CN213783156U

CN213783156U - Novel power adapter

Info

Publication number: CN213783156U
Application number: CN202023150906.1U
Authority: CN
Inventors: 陈海城
Original assignee: Shenzhen Youde Electronic Industry Co ltd
Current assignee: Shenzhen Youde Electronic Industry Co ltd
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-07-23
Anticipated expiration: 2030-12-24

Abstract

The utility model discloses a novel power adapter. The high-frequency power supply comprises a surge protection circuit, an EMI filter circuit, a rectifying filter circuit, a high-frequency transformer, a synchronous rectifying circuit, a filter output circuit, a detection circuit, a negative feedback circuit and a PWM control circuit, wherein a network compensation circuit is connected between the rectifying filter circuit and the high-frequency transformer. The utility model discloses add network compensating circuit in whole circuit, and then improve feedback stability, reduce the EMC interference in the whole circuit, can reduce one-level filter screen in with EMI filter circuit, and then reduce circuit board area, reduce electronic components, reduce whole machine volume, save the cost to and reduced stand-by power consumption.

Description

Novel power adapter

Technical Field

The utility model belongs to the technical field of power adapter technique and specifically relates to a novel power adapter.

Background

As is well known, a Power adapter (Power adapter) is a Power conversion device for small portable electronic devices and electronic appliances, and generally comprises a housing, a transformer, an inductor, a capacitor, a control IC, a PCB board, and other components, and its operating principle is to convert ac input into dc output.

The existing power adapter, the whole circuit frame includes surge protection circuit, EMI filter circuit, rectifier filter circuit, PWM control circuit, the transformer, electronic switch, negative feedback circuit, synchronous rectification circuit, detection circuitry and filtering output current constitute, but current for guaranteeing EMI interference problem, often can choose to design multistage filter network at EMI filter circuit, and every filter network all is to connect a set of isolation transformer and some electronic components, wherein isolation transformer is bulky, thereby make the whole volume of adapter great, and isolation transformer consumption is great, also further caused the great problem of standby power consumption.

Disclosure of Invention

To the not enough of existence among the above-mentioned prior art, the utility model aims to provide a novel power adapter.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a novel power adapter, includes surge protection circuit, EMI filter circuit, rectifier filter circuit, high frequency transformer, synchronous rectification circuit, filtering output circuit, detection circuitry, negative feedback circuit and PWM control circuit, surge protection circuit inserts the commercial power and is connected with EMI filter circuit, rectifier filter circuit, high frequency transformer, synchronous rectification circuit and filtering output circuit in proper order, detection circuitry is connected with filtering output circuit and is connected with negative feedback circuit, negative feedback circuit is connected with PWM control circuit, PWM control circuit connects electronic switch and is connected with high frequency transformer and detection circuitry through electronic switch, be connected with network compensation circuit between rectifier filter circuit and the high frequency transformer, network compensation circuit includes first inductance and second inductance, second inductance one end is connected in on the primary coil of high frequency transformer, The other end is connected with a rectification filter circuit, one end of the first inductor is connected with a feedback coil of the high-frequency transformer, the other end is grounded through a second diode and a sixth capacitor which are sequentially connected in series, the second diode is connected with a sixteenth resistor and a fifteenth capacitor which are sequentially connected in series in parallel, the negative electrode of the second diode is connected with a third diode and is connected with the positive electrode of the third diode, the negative electrode of the third diode is connected with a fifth capacitor and a fourth capacitor through a fifth resistor and is grounded through the fifth capacitor and the fourth capacitor respectively, the positive electrode of the second diode is connected with a PWM control circuit through the sixth resistor, and the fifth capacitor and the sixth capacitor are electrolytic capacitors.

Preferably, the EMI filter circuit includes an isolation transformer, and one end of the isolation transformer is connected to the rectifier filter circuit, and the other end of the isolation transformer is connected to the surge protection circuit and connected to the filter capacitor.

Preferably, the rectifier filter circuit includes a rectifier bridge, an input end of the rectifier bridge is connected with an isolation transformer of the EMI filter circuit, an output end of the rectifier bridge is grounded through a first capacitor and a second capacitor respectively and is connected with a primary coil of the high-frequency transformer, and is connected with a second inductor through a third capacitor and a first diode which are sequentially connected in series, and the third capacitor is connected in parallel with two fourth resistors which are sequentially connected in series.

Due to the adoption of the scheme, the utility model is additionally provided with the network compensation circuit, and utilizes the connection of the second inductor at the primary coil of the rectification filter circuit and the high-frequency transformer, thereby effectively improving the node of the feedback loop, inhibiting and absorbing high-frequency electromagnetic signals and further reducing EMC interference; meanwhile, a feedback loop is formed by the first inductor, the third triode, the sixteenth resistor, the fifth resistor, the fifteenth capacitor and the sixth resistor, when the feedback coil of the high-frequency transformer induces feedback electric quantity, wherein various electromagnetic high-frequency signals are contained, high-frequency interference electromagnetic signals are simulated through the first inductor, and further absorbs high-frequency electromagnetic noise through a filter absorption network consisting of a fifth resistor, a sixteenth resistor, a fifteenth capacitor and a sixth capacitor, so as to reduce bad electromagnetic waves in an auxiliary feedback power supply loop and obtain a clean and useful electromagnetic feedback signal, the voltage is transmitted to a multi-kinetic energy compensation control terminal 3PIN of an IC in the PWM control circuit through a sixth resistor, the internal discharge gain is improved through an ic internal loop control network, and a feedback node is improved to adjust an electronic switch, so that the EMI interference of the whole machine is weakened. Therefore, the EMI filter circuit can achieve the effect of weakening the EMI interference of the whole machine without designing a multi-stage filter network, greatly reduces the volume of the whole machine and reduces the circuit cost.

Drawings

Fig. 1 is a schematic diagram of the structural principle of the embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a network compensation circuit according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of an EMI filter circuit according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a rectifying and filtering circuit according to an embodiment of the present invention.

Detailed Description

The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.

As shown in fig. 1 to 4, the novel power adapter provided in this embodiment includes a surge protection circuit 200, an EMI filter circuit 201, a rectifier filter circuit 202, a high-frequency transformer 207, a synchronous rectifier circuit 208, a filter output circuit 209, a detection circuit 204, a negative feedback circuit 205 and a PWM control circuit 203, the surge protection circuit 200 is connected to a mains supply and is sequentially connected to the EMI filter circuit 201, the rectifier filter circuit 202, the high-frequency transformer 207, the synchronous rectifier circuit 208 and the filter output circuit 209, the detection circuit 204 is connected to the filter output circuit 209 and is connected to the negative feedback circuit 205, the negative feedback circuit 205 is connected to the PWM control circuit 203, the PWM control circuit 203 is connected to an electronic switch 206 and is connected to the high-frequency transformer 207 and the detection circuit 204 through the electronic switch 206, a network compensation circuit 100 is connected between the rectifier filter circuit 202 and the high-frequency transformer 207, the circuit structure of the network compensation circuit 100 is shown in fig. 2, the PWM controller comprises a first inductor L1 and a second inductor L2, one end of a second inductor L2 is connected to the primary coil of the high-frequency transformer 207, the other end of the second inductor L1 is connected to the feedback coil of the high-frequency transformer 207, the other end of the second inductor L1 is connected to the ground through a second diode D2 and a sixth capacitor C6 which are sequentially connected in series, the second diode D2 is connected in parallel with a sixteenth resistor R16 and a fifteenth capacitor C15 which are sequentially connected in series, the negative electrode of the second diode D2 is connected to a third diode D3 and connected to the positive electrode of a third diode D3, the negative electrode of the third diode D3 is connected to a fifth capacitor C5 and a fourth capacitor C4 through a fifth resistor R5 and connected to the ground through a fifth capacitor C5 and a fourth capacitor C4, the positive electrode of the second diode D2 is connected to the PWM controller 203 through a sixth resistor R6, and the fifth capacitor C5 and the sixth capacitor C6 are electrolytic capacitors C6.

Further, the EMI filter circuit 201 of the present embodiment has only one filter network in design, and the circuit structure thereof is as shown in fig. 3, that is, the EMI filter circuit includes an isolation transformer LF2, one end of the isolation transformer LF2 is connected to the rectifying and filtering circuit 202, and the other end is connected to the surge protection circuit 200 and connected to the filter capacitor CX 1.

Further, the circuit structure of the rectifying and filtering circuit 202 of the present embodiment is as shown in fig. 4, that is, the circuit structure includes a rectifying bridge BD1, an input end of the rectifying bridge BD1 is connected to the isolation transformer LF2 of the EMI filtering circuit 201, an output end of the rectifying bridge BD1 is grounded through a first capacitor C1 and a second capacitor C2 respectively and is connected to the primary coil of the high-frequency transformer 207, and is connected to the second inductor C2 through a third capacitor C3 and a first diode D1 which are sequentially connected in series, and two fourth resistors R4 which are sequentially connected in series are connected in parallel to the third capacitor C3.

Due to the adoption of the scheme, the utility model discloses add and establish a network compensation circuit 100, utilize and connect a second inductance L2 in rectifier filter circuit 202 and high frequency transformer 207's primary coil department, effectively improve the feedback loop node, restrain and absorb high frequency electromagnetic signal, and then reduce EMC interference; meanwhile, a feedback loop is formed by a first inductor L1, a third triode D3, a sixteenth resistor R16, a fifth resistor R5, a fifteenth capacitor C15 and a sixth resistor R6, when feedback electric quantity is induced by a feedback coil of the high-frequency transformer 207, various electromagnetic high-frequency signals are included, high-frequency interference electromagnetic signals are simulated through the first inductor L1 and attenuated through the fifth resistor R5, a filter absorption network formed by the sixteenth resistor R16, the fifteenth capacitor C15 and the sixth capacitor C6 further absorbs the high-frequency electromagnetic noise, bad electromagnetic waves in the auxiliary feedback power supply loop are reduced, a clean and useful electromagnetic feedback signal is obtained and transmitted to a multi-kinetic energy compensation control end 3PIN of an IC (ob 2365) in the PWM control circuit 203 through the sixth resistor R6, internal discharge gain is improved through an internal loop control network of the IC, and a feedback node is improved to adjust the electronic switch, the EMI interference of the whole machine is weakened. Therefore, the EMI filter circuit 201 can achieve the effect of reducing the EMI interference of the whole machine without designing a multi-stage filter network, thereby greatly reducing the volume of the whole machine and reducing the circuit cost.

The above is only the preferred embodiment of the present invention, and not the scope of the present invention, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings or the direct or indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. The utility model provides a novel power adapter, includes surge protection circuit, EMI filter circuit, rectifier filter circuit, high frequency transformer, synchronous rectification circuit, filtering output circuit, detection circuitry, negative feedback circuit and PWM control circuit, surge protection circuit inserts the commercial power and is connected with EMI filter circuit, rectifier filter circuit, high frequency transformer, synchronous rectification circuit and filtering output circuit in proper order, detection circuitry is connected with filtering output circuit and is connected with negative feedback circuit, negative feedback circuit is connected with PWM control circuit, PWM control circuit connects electronic switch and is connected with high frequency transformer and detection circuitry through electronic switch, its characterized in that: a network compensation circuit is connected between the rectification filter circuit and the high-frequency transformer and comprises a first inductor and a second inductor, one end of the second inductor is connected with the primary coil of the high-frequency transformer, the other end of the second inductor is connected with the rectifying and filtering circuit, one end of the first inductor is connected with a feedback coil of the high-frequency transformer, the other end of the first inductor is grounded through a second diode and a sixth capacitor which are sequentially connected in series, the second diode is connected in parallel with a sixteenth resistor and a fifteenth capacitor which are sequentially connected in series, the cathode of the second diode is connected with a third diode and is connected with the anode of the third diode, the cathode of the third diode is connected with a fifth capacitor and a fourth capacitor through a fifth resistor and is grounded through the fifth capacitor and the fourth capacitor respectively, and the anode of the second diode is connected with the PWM control circuit through a sixth resistor, and the fifth capacitor and the sixth capacitor are electrolytic capacitors.

2. The new power adapter as claimed in claim 1, wherein: the EMI filter circuit comprises an isolation transformer, wherein one end of the isolation transformer is connected with the rectification filter circuit, and the other end of the isolation transformer is connected with the surge protection circuit and is connected with a filter capacitor.

3. The new power adapter as claimed in claim 2, wherein: the rectifier filter circuit comprises a rectifier bridge, the input end of the rectifier bridge is connected with an isolation transformer of the EMI filter circuit, the output end of the rectifier bridge is grounded through a first capacitor and a second capacitor respectively and is connected with a primary coil of a high-frequency transformer, and is connected with a second inductor through a third capacitor and a first diode which are sequentially connected in series, and the third capacitor is connected with two fourth resistors which are sequentially connected in series in parallel.