Constant current driving circuit of LED lamp

Abstract

The utility model discloses a constant current drive circuit of LED lamp, including: voltage input unit, rectifier bridge module, constant current output module, ground terminal and power supply unit, the output terminal of voltage input unit is connected with the input terminal of rectifier bridge module, the output terminal of rectifier bridge module is connected with constant current output module and power supply unit respectively, the output terminal of rectifier bridge module is connected with the ground terminal, and the power supply unit is connected with the ground terminal. And the constant current output module is connected with the power supply unit. According to the power supply circuit of the LED lamp, the direct current converted by the rectifier bridge module is subjected to voltage reduction and current stabilization through the constant current output module, so that the power supply unit can output constant current to the external LED lamp, the power supply circuit of the LED lamp is simplified, and the production cost of the LED lamp is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to LED power supply technical field especially relates to a constant current drive circuit of LED lamp. BACKGROUND

[0002] LED is regarded as the 21st century lighting source with the advantages of environmental protection, energy saving, long service life and so on, and has begun to replace traditional light source and is applied in various lighting lamps in large quantities. However, due to the characteristics of LED itself, the driving power supply thereof cannot adopt the same power supply as ordinary incandescent lamps, so as to avoid that voltage fluctuation leads to current increase and thus damages LED, and therefore a new power supply must be designed to fully meet the driving requirements required by LED work, so as to maximize the performance of LED and reduce the failure rate. However, the existing LED constant current drive circuit structure is relatively complex, leading to high production cost of LED lamp. SUMMARY

[0003] In order to solve the problem of complex structure of the existing LED constant current drive circuit, the utility model provides a constant current drive circuit of LED lamp. The specific technical scheme of the utility model is as follows:

[0004] A constant current drive circuit of LED lamp, comprising: a voltage input unit, a rectifier bridge module, a constant current output module, a ground terminal and a power supply unit, the output end of the voltage input unit is connected with the input end of the rectifier bridge module, the output end of the rectifier bridge module is connected with the constant current output module and the power supply unit respectively, and the constant current output module is connected with the power supply unit; the voltage input unit is used for being connected with external alternating current, the rectifier bridge module is used for converting alternating current received by the voltage input unit into direct current, the constant current output module is used for outputting constant current to the power supply unit after the direct current converted by the rectifier bridge module is stepped down, and the power supply unit is used for outputting constant current output by the constant current output module to external LED lamp.

[0005] Further, the constant current output module comprises an LED constant current drive chip U1, a diode D1, an inductor T1, a resistor R1, a resistor R3, a resistor R4 and a resistor R5, pin 1 of the LED constant current drive chip U1 is connected with the ground terminal, pin 2 is connected with the ground terminal through the resistor R4, pin 4 is connected with the output end of the rectifier bridge module, pin 5 is connected with the power supply unit through the diode D1 and the inductor T1 respectively, pin 6 is connected with pin 5, the resistor R1 and the resistor R5 are connected in parallel, one end of which is connected with pin 8 of the LED constant current drive chip U1, and the other end is connected with the ground terminal, one end of the capacitor R3 is connected with the diode D1, and the other end is connected with the inductor T1.

[0006] Further, the model of the LED constant current drive chip U1 is BP2851.

[0007] Further, the rectifier bridge module comprises a rectifier bridge stack DB1 and a polarity capacitor C1, an input end of the rectifier bridge stack DB1 is connected with an output end of the voltage input unit, output ends of the rectifier bridge stack DB1 are connected with the polarity capacitor C1 and the LED constant current driving chip U1 respectively, a positive pole of the polarity capacitor is connected with the output end of the rectifier bridge stack DB1, and a negative pole is connected with a ground end.

[0008] Further, the rectifier bridge stack DB1 is of a model of MB10f.

[0009] Further, the power supply unit comprises a positive end vout+, a negative end vout- and a polarity capacitor C3, the positive end vout+ is connected with a pin 5 of the LED constant current driving chip U1 through a diode D1, the negative end vout- is connected with the pin 5 of the LED constant current driving chip U1 through an inductor T1, and a positive pole of the polarity capacitor C3 is connected with the positive end vout+ and a negative pole is connected with the negative end vout-.

[0010] Compared with the prior art, the LED lamp has at least the following beneficial effects: the power supply circuit of the LED lamp converts the direct current converted by the rectifier bridge module through the constant current output module, so that the power supply unit can output constant current to the external LED lamp, the power supply circuit of the LED lamp is simplified, and the production cost of the LED lamp is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a circuit schematic diagram of an embodiment;

[0012] Figure 2 is a circuit diagram of an embodiment. DETAILED DESCRIPTION

[0013] The following embodiments are used to illustrate the present application, but the present application is not limited by these embodiments. The specific implementation of the present application is modified or some technical features are replaced equivalently without departing from the spirit of the present application, and all should be covered in the technical scheme range of the present application.

[0014] As Figure 1 and Figure 2As shown in the constant current driving circuit of the LED lamp, it comprises a voltage input unit, a rectifier bridge module, a constant current output module, a grounding terminal and a power supply unit, the output end of the voltage input unit is connected with the input end of the rectifier bridge module, the output end of the rectifier bridge module is connected with the constant current output module and the power supply unit respectively, and the constant current output module is connected with the power supply unit; the voltage input unit is used for being connected with external alternating current, the rectifier bridge module is used for converting the alternating current received by the voltage input unit into direct current, the constant current output module is used for outputting constant current to the power supply unit after the direct current converted by the rectifier bridge module is stepped down, and the power supply unit is used for outputting the constant current output by the constant current output module to external LED lamp. The external alternating current is 220V.

[0015] As one of the embodiments, the constant current output module comprises an LED constant current driving chip U1, a diode D1, an inductor T1, a resistor R1, a resistor R3, a resistor R4 and a resistor R5, the pin 1 of the LED constant current driving chip U1 is connected with the grounding terminal, the pin 2 is connected with the grounding terminal through the resistor R4, the pin 4 is connected with the output end of the rectifier bridge module, the pin 5 is connected with the power supply unit through the diode D1 and the inductor T1 respectively, the pin 6 is connected with the pin 5, the resistor R1 and the resistor R5 are connected in parallel, one end of which is connected with the pin 8 of the LED constant current driving chip U1, and the other end is connected with the grounding terminal, and the capacitor R3 is connected with the diode D1 at one end and the inductor T1 at the other end. The pin functions of the LED constant current driving chip U1 are as follows: the pin 1 is the grounding terminal of the chip, the symbol of which is GND; the pin 2 is the feedback signal input end of the chip, the symbol of which is FB; the pin 3 is the test pin, the symbol of which is TM, and it must be connected to the grounding terminal (Pin 1) of the chip; the pin 4 is the input power end of the chip, the symbol of which is VCC; the pins 5 and 6 are the internal high-voltage power tube drain, the symbol of which is DRAIN; the pins 7 and 8 are the current sampling end of the chip, the symbol of which is CS, and the sampling resistor is connected between CS and GND.

[0016] As one of the embodiments, the model of the LED constant current driving chip U1 is BP2851. BP2851 is a high-precision step-down LED constant current driving chip. The chip works in the inductor current critical continuous mode, is suitable for non-isolated step-down LED constant current power supply with full range input voltage of 85Vac-265Vac. BP2851 chip integrates 500V power switch inside, adopts the patented floating ground driving framework and current detection mode, the working current of the chip is extremely low, and it does not need auxiliary winding detection and power supply. Only a few peripheral elements are needed to achieve excellent constant current characteristics, greatly saving the system cost and volume. The power supply circuit of the LED lamp adopts BP2851 chip to step down the working voltage of the LED lamp, which simplifies the power supply circuit of the LED lamp.

[0017] As one of the embodiments, the rectifier bridge module comprises a rectifier bridge stack DB1 and a polarity capacitor C1, an input end of the rectifier bridge stack DB1 is connected with an output end of the voltage input unit, output ends of the rectifier bridge stack DB1 are connected with the polarity capacitor C1 and the LED constant current driving chip U1 respectively, a positive pole of the polarity capacitor is connected with the output end of the rectifier bridge stack DB1, and a negative pole is connected with a ground end.

[0018] As one of the embodiments, the rectifier bridge stack DB1 is of a model of MB10f.

[0019] As one of the embodiments, the power supply unit comprises a positive pole end vout+, a negative pole end vout- and a polarity capacitor C3, the positive pole end vout+ is connected with a pin 5 of the LED constant current driving chip U1 through a diode D1, the negative pole end vout- is connected with the pin 5 of the LED constant current driving chip U1 through an inductor T1, a positive pole of the polarity capacitor C3 is connected with the positive pole end vout+, and a negative pole is connected with the negative pole end vout-. An input end of the diode D1 is connected with the pin 5 of the LED constant current driving chip U1, and an output end is connected with the positive pole end vout+.

[0020] Compared with the prior art, the LED lamp power supply circuit of the present application has at least the following beneficial effects: the LED lamp power supply circuit of the present application can output constant current to the external LED lamp through the constant current output module to reduce the production cost of the LED lamp.

[0021] The above only describes some embodiments of the present application. For those skilled in the art, without departing from the inventive concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application.

Claims

1. A constant current driving circuit for an LED lamp, characterized in that: include: A voltage input unit, a rectifier bridge module, a constant current output module, a ground terminal and a power supply unit, wherein the output terminal of the voltage input unit is connected to the input terminal of the rectifier bridge module, the output terminal of the rectifier bridge module is respectively connected to the constant current output module and the power supply unit, and the constant current output module is connected to the power supply unit; The voltage input unit is used to connect to external alternating current, the rectifier bridge module is used to convert the alternating current received by the unit input unit into direct current, the constant current output module is used to step down the direct current converted by the rectifier bridge module and output a constant current to the power supply unit, and the power supply unit is used to output the constant current output by the constant current output module to an external LED lamp.

2. The constant current driving circuit for LED lamp according to claim 1, characterized in that: The constant current output module includes an LED constant current driver chip U1, a diode D1, an inductor T1, a resistor R1, a resistor R3, a resistor R4 and a resistor R5. Pin 1 of the LED constant current driver chip U1 is connected to the ground end, pin 2 is connected to the ground end through the resistor R4, pin 4 is connected to the output end of the rectifier bridge module, pin 5 is connected to the power supply unit through the diode D1 and the inductor T1 respectively, and pin 6 is connected to pin 5. After the resistor R1 and the resistor R5 are connected in parallel, one end is connected to pin 8 of the LED constant current driver chip U1, and the other end is connected to the ground end. One end of the capacitor R3 is connected to the diode D1, and the other end is connected to the inductor T1.

3. The constant current driving circuit for an LED lamp according to claim 2, characterized in that: The model of the LED constant current driver chip U1 is BP2851.

4. The constant current driving circuit for an LED lamp according to claim 2, characterized in that: The rectifier bridge module includes a rectifier bridge stack DB1 and a polarity capacitor C1. The input end of the rectifier bridge stack DB1 is connected to the output end of the voltage input unit. The output end of the rectifier bridge stack DB1 is respectively connected to the polarity capacitor C1 and the LED constant current driver chip U1. The positive pole of the polarity capacitor is connected to the output end of the rectifier bridge stack DB1, and the negative pole is connected to the ground end.

5. The constant current driving circuit for an LED lamp according to claim 4, characterized in that: The model of the rectifier bridge DB1 is MB10f.

6. The constant current driving circuit for an LED lamp according to claim 2, characterized in that: The power supply unit includes a positive terminal vout+, a negative terminal vout- and a polarity capacitor C3, the positive terminal vout+ is connected to pin 5 of the LED constant current driver chip U1 through a diode D1, the negative terminal vout- is connected to pin 5 of the LED constant current driver chip U1 through an inductor T1, the positive pole of the polarity capacitor C3 is connected to the positive terminal vout+, and the negative pole is connected to the negative terminal vout-.

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