Open circuit and overload detection circuit

Abstract

The utility model discloses an open circuit and overload detection circuit which comprises a main circuit module, an MCU module and an open circuit and overload detection module. The input end of the main circuit module is connected to an external power supply, and a load can be connected to the output end of the main circuit module. The MCU module is connected with the main circuit module; the open circuit and overload detection module is respectively connected with the output end of the main circuit module, the MCU module and a load, and is used for feeding back a detected open circuit signal and / or overload signal to the MCU module; by means of the structure, open circuit detection and overload detection can share one detection signal, the circuit connection is simple, the number of devices is small, the cost is low, the performance is stable, the space is saved, and product miniaturization is better facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of LED dimming drive power supply and switch power supply, in particular to an open circuit and overload detection circuit. Background Art

[0002] In the existing power supply, the open circuit detection circuit and the overload detection circuit are detected separately, and the circuit structure is not only complex but also costly, which is not conducive to the miniaturization of the product and the reduction of the cost. Therefore, an open circuit and overload detection circuit is urgently needed to solve the above problems. Utility Model Content

[0003] 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 an open circuit and overload detection circuit.

[0004] The technical solution adopted by an embodiment of the utility model to solve the technical problem is: an open circuit and overload detection circuit, including a main circuit module, an MCU module and an open circuit and overload detection module;

[0005] The input end of the main circuit module is connected to an external power supply, and the load can be connected to the output end of the main circuit module;

[0006] The MCU module is connected to the main circuit module;

[0007] The open circuit and overload detection modules are respectively connected to the output end of the main circuit module, the MCU module and the load, and are used to feed back the detected open circuit signal and / or overload signal to the MCU module.

[0008] As one of the preferred embodiments of the utility model, the open circuit and overload detection module includes an operational amplifier U1 A, an operational amplifier U1 B, and resistors R2-9, the positive end of the operational amplifier U1 A is respectively connected to one end of the resistor R5 and one end of the resistor R6, the other end of the resistor R5 is respectively connected to the output end of the operational amplifier U1 B and the negative end of the operational amplifier U1 B through the resistor R2, the other end of the resistor R6 is connected to the output end of the main circuit module, the negative end of the operational amplifier U1 A is respectively connected to one end of the resistor R8 and one end of the resistor R9, the other end of the resistor R9 is respectively connected to one end of the resistor R7 and the output end of the operational amplifier U1 A, the other end of the resistor R7 is connected to the MCU module, the positive end of the operational amplifier U1 B is respectively connected to one end of the resistor R3 and one end of the resistor R4, the power supply end of the operational amplifier U1 A and the other end of the resistor R3 are connected to the power supply VCC, and the ground end of the operational amplifier U1 A, the other end of the resistor R8, and the other end of the resistor R4 are grounded.

[0009] As one of the preferred embodiments of the utility model, the main circuit module includes an EMI filter module, an AC-DC module and a chopper module connected in sequence, the load is connected to the output end of the chopper module, and the MCU module is connected to the chopper module.

[0010] As one of the preferred embodiments of the utility model, the main circuit module includes an EMI filter module, an AC-DC module and a DC-DC module connected in sequence, the load is connected to the output end of the DC-DC module, and the MCU module is connected to the DC-DC module.

[0011] The beneficial effects of the utility model include: an open circuit and overload detection circuit, comprising a main circuit module, an MCU module and an open circuit and overload detection module; the input end of the main circuit module is connected to an external power supply, and the load can be connected to the output end of the main circuit module; the MCU module is connected to the main circuit module; the open circuit and overload detection module is respectively connected to the output end of the main circuit module, the MCU module and the load, and is used to feed back the detected open circuit signal and / or overload signal to the MCU module; through the above structure, it is possible to realize that open circuit detection and overload detection share one detection signal, which has the advantages of simple circuit connection, small number of components, low cost, stable performance, and space saving, and is more conducive to product miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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:

[0013] Figure 1 It is a principle block diagram of a first embodiment of an open circuit and overload detection circuit;

[0014] Figure 2 is a principle block diagram of a second embodiment of an open circuit and overload detection circuit;

[0015] Figure 3 The figure is a circuit schematic diagram of a first embodiment of an open circuit and overload detection circuit. DETAILED DESCRIPTION

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] Reference Figures 1 to 3 , an open circuit and overload detection circuit, comprising a main circuit module 10, an MCU module 20 and an open circuit and overload detection module 30;

[0021] The input end of the main circuit module 10 is connected to an external power supply, and the load can be connected to the output end of the main circuit module 10;

[0022] The MCU module 20 is connected to the main circuit module 10;

[0023] The open circuit and overload detection module 30 is respectively connected to the output end of the main circuit module 10 , the MCU module 20 and the load, and is used to feed back the detected open circuit signal and / or overload signal to the MCU module 20 .

[0024] In this utility model, reference is made to Figure 1-2When the system is powered on, the AC power passes through the EM I filter module 11 and is rectified into DC power through the rectifier bridge. When the AC-DC module 12 is working stably, due to the voltage outer loop feedback and the fixed turns ratio of the voltage regulator, the output stable voltages are V+ and VCC, respectively. Among them, V+ is supplied to the chopper module 13 or / DC-DC module 14, and then connected to the lamp LED (load), and VCC is supplied to the MCU module 20 and other auxiliary circuits. At this time, the MCU module 20 outputs PWM to the chopper module 13 or / DC-DC module 14, and the lamp LED (load) is lit; as a preferred embodiment of the open circuit and overload detection module 30, refer to Figure 3 The open circuit and overload detection module 30 includes an operational amplifier U1A, an operational amplifier U1B, and resistors R2-9. The positive end of the operational amplifier U1A is respectively connected to one end of the resistor R5 and one end of the resistor R6. The other end of the resistor R5 is respectively connected to the output end of the operational amplifier U1B and the negative end of the operational amplifier U1B through the resistor R2. The other end of the resistor R6 is connected to the output end of the main circuit module 10. The negative end of the operational amplifier U1A is respectively connected to one end of the resistor R8 and one end of the resistor R9. The other end of the resistor R9 is respectively connected to one end of the resistor R7 and the output end of the operational amplifier U1A. The other end of the resistor R7 is connected to the MCU module 20. The positive end of the operational amplifier U1B is respectively connected to one end of the resistor R3 and one end of the resistor R4. The power supply end of the operational amplifier U1A and the other end of the resistor R3 are connected to the power supply VCC. The ground end of the operational amplifier U1A, the other end of the resistor R8, and the other end of the resistor R4 are grounded.

[0025] The working principle of the utility model is as follows: U1 is a dual-channel operational amplifier (operational amplifier U1A+operational amplifier U1B). First, the voltage when the power supply output is fully loaded is calculated, Vcs full-load voltage = output power Pout / output voltage Vout*resistance R1, U1B is used as an operational amplifier follower circuit, and the voltage of resistor R4 is equal to voltage V1; U1A is used as a differential proportional operational circuit, the resistance value of resistor R5 is equal to resistor R9, and the resistance value of resistor R6 is equal to resistor R8. Therefore, the AD full-load signal voltage of the MCU module 20 = Vcs full-load voltage*R9 / R8+V1;

[0026] When overloaded, the output lamp LED (load) exceeds the rated output power of the power supply, then the Vcs overload voltage value > Vcs full load voltage value, so the AD overload signal voltage value > AD full load signal voltage value, and it is determined to be an overload state;

[0027] When not overloaded: When the output lamp LED (load) does not exceed the rated output power of the power supply, the Vcs non-overload voltage value ≤ Vcs full-load voltage value, so the AD non-overload signal voltage value ≤ AD full-load signal voltage value, it is determined to be in a non-overload state;

[0028] When the circuit is open, the two ends of the lamp LED (load) are disconnected, and the output of the main circuit module 10 does not form a loop. At this time, the Vcs voltage is 0, and U1 B is used as an op amp follower circuit, so the voltage of resistor R4 = V1; U1 A is used as a differential proportional operation circuit, the resistance value of resistor R5 is equal to resistor R9, and the resistance value of resistor R6 is equal to resistor R8, so the AD signal voltage = Vcs*R9 / R8+V1, because Vcs = 0 when the circuit is open, so the AD signal voltage = V1, at this time, when the AD signal voltage ≤ V1, it is determined to be an open circuit state;

[0029] When the circuit is not open, the two ends of the lamp LED (load) are not disconnected, and the output of the main circuit module 10 forms a loop. At this time, the Vcs voltage is not 0, and U1 B is used as an op amp follower circuit, so the voltage of resistor R4 = V1; U1 A is used as a differential proportional operation circuit, the resistance value of resistor R5 is equal to resistor R9, and the resistance value of resistor R6 is equal to resistor R8, so the AD signal voltage = Vcs*R9 / R8+V1, because Vcs>0 when the circuit is not open, so the AD signal voltage>V1, at this time, when the AD signal voltage>V1 and ≤AD full load signal voltage value, it is determined to be a non-open state.

[0030] The utility model has the advantages that: through the above structure, open circuit detection and overload detection can share a detection signal, has the advantages of simple circuit connection, small number of components, low cost, stable performance, space saving, and is more conducive to product miniaturization.

[0031] Reference Figure 1 As a first embodiment of the main circuit module 10, the main circuit module 10 includes an EMI filter module 11, an AC-DC module 12 and a chopper module 13 connected in sequence, the load is connected to the output end of the chopper module 13, and the MCU module 20 is connected to the chopper module 13.

[0032] Reference Figure 2 As a second embodiment of the main circuit module 10, the main circuit module 10 includes an EMI filter module 11, an AC-DC module 12 and a DC-DC module 14 connected in sequence, the load is connected to the output end of the DC-DC module 14, and the MCU module 20 is connected to the DC-DC module 14.

[0033] 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. An open circuit and overload detection circuit, characterized in that: It comprises a main circuit module (10), an MCU module (20) and an open circuit and overload detection module (30); The input end of the main circuit module (10) is connected to an external power supply, and the load can be connected to the output end of the main circuit module (10); The MCU module (20) is connected to the main circuit module (10); The open circuit and overload detection module (30) is respectively connected to the output end of the main circuit module (10), the MCU module (20) and the load, and is used to feed back the detected open circuit signal and / or overload signal to the MCU module (20).

2. An open circuit and overload detection circuit according to claim 1, characterized in that: The open circuit and overload detection module (30) comprises an operational amplifier U1A, an operational amplifier U1B, and resistors R2-9, the positive end of the operational amplifier U1A is respectively connected to one end of the resistor R5 and one end of the resistor R6, the other end of the resistor R5 is respectively connected to the output end of the operational amplifier U1B and the negative end of the operational amplifier U1B via the resistor R2, the other end of the resistor R6 is connected to the output end of the main circuit module (10), the negative end of the operational amplifier U1A is respectively connected to one end of the resistor R8 and one end of the resistor R9, the other end of the resistor R9 is respectively connected to one end of the resistor R7 and the output end of the operational amplifier U1A, the other end of the resistor R7 is connected to the MCU module (20), the positive end of the operational amplifier U1B is respectively connected to one end of the resistor R3 and one end of the resistor R4, the power supply end of the operational amplifier U1A and the other end of the resistor R3 are connected to the power supply VCC, and the ground end of the operational amplifier U1A, the other end of the resistor R8, and the other end of the resistor R4 are grounded.

3. An open circuit and overload detection circuit according to claim 1, characterized in that: The main circuit module (10) comprises an EMI filter module (11), an AC-DC module (12) and a chopper module (13) which are connected in sequence, a load is connected to the output end of the chopper module (13), and the MCU module (20) is connected to the chopper module (13).

4. An open circuit and overload detection circuit according to claim 1, characterized in that: The main circuit module (10) comprises an EMI filter module (11), an AC-DC module (12) and a DC-DC module (14) which are connected in sequence, a load is connected to the output end of the DC-DC module (14), and the MCU module (20) is connected to the DC-DC module (14).

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