electrolytic capacitor through the positive terminal of the DC power supply, the negative terminal of the DC power supply, and the anode of the third diode back to the negative terminal of the first electrolytic capacitor.

4. The passive PFC valley-fill circuit as described in claim 2 or 3, characterized in that, The DC circuit further includes a fourth diode and a fifth diode. The anode of the fourth diode is connected to the positive terminal of the second electrolytic capacitor, and the cathode of the fourth diode is connected to the positive terminal of the DC power supply. The anode of the fifth diode is connected to the negative terminal of the second electrolytic capacitor, and the cathode of the fifth diode is connected to the negative terminal of the DC power supply. A second discharge circuit with a DC circuit is formed by passing from the positive terminal of the second electrolytic capacitor through the fourth diode, the positive terminal of the DC power supply, the negative terminal of the DC power supply, and the fifth diode back to the negative terminal of the second electrolytic capacitor.

5. The passive PFC valley-fill circuit as described in claim 2 or 3, characterized in that, The DC circuit also includes a sixth diode, the anode of which is connected to the positive terminal of the third electrolytic capacitor, and the cathode of which is connected to the positive terminal of the DC power supply. The DC circuit forms a third discharge loop, which passes sequentially from the positive terminal of the third electrolytic capacitor through the sixth diode, the positive terminal of the DC power supply, and the negative terminal of the DC power supply back to the negative terminal of the third electrolytic capacitor.

6. The passive PFC valley-fill circuit as described in claim 2 or 3, characterized in that, The anode of the first diode is connected to the cathode of the first electrolytic capacitor, the cathode of the first diode is connected to the anode of the second electrolytic capacitor, the anode of the second diode is connected to the cathode of the second electrolytic capacitor, and the cathode of the second diode is connected to the anode of the third electrolytic capacitor.

7. The passive PFC valley-fill circuit as described in claim 2 or 3, characterized in that, The output terminal of the AC circuit includes a first AC output circuit and a second AC output circuit, both of which are connected to the input terminal of the rectifier bridge.

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