High-precision detection circuit for output current of LED constant-voltage power supply

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By designing a high-precision detection circuit for output current of LED constant voltage power supply, using multiple channel current signals and amplification modules for precise detection and control, the problems of low current detection accuracy and system efficiency in switching power supply are solved, and high-precision detection and good heat dissipation effect are achieved.

CN222564009UActive Publication Date: 2025-03-04ZHUHAI SHENGCHANG ELECTRONICS CO LTD

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Patent Information

Application Number: CN202421195430.9
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2024-05-28
Publication Date: 2025-03-04
Estimated Expiration: 2034-05-28

AI Technical Summary

Technical Problem

In switching power supplies, especially in low voltage and high current application scenarios, high-precision output current detection is crucial, but in the prior art, increasing the resistance value of the detection current resistor to improve accuracy will aggravate losses, and reducing the detection resistance will lead to weakening of the common mode signal suppression and increase of the interference signal, which will lead to an increase in detection error.

Method used

A high-precision detection circuit for output current of LED constant voltage power supply is designed, including a main circuit, a main control module, a first amplification module, a number of current detection modules and a number of dimming and color tuning modules. By connecting the current detection module and the dimming color tuning module one by one, several channel current signals are formed, and the channel current signal is received by the first amplification module for amplification and transmission to the main control module to control the load through the dimming color tuning module.

Benefits of technology

It realizes high-precision current detection, while avoiding the problem of low system efficiency, and makes the output power tube have good heat dissipation and very practical.

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Abstract

The utility model discloses a high-precision detection circuit for output current of an LED constant-voltage power supply. The high-precision detection circuit comprises a main circuit, a main control module, a first amplification module, a plurality of current detection modules and a plurality of dimming and color adjusting modules, the input end of the main circuit is connected with an external power supply; the current detection modules are in one-to-one correspondence with the dimming and color adjusting modules and are connected between the output end of the main circuit and the load so as to form a plurality of channel current signals; the input end of the first amplification module is connected with the plurality of current detection modules and is connected with a reference voltage; the main control module is respectively connected with the output end of the first amplification module and the dimming and color adjusting module; the first amplification module receives and amplifies the channel current signal and then transmits the channel current signal to the main control module so as to control a load through the dimming and color modulation module; according to the LED constant-voltage power supply, the problem that the current detection precision of the LED constant-voltage power supply is difficult to be compatible with the low system efficiency can be solved, meanwhile, the output power tube can have good heat dissipation, and the LED constant-voltage power supply has very good practicability.

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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 a high-precision detection circuit for output current of an LED constant voltage power supply. Background Art

[0002] In switching power supplies, especially in low-voltage and high-current applications, high-precision output current detection is crucial. In order to improve the current detection accuracy, it is generally necessary to increase the resistance of the detection current resistor, but this will increase the loss and reduce the system efficiency. Reducing the detection resistance requires increasing the gain of the op amp, which will lead to weakened common-mode signal suppression and amplified interference signals, which will lead to increased detection errors. Therefore, it is very meaningful to use a small current detection resistor to achieve high-precision current detection. 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 a high-precision detection circuit for the output current of an LED constant voltage power supply.

[0004] The technical solution adopted by an embodiment of the utility model to solve the technical problem is: a high-precision detection circuit for output current of an LED constant voltage power supply, including a main circuit, a main control module, a first amplification module, a plurality of current detection modules and a plurality of dimming and color adjustment modules;

[0005] The input end of the main circuit is connected to an external power supply;

[0006] The current detection module corresponds to the dimming and color adjustment module one by one and is connected between the output end of the main circuit and the load to form a plurality of channel current signals;

[0007] The input end of the first amplifying module is connected to a plurality of current detecting modules and is connected to a reference voltage;

[0008] The main control module is connected to the output end of the first amplification module and the dimming and color adjustment module respectively;

[0009] The first amplifying module receives the channel current signal, amplifies it and transmits it to the main control module, so as to control the load through the dimming and color adjustment module.

[0010] As one of the preferred embodiments of the utility model, four current detection modules are set, four dimming and color adjustment modules are set, the first amplification module includes an operational amplifier OP1, a capacitor C2, a resistor R20, a resistor R21 and capacitors RM1-5, one end of the resistor RM1, one end of the resistor RM2, one end of the resistor RM3 and one end of the resistor RM4 are connected to the current detection module one by one, the other end of the resistor RM1, the other end of the resistor RM2, the other end of the resistor RM3 and the other end of the resistor RM4 are respectively connected to one end of the resistor RM5, one end of the capacitor C2 and the positive input end of the operational amplifier OP1, the other end of the resistor RM5 is connected to the reference voltage, the reverse input end of the operational amplifier OP1 is respectively connected to one end of the resistor R20 and one end of the resistor R21, the other end of the resistor R20 is respectively connected to the output end of the operational amplifier OP1 and the main control module, the other end of the capacitor C2, the other end of the resistor R21 and the ground end of the operational amplifier OP1 are connected to the SGND end.

[0011] As one of the preferred embodiments of the utility model, a high-precision detection circuit for output current of an LED constant-voltage power supply further includes a resistor RM6 connected in parallel with the capacitor C2.

[0012] As one of the preferred embodiments of the utility model, a high-precision detection circuit for output current of a LED constant voltage power supply further includes a filter module connected between the output end of the operational amplifier OP1 and the main control module.

[0013] As one of the preferred embodiments of the present invention, the filtering module includes a resistor R18 and a capacitor C3, one end of the resistor R18 is connected to the output end of the operational amplifier OP1, and the other end of the resistor R18 is connected to the main control module and to the SGND end via the capacitor C3.

[0014] As one of the preferred embodiments of the present utility model, the dimming and color adjustment module includes a MOS tube Q1 and resistors R3-4, the source of the MOS tube Q1 is respectively connected to the current detection module and one end of the resistor R3, the drain of the MOS tube Q1 is connected to one end of the load, the gate of the MOS tube Q1 is respectively connected to the other end of the resistor R3 and one end of the resistor R4, and the other end of the resistor R4 is connected to the main control module.

[0015] As one of the preferred embodiments of the utility model, a high-precision detection circuit for output current of an LED constant-voltage power supply further includes a plurality of second amplification modules connected in series and / or in parallel between the first amplification module and the main control module.

[0016] As one of the preferred embodiments of the utility model, the second amplification module includes an operational amplifier OP2 and resistors R22-23, the positive input end of the operational amplifier OP2 is connected to the first amplification module, the reverse input end of the operational amplifier OP2 is connected to one end of the resistor R22 and one end of the resistor R23, the output end of the operational amplifier OP2 is respectively connected to the other end of the resistor R23 and the main control module, the power supply end of the operational amplifier OP2 is connected to the VCC end, and the other end of the resistor R22 and the ground end of the operational amplifier OP2 are connected to the SGND end.

[0017] The beneficial effects of the utility model are as follows: a high-precision detection circuit for the output current of an LED constant-voltage power supply comprises a main circuit, a main control module, a first amplifying module, a plurality of current detection modules and a plurality of dimming and color-adjusting modules; the input end of the main circuit is connected to an external power supply; the current detection module corresponds to the dimming and color-adjusting module one by one and is connected between the output end of the main circuit and the load to form a plurality of channel current signals; the input end of the first amplifying module is connected to the plurality of current detection modules and is connected to a reference voltage; the main control module is respectively connected to the output end of the first amplifying module and the dimming and color-adjusting module; the first amplifying module receives the channel current signal and transmits it to the main control module after amplification, so as to control the load through the dimming and color-adjusting module; the above-mentioned problem of the incompatibility between the current detection accuracy of the LED constant-voltage power supply and the low system efficiency can be overcome, and at the same time, the output power tube can have good heat dissipation, and has very good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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:

[0019] Figure 1 It is a principle block diagram of a first embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply;

[0020] Figure 2 It is a principle block diagram of a second embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply;

[0021] Figure 3 It is a circuit principle diagram of a second embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply;

[0022] Figure 4 It is a principle block diagram of a third embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply;

[0023] Figure 5 It is a principle block diagram of a fourth embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply;

[0024] Figure 6The fifth embodiment is a principle block diagram of a high-precision detection circuit for output current of an LED constant voltage power supply. DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] Reference Figures 1 to 6 , a high-precision detection circuit for output current of an LED constant voltage power supply, comprising a main circuit 10, a main control module 20, a first amplification module 30, a plurality of current detection modules 40 and a plurality of dimming and color adjustment modules 50;

[0030] The input end of the main circuit 10 is connected to an external power supply;

[0031] The current detection module 40 corresponds to the dimming and color adjustment module 50 one by one and is connected between the output end of the main circuit 10 and the load to form a plurality of channel current signals;

[0032] The input end of the first amplifying module 30 is connected to a plurality of current detecting modules 40 and is connected to a reference voltage;

[0033] The main control module 20 is respectively connected to the output end of the first amplification module 30 and the dimming and color adjustment module 50;

[0034] The first amplifying module 30 receives the channel current signal and transmits it to the main control module 20 after amplification, so as to control the load through the dimming and color adjustment module 50 .

[0035] In this utility model, reference is made to Figure 1-2 , are respectively principle block diagrams of a first embodiment and a second embodiment of a high-precision detection circuit for output current of an LED constant voltage power supply, wherein: Figure 1 The current detection module 40 and the dimming and color adjustment module 50 are both set to three, so that one current detection module 40 and one dimming and color adjustment module 50 form one channel current signal, and there are three channel current signals in total; Figure 2 The number of the current detection module 40 and the dimming and color adjustment module 50 are both set to 4, so that one current detection module 40 and one dimming and color adjustment module 50 form one channel current signal, and there are 4 channel current signals in total.

[0036] ①Reference Figure 3 , is a circuit schematic diagram of a second embodiment of a high-precision detection circuit for output current of an LED constant voltage power supply, wherein four current detection modules 40 respectively include a resistor RN1, a resistor RN2, a resistor RN3 and a resistor RN4, and four dimming and color adjustment modules 50 respectively include a MOS tube Q1 and resistors R3-4, a MOS tube Q2 and resistors R5-6, a MOS tube Q3 and resistors R8-9, and a MOS tube Q4 and resistors R14-15; since the current to be measured is large, in order to reduce the measurement error and increase the actual signal, multiple sampling resistors are selected to form a channel current signal, and the MOS tube can have good heat dissipation, and the current detection is split into multi-channel detection.

[0037] Specifically, resistors RN1, RN2, RN3, and RN4 are current detection resistors (this is not limited to the specific number of paths), which can convert current signals into voltage signals and send them to operational amplifier OP1. VCC_ref is used to provide a reference signal higher than the ground to reduce ground interference. For the accuracy and convenience of calculation, the resistance values of resistors RN1, RN2, RN3, and RN4 are generally equal, and the resistance values of resistors RM1, RM2, RM3, RM4, RM5, and RM6 are also equal (wherein, resistor RM6 may not be mounted). The current calculation value is calculated by the following formula:

[0038] When the resistor RM6 is not attached, the voltage value received by the main control module 20 is:

[0039] Vcur rent=(I out / 5)*(R21+R20) / R21

[0040] When the resistor RM6 is attached, the voltage value received by the main control module 20 is:

[0041] Vcur rent=(I out / 6)*(R21+R20) / R21

[0042] The main control module 20 performs output chopping control through the duty cycle;

[0043] ②Reference Figure 4 , is a principle block diagram of a third embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply. In this embodiment, Figure 3 On the basis of the embodiment of FIG. 1 , a first level of in-phase amplifier is added, that is, a second amplifier module 70 is connected in series between the main control module 20 and the first amplifier module 30, and its gain is:

[0044] G=(R23+R22) / R22

[0045] ③Reference Figure 5 , is a principle block diagram of a fourth embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply. In this embodiment, Figure 3 A schematic diagram of a multi-channel application circuit of a common-mode amplifier of an embodiment, the principle of which will not be described in detail;

[0046] ④Reference Figure 6 , is a principle block diagram of a fifth embodiment of a high-precision detection circuit for output current of a LED constant voltage power supply. In this embodiment, Figure 3 Another multi-channel application circuit schematic diagram of the embodiment of the in-phase amplifier is shown, that is, multiple second amplifying modules 70 are connected in series and in parallel between the main control module 20 and the first amplifying module 30, and the principle is not repeated here.

[0047] The advantages of the utility model are: it can overcome the incompatibility problem between the current detection accuracy of the LED constant voltage power supply and the low system efficiency, and at the same time it can also make the output power tube have good heat dissipation, and has very good practicality.

[0048] As a preferred embodiment of the first amplification module 30, four current detection modules 40 are set, and four dimming and color adjustment modules 50 are set. The first amplification module 30 includes an operational amplifier OP1, a capacitor C2, a resistor R20, a resistor R21 and capacitors RM1-5. One end of the resistor RM1, one end of the resistor RM2, one end of the resistor RM3 and one end of the resistor RM4 are connected to the current detection module 40 one by one, and the other end of the resistor RM1, the other end of the resistor RM2, the other end of the resistor RM3 and the other end of the resistor RM4 are respectively connected to one end of the resistor RM5, one end of the capacitor C2 and the positive input end of the operational amplifier OP1, and the other end of the resistor RM5 is connected to the reference voltage. The reverse input end of the operational amplifier OP1 is respectively connected to one end of the resistor R20 and one end of the resistor R21, and the other end of the resistor R20 is respectively connected to the output end of the operational amplifier OP1 and the main control module 20, and the other end of the capacitor C2, the other end of the resistor R21 and the ground end of the operational amplifier OP1 are connected to the SGND end.

[0049] In one embodiment, a high-precision detection circuit for output current of a LED constant-voltage power supply further includes a resistor RM6 connected in parallel with the capacitor C2.

[0050] In one embodiment, a high-precision detection circuit for the output current of an LED constant-voltage power supply also includes a filter module 60 connected between the output end of the operational amplifier OP1 and the main control module 20; as a preferred embodiment of the filter module 60, the filter module 60 includes a resistor R18 and a capacitor C3, one end of the resistor R18 is connected to the output end of the operational amplifier OP1, and the other end of the resistor R18 is connected to the main control module 20 and connected to the SGND end via the capacitor C3.

[0051] As a preferred embodiment of the dimming and color adjustment module 50, the dimming and color adjustment module 50 includes a MOS tube Q1 and resistors R3-4, the source of the MOS tube Q1 is respectively connected to the current detection module 40 and one end of the resistor R3, the drain of the MOS tube Q1 is connected to one end of the load, the gate of the MOS tube Q1 is respectively connected to the other end of the resistor R3 and one end of the resistor R4, and the other end of the resistor R4 is connected to the main control module 20.

[0052] In one embodiment, a high-precision detection circuit for the output current of an LED constant-voltage power supply further includes a plurality of second amplifying modules 70 connected in series and / or in parallel between the first amplifying module 30 and the main control module 20; as a preferred embodiment of the second amplifying module 70, the second amplifying module 70 includes an operational amplifier OP2 and resistors R22-23, the positive input end of the operational amplifier OP2 is connected to the first amplifying module 30, the reverse input end of the operational amplifier OP2 is connected to one end of the resistor R22 and one end of the resistor R23, the output end of the operational amplifier OP2 is respectively connected to the other end of the resistor R23 and the main control module 20, the power supply end of the operational amplifier OP2 is connected to the VCC end, and the other end of the resistor R22 and the ground end of the operational amplifier OP2 are connected to the SGND end.

[0053] 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 high-precision detection circuit for output current of a LED constant voltage power supply, characterized in that: It comprises a main circuit (10), a main control module (20), a first amplification module (30), a plurality of current detection modules (40) and a plurality of light adjustment and color adjustment modules (50); The input end of the main circuit (10) is connected to an external power supply; The current detection module (40) corresponds to the dimming and color adjustment module (50) in a one-to-one manner and is connected between the output end of the main circuit (10) and the load to form a plurality of channel current signals; The input end of the first amplification module (30) is connected to a plurality of current detection modules (40) and is connected to a reference voltage; The main control module (20) is respectively connected to the output end of the first amplification module (30) and the dimming and color adjustment module (50); The first amplifying module (30) receives the channel current signal, amplifies it, and transmits it to the main control module (20) so as to control the load through the dimming and color adjustment module (50).

2. The high-precision detection circuit for output current of a LED constant voltage power supply according to claim 1, characterized in that: The number of the current detection modules (40) is four, the number of the dimming and color adjustment modules (50) is four, the first amplification module (30) comprises an operational amplifier OP1, a capacitor C2, a resistor R20, a resistor R21 and capacitors RM1-5, one end of the resistor RM1, one end of the resistor RM2, one end of the resistor RM3 and one end of the resistor RM4 are connected to the current detection module (40) one by one, the other end of the resistor RM1, the other end of the resistor RM2, the other end of the resistor RM3 and the other end of the resistor RM4 are respectively connected to one end of the resistor RM5, one end of the capacitor C2 and the positive input end of the operational amplifier OP1, the other end of the resistor RM5 is connected to a reference voltage, the reverse input end of the operational amplifier OP1 is respectively connected to one end of the resistor R20 and one end of the resistor R21, the other end of the resistor R20 is respectively connected to the output end of the operational amplifier OP1 and the main control module (20), the other end of the capacitor C2, the other end of the resistor R21 and the ground end of the operational amplifier OP1 are connected to the SGND end.

3. The high-precision detection circuit for output current of a LED constant voltage power supply according to claim 2, characterized in that: A resistor RM6 is also included which is connected in parallel with the capacitor C2.

4. The high-precision detection circuit for output current of a LED constant voltage power supply according to claim 2, characterized in that: It also includes a filter module (60) connected between the output end of the operational amplifier OP1 and the main control module (20).

5. The high-precision detection circuit for output current of a LED constant voltage power supply according to claim 4, characterized in that: The filter module (60) comprises a resistor R18 and a capacitor C3, one end of the resistor R18 is connected to the output end of the operational amplifier OP1, and the other end of the resistor R18 is connected to the main control module (20) and to the SGND end via the capacitor C3.

6. The high-precision detection circuit for output current of a LED constant voltage power supply according to claim 1, characterized in that: The dimming and color adjustment module (50) comprises a MOS tube Q1 and resistors R3-4, the source of the MOS tube Q1 is respectively connected to the current detection module (40) and one end of the resistor R3, the drain of the MOS tube Q1 is connected to one end of the load, the gate of the MOS tube Q1 is respectively connected to the other end of the resistor R3 and one end of the resistor R4, and the other end of the resistor R4 is connected to the main control module (20).

7. The high-precision detection circuit for output current of a LED constant voltage power supply according to claim 1, characterized in that: It also includes a plurality of second amplification modules (70) connected in series and / or in parallel between the first amplification module (30) and the main control module (20).

8. The high-precision detection circuit for output current of a LED constant voltage power supply according to claim 7, characterized in that: The second amplification module (70) comprises an operational amplifier OP2 and resistors R22-23, the positive input end of the operational amplifier OP2 is connected to the first amplification module (30), the negative input end of the operational amplifier OP2 is connected to one end of the resistor R22 and one end of the resistor R23, the output end of the operational amplifier OP2 is respectively connected to the other end of the resistor R23 and the main control module (20), the power supply end of the operational amplifier OP2 is connected to the VCC end, and the other end of the resistor R22 and the ground end of the operational amplifier OP2 are connected to the SGND end.