High-side current detection circuit of LED constant-current power supply

Abstract

The utility model discloses a high-side current detection circuit of an LED constant-current power supply. The high-side current detection circuit comprises a power supply main circuit, an output constant-current circuit, a single-chip microcomputer circuit, a current detection circuit and resistors R1-2. The output constant current circuit can adjust the magnitude of output current according to the collected voltage drop signal on the resistor R1, and the single-chip microcomputer circuit can monitor the output current according to the voltage drop signal on the resistor R2 collected by the current detection circuit. Through the above structure, the LED constant-current circuit which adopts a constant-current chip with a built-in dimming MOS tube to realize constant-current output is adapted, high-side current detection is realized, and the LED constant-current circuit has very good practicability.

Description

Technical Field

[0001] The utility model relates to the field of LED power supplies, in particular to a high-side current detection circuit of an LED constant current power supply. Background Art

[0002] With the rapid development of LED lighting industry, LEDs are installed in every household and outdoor lighting, which makes the LED power supply market flourish and the requirements for LED power supply are getting higher and higher. At present, in practical applications, many power supplies require the addition of current monitoring function at the output end of the power supply. However, in constant current power supply, most of the constant current chips at the output end have built-in dimming MOS tubes, and it is impossible to add current sampling resistors at the source back end of the built-in MOS tube of the constant current chip, so it is impossible to detect the current size at the output end in the low-side circuit. In order to continue to use these constant current chips with built-in dimming MOS tubes, it is necessary to develop a high-side current detection circuit for LED constant current power supply. 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 provides a high-side current detection circuit of an LED constant current power supply.

[0004] The technical solution adopted by an embodiment of the utility model to solve the technical problem is: a high-side current detection circuit of an LED constant current power supply, including a power supply main circuit, an output constant current circuit, a single-chip circuit, a current detection circuit and a resistor R1-2;

[0005] The output end of the power main circuit is connected to the external power supply, and the output end leads to the Vin+ end, the VCC end and the GNS end;

[0006] One end of the resistor R1 is connected to the Vin+ terminal and the output constant current circuit, and the other end of the resistor R1 is connected to the output constant current circuit, the current detection circuit and one end of the resistor R2 respectively;

[0007] The other end of the resistor R2 is connected to the current detection circuit and one end of the load respectively, and the other end of the load is connected to the output constant current circuit;

[0008] The single chip microcomputer circuit is respectively connected with the VCC terminal, the output constant current circuit and the current detection circuit;

[0009] The output constant current circuit can adjust the output current according to the voltage drop signal collected on the resistor R1, and the single-chip microcomputer circuit can monitor the output current according to the voltage drop signal collected on the resistor R2 by the current detection circuit.

[0010] As one of the preferred embodiments of the utility model, the output constant current circuit includes a constant current chip U1, an inductor L1 and a diode D1. The VIN pin of the constant current chip U1 is respectively connected to the Vin+ end, one end of the resistor R1 and the cathode of the diode D1, the GND pin of the constant current chip U1 is connected to the GNS end, the ISEN pin of the constant current chip U1 is respectively connected to the other end of the resistor R1, the current detection circuit and one end of the resistor R2, the ADJ pin of the constant current chip U1 is connected to the single-chip computer circuit, the LX pin of the constant current chip U1 is respectively connected to one end of the inductor L1 and the anode of the diode D1, and the other end of the inductor L1 is connected to the other end of the load.

[0011] As one of the preferred embodiments of the utility model, the current detection circuit includes resistors R3-6, a capacitor C1 and an operational amplifier U2, the positive input end of the operational amplifier U2 is respectively connected to one end of the resistor R3, one end of the capacitor C1 and one end of the resistor R4, the other end of the resistor R4 is connected to the other end of the resistor R2, the other end of the resistor R3 and the other end of the capacitor C1 are connected to the GNS end, the reverse input end of the operational amplifier U2 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 connected to one end of the resistor R2, and the other end of the resistor R6 is respectively connected to the microcontroller circuit and the output end of the operational amplifier U2.

[0012] As one of the preferred embodiments of the utility model, a high-side current detection circuit of an LED constant current power supply further includes a first filter circuit connected between the single-chip computer circuit and the current detection circuit.

[0013] As one of the preferred embodiments of the utility model, the first filtering circuit includes resistors R7-8 and capacitor C2, one end of the resistor R7 is connected to the current detection circuit, the other end of the resistor R7 is respectively connected to one end of the resistor R8, one end of the capacitor C2 and the single-chip computer circuit, and the other end of the resistor R8 and the other end of the capacitor C2 are connected to the GNS end.

[0014] As one of the preferred embodiments of the utility model, a high-side current detection circuit of an LED constant current power supply further includes a second filter circuit connected between the single-chip microcomputer circuit and the output constant current circuit.

[0015] As one of the preferred embodiments of the utility model, the second filtering circuit includes a resistor R9 and a capacitor C3, one end of the resistor R9 is connected to the single-chip circuit, the other end of the resistor R9 is respectively connected to one end of the capacitor C3 and the output constant current circuit, and the other end of the capacitor C3 is connected to the GNS end.

[0016] The beneficial effects of the utility model are as follows: a high-side current detection circuit of an LED constant current power supply comprises a power supply main circuit, an output constant current circuit, a single-chip computer circuit, a current detection circuit and a resistor R1-2; the output end of the power supply main circuit is connected to an external power supply, and the output end leads to a Vin+ end, a VCC end and a GNS end; one end of the resistor R1 is connected to the Vin+ end and the output constant current circuit, and the other end of the resistor R1 is respectively connected to the output constant current circuit, the current detection circuit and one end of the resistor R2; the other end of the resistor R2 is respectively connected to the current detection circuit and one end of the load, and the other end of the load is connected to the output constant current circuit; the single-chip computer circuit is respectively connected to the VCC end, the output constant current circuit and the current detection circuit; the output constant current circuit can adjust the size of the output current according to the voltage drop signal collected on the resistor R1, and the single-chip computer circuit can monitor the output current according to the voltage drop signal collected on the resistor R2 by the current detection circuit; the above structure is adapted to use a constant current chip with a built-in dimming MOS tube to realize an LED constant current circuit with constant current output, and realize high-side current detection, which has very good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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:

[0018] Figure 1 This is a principle block diagram of a high-side current detection circuit for an LED constant current power supply;

[0019] Figure 2 The schematic diagram of a high-side current detection circuit for an LED constant current power supply is shown in FIG. DETAILED DESCRIPTION

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Reference Figure 1 to Figure 2 , a high-side current detection circuit of an LED constant current power supply, comprising a power supply main circuit 10, an output constant current circuit 20, a single-chip computer circuit 30, a current detection circuit 40 and a resistor R1-2;

[0025] The output end of the power main circuit 10 is connected to an external power supply, and the output end leads to a Vin+ end, a VCC end, and a GNS end;

[0026] One end of the resistor R1 is connected to the Vin+ terminal and the output constant current circuit 20, and the other end of the resistor R1 is connected to the output constant current circuit 20, the current detection circuit 40 and one end of the resistor R2 respectively;

[0027] The other end of the resistor R2 is connected to the current detection circuit 40 and one end of the load respectively, and the other end of the load is connected to the output constant current circuit 20;

[0028] The single chip circuit 30 is connected to the VCC terminal, the output constant current circuit 20 and the current detection circuit 40 respectively;

[0029] The output constant current circuit 20 can adjust the output current according to the voltage drop signal collected on the resistor R1, and the single chip microcomputer circuit 30 can monitor the output current according to the voltage drop signal collected on the resistor R2 by the current detection circuit 40.

[0030] The working principle of the utility model is as follows:

[0031] 1. When the system is powered on, the power supply circuit transmits the received AC input voltage to the input ends of the power main circuit 10 through the input live terminal L and the input neutral terminal N, and then outputs the Vin+ terminal, VCC terminal and GNS terminal after being processed by the power main circuit 10. The Vin+ terminal voltage is input to the 5th pin (VIN pin) of the constant current chip U1, and is connected to the positive terminal of the LED lamp (load) through the resistor R1 and the resistor R2. When the 7th pin of the single-chip microcomputer U3 (single-chip microcomputer circuit 30) outputs a PWM dimming signal, it passes through the second filter circuit 60 composed of the resistor R9 and the capacitor C3 and is connected to the 3rd pin (ADJ pin) of the constant current chip U1. After being processed by the constant current chip U1, a chopping signal is output through the 1st pin (LX pin) of the constant current chip U1 to chop the inductor L1, and is connected to the negative terminal of the LED lamp through the inductor L1 to light up the LED lamp;

[0032] 2. The inductor L1 is connected to the Vin+ terminal through the diode D1 to carry out freewheeling of the inductor L1. At the same time, the current passes through the resistors R1 and R2, generating voltage drop signals on the resistors R1 and R2. The voltage drop signal on the resistor R1 is connected to the 4th pin (ISEN pin) of the constant current chip U1 and the 5th pin (VIN pin) of the constant current chip U1 respectively. The constant current chip U1 completes the collection of the output current. Changing the parameters of the resistor R1 can change the size of the output current; one end of the resistor R2 is connected to the 4th pin (ISEN pin) of the constant current chip U1, and the other end is connected to the load LED The lamp is connected, the voltage drop signal on the resistor R2 is connected to the 1st pin (positive input terminal) and the 3rd pin (reverse input terminal) of the operational amplifier U2 through the resistors R4 and R5 respectively. After the voltage drop signal on the resistor R2 is amplified by the operational amplifier U2, the 4th pin (output terminal) of the operational amplifier U2 outputs a signal, which is connected to the 5th pin of the single-chip microcomputer U3 after being filtered by the voltage divider of the first filtering circuit 50 composed of the resistor R7, the resistor R8 and the capacitor C2. After the 5th pin of the single-chip microcomputer U3 receives the voltage value, the single-chip microcomputer U3 completes the collection of the output current;

[0033] 3. The operational amplifier U2, the resistor R3, the resistor R4, the resistor R5 and the resistor R6 form a differential operational amplifier, and the gain of the differential operational amplifier can be adjusted by adjusting the parameters of the resistor R3, the resistor R4, the resistor R5 and the resistor R6;

[0034] 4. The advantages of the utility model are that: through the above structure, the constant current chip with built-in dimming MOS tube is adapted to realize the LED constant current circuit with constant current output, and high-side current detection is realized, which has very good practicality.

[0035] As a preferred embodiment of the output constant current circuit 20, the output constant current circuit 20 includes a constant current chip U1, an inductor L1 and a diode D1. The VIN pin of the constant current chip U1 is respectively connected to the Vin+ end, one end of the resistor R1 and the cathode of the diode D1, the GND pin of the constant current chip U1 is connected to the GNS end, the ISEN pin of the constant current chip U1 is respectively connected to the other end of the resistor R1, the current detection circuit 40 and one end of the resistor R2, the ADJ pin of the constant current chip U1 is connected to the single-chip computer circuit 30, the LX pin of the constant current chip U1 is respectively connected to one end of the inductor L1 and the anode of the diode D1, and the other end of the inductor L1 is connected to the other end of the load.

[0036] As a preferred embodiment of the current detection circuit 40, the current detection circuit 40 includes resistors R3-6, a capacitor C1 and an operational amplifier U2, the positive input terminal of the operational amplifier U2 is respectively connected to one end of the resistor R3, one end of the capacitor C1 and one end of the resistor R4, the other end of the resistor R4 is connected to the other end of the resistor R2, the other end of the resistor R3 and the other end of the capacitor C1 are connected to the GNS terminal, the reverse input terminal of the operational amplifier U2 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 connected to one end of the resistor R2, and the other end of the resistor R6 is respectively connected to the microcontroller circuit 30 and the output terminal of the operational amplifier U2.

[0037] The high-side current detection circuit of the LED constant current power supply further includes a first filter circuit 50 connected between the single-chip computer circuit 30 and the current detection circuit 40 .

[0038] As a preferred embodiment of the first filter circuit 50, the first filter circuit 50 includes resistors R7-8 and a capacitor C2, one end of the resistor R7 is connected to the current detection circuit 40, the other end of the resistor R7 is respectively connected to one end of the resistor R8, one end of the capacitor C2 and the single-chip computer circuit 30, and the other end of the resistor R8 and the other end of the capacitor C2 are connected to the GNS end.

[0039] The high-side current detection circuit of the LED constant current power supply further includes a second filter circuit 60 connected between the single-chip computer circuit 30 and the output constant current circuit 20 .

[0040] As a preferred embodiment of the second filter circuit 60, the second filter circuit 60 includes a resistor R9 and a capacitor C3, one end of the resistor R9 is connected to the single-chip computer circuit 30, the other end of the resistor R9 is respectively connected to one end of the capacitor C3 and the output constant current circuit 20, and the other end of the capacitor C3 is connected to the GNS end.

[0041] 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-side current detection circuit for an LED constant current power supply, characterized in that: It comprises a power supply main circuit (10), an output constant current circuit (20), a single chip computer circuit (30), a current detection circuit (40) and a resistor R1-2; The output end of the power main circuit (10) is connected to an external power supply, and the output end leads to a Vin+ end, a VCC end and a GNS end; One end of the resistor R1 is connected to the Vin+ end and the output constant current circuit (20), and the other end of the resistor R1 is respectively connected to the output constant current circuit (20), the current detection circuit (40) and one end of the resistor R2; The other end of the resistor R2 is connected to the current detection circuit (40) and one end of the load respectively, and the other end of the load is connected to the output constant current circuit (20); The single chip computer circuit (30) is respectively connected to the VCC terminal, the output constant current circuit (20) and the current detection circuit (40); The output constant current circuit (20) can adjust the magnitude of the output current according to the voltage drop signal collected on the resistor R1, and the single-chip computer circuit (30) can monitor the output current according to the voltage drop signal collected on the resistor R2 by the current detection circuit (40).

2. The high-side current detection circuit of a LED constant current power supply according to claim 1, characterized in that: The output constant current circuit (20) comprises a constant current chip U1, an inductor L1 and a diode D1, the VIN pin of the constant current chip U1 is respectively connected to the Vin+ terminal, one end of the resistor R1 and the cathode of the diode D1, the GND pin of the constant current chip U1 is connected to the GNS terminal, the ISEN pin of the constant current chip U1 is respectively connected to the other end of the resistor R1, the current detection circuit (40) and one end of the resistor R2, the ADJ pin of the constant current chip U1 is connected to the single-chip computer circuit (30), the LX pin of the constant current chip U1 is respectively connected to one end of the inductor L1 and the anode of the diode D1, and the other end of the inductor L1 is connected to the other end of the load.

3. The high-side current detection circuit of a LED constant current power supply according to claim 1, characterized in that: The current detection circuit (40) comprises resistors R3-6, a capacitor C1 and an operational amplifier U2, the positive input end of the operational amplifier U2 is respectively connected to one end of the resistor R3, one end of the capacitor C1 and one end of the resistor R4, the other end of the resistor R4 is connected to the other end of the resistor R2, the other end of the resistor R3 and the other end of the capacitor C1 are connected to the GNS end, the negative input end of the operational amplifier U2 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 connected to one end of the resistor R2, and the other end of the resistor R6 is respectively connected to the output end of the single-chip circuit (30) and the operational amplifier U2.

4. The high-side current detection circuit of a LED constant current power supply according to claim 1, characterized in that: It also includes a first filter circuit (50) connected between the single chip computer circuit (30) and the current detection circuit (40).

5. The high-side current detection circuit of a LED constant current power supply according to claim 4, characterized in that: The first filter circuit (50) comprises resistors R7-8 and a capacitor C2, one end of the resistor R7 is connected to the current detection circuit (40), the other end of the resistor R7 is respectively connected to one end of a resistor R8, one end of the capacitor C2 and the single-chip computer circuit (30), and the other end of the resistor R8 and the other end of the capacitor C2 are connected to the GNS end.

6. The high-side current detection circuit of a LED constant current power supply according to claim 1, characterized in that: It also includes a second filter circuit (60) connected between the single chip computer circuit (30) and the output constant current circuit (20).

7. The high-side current detection circuit of a LED constant current power supply according to claim 6, characterized in that: The second filter circuit (60) comprises a resistor R9 and a capacitor C3, one end of the resistor R9 is connected to the single-chip computer circuit (30), the other end of the resistor R9 is respectively connected to one end of the capacitor C3 and the output constant current circuit (20), and the other end of the capacitor C3 is connected to the GNS end.

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