Simple overharmonic circuit of power adapter

Abstract

The utility model relates to an overharmonic circuit, in particular to a simple overharmonic circuit of a power adapter. The overharmonic circuit comprises a rectifier bridge BD1, a capacitor CX1, a capacitor C1, a capacitor C2, a capacitor CE1, a capacitor CE2, a capacitor CE5, a capacitor C4, a capacitor C6, a capacitor C8, a capacitor C9, a capacitor C16, a resistor RX1, a resistor RX2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R16, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R36, an inductor LF1, an inductor L1, an inductor L2, a PWM control chip U4, a diode ZD1, a diode ZD2, a diode D2 The circuit comprises a diode D4, a diode D5, a diode D10, a diode D11, a photoelectric coupler U1A, a photoelectric coupler U1B, a transformer T1, a transformer T2, an MOS tube Q1 and an MOS tube Q3. The overharmonic circuit is simple in structure, reasonable in design and low in cost, the PF value of the circuit is larger than 0.9, and the requirement for harmonic waves larger than 25 W is met.

Description

Technical Field

[0001] This utility model relates to an over-harmonic circuit, specifically a simplified over-harmonic circuit for a power adapter. Background Technology

[0002] A power adapter is a power conversion device for small portable electronic devices and appliances. Also called an external power supply, it is a voltage conversion device for small portable electronic devices and appliances. It is commonly found in small electronic products such as mobile phones, LCD monitors, and laptops. With the progress of society, there are more and more types of electronic products, and therefore more and more power adapters.

[0003] Existing overharmonic adapters generally use two types of overharmonic circuits: one is an active PFC correction circuit, which has many ICs and peripheral components, occupies a large casing space, and is costly; the other is a passive valley-fill circuit, which is only suitable for the 5-25W power range and cannot meet the harmonic requirements below 25W. To address this problem, the inventor designed a simplified overharmonic circuit for power adapters. Utility Model Content

[0004] The purpose of this utility model is to provide a simple overharmonic circuit for a power adapter. This overharmonic circuit has a simple structure, reasonable design, low cost, and a power factor (PF) greater than 0.9, which meets the requirements for harmonics greater than 25W. It solves the problems mentioned in the above-mentioned technical background.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a simple harmonic bypass circuit for a power adapter, comprising a rectifier bridge BD1, capacitors CX1, C1, C2, CE1, CE2, CE5, C4, C6, C8, C9, C16, resistors RX1, RX2, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R16, R20, R21, R22, and R23. The following components are included: resistor R36, inductors LF1, L1, L2, PWM control chip U4, diodes ZD1, ZD2, D2, D3, D4, D5, D10, D11, optocoupler U1A, optocoupler U1B, transformer T1, transformer T2, MOSFET Q1 and Q3. Resistors RX1 and RX2 are connected in series and then in parallel with capacitor CX1 and inductor LF1. One end of rectifier bridge BD1 is connected to inductor LF1, and the other end is connected to capacitor C1 and inductor L1. The end of inductor L1 furthest from capacitor C1 is connected to capacitor C2, diode D3, and... Diode D4 is connected; one end of capacitor CE1 is grounded, and the other end is connected to diode D3, resistor R1, capacitor C8, and the primary winding T1A of transformer T1; one end of resistor R2 is connected to resistor R1, and the other end is connected to resistor R5 and capacitor CE2; one end of diode D2 is connected to resistor R5, and the other end is connected to the secondary winding T1B of transformer T1; one end of inductor L2 is connected to diode D5 and the drain of MOSFET Q1; resistor R9 and diode ZD2 are connected in parallel, and one end of resistor R9 and diode ZD2 is connected to resistor R7 and the gate of MOSFET Q1, while the other end is grounded. Resistor R7 is located away from the transformer. One end of resistor R9 and diode ZD2 is connected to the secondary winding T2C of transformer T2; resistor R8 and diode ZD1 are connected in parallel, with one end of resistor R8 and diode ZD1 grounded and the other end connected to resistor R6 and the gate of MOSFET Q3 respectively; the end of resistor R6 away from resistor R8 and diode ZD1 is connected to the secondary coil T2B of transformer T2; pin 1 of PWM control chip U4 is grounded, pin 2 is connected to capacitor C6 and optocoupler U1B respectively, pin 4 is connected to capacitor C9 and resistor R13 respectively, pin 5 is connected to VCC terminal, and pin 6 is connected to resistor R10 and then to the primary coil T2A of transformer T2;Resistors R20 and R22 are connected in series, as are resistors R21 and R23. Optocoupler U1A is connected in parallel across resistor R21. One end of capacitor C4 is connected to resistor R20, and the other end is connected to the three-terminal voltage regulator U3, resistor R21, and optocoupler U1A. One end of resistor R16 is grounded, and the other end is connected to both resistors R20 and R22.

[0006] Preferably, the overharmonic circuit further includes a fuse F1, which is connected to the live wire L.

[0007] Preferably, the resistor R3 and capacitor C8 are connected in parallel, with one end of the resistor R3 and capacitor C8 connected to the high-voltage power supply terminal HV, and the other end connected to the resistor R4. The end of the resistor R4 away from the resistor R3 and capacitor C8 is connected to the diode D11.

[0008] Preferably, the resistor R36 is connected in series with the capacitor C16 and then in parallel with the diode D10. One end of the diode D10 is connected to the power output terminal V+ and the capacitor CE5, and the other end is connected to the secondary winding T1C of the transformer T1.

[0009] Preferably, resistors R11 and R12 are connected in parallel, with one end of resistors R11 and R12 grounded and the other end connected to resistor R13 and the source of MOSFET Q3, respectively.

[0010] Preferably, diodes D3, D4, and D5 are isolation diodes.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] 1. This utility model provides a simple harmonic bypass circuit for a power adapter. The harmonic bypass circuit includes a rectifier bridge BD1, capacitors CX1, C1, C2, CE1, CE2, CE5, C4, C6, C8, C9, and C16, resistors RX1, RX2, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R16, R20, R21, R22, R23, and R36, and inductors LF1 and L26. 1. The circuit consists of inductor L2, PWM control chip U4, diodes ZD1, ZD2, D2, D3, D4, D5, D10, D11, optocoupler U1A, optocoupler U1B, transformer T1, transformer T2, MOSFETs Q1 and Q3. The overall structure is simple and reasonably designed. Compared with conventional adapter power supply circuits, the increased energy storage and discharge of inductor L2 during power supply operation effectively extends the conduction time of diode D4. This is equivalent to increasing the conduction angle of the diodes in the rectifier bridge BD1, thereby increasing the power factor (PF) value to greater than 0.9, thus meeting the requirement of harmonic distortion greater than 25W. Attached Figure Description

[0013] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] In the description of the embodiments of this utility model, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the embodiments of this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0016] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0017] Please see Figure 1This utility model provides an embodiment of a simple over-harmonic circuit for a power adapter. The over-harmonic circuit includes a rectifier bridge BD1, capacitors CX1, C1, C2, CE1, CE2, CE5, C4, C6, C8, C9, and C16, and resistors RX1, RX2, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R16, R20, R21, R22, and R23. 6. Inductors LF1, L1, L2, PWM control chip U4, diodes ZD1, ZD2, D2, D3, D4, D5, D10, D11, optocoupler U1A, optocoupler U1B, transformer T1, transformer T2, MOSFETs Q1 and Q3. Resistors RX1 and RX2 are connected in series and then in parallel with capacitor CX1 and inductor LF1. One end of rectifier bridge BD1 is connected to inductor LF1, and the other end is connected to capacitor C1 and inductor L1 respectively. The end of inductor L1 furthest from capacitor C1 is connected to capacitor C2, diode D3, and diode D4. D4 is connected; one end of capacitor CE1 is grounded, and the other end is connected to diode D3, resistor R1, capacitor C8, and the primary winding T1A of transformer T1; one end of resistor R2 is connected to resistor R1, and the other end is connected to resistor R5 and capacitor CE2; one end of diode D2 is connected to resistor R5, and the other end is connected to the secondary winding T1B of transformer T1; one end of inductor L2 is connected to diode D5 and the drain of MOSFET Q1; resistor R9 and diode ZD2 are connected in parallel, and one end of resistor R9 and diode ZD2 is connected to resistor R7 and the gate of MOSFET Q1, and the other end is grounded. Resistor R7 is located away from resistor R1. 9 and one end of diode ZD2 are connected to the secondary winding T2C of transformer T2; resistor R8 and diode ZD1 are connected in parallel, with one end of resistor R8 and diode ZD1 grounded, and the other end connected to resistor R6 and the gate of MOSFET Q3 respectively; the end of resistor R6 away from resistor R8 and diode ZD1 is connected to the secondary coil T2B of transformer T2; pin 1 of PWM control chip U4 is grounded, pin 2 is connected to capacitor C6 and optocoupler U1B respectively, pin 4 is connected to capacitor C9 and resistor R13 respectively, pin 5 is connected to VCC terminal, and pin 6 is connected to resistor R10 and then to the primary coil T2A of transformer T2;Resistors R20 and R22 are connected in series, and resistors R21 and R23 are also connected in series. Optocoupler U1A is connected in parallel across resistor R21. One end of capacitor C4 is connected to resistor R20, and the other end is connected to the three-terminal voltage regulator U3, resistor R21, and optocoupler U1A. One end of resistor R16 is grounded, and the other end is connected to resistors R20 and R22. The over-harmonic circuit also includes fuse F1, which is connected to the live wire L.

[0018] Specifically, resistor R3 and capacitor C8 are connected in parallel, with one end of resistor R3 and capacitor C8 connected to the high-voltage power supply terminal HV, and the other end connected to resistor R4. The end of resistor R4 away from resistor R3 and capacitor C8 is connected to diode D11.

[0019] Specifically, the resistor R36 and capacitor C16 are connected in series and then connected in parallel with diode D10. One end of diode D10 is connected to the power output terminal V+ and capacitor CE5, and the other end is connected to the secondary winding T1C of transformer T1.

[0020] Specifically, resistors R11 and R12 are connected in parallel, with one end of resistors R11 and R12 grounded and the other end connected to resistor R13 and the source of MOSFET Q3, respectively.

[0021] Specifically, diodes D3, D4, and D5 are isolation diodes.

[0022] It should be noted that in this embodiment, the PWM control chip U4 is model AP8267, the optocouplers U1A and U1B are model BPC817, and the three-terminal regulator U3 is model TL431.

[0023] Please refer to it again. Figure 1When the power PWM control chip U4 starts supplying power via VCC, pin 6 of the PWM control chip U4 begins to output. When the output is high, the current in the primary winding T2A of transformer T2 flows from the upper pin 6 to GND. Since the inductor suppresses current changes, the induced voltage in the primary winding T2A of transformer T2 is + on and - on. The induced voltage at the same terminal of the secondary winding T2C of transformer T2 is - on and + on. MOSFET Q1 is off, and the induced voltage at the same terminal of the secondary winding T2B of transformer T2 is + on and - on. When the output is high, MOSFET Q3 is on, capacitor CE1 discharges, and the primary winding T1A of transformer T1 stores energy. VIN charges capacitor CE1 through diode D3 and flows to GND through inductor L2. When pin 6 of the PWM control chip U4 starts to output, when the output is low, the current in the primary winding T2A of transformer T2 is cut off. Since the inductor suppresses current changes, the induced voltage in the primary winding T2A of transformer T2 is - on and + on. The secondary winding T2C of transformer T2 is induced to be positive (+) and negative (-), MOSFET Q1 is turned on. The secondary winding T2B of transformer T2 is induced to be negative (-) and positive (+), outputting a high level. MOSFET Q3 is turned off. The primary winding T1A of transformer T1 stores energy and couples it to the secondary winding for discharge. VIN charges capacitor CE1 through diode D3. VIN flows to GND through inductor L2, which stores energy. The power factor (PF) value of the circuit mainly depends on the conduction angle of the diodes in rectifier bridge BD1. The current and voltage phases remain in phase and follow each other. The larger the conduction angle, the higher the PF value and the lower the harmonic value. Compared with conventional adapter power supply circuits, the increased energy storage and discharge of inductor L2 during power supply operation effectively prolongs the diode conduction time, which is equivalent to increasing the conduction angle of the diodes in rectifier bridge BD1, thus increasing the PF value to greater than 0.9. Therefore, it can meet the requirement of harmonics greater than 25W.

[0024] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A simple over-harmonic circuit for a power adapter, characterized in that: This includes rectifier bridge BD1, capacitors CX1, C1, C2, CE1, CE2, CE5, C4, C6, C8, C9, and C16, resistors RX1, RX2, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R16, R20, R21, R22, R23, and R36, inductors LF1, L1, and L2, PWM control chip U4, and diodes ZD1, ZD2, D2, D3, and D4. The circuit consists of diodes D5, D10, and D11; optocouplers U1A and U1B; transformers T1 and T2; MOSFETs Q1 and Q3; resistors RX1 and RX2 connected in series and then in parallel with capacitor CX1 and inductor LF1; rectifier bridge BD1 is connected at one end to inductor LF1, and at the other end to capacitor C1 and inductor L1; the end of inductor L1 furthest from capacitor C1 is connected to capacitor C2, diode D3, and diode D4; capacitor CE1 is grounded at one end, and at the other end is connected to diode D3, resistor R1, resistor R3, capacitor C8, and the primary coil T1A of transformer T1; resistor R2 is connected at one end to resistor R1, and at the other end to resistor R5. Connect capacitor CE2; one end of diode D2 is connected to resistor R5, and the other end is connected to the secondary winding T1B of transformer T1; one end of inductor L2 is connected to the drain of diode D5 and MOSFET Q1; resistor R9 and diode ZD2 are connected in parallel, with one end of resistor R9 and diode ZD2 connected to the gate of resistor R7 and MOSFET Q1, and the other end grounded; the end of resistor R7 away from resistor R9 and diode ZD2 is connected to the secondary winding T2C of transformer T2; resistor R8 and diode ZD1 are connected in parallel, with one end of resistor R8 and diode ZD1 grounded, and the other end connected to resistor R6 and the gate of MOSFET Q3 respectively; the end of resistor R6 away from resistor R8 and diode ZD1 is connected to the transformer... The secondary coil T2B of T2 is connected; pin 1 of the PWM control chip U4 is grounded, pin 2 is connected to capacitor C6 and optocoupler U1B respectively, pin 4 is connected to capacitor C9 and resistor R13 respectively, pin 5 is connected to VCC terminal, and pin 6 is connected to resistor R10 and then to the primary coil T2A of transformer T2; resistors R20 and R22 are connected in series, resistors R21 and R23 are connected in series, optocoupler U1A is connected in parallel across resistor R21, one end of capacitor C4 is connected to resistor R20, and the other end is connected to three-terminal regulator U3, resistor R21 and optocoupler U1A respectively, one end of resistor R16 is grounded, and the other end is connected to resistors R20 and R22 respectively.

2. The simplified overharmonic circuit for a power adapter according to claim 1, characterized in that: It also includes fuse F1, which is connected to the live wire L.

3. A simplified overharmonic circuit for a power adapter according to claim 1, characterized in that: The resistor R3 and capacitor C8 are connected in parallel, with one end of the resistor R3 and capacitor C8 connected to the high-voltage power supply terminal HV, and the other end connected to the resistor R4. The end of the resistor R4 away from the resistor R3 and capacitor C8 is connected to the diode D11.

4. A simplified overharmonic circuit for a power adapter according to claim 1, characterized in that: The resistor R36 and capacitor C16 are connected in series and then connected in parallel with diode D10. One end of diode D10 is connected to the power output terminal V+ and capacitor CE5, and the other end is connected to the secondary winding T1C of transformer T1.

5. A simplified overharmonic circuit for a power adapter according to claim 1, characterized in that: The resistors R11 and R12 are connected in parallel, with one end of R11 and R12 grounded and the other end connected to the source of the resistor R13 and the MOSFET Q3, respectively.

6. A simplified overharmonic circuit for a power adapter according to claim 1, characterized in that: Diodes D3, D4, and D5 are isolation diodes.

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