BUCK switching power supply with high-precision output voltage sampling

Abstract

The utility model discloses a BUCK switching power supply with high-precision output voltage sampling. The BUCK switching power supply comprises a BUCK power supply main circuit and an output voltage sampling module. The input end of the BUCK power supply main circuit is connected with an alternating current power supply; a first sampling end of the output voltage sampling module is connected between the BUCK power supply main circuit and a power supply output V + end, a second sampling end of the output voltage sampling module is connected between the BUCK power supply main circuit and a power supply output V-end, and a load is connected between the power supply output V + end and the power supply output V-end; the output voltage sampling module is used for carrying out differential proportion operation processing on signals of a power supply output V + end and a power supply output V-end so as to obtain the output voltage of the BUCK power supply main circuit; through the above structure, when the input voltage or the output load of the power supply changes, the changing signals of the power supply output V + end and the power supply output V-end can be sampled in real time, so that the output voltage of the switching power supply can be accurately obtained.

Description

Technical Field

[0001] The utility model relates to the field of switching power supplies, in particular to a BUCK switching power supply with high-precision output voltage sampling. Background Art

[0002] With the rapid development of LED power supplies, the market has higher and higher requirements for products. The detection and feedback of power supply parameters is also an important part of product quality. As one of the parameters of the power supply, the output voltage can intuitively judge the status of the switching power supply.

[0003] BUCK switching power supply is favored by many designers for its high efficiency and low cost. When its switch tube and inductor are placed at the negative end of the power supply and connected to GND, the negative pole of the output end of the power supply is a high voltage for GND, and the voltage drop of the positive pole of the power supply output end to GND will change with the change of input voltage, and the voltage drop of the negative pole of the power supply output end to GND will change with the change of load, resulting in the inability to directly sample the output voltage; therefore, it is very necessary to develop a BUCK switching power supply with high-precision output voltage sampling. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a BUCK switching power supply with high-precision output voltage sampling.

[0005] The technical solution adopted by an embodiment of the utility model to solve the technical problem is: a BUCK switching power supply with high-precision output voltage sampling, including a BUCK power supply main circuit and an output voltage sampling module;

[0006] The input end of the BUCK power supply main circuit is connected to the AC power supply;

[0007] The first sampling terminal of the output voltage sampling module is connected between the BUCK power supply main circuit and the power supply output V+ terminal, the second sampling terminal is connected between the BUCK power supply main circuit and the power supply output V- terminal, and the load is connected between the power supply output V+ terminal and the power supply output V- terminal;

[0008] The output voltage sampling module performs differential proportional operation on the signals at the power output V+ terminal and the power output V- terminal to obtain the output voltage of the BUCK power supply main circuit.

[0009] As one of the preferred embodiments of the utility model, the output voltage sampling module includes a resistor R1, a resistor R2, a resistor R4, a resistor R5, a resistor R6 and an operational amplifier U1 B, one end of the resistor R1 is connected between the BUCK power supply main circuit and the power supply output V-terminal, the other end of the resistor R1 is connected with one end of R6 and the inverting input terminal of the operational amplifier U1 B, the other end of the resistor R6 is connected with one end of the resistor R4 and the output terminal of the operational amplifier U1 B, one end of the resistor R2 is connected between the BUCK power supply main circuit and the power supply output V+ terminal, the other end of the resistor R2 is connected with one end of the resistor R5 and the positive input terminal of the operational amplifier U1 B, the other end of the resistor R5 is connected to GND, and the other end of the resistor R4 is connected to the single-chip computer.

[0010] The beneficial effects of the utility model are as follows: a BUCK switching power supply with high-precision output voltage sampling, comprising a BUCK power supply main circuit and an output voltage sampling module; the input end of the BUCK power supply main circuit is connected to an AC power supply; the first sampling end of the output voltage sampling module is connected between the BUCK power supply main circuit and a power supply output V+ end, the second sampling end is connected between the BUCK power supply main circuit and a power supply output V- end, and the load is connected between the power supply output V+ end and the power supply output V- end; the output voltage sampling module performs differential proportional operation processing on signals at the power supply output V+ end and the power supply output V- end to obtain the output voltage of the BUCK power supply main circuit; through the above structure, when the power supply input voltage or the output load changes, the signals of the changes at the power supply output V+ end and the power supply output V- end can be sampled in real time, thereby accurately obtaining the output voltage of the switching power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0012] Figure 1 The schematic diagram of a BUCK switching power supply with high-precision output voltage sampling is shown in the figure. DETAILED DESCRIPTION

[0013] This section will describe in detail the specific embodiments of the utility model. The preferred embodiments of the utility model are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the utility model, but it cannot be understood as a limitation on the protection scope of the utility model.

[0014] In the description of the present utility model, the meaning of "more than" is more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0015] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0016] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0017] Reference Figure 1 , a BUCK switching power supply with high-precision output voltage sampling, comprising a BUCK power supply main circuit 10 and an output voltage sampling module 20;

[0018] The input end of the BUCK power supply main circuit 10 is connected to an AC power supply;

[0019] The first sampling terminal of the output voltage sampling module 20 is connected between the BUCK power supply main circuit 10 and the power supply output V+ terminal, the second sampling terminal is connected between the BUCK power supply main circuit 10 and the power supply output V- terminal, and the load is connected between the power supply output V+ terminal and the power supply output V- terminal;

[0020] The output voltage sampling module 20 performs differential proportional operation processing on the signals at the power output V+ terminal and the power output V− terminal to obtain the output voltage of the BUCK power main circuit 10 .

[0021] In this utility model, the working principle is as follows:

[0022] When the system is powered on, the BUCK power supply main circuit 10 is connected to the L and N terminals of the AC power supply, and a stable output voltage is achieved through the control of the power supply chip U2. At this time, the MOS tube Q1 and the inductor L1 are both at the power supply output V-end, and are connected to GND through the sampling resistor RS1. The power supply output V+ end and the power supply output V-end are both high voltages with respect to GND. In one embodiment, the output voltage sampling module 20 includes a resistor R1, a resistor R2, a resistor R4, a resistor R5, a resistor R6 and an operational amplifier U1 B, one end of the resistor R1 is connected between the BUCK power supply main circuit 10 and the power supply output V-end, the other end of the resistor R1 is connected to one end of R6 and the inverting input end of the operational amplifier U1 B, the other end of the resistor R6 is connected to one end of the resistor R4 and the output end of the operational amplifier U1 B, one end of the resistor R2 is connected between the BUCK power supply main circuit 10 and the power supply output V+ end, the other end of the resistor R2 is connected to one end of the resistor R5 and the operational amplifier U1 B. The positive input terminal of B is connected, the other end of the resistor R5 is connected to GND, and the other end of the resistor R4 is connected to the microcontroller.

[0023] Specifically, the power supply output V+ terminal is connected to the positive input terminal of the operational amplifier through the voltage divider of resistors R2 and R5, and the power supply output V- terminal is connected to the negative input terminal of the operational amplifier U1 B through resistor R1 and feedback resistor R6. The operational amplifier U1 B performs differential proportional operation on the signals at the positive input terminal and the negative input terminal, and the processed output voltage signal is transmitted to the single-chip microcomputer through resistor R4. The calculation formula of the output voltage is:

[0024] Vout=VSEN / R6*R1;

[0025] The utility model has the advantage that: through the above structure, when the power input voltage or output load changes, the signals of the power output V+ terminal and the power output V- terminal can be sampled in real time, so as to accurately obtain the output voltage of the switching power supply.

[0026] Of course, the present invention is not limited to the above-mentioned embodiments, and technicians familiar with the field may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A BUCK switching power supply with high-precision output voltage sampling, characterized in that: It comprises a BUCK power supply main circuit (10) and an output voltage sampling module (20); The input end of the BUCK power supply main circuit (10) is connected to an AC power supply; The first sampling end of the output voltage sampling module (20) is connected between the BUCK power supply main circuit (10) and the power supply output V+ end, the second sampling end is connected between the BUCK power supply main circuit (10) and the power supply output V- end, and the load is connected between the power supply output V+ end and the power supply output V- end; The output voltage sampling module (20) performs differential proportional operation processing on the signals at the power supply output V+ terminal and the power supply output V- terminal to obtain the output voltage of the BUCK power supply main circuit (10).

2. The BUCK switching power supply with high-precision output voltage sampling according to claim 1, characterized in that: The output voltage sampling module (20) comprises a resistor R1, a resistor R2, a resistor R4, a resistor R5, a resistor R6 and an operational amplifier U1B, one end of the resistor R1 is connected between the BUCK power supply main circuit (10) and a power supply output V-terminal, the other end of the resistor R1 is connected with one end of R6 and an inverting input terminal of the operational amplifier U1B, the other end of the resistor R6 is connected with one end of the resistor R4 and an output terminal of the operational amplifier U1B, one end of the resistor R2 is connected between the BUCK power supply main circuit (10) and a power supply output V+terminal, the other end of the resistor R2 is connected with one end of the resistor R5 and a positive input terminal of the operational amplifier U1B, the other end of the resistor R5 is connected to GND, and the other end of the resistor R4 is connected to a single-chip computer.

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