CN220382954U

CN220382954U - Efficient switching power supply circuit

Info

Publication number: CN220382954U
Application number: CN202321869344.7U
Authority: CN
Inventors: 刘国强; 何颖彦
Original assignee: Joulwatt Technology Co Ltd
Current assignee: Joulwatt Technology Co Ltd
Priority date: 2023-07-14
Filing date: 2023-07-14
Publication date: 2024-01-23
Anticipated expiration: 2033-07-14

Abstract

The utility model provides a high-efficiency switching power supply circuit, which comprises: the switching type conversion circuit converts the input voltage into output voltage; the switching power supply can reduce switching loss and power supply loss, and improves the conversion efficiency of the switching power supply.

Description

Efficient switching power supply circuit

Technical Field

The utility model relates to the field of power electronics, in particular to a high-efficiency switching power supply circuit.

Background

Along with the improvement of the energy consumption requirements at home and abroad, the requirements of the electronic and electric products on the conversion efficiency are higher and higher. For example, adapter chargers in consumer electronics have clear standby power consumption requirements in various countries, such as the photoelectric conversion efficiency of lamps in europe, the united states, etc. Thus, there is a continuing need for improved switching power conversion efficiency.

At present, the main method for improving efficiency is to reduce power consumption, as shown in fig. 1 and 2, in fig. 1, a power supply end is moved from an input end to an output end, and a power supply voltage is reduced from VBUS to VBUS-VO; in fig. 2, the supply voltage is reduced from VBUS to VIN by adding an auxiliary winding; the main topology level has no good method at present, and power devices with higher efficiency, such as more suitable semiconductor switching tubes, larger and better magnetic cores and the like, are selected mainly; however, the solutions shown in fig. 1 and 2 above require significant increases in costs, such as replacement of more efficient power devices, addition of auxiliary windings, etc., on the one hand, and on the other hand affect part of the performance, such as EMC, open circuit protection, etc.

Disclosure of Invention

The utility model aims to provide a high-efficiency switching power supply circuit which is used for reducing the power supply loss and the switching loss of the traditional switching power supply and realizing high-efficiency power supply conversion.

In order to achieve the above object, the present utility model provides a high-efficiency switching power supply circuit, comprising: a rectifying circuit, a first capacitance circuit and a switch-type converting circuit,

the first capacitance circuit is connected in series between at least one input terminal of the rectifying circuit and an ac input power source,

the alternating current input power supply obtains input voltage through the rectifying circuit and the first capacitor circuit, and the switch-type conversion circuit converts the input voltage into output voltage.

Optionally, the switch-mode conversion circuit includes a controller, the controller is used for controlling the switch state of the main power tube in the switch-mode conversion circuit, and the power supply end of the controller is connected with the input/output end of the switch-mode conversion circuit.

Optionally, when the power supply end of the controller is connected to the output end of the switch-type conversion circuit, the power supply end of the controller is connected to the low-potential output end of the switch-type conversion circuit.

Optionally, the first capacitance circuit includes one capacitance or a series-parallel combination of a plurality of capacitances.

Optionally, a second capacitance circuit is also included,

the first capacitor circuit is connected in series between the first input end of the rectifying circuit and the alternating current input power supply;

the second capacitance circuit is connected in series between the other input end of the rectification circuit and the alternating current input power supply.

Optionally, the capacitance value of the first capacitance circuit and the capacitance value of the second capacitance circuit are set to be equal.

Optionally, the second capacitance circuit includes one capacitance or a series-parallel combination of a plurality of capacitances.

Optionally, the switching type switching circuit further comprises an auxiliary winding, the auxiliary winding is inductively coupled with the switching type switching circuit, a high potential end of the auxiliary winding is connected with a power supply end of a controller in the switching type switching circuit, and the controller is used for controlling the switching state of a main power tube in the switching type switching circuit.

Optionally, the rectifier circuit also comprises a filter capacitor which is connected with the output end of the rectifier circuit,

the filter capacitor and the first capacitor circuit are subjected to voltage division processing so as to reduce the input voltage of the switch-type conversion circuit.

Optionally, the switching circuit is one of a buck switching circuit, a boost switching circuit, a buck-boost switching circuit and a flyback switching circuit.

Compared with the prior art: a capacitor circuit is added in front of the rectifier bridge to play a role of voltage division, and the bus voltage VBUS voltage is obviously reduced after the capacitor is a lossless device and passes through the rectifier circuit and the filter capacitor; when the busbar voltage VBUS is close to the output voltage, the power supply loss is smaller, and the scheme of adopting an auxiliary winding to supply power is close; in addition, the switching loss of the power semiconductor switching device is reduced, and the overlapping area is reduced when the power semiconductor switching device is turned on and turned off; aiming at low-power application, the method can effectively reduce system loss, fully utilize power switching devices and inductors, and improve conversion efficiency on the premise of ensuring cost performance.

Drawings

FIG. 1 is a schematic diagram of a power supply embodiment of a prior art switching power supply;

FIG. 2 is a schematic diagram of a second embodiment of a prior art switching power supply;

FIG. 3 is a schematic diagram of a switching power supply according to an embodiment of the present utility model;

FIG. 4 is a schematic diagram of a second embodiment of the switching power supply of the present utility model;

FIG. 5 is a waveform diagram of a switching power supply circuit of the present utility model;

fig. 6 is a waveform diagram of an electrical signal of a switching power supply circuit power tube according to the present utility model.

Detailed Description

The preferred embodiments of the present utility model will be described in detail below with reference to the accompanying drawings, but the present utility model is not limited to these embodiments only. The utility model is intended to cover any alternatives, modifications, equivalents, and variations that fall within the spirit and scope of the utility model.

In the following description of preferred embodiments of the utility model, specific details are set forth in order to provide a thorough understanding of the utility model, and the utility model will be fully understood to those skilled in the art without such details.

The utility model is more particularly described by way of example in the following paragraphs with reference to the drawings. It should be noted that the drawings are in a simplified form and are not to scale precisely, but rather are merely intended to facilitate and clearly illustrate the embodiments of the present utility model.

Referring to fig. 3, a schematic diagram of a power supply embodiment of the switching power supply of the present utility model is illustrated, in which a switching-type conversion circuit of the switching power supply is exemplified by a commonly used buck switching circuit, and the switching power supply of the present application includes a rectifying circuit, a first capacitor C1, a filter capacitor C2, a switching-type conversion circuit exemplified by a buck switching circuit, and a controller. As shown in the figure, a first capacitor circuit is connected in series between one end of an AC input power supply AC and one input end of a rectifying circuit, the first capacitor circuit is selected as one capacitor or a series-parallel combination of a plurality of capacitors, preferably a first capacitor C1, one end of the rectifying circuit connected with the first capacitor C1 is a first input end of the rectifying circuit, the other input end of the rectifying circuit is a second input end, one end of the AC input power supply AC connected with the first capacitor C1 is a first end of the AC input power supply AC, and the other end of the AC input power supply AC is a second end; the voltage of the first end of the AC input power supply AC is reduced by a first capacitor C1 and then is input into a rectifying circuit, a filter capacitor C2 is connected in parallel with the output end of the rectifying circuit, the AC input power supply obtains bus voltage VBUS, namely the input voltage of a switch-type converting circuit, after passing through the rectifying circuit and the filter capacitor C2, the input voltage VBUS is converted into output voltage VO after passing through the switch-type converting circuit; the controller is used for controlling the working state of the switch-type converting circuit, the output end of the controller is connected with the control end of the power tube of the switch-type converting circuit, in the embodiment diagram, the power tube and the controller are integrated in a chip, the chip is a control chip for controlling the working state of the power circuit and is also equivalent to the controller, the input end VIN of the control chip is connected with the low potential output end of the voltage reducing circuit, and the voltage of the low potential output end is converted into the power supply voltage of the chip.

The voltage of one end of the AC input power supply AC is divided by the first capacitor C1 and then is input to the rectifying circuit, the first capacitor C1 plays a role in dividing voltage in the application, and as the first capacitor C1 is a lossless device, the bus voltage VBUS obtained after the AC input power supply is divided by the first capacitor C1, the rectifying circuit and the filter capacitor C2 is obviously reduced compared with the bus voltage VBUS obtained when the first capacitor C1 is absent. The power supply loss of the switching power supply circuit is P _iq When the bus voltage VBUS approaches the output voltage VO, the power supply loss of the scheme of the embodiment that the first capacitor C1 is arranged before the bridge is close to that of the scheme that the auxiliary winding is independently used for power supply is adopted, but only one lossless capacitor is adopted in the embodiment, so that the volume and the cost of the switching power supply circuit are greatly saved, and the circuit structure is simplified. In this embodiment, the input end VIN (also called a power supply end) of the control chip is connected to the low-potential output end of the voltage-reducing circuit, and when the power supply can meet the requirement, the current passing through the switch-type conversion circuit is controllable, so that the power supply loss is low; in other embodiments, the control chip input may be connected to other ports of the circuit or the power supply port of the auxiliary circuit, except for power supply efficiencyThere is some difference in the above; alternatively, the input terminal VIN of the control chip may also receive the bus voltage or be connected to the high-potential output terminal of the switch-type conversion circuit; alternatively, the power is supplied by providing an auxiliary winding coupled to the inductance of the switching circuit, the input of the control chip VIN being connected to one end of the auxiliary winding. The utility model further sets the first capacitor circuit in front of the rectifying circuit based on the existing power supply scheme, can further reduce the power supply loss and the switching loss, further effectively reduce the system loss, fully utilizes the power switching device and the inductance in the switching type converting circuit, and further improves the converting efficiency of the switching type converting circuit on the premise of ensuring the cost performance. When the application is applied to low power, the efficiency can be greatly improved compared with the prior art, because the switching loss and the power supply loss of the circuit are very outstanding in the occasion with low power, the application can control the absolute value of working current by utilizing the switching circuit, so that the copper loss of a control system is small, the loss is low, the switching loss can be controlled to be reduced, and the switching loss and the power supply loss of the whole system are greatly reduced.

As shown in fig. 4, a second schematic diagram illustrating a power supply embodiment of the switching power supply of the present utility model is consistent with the power supply principle illustrated in fig. 3, in this example, two pre-bridge capacitor circuits are provided, which are a first capacitor circuit and a second capacitor circuit respectively, where the first capacitor circuit is selected from a capacitor or a series-parallel combination of multiple capacitors, and is preferably a first capacitor C1; the second capacitor circuit is a series-parallel combination of one capacitor and a plurality of capacitors, preferably a second capacitor C0, a first capacitor C1 is connected in series between the first end of the ac input power source and the first input end of the rectifying circuit, a second capacitor C0 is connected in series between the second end of the ac input power source and the second input end of the rectifying circuit, and the output end of the rectifying circuit is connected in parallel with a filter capacitor C2 and a connection switch type conversion circuit, which will not be further described herein. The first capacitor C1 and the second capacitor C0 are lossless devices and have voltage division effect, and the voltage division effect is equivalent to that the first capacitor C1 and the second capacitor C0 are connected in series between an alternating current input power supply and a rectifying circuit; because of the characteristic of series connection of the capacitors, if smaller voltage division is needed between the rectifying circuit and the alternating current input power supply, two capacitors with larger values can be selected, and if larger voltage division is needed between the rectifying circuit and the alternating current input power supply, one capacitor can be selected; preferably, the equal capacitance values of the first capacitor C1 and the second capacitor C0 are C, which is equivalent to the capacitance value of C/2 connected in series between the AC input power supply and the rectifying circuit, and the voltage equalizing circuit is applicable to the voltage dividing effect between the rectifying circuit and the AC input power supply with smaller requirement in combination with the power supply requirement, so that a better voltage equalizing effect can be obtained.

As shown in fig. 5, a waveform diagram of the switching power supply circuit of the present utility model is illustrated, and an ac input power supply waveform Vin (a 220V ac waveform as a reference), a first capacitor C1 voltage waveform VC1 and a rectified bus voltage waveform VBUS are illustrated respectively; in the figure, the amplitude of the voltage VC1 of the first capacitor C1 is obviously reduced compared with the amplitude of the ac input power Vac, the peak value of the voltage VC1 is less than 200V, and the peak value of the ac input power Vac is 311V; the bus voltage VBUS is obtained after the ac input power passes through the first capacitor C1 and then passes through the rectifying circuit, and since a part of voltage is present on the first capacitor C1, the peak value of the bus voltage VBUS obtained after the ac input voltage Vin is divided and rectified by the first capacitor C1 is about 150V, and the bus voltage peak value also reaches 311V when the first capacitor C1 is not present. Particularly, when the bus voltage VBUS and the output voltage VO are close to each other during voltage reduction output, the circuit loss and the power supply loss of the whole circuit of the system can be effectively reduced.

As shown in fig. 6, the waveform of the electric signal of the power tube of the switching power supply circuit of the present utility model is shown in fig. 6, the waveform of the upper graph of fig. 6 is the waveform of the drain voltage VDrain of the power tube, and the waveform of the current IDrain flowing through the power tube in the lower graph, because the bus voltage VBUS is obviously reduced after the first capacitor C1 is added, the drain voltage VDrain of the power tube is reduced, the switching loss is reduced, and the overlapping area between the power tube being turned on and off is reduced, thereby further reducing the switching loss.

Although the embodiments have been described and illustrated separately above, and with respect to a partially common technique, it will be apparent to those skilled in the art that alternate and integration may be made between embodiments, with reference to one embodiment not explicitly described, and reference may be made to another embodiment described.

The above-described embodiments do not limit the scope of the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the above embodiments should be included in the scope of the present utility model.

Claims

1. An efficient switching power supply circuit, comprising: a rectifying circuit, a first capacitance circuit and a switch-type converting circuit,

2. The switching power supply circuit according to claim 1, wherein: the switch-type conversion circuit comprises a controller, wherein the controller is used for controlling the switching state of a main power tube in the switch-type conversion circuit, and a power supply end of the controller is connected with an input/output end of the switch-type conversion circuit.

3. The switching power supply circuit according to claim 2, wherein: when the power supply end of the controller is connected with the output end of the switch-type converting circuit, the power supply end of the controller is connected with the low-potential output end of the switch-type converting circuit.

4. The switching power supply circuit according to claim 1, wherein: the first capacitance circuit comprises one capacitance or a series-parallel combination of a plurality of capacitances.

5. The switching power supply circuit according to claim 1, wherein: also included is a second capacitance circuit that is configured to provide a second capacitance,

6. The switching power supply circuit according to claim 5, wherein: the capacitance value of the first capacitance circuit and the capacitance value of the second capacitance circuit are set to be equal.

7. The switching power supply circuit according to claim 6, wherein: the second capacitance circuit comprises one capacitance or a series-parallel combination of a plurality of capacitances.

8. The switching power supply circuit according to claim 1, wherein: the auxiliary winding is inductively coupled with the switch-type conversion circuit, a high-potential end of the auxiliary winding is connected with a power supply end of a controller in the switch-type conversion circuit, and the controller is used for controlling the switching state of a main power tube in the switch-type conversion circuit.

9. The switching power supply circuit according to claim 1, wherein: the filter capacitor is connected with the output end of the rectifying circuit,

10. A switching power supply circuit according to any one of claims 1-9, wherein: the switch-type converting circuit is one of a buck switch circuit, a boost switch circuit, a buck-boost switch circuit and a flyback switch circuit.