Constant current power supply circuit of LED lamp

Abstract

The utility model discloses a constant current power supply circuit of an LED lamp, which comprises a voltage input module, a rectifier bridge module, a constant current control module, a transformer unit, a power supply module and a grounding end, the voltage input unit, the piezoresistor, the rectifier bridge module, the transformer unit and the power supply module are connected in sequence; according to the constant-current power supply circuit of the LED lamp, the voltage dependent resistor is arranged between the voltage input unit and the rectifier bridge module, the voltage, input to the rectifier bridge module, of external alternating current is clamped through the voltage dependent resistor, the voltage output by the rectifier bridge module is within a set range, and under the condition that the current is constant, the constant-current power supply circuit of the LED lamp is stable. The output power of the constant-current power supply circuit is also in a set range, the use safety of the LED lamp is improved, and the working energy consumption of the constant-current power supply circuit is reduced.

Description

TECHNICAL FIELD

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

[0002] The LED itself characteristic decides that its drive power supply cannot with common incandescent lamp uses same power supply, to avoid voltage fluctuation to cause current increase to be thus to damage LED, and thus must design new power supply to fully satisfy the drive requirement required by LED work to maximize the performance of LED, reduces failure rate. Because the working voltage of LED is generally 5V-48V, therefore, if the output voltage of LED drive circuit is too high, will lead to LED lamp is burnt. SUMMARY

[0003] In order to solve the problem that the constant current power supply circuit of the prior art LED lamp lacks voltage limiting, the utility model provides a constant current power supply circuit of LED lamp.The specific technical scheme of the utility model is as follows:

[0004] A constant current power supply circuit of LED lamp, comprising: voltage input module, rectifier bridge module, constant current control module, transformer unit, power supply unit and ground terminal, the voltage input module includes voltage input unit and voltage-dependent resistor, the voltage input unit, voltage-dependent resistor, rectifier bridge module, transformer unit and power supply unit are sequentially connected, the constant current control module is connected with rectifier bridge module and transformer unit respectively;The voltage input unit is used for receiving external AC, the rectifier bridge module is used for converting the AC received by the voltage input unit into DC, the transformer unit is used for delivering the DC converted by the rectifier bridge module to the power supply unit after voltage transformation, the constant current control module is used for making the current of the DC delivered by the rectifier bridge module to the transformer unit constant, and the power supply unit is used for supplying power to external LED lamp;The voltage-dependent resistor is used for clamping the voltage input by the voltage input unit to the rectifier bridge module, so that the output power of the constant current power supply circuit is within the set range.

[0005] Further, the voltage input module further includes a capacitor C3 and a fuse, the voltage-dependent resistor RV and the capacitor C3 are connected in parallel and then connected in series between the output terminals of the voltage input unit, and the fuse F1 is arranged between the voltage-dependent resistor RV and the voltage input unit.

[0006] Further, the constant current control module comprises an LED constant current drive chip IC, a resistor R1, a resistor R2, resistors RS1 and RS2, a capacitor C2 and a diode D7, a pin 1 of the LED constant current drive chip IC is connected with a ground end through the resistor R1, a pin 2 is connected with the ground end, a pin 4 is connected with an output end of the rectifier bridge module, a pin 5 is connected with an input end of the diode D7 and an input end of a transformer unit T1 respectively, a pin 6 is connected with the pin 5, a pin 8 is connected with the ground end through the resistor RS1 and the resistor RS2 respectively, the resistor R2 is connected with the capacitor C2 in parallel, one end of the resistor R2 is connected with an output end of the diode D7, and the other end of the resistor R2 is connected with the transformer unit T1 and the pin 4 of the LED constant current drive chip IC respectively.

[0007] Further, the model of the LED constant current drive chip U1 is BP2851.

[0008] Further, the rectifier bridge module comprises a rectifier bridge DB1 and a polarity capacitor C1, input ends of the rectifier bridge DB1 are connected with a pressure resistor RV respectively, output ends of the rectifier bridge DB1 are connected with the polarity capacitor C1, the pin 4 of the LED constant current drive chip IC and an input end of the transformer unit T1 respectively, a positive pole of the polarity capacitor C1 is connected with the output end of the rectifier bridge DB1, and a negative pole of the polarity capacitor C1 is connected with a ground end.

[0009] Further, the model of the rectifier bridge DB1 is MB10f.

[0010] Further, the power supply unit comprises a positive pole output end vout+, a ground end GND, a diode D1, a resistor R5 and a polarity capacitor C8, an input end of the diode D1 is connected with a first output end of the transformer unit T1, an output end of the diode D1 is connected with the positive pole output end vout+, a negative pole output end vout- is connected with a second output end of the transformer unit T1, the resistor R5 and the polarity capacitor C8 are connected in parallel and are connected in series between the positive pole output end vout+ and the negative pole output end vout-, and the positive pole output end vout+ and the negative pole output end vout- are used for being connected with a positive pole and a negative pole of an external LED lamp respectively.

[0011] Compared with the prior art, the LED lamp constant current power supply circuit has at least the following beneficial effects: the LED lamp constant current power supply circuit disclosed by the application is provided with a pressure resistor between a voltage input unit and a rectifier bridge module, the voltage of external alternating current input to the rectifier bridge module is clamped through the pressure resistor, the voltage output by the rectifier bridge module is in a set range, the output power of the constant current power supply circuit is also in a set range under the condition of constant current, the use safety of the LED lamp is improved, and the working energy consumption of the constant current power supply circuit is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1This is a circuit schematic diagram of an embodiment;

[0013] Figure 2 This is a circuit diagram of an embodiment. Detailed Implementation

[0014] The following embodiments illustrate the present invention, but the present invention is not limited to these embodiments. Modifications to the specific implementation of the present invention or equivalent substitutions for some technical features, without departing from the spirit of the present invention, should all be covered within the scope of the technical solution claimed by the present invention.

[0015] like Figure 1 and Figure 2 As shown, a constant current power supply circuit for an LED lamp includes: a voltage input module, a rectifier bridge module, a constant current control module, a transformer unit, a power supply unit, and a ground terminal. The voltage input module includes a voltage input unit and a varistor. The voltage input unit, varistor, rectifier bridge module, transformer unit, and power supply unit are connected sequentially. The constant current control module is connected to both the rectifier bridge module and the transformer unit. The voltage input unit receives external AC power. The rectifier bridge module converts the AC power received by the voltage input unit into DC power. The transformer unit transforms the DC power converted by the rectifier bridge module and supplies it to the power supply unit. The constant current control module maintains a constant current in the DC power supplied by the rectifier bridge module to the transformer unit. The power supply unit supplies power to the external LED lamp. The varistor clamps the voltage input from the voltage input unit to the rectifier bridge module, ensuring the output power of the constant current power supply circuit remains within a set range. The external AC power is 220V.

[0016] In one embodiment, the voltage input module further includes a capacitor C3 and a fuse. The varistor RV and the capacitor C3 are connected in parallel and then in series between the output terminals of the voltage input unit. The fuse F1 is disposed between the varistor RV and the voltage input unit.

[0017] As one of the embodiments, the constant current control module comprises an LED constant current drive chip IC, a resistor R1, a resistor R2, a resistor RS1, a resistor RS2, a capacitor C2 and a diode D7, the pin 1 of the LED constant current drive chip IC is connected with the ground end through the resistor R1, the pin 2 is connected with the ground end, the pin 4 is connected with the output end of the rectifier bridge module, the pin 5 is connected with the input end of the transformer unit T1 and the input end of the diode D7 respectively, the pin 6 is connected with the pin 5, the pin 8 is connected with the ground end through the resistor RS1 and the resistor RS2 respectively, the resistor R2 is connected with the capacitor C2 in parallel, one end of which is connected with the output end of the diode D7, and the other end is connected with the transformer unit T1 and the pin 4 of the LED constant current drive chip IC respectively. The pin function of the LED constant current drive chip IC is as follows: the pin 1 is the ground end of the chip, the symbol is GND; the pin 2 is the feedback signal input end of the chip, the symbol is FB; the pin 3 is the test pin, the symbol is TM, which must be connected to the chip ground end (Pinl); the pin 4 is the input power end of the chip, the symbol is VCC; the pin 5 and the pin 6 are the internal high-voltage power tube drain, the symbol is DRAIN; the pin 7 and the pin 8 are the chip current sampling end, the symbol is CS, and the sampling resistor is connected between CS and GND.

[0018] As one of the embodiments, the model of the LED constant current drive chip IC is BP2851. BP2851 is a high-precision step-down LED constant current drive chip. The chip works in the inductive current critical continuous mode, and 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 patented floating ground drive framework and current detection method, the working current of the chip is extremely low, and auxiliary winding detection and power supply are not needed. Only a few peripheral elements are needed to achieve excellent constant current characteristics, greatly saving system cost and volume. The power supply circuit of the LED lamp adopts the BP2851 chip to step down the working voltage of the LED lamp, which simplifies the power supply circuit of the LED lamp.

[0019] As one of the embodiments, the rectifier bridge module comprises a rectifier bridge stack DB1 and a polarity capacitor C1, the input end of the rectifier bridge stack DB1 is connected with the pressure resistor RV respectively, the output end is connected with the polarity capacitor C1, the pin 4 of the LED constant current drive chip IC and the input end of the transformer unit T1 respectively, the positive electrode of the polarity capacitor C1 is connected with the output end of the rectifier bridge stack DB1, and the negative electrode is connected with the ground end.

[0020] As one of the embodiments, the model of the rectifier bridge stack DB1 is MB10F. MB10F is a super-thin patch rectifier bridge stack, which is used to convert alternating current into direct current by using the single-phase conductivity of diode.

[0021] As one of the embodiments, the power supply unit comprises a positive output terminal vout+, a ground terminal GND, a diode D1, a resistor R5 and a polarity capacitor C8, an input terminal of the diode D1 is connected with a first output terminal of the transformer unit T1, an output terminal of the diode D1 is connected with the positive output terminal vout+, a negative output terminal vout- is connected with a second output terminal of the transformer unit T1, the resistor R5 and the polarity capacitor C8 are connected in parallel and then connected in series between the positive output terminal vout+ and the negative output terminal vout-, and the positive output terminal vout+ and the negative output terminal vout- are used for being connected with a positive pole and a negative pole of an external LED lamp respectively.

[0022] The constant current power supply circuit of the LED lamp provided in the application is provided with a pressure-sensitive resistor between the voltage input unit and the rectifier bridge module, the voltage of the external alternating current input to the rectifier bridge module is clamped through the pressure-sensitive resistor, the voltage output by the rectifier bridge module is in a set range, the output power of the constant current power supply circuit is also in a set range in the case of constant current, the use safety of the LED lamp is improved, and the working energy consumption of the constant current power supply circuit is reduced.

[0023] The above only describes some embodiments of the application. For those skilled in the art, without departing from the creative concept of the application, a number of modifications and improvements can be made, which all belong to the protection scope of the application.

Claims

1. A constant current power supply circuit for an LED lamp, characterized by, include: The system includes a voltage input module, a rectifier bridge module, a constant current control module, a transformer unit, a power supply unit, and a grounding terminal. The voltage input module includes a voltage input unit and a varistor. The voltage input unit, varistor, rectifier bridge module, transformer unit, and power supply unit are connected in sequence. The constant current control module is connected to both the rectifier bridge module and the transformer unit. The voltage input unit is used to receive external AC power, the rectifier bridge module is used to convert the AC power received by the voltage input unit into DC power, the transformer unit is used to transform the DC power converted by the rectifier bridge module and then supply it to the power supply unit, the constant current control module is used to keep the current of the DC power supplied by the rectifier bridge module to the transformer unit constant, and the power supply unit is used to supply power to the external LED lights. The varistor is used to clamp the voltage input from the voltage input unit to the rectifier bridge module, so that the output power of the constant current power supply circuit is within the set range.

2. The constant current power supply circuit for LED lamps according to claim 1, characterized in that, The voltage input module also includes a capacitor C3 and a fuse. The varistor RV and the capacitor C3 are connected in parallel and then in series between the output terminals of the voltage input unit. The fuse F1 is disposed between the varistor RV and the voltage input unit.

3. The constant current power supply circuit for an LED lamp according to claim 2, wherein The constant current control module includes an LED constant current driver chip IC, resistors R1, R2, RS1, RS2, capacitor C2, and diode D7. Pin 1 of the LED constant current driver chip IC is connected to the ground terminal through resistor R1, pin 2 is connected to the ground terminal, pin 4 is connected to the output terminal of the rectifier bridge module, pin 5 is connected to the input terminal of diode D7 and the input terminal of transformer unit T1 respectively, pin 6 is connected to pin 5, and pin 8 is connected to the ground terminal through resistors RS1 and RS2 respectively. After resistor R2 and capacitor C2 are connected in parallel, one end is connected to the output terminal of diode D7, and the other end is connected to the transformer unit T1 and pin 4 of LED constant current driver chip IC respectively.

4. The constant current power supply circuit for an LED lamp according to claim 3, wherein The LED constant current driver chip U1 is model BP2851.

5. The constant current power supply circuit for an LED lamp according to claim 3, wherein The rectifier bridge module includes a rectifier bridge stack DB1 and a polarized capacitor C1. The input terminals of the rectifier bridge stack DB1 are connected to the varistor RV, and the output terminals are connected to the polarized capacitor C1, pin 4 of the LED constant current driver chip IC, and the input terminal of the transformer unit T1. The positive terminal of the polarized capacitor C1 is connected to the output terminal of the rectifier bridge stack DB1, and the negative terminal is connected to the ground terminal.

6. The constant current power supply circuit for an LED lamp according to claim 5, wherein The rectifier bridge DB1 is model MB10f.

7. The constant current power supply circuit for LED lamps according to claim 3, characterized in that, The power supply unit includes a positive output terminal vout+, a ground terminal GND, a diode D1, a resistor R5, and a polarized capacitor C8. The input terminal of the diode D1 is connected to the first output terminal of the transformer unit T1, and the output terminal of the diode D1 is connected to the positive output terminal vout+. The negative output terminal vout- is connected to the second output terminal of the transformer unit T1. The resistor R5 and the polarized capacitor C8 are connected in parallel and then in series between the positive output terminal vout+ and the negative output terminal vout-. The positive output terminal vout+ and the negative output terminal vout- are used to connect to the positive and negative terminals of the external LED light, respectively.

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